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2017 Volume 37 Issue 6
2017, 37(6): 1309-1321
doi: 10.6023/cjoc201701031
Abstract:
Carbon dioxide is a cheap, abundant and renewable C1 feedstock. Methodology study on the transformation of carbon dioxide into highly value-added chemicals has become one of the most active topics in organic chemistry. Owing to the diversity of cyclization reaction and vast occurrence of various heterocyclic motifs in biologically important molecules, the cyclization reactions using carbon dioxide have gained much attention. This review therefore aims to principally describe the recent progress in the new cyclization reactions using carbon dioxide as feedstock to synthesize lactams, lactones, cyclic anhydrides, benzothiazoles, benzimidazoles and other heterocyclic compounds.
Carbon dioxide is a cheap, abundant and renewable C1 feedstock. Methodology study on the transformation of carbon dioxide into highly value-added chemicals has become one of the most active topics in organic chemistry. Owing to the diversity of cyclization reaction and vast occurrence of various heterocyclic motifs in biologically important molecules, the cyclization reactions using carbon dioxide have gained much attention. This review therefore aims to principally describe the recent progress in the new cyclization reactions using carbon dioxide as feedstock to synthesize lactams, lactones, cyclic anhydrides, benzothiazoles, benzimidazoles and other heterocyclic compounds.
2017, 37(6): 1322-1337
doi: 10.6023/cjoc201702051
Abstract:
Palladium-catalyzed cross-coupling reactions have been developed for decades as useful methods in organic synthesis. Compared to aryl and alkenyl halides, alkyl halides are more challenging to be applied in cross-coupling reactions. This mainly arises from the difficulty in oxidative addition of alkyl halides to palladium catalyst, sluggish reductive elimination and competitive side reactions, such as β-H elimination and protonation, of the resulting alkylpalladium intermediates. These challenges have partly been overcome with the significant development of novel palladium catalysis involving single election transfer. A variety of cross couplings of alkyl halides have been developed. In this review the recent palladium-catalyzed radical alkylation using alkyl halides with the order of different types of coupling partners is summarized.
Palladium-catalyzed cross-coupling reactions have been developed for decades as useful methods in organic synthesis. Compared to aryl and alkenyl halides, alkyl halides are more challenging to be applied in cross-coupling reactions. This mainly arises from the difficulty in oxidative addition of alkyl halides to palladium catalyst, sluggish reductive elimination and competitive side reactions, such as β-H elimination and protonation, of the resulting alkylpalladium intermediates. These challenges have partly been overcome with the significant development of novel palladium catalysis involving single election transfer. A variety of cross couplings of alkyl halides have been developed. In this review the recent palladium-catalyzed radical alkylation using alkyl halides with the order of different types of coupling partners is summarized.
2017, 37(6): 1338-1351
doi: 10.6023/cjoc201702022
Abstract:
The ketones are important intermediates for the synthesis of fine chemicals, such as pharmaceuticals, natural products, agricultural chemicals, dyes, etc. The oxidation of C—H bonds is one of the most direct and efficient synthetic methods for the preparation of ketones. In this review, the oxidation of C—H bonds to ketones is reviewed.
The ketones are important intermediates for the synthesis of fine chemicals, such as pharmaceuticals, natural products, agricultural chemicals, dyes, etc. The oxidation of C—H bonds is one of the most direct and efficient synthetic methods for the preparation of ketones. In this review, the oxidation of C—H bonds to ketones is reviewed.
2017, 37(6): 1352-1367
doi: 10.6023/cjoc201701027
Abstract:
Ruthenium and its complex possess various catalytic activities such as oxidation and reduction. Ruthenium as a cheap and efficient catalyst was also widely used in such field as C—H activation. Considerable attention has been paid to it for its great applications in organic chemistry. The last decade's ruthenium-catalyzed deydrogenation C—N/C—C coupling reactions from acohols classified by their machanisms are summarized in this paper. Creative C—N/C—C coupling reactions are expected be designed by means of dehydrogenation catalyzed by ruthenium from acohols.
Ruthenium and its complex possess various catalytic activities such as oxidation and reduction. Ruthenium as a cheap and efficient catalyst was also widely used in such field as C—H activation. Considerable attention has been paid to it for its great applications in organic chemistry. The last decade's ruthenium-catalyzed deydrogenation C—N/C—C coupling reactions from acohols classified by their machanisms are summarized in this paper. Creative C—N/C—C coupling reactions are expected be designed by means of dehydrogenation catalyzed by ruthenium from acohols.
2017, 37(6): 1368-1381
doi: 10.6023/cjoc201702010
Abstract:
Antimycin A is a class of natural products bearing a dilactone-ring moiety as the core skeleton. These compounds have been identified as specific inhibitors of the mitochondrial respiratory chain and bind to the Qi site of the cytochrome bc1 complex. Due to its unique structure and extremly high activity, it has aroused great interest of researchers. The development and biological activities of antimycin A are mainly described, and the recent results of its structural modifications are summarized.
Antimycin A is a class of natural products bearing a dilactone-ring moiety as the core skeleton. These compounds have been identified as specific inhibitors of the mitochondrial respiratory chain and bind to the Qi site of the cytochrome bc1 complex. Due to its unique structure and extremly high activity, it has aroused great interest of researchers. The development and biological activities of antimycin A are mainly described, and the recent results of its structural modifications are summarized.
2017, 37(6): 1382-1391
doi: 10.6023/cjoc201612031
Abstract:
C-Glycosides in which the interglycosidic oxygen atom have been replaced by carbon atom are widely found in natural products and drug molecules. They have better enzymatic and hydrolytic stablility compared to their corresponding O-glycosides and N-glycosides. The syntheses of them have received considerable attention because of their unique chemical structure and extensive application value. Rencent advances in the synthesis of C-glycosides through coupling reactions catalyzed by transition metal are summarized in this review. A summary of the advantages and disadavatages of different synthetic methods will be beneficial to the develepment of new synthetic method for C-glycosides.
C-Glycosides in which the interglycosidic oxygen atom have been replaced by carbon atom are widely found in natural products and drug molecules. They have better enzymatic and hydrolytic stablility compared to their corresponding O-glycosides and N-glycosides. The syntheses of them have received considerable attention because of their unique chemical structure and extensive application value. Rencent advances in the synthesis of C-glycosides through coupling reactions catalyzed by transition metal are summarized in this review. A summary of the advantages and disadavatages of different synthetic methods will be beneficial to the develepment of new synthetic method for C-glycosides.
2017, 37(6): 1392-1397
doi: 10.6023/cjoc201702047
Abstract:
A mononuclear cobalt(Ⅱ) complex[Co(4-MeOC6H4Se)2(PMe3)3] (1) and a dinuclear cobalt diphenylselenolato complex[Co(PMe3)2(SeC6H4-2-Me)]2 (2) were obtained from the reaction of 4-methoxyselenophenol and 2-methylseleno-phenol with Co(PMe3)4, respectively. The dicarbonyl cobalt(Ⅰ) complex[Co(PMe3)2(CO)2(SeC6H4-2-Me)] (3) was formed through the reaction of complex 2 with carbon monoxide. A novel selenophenolato hydridocobalt(Ⅲ) complex[mer-Co(H)(SePh)2(PMe3)3] (4) and a dinuclear cobalt diphenylselenolato complex[Co(PMe3)2(SePh)]2 (5) were synthesized by the reaction of selenophenol with Co(PMe3)4. It was found that complex 4 could catalyze the hydrosilylation of aldehydes and ketones. The molecular structures of 1, 3 and 4 were determined by X-ray diffraction.
A mononuclear cobalt(Ⅱ) complex[Co(4-MeOC6H4Se)2(PMe3)3] (1) and a dinuclear cobalt diphenylselenolato complex[Co(PMe3)2(SeC6H4-2-Me)]2 (2) were obtained from the reaction of 4-methoxyselenophenol and 2-methylseleno-phenol with Co(PMe3)4, respectively. The dicarbonyl cobalt(Ⅰ) complex[Co(PMe3)2(CO)2(SeC6H4-2-Me)] (3) was formed through the reaction of complex 2 with carbon monoxide. A novel selenophenolato hydridocobalt(Ⅲ) complex[mer-Co(H)(SePh)2(PMe3)3] (4) and a dinuclear cobalt diphenylselenolato complex[Co(PMe3)2(SePh)]2 (5) were synthesized by the reaction of selenophenol with Co(PMe3)4. It was found that complex 4 could catalyze the hydrosilylation of aldehydes and ketones. The molecular structures of 1, 3 and 4 were determined by X-ray diffraction.
2017, 37(6): 1407-1411
doi: 10.6023/cjoc201701040
Abstract:
Transfer hydrogenation is a mild and effective way in reduction reaction. In this paper, a simple approach of selectively hydrogenation of alkynes to cis-alkenes with NH2NH2·H2O as a transfer hydrogenation agent in the presence of air without any catalysts or metals was developed. Furthermore, the configuration of cis-alkene was confirmed by the 2D NOESY spectrum.
Transfer hydrogenation is a mild and effective way in reduction reaction. In this paper, a simple approach of selectively hydrogenation of alkynes to cis-alkenes with NH2NH2·H2O as a transfer hydrogenation agent in the presence of air without any catalysts or metals was developed. Furthermore, the configuration of cis-alkene was confirmed by the 2D NOESY spectrum.
2017, 37(6): 1412-1416
doi: 10.6023/cjoc201611037
Abstract:
Five novel ferrocenyl thiazole and imidazole derivatives were synthesized. The structure characterization of the five products showed that ferrocene conjugative unit and thiazole or imidazole conjugative unit were linked by carbonyl methylene skeleton (COCH2). Chloroacetylferrocene (1a) was prepared by chloroacetylation of ferrocene which reacted with different heterocyclic compounds (2-mercaptobenzothiazole, 2-mercaptobenzimidazole, imidazole and benzimidazole) to give four novel compounds, respectively. 1, 1'-Bis(bromoacetyl)ferrocene (1b) was prepared by acetylation and subsequent bromination of ferrocene, which then reacted with 2-mercaptobenzothiazole to produce 2e. All the new compounds were confirmed by 1H NMR, 13C NMR, ESI-MS, HRMS and IR. Three single crystal structures were obtained. Recognition properties on 14 metal ions of the five new compounds were investigated by UV-vis spectrum. The results showed that the five new compounds possessed recognition properties only to iron(Ⅲ), in which 2a had maximum spectra response.
Five novel ferrocenyl thiazole and imidazole derivatives were synthesized. The structure characterization of the five products showed that ferrocene conjugative unit and thiazole or imidazole conjugative unit were linked by carbonyl methylene skeleton (COCH2). Chloroacetylferrocene (1a) was prepared by chloroacetylation of ferrocene which reacted with different heterocyclic compounds (2-mercaptobenzothiazole, 2-mercaptobenzimidazole, imidazole and benzimidazole) to give four novel compounds, respectively. 1, 1'-Bis(bromoacetyl)ferrocene (1b) was prepared by acetylation and subsequent bromination of ferrocene, which then reacted with 2-mercaptobenzothiazole to produce 2e. All the new compounds were confirmed by 1H NMR, 13C NMR, ESI-MS, HRMS and IR. Three single crystal structures were obtained. Recognition properties on 14 metal ions of the five new compounds were investigated by UV-vis spectrum. The results showed that the five new compounds possessed recognition properties only to iron(Ⅲ), in which 2a had maximum spectra response.
2017, 37(6): 1417-1425
doi: 10.6023/cjoc201610033
Abstract:
By means of computer aided drug design, simulation of apoptosis inhibiting protein complex glycine receptor kinase C-kit docking with active small molecules. Ten analogues were successfully synthesized by the introduction of nitrogen-containing heterocyclic compounds at ring A and the modification of the esterification and amidation at C(28) position in the natural product oleanolic acid. Their structures were charachterized by 1H NMR, 13C NMR, MS and so forth. Their anti-tumor activities against KB, A549 cells in vitro were evaluated by methyl thiazolyl tetrazolium (MTT) assay. These results indicated that the objective of test compounds of two kinds of tumor cells have good inbitory activity, and 5', 6'-dihydro-olean-2-ene-[2, 3-b]pyrazin-12-ene-28-acyl-4"-monomethylaniline (Ⅰ4) (IC50＝2.67 μmol/L) and olean-2-ene-[2, 3-b]pyrimidine-12-ene-28-oic acid n-hextyl ester (Ⅱ3) (IC50＝1.03 μmol/L) have especially more potent inbitory activity on A549 tumor cells than 5-fluorouracil (IC50＝7.39 μmol/L), which are worthy to be studied further.
By means of computer aided drug design, simulation of apoptosis inhibiting protein complex glycine receptor kinase C-kit docking with active small molecules. Ten analogues were successfully synthesized by the introduction of nitrogen-containing heterocyclic compounds at ring A and the modification of the esterification and amidation at C(28) position in the natural product oleanolic acid. Their structures were charachterized by 1H NMR, 13C NMR, MS and so forth. Their anti-tumor activities against KB, A549 cells in vitro were evaluated by methyl thiazolyl tetrazolium (MTT) assay. These results indicated that the objective of test compounds of two kinds of tumor cells have good inbitory activity, and 5', 6'-dihydro-olean-2-ene-[2, 3-b]pyrazin-12-ene-28-acyl-4"-monomethylaniline (Ⅰ4) (IC50＝2.67 μmol/L) and olean-2-ene-[2, 3-b]pyrimidine-12-ene-28-oic acid n-hextyl ester (Ⅱ3) (IC50＝1.03 μmol/L) have especially more potent inbitory activity on A549 tumor cells than 5-fluorouracil (IC50＝7.39 μmol/L), which are worthy to be studied further.
2017, 37(6): 1426-1432
doi: 10.6023/cjoc201612037
Abstract:
2-O-(β-D-Glucopyranosyl)-L-ascorbic acid, a natural β-glycoside with ascorbic acid moiety present in Lycium barbarum, and its two analogues were chemically synthesized. Their inhibitory effect on yeast α-glucosidase and α-amylase were investigated with commercially available acarbose as positive control. The biological assays demonstrated the distinct inhibitory effect of these compounds on α-glucosidase activity and weak inhibitory activity against pancreatic α-amylase. The kinetic study indicated that these compounds were competitive inhibitors. These results imply that these three β-glycosides have the potential to be developed as α-glucosidase inhibitors.
2-O-(β-D-Glucopyranosyl)-L-ascorbic acid, a natural β-glycoside with ascorbic acid moiety present in Lycium barbarum, and its two analogues were chemically synthesized. Their inhibitory effect on yeast α-glucosidase and α-amylase were investigated with commercially available acarbose as positive control. The biological assays demonstrated the distinct inhibitory effect of these compounds on α-glucosidase activity and weak inhibitory activity against pancreatic α-amylase. The kinetic study indicated that these compounds were competitive inhibitors. These results imply that these three β-glycosides have the potential to be developed as α-glucosidase inhibitors.
2017, 37(6): 1433-1442
doi: 10.6023/cjoc201612038
Abstract:
A concise and environment friendly route for the synthesis of multisubstituted chromone-fused bicyclic pyridine compounds via one-step reaction of chromone-3-carboxaldehyde 1 and N-benzyl nitro ketene aminals (NBNKAs, 2) in ethanol media has been developed. The targeted compounds 3 can efficiently obtain by filter without extra post-treatment. The reaction is particularly attractive due to following features: low-cost and biocompatibility solvent, mild temperature, atom economy, high yields, and potential biological activity.
A concise and environment friendly route for the synthesis of multisubstituted chromone-fused bicyclic pyridine compounds via one-step reaction of chromone-3-carboxaldehyde 1 and N-benzyl nitro ketene aminals (NBNKAs, 2) in ethanol media has been developed. The targeted compounds 3 can efficiently obtain by filter without extra post-treatment. The reaction is particularly attractive due to following features: low-cost and biocompatibility solvent, mild temperature, atom economy, high yields, and potential biological activity.
2017, 37(6): 1443-1449
doi: 10.6023/cjoc201612056
Abstract:
A new Methoxy poly(ethylene glycol)-anchored polymer sensor P1, which contains anthracene fluorephore and di-2-picolylamine metal ions binding site, has been easily synthesized by "click reaction". In pure aqueous solution, P1 can coordinate with Hg2+ quickly to form 1:1 stoichiometry P1-Hg2+ complex, with quenching the fluorescence of P1. In addition, P1-Hg2+ shows exclusive fluorescence turn-on sensing of cysteine (Cys) over other amino acids for the displacement method.
A new Methoxy poly(ethylene glycol)-anchored polymer sensor P1, which contains anthracene fluorephore and di-2-picolylamine metal ions binding site, has been easily synthesized by "click reaction". In pure aqueous solution, P1 can coordinate with Hg2+ quickly to form 1:1 stoichiometry P1-Hg2+ complex, with quenching the fluorescence of P1. In addition, P1-Hg2+ shows exclusive fluorescence turn-on sensing of cysteine (Cys) over other amino acids for the displacement method.
2017, 37(6): 1450-1455
doi: 10.6023/cjoc201610030
Abstract:
The reaction of arylboronic acids with bismuth(Ⅲ) nitrate pentahydrate resulted in a series of nitroarenes when the reaction was carried out under microwave (120 ℃) for 1 min in 1, 2-dichloroethane. Compared with traditional heating condition, the method of microwave condition for the preparation of nitroarenes was simple, efficient, time-saving, and of less by-products. In addition, possible free radical mechanism was proposed.
The reaction of arylboronic acids with bismuth(Ⅲ) nitrate pentahydrate resulted in a series of nitroarenes when the reaction was carried out under microwave (120 ℃) for 1 min in 1, 2-dichloroethane. Compared with traditional heating condition, the method of microwave condition for the preparation of nitroarenes was simple, efficient, time-saving, and of less by-products. In addition, possible free radical mechanism was proposed.
2017, 37(6): 1456-1462
doi: 10.6023/cjoc201612034
Abstract:
1, 2-Dihexadecyl-sn-glycero-3-phosphoethanolamine (DHPE) is one type of glycerophospholipids, and it has a wide range of application in biology. A new and efficient method was developed to synthesis DHPE using (S)-2, 2-dimethyl-1, 3-dioxolane-4-methanol, hexadecanol and ethanolamine as starting materials. 1, 2-Dihexadecyl-sn-glycerol and N-Boc-etha-nolamine were synthesized as two key intermediates, which were coupled under condition of Still-Gennari reagent. Then Horner-Wadsworth-Emmons reaction condition was applied to deprotect methyl acetate group of glycerophospholipid efficiently. The target compound DHPE was obtained in 32% overall yield by 8 steps.
1, 2-Dihexadecyl-sn-glycero-3-phosphoethanolamine (DHPE) is one type of glycerophospholipids, and it has a wide range of application in biology. A new and efficient method was developed to synthesis DHPE using (S)-2, 2-dimethyl-1, 3-dioxolane-4-methanol, hexadecanol and ethanolamine as starting materials. 1, 2-Dihexadecyl-sn-glycerol and N-Boc-etha-nolamine were synthesized as two key intermediates, which were coupled under condition of Still-Gennari reagent. Then Horner-Wadsworth-Emmons reaction condition was applied to deprotect methyl acetate group of glycerophospholipid efficiently. The target compound DHPE was obtained in 32% overall yield by 8 steps.
2017, 37(6): 1463-1472
doi: 10.6023/cjoc201611005
Abstract:
A series of novel 3, 4-dihydro-benzo[b]oxazepin-5(2H)-one derivatives were designed and synthesized as potent protein-tyrosine kinases (PTKs, e.g. ErbB1, ErbB2, c-Met, ALK, FGFR1, RET, KDR) inhibitors. All compounds were characterized by NMR and MS. E-7-[(2, 5-dihydroxy)phenylmethylene]amino-3, 4-dihydro-benzo[b]oxazepin-5(2H)-one (8k) and E-7-[(2, 3, 4-trihydroxy)phenylmethylene]amino-3, 4-dihydro-benzo[b]oxazepin-5(2H)-one (8n) were further characterized by X-ray single-crystal analysis. The synthesized compounds were further tested for their inhibitory activity on PTKs. The results display compounds with catechol-substitution display the most potent inhibitory activities toward PTKs. The IC50 values for E-7-[(3, 4-dihydroxy)phenylmethylene]amino-3, 4-dihydro-benzo[b]oxazepin-5(2H)-one (8i) against ErbB1, ErbB2 are 1.0 and 0.33 μmol/L, respectively. The IC50 value for 8n against RET is 0.7 μmol/L, while the IC50 value for 7-[(3, 4-dihydroxyphenyl)methyl]amino-2, 3, 4, 5-tetrahydro-benzo[b]oxazepin-5-ol (10b) against ErbB2 is 1.02 μmol/L.
A series of novel 3, 4-dihydro-benzo[b]oxazepin-5(2H)-one derivatives were designed and synthesized as potent protein-tyrosine kinases (PTKs, e.g. ErbB1, ErbB2, c-Met, ALK, FGFR1, RET, KDR) inhibitors. All compounds were characterized by NMR and MS. E-7-[(2, 5-dihydroxy)phenylmethylene]amino-3, 4-dihydro-benzo[b]oxazepin-5(2H)-one (8k) and E-7-[(2, 3, 4-trihydroxy)phenylmethylene]amino-3, 4-dihydro-benzo[b]oxazepin-5(2H)-one (8n) were further characterized by X-ray single-crystal analysis. The synthesized compounds were further tested for their inhibitory activity on PTKs. The results display compounds with catechol-substitution display the most potent inhibitory activities toward PTKs. The IC50 values for E-7-[(3, 4-dihydroxy)phenylmethylene]amino-3, 4-dihydro-benzo[b]oxazepin-5(2H)-one (8i) against ErbB1, ErbB2 are 1.0 and 0.33 μmol/L, respectively. The IC50 value for 8n against RET is 0.7 μmol/L, while the IC50 value for 7-[(3, 4-dihydroxyphenyl)methyl]amino-2, 3, 4, 5-tetrahydro-benzo[b]oxazepin-5-ol (10b) against ErbB2 is 1.02 μmol/L.
2017, 37(6): 1473-1478
doi: 10.6023/cjoc201612047
Abstract:
An efficient synthesis of 2-vinyl furans and thiophenes through oxidative Heck reaction has been explored under solvent-less high-speed ball-milling conditions. This Pd-catalyzed oxidative Heck reaction proceeded well with both acrylates and styrenes, which afford desired product in 45 min, with moderate to high yields.
An efficient synthesis of 2-vinyl furans and thiophenes through oxidative Heck reaction has been explored under solvent-less high-speed ball-milling conditions. This Pd-catalyzed oxidative Heck reaction proceeded well with both acrylates and styrenes, which afford desired product in 45 min, with moderate to high yields.
2017, 37(6): 1479-1486
doi: 10.6023/cjoc201611031
Abstract:
A series of novel purin-8-one derivatives were prepared with the starting materials of 2, 4-dichloro-5-nitropyrimidine and followed by multi-step reactions. The structures of all target compounds were identified by 1H NMR, 13C NMR and HRMS. The preliminary biological evaluations were performed using thiazolyl blue tetrazolium bromide (MTT) method to test their antiproliferative activities against some tumor cell lines. The results suggested that some compounds exhibited good anti-proliferative activities against tumor cell lines. Especially, four compounds showed similar or better inhibitory activities against Hela, MOLT-4 and K562 tumor cell lines compared with R-roscovitine.
A series of novel purin-8-one derivatives were prepared with the starting materials of 2, 4-dichloro-5-nitropyrimidine and followed by multi-step reactions. The structures of all target compounds were identified by 1H NMR, 13C NMR and HRMS. The preliminary biological evaluations were performed using thiazolyl blue tetrazolium bromide (MTT) method to test their antiproliferative activities against some tumor cell lines. The results suggested that some compounds exhibited good anti-proliferative activities against tumor cell lines. Especially, four compounds showed similar or better inhibitory activities against Hela, MOLT-4 and K562 tumor cell lines compared with R-roscovitine.
2017, 37(6): 1487-1493
doi: 10.6023/cjoc201612029
Abstract:
A fast and efficient CuI-catalyzed intramolecular C—N coupling reaction of N-(2-bromoaryl)-1H-pyrazol-5-amines to synthesize benzo[4, 5]imidazo[1, 2-b]pyrazoles has been developed from N-(2-bromoaryl)-thioacetanilides. A series of benzo[4, 5]imidazo[1, 2-b]pyrazoles were obtained in excellent yields with CuI/heterocyclic ketene aminals catalytic system in the presence of Cs2CO3 in dimethyl sulfoxide (DMSO) at 120 ℃ within 10 min. The reaction provides an fast and efficient protocol to access a series of benzo[4, 5]imidazo[1, 2-b]pyrazoles in good to high yields.
A fast and efficient CuI-catalyzed intramolecular C—N coupling reaction of N-(2-bromoaryl)-1H-pyrazol-5-amines to synthesize benzo[4, 5]imidazo[1, 2-b]pyrazoles has been developed from N-(2-bromoaryl)-thioacetanilides. A series of benzo[4, 5]imidazo[1, 2-b]pyrazoles were obtained in excellent yields with CuI/heterocyclic ketene aminals catalytic system in the presence of Cs2CO3 in dimethyl sulfoxide (DMSO) at 120 ℃ within 10 min. The reaction provides an fast and efficient protocol to access a series of benzo[4, 5]imidazo[1, 2-b]pyrazoles in good to high yields.
2017, 37(6): 1494-1500
doi: 10.6023/cjoc201612035
Abstract:
This article describes the synthesis of warfarin and its derivatives by using the crude earthwarm extract as a biocatalyst. Warfarin, an effective anticogulant being used for half a century, has enormous clinic and commercial value. Warfarin and its derivatives are usually prepared through chemical catalysis while biocatalysis was rarely explored. Because biocatalysis is green, sustainable and usually under mild conditions, it is necessary to develop biocatalytic methods for these compounds. It is found that the crude extract of earthwarms is a fine biocatalyst. Earthwarms are harmless and abundant in nature. There are many hydrolases in the alimentary tract of earthwarms, and among of them, proteases are most thoroughly studied. The crude earthwarm extract from Eisenia foetida was prepared, and it was used as a cheap and ecologically friendly biocatalyst for the synthesis of warfarin and its derivatives. The procedure is simple and no additional cofactors and equipments are required. The best results were obtained using l00 mg of earthworm extract in DMSO/water (10% water, V/V) with 1:3 molar ratio of 4-hydroxycoumarin to benzylideneacetone at 50 ℃ for 48 h. Warfarin was obtained in an excellent yield of 98%, and its derivatives were achieved in yields of 57%~99% with some enantioselectivities (up to 20% ee). In addition, control experiments demonstrated that enzyme(s) in the crude extract of earthwarms catalyzed Michael addition reaction. This work provides an alternative method for the synthesis of warfarin and its derivatives by using an easily available natural catalyst.
This article describes the synthesis of warfarin and its derivatives by using the crude earthwarm extract as a biocatalyst. Warfarin, an effective anticogulant being used for half a century, has enormous clinic and commercial value. Warfarin and its derivatives are usually prepared through chemical catalysis while biocatalysis was rarely explored. Because biocatalysis is green, sustainable and usually under mild conditions, it is necessary to develop biocatalytic methods for these compounds. It is found that the crude extract of earthwarms is a fine biocatalyst. Earthwarms are harmless and abundant in nature. There are many hydrolases in the alimentary tract of earthwarms, and among of them, proteases are most thoroughly studied. The crude earthwarm extract from Eisenia foetida was prepared, and it was used as a cheap and ecologically friendly biocatalyst for the synthesis of warfarin and its derivatives. The procedure is simple and no additional cofactors and equipments are required. The best results were obtained using l00 mg of earthworm extract in DMSO/water (10% water, V/V) with 1:3 molar ratio of 4-hydroxycoumarin to benzylideneacetone at 50 ℃ for 48 h. Warfarin was obtained in an excellent yield of 98%, and its derivatives were achieved in yields of 57%~99% with some enantioselectivities (up to 20% ee). In addition, control experiments demonstrated that enzyme(s) in the crude extract of earthwarms catalyzed Michael addition reaction. This work provides an alternative method for the synthesis of warfarin and its derivatives by using an easily available natural catalyst.
2017, 37(6): 1501-1505
doi: 10.6023/cjoc201610031
Abstract:
The haloalkynes were hydrolyzed to α-haloketones by sulfuric acid promotion in ionic liquids (ILs) with 85%~94% yields. The ILs-H2SO4 reaction system could be easily recycled (more five times) without any effect for reaction yield. At the same time, a wide scope of substrates haloalkynes were proper in this reaction system and a series of α-chloro/bromo/iodo acetophenones with different substituent (such as methyl, methoxyl, hydroxyl, nitro etc.) and aliphatic α-haloketones have been obtained in good yields.
The haloalkynes were hydrolyzed to α-haloketones by sulfuric acid promotion in ionic liquids (ILs) with 85%~94% yields. The ILs-H2SO4 reaction system could be easily recycled (more five times) without any effect for reaction yield. At the same time, a wide scope of substrates haloalkynes were proper in this reaction system and a series of α-chloro/bromo/iodo acetophenones with different substituent (such as methyl, methoxyl, hydroxyl, nitro etc.) and aliphatic α-haloketones have been obtained in good yields.
2017, 37(6): 1506-1515
doi: 10.6023/cjoc201610043
Abstract:
A series of novel hybrid compounds between indolo[b]tetrahydrofuran and imidazolium salts were prepared from tryptophol by four steps of Sharpless epoxidation, amidation, coupling and salt formation. Their structures were confirmed by 1H NMR, 13C NMR, HRMS and X-ray crystallographic analysis. These compounds were evaluated in vitro against a panel of human tumor cell lines. The results showed that 1-((3aR, 8aS)-3, 3a-dihydro-3a-hydroxy-2H-furo[2, 3-b]indol-8(8aH)-yl)etha-none-3-(2-(naphthalen-2-yl)-2-oxoethyl)-5, 6-dimethyl-1H-benzo[d]-imidazol-3-ium bromide (20) and 1-((3aR, 8aS)-3, 3a-di-hydro-3a-hydroxy-2H-furo[2, 3-b]indol-8(8aH)-yl)ethanone-3-(2-naphthylmethyl)-5, 6-dimethyl-1H-benzo[d]imidazol-3-ium bromide (22) exhibited higher inhibitory activity selectively against SMMC-7721, MCF-7 and SW480 cell lines compared with DDP. In particular, 1-((3aR, 8aS)-3, 3a-dihydro-3a-hydroxy-2H-furo[2, 3-b]indol-8(8aH)-yl)ethanone-3-(2-bromobenzyl)-5, 6-dimethyl-1H-benzo[d]imidazol-3-ium bromide (24) was more selective to SW-480 cell lines with IC50 values 2.0-fold lower than DDP.
A series of novel hybrid compounds between indolo[b]tetrahydrofuran and imidazolium salts were prepared from tryptophol by four steps of Sharpless epoxidation, amidation, coupling and salt formation. Their structures were confirmed by 1H NMR, 13C NMR, HRMS and X-ray crystallographic analysis. These compounds were evaluated in vitro against a panel of human tumor cell lines. The results showed that 1-((3aR, 8aS)-3, 3a-dihydro-3a-hydroxy-2H-furo[2, 3-b]indol-8(8aH)-yl)etha-none-3-(2-(naphthalen-2-yl)-2-oxoethyl)-5, 6-dimethyl-1H-benzo[d]-imidazol-3-ium bromide (20) and 1-((3aR, 8aS)-3, 3a-di-hydro-3a-hydroxy-2H-furo[2, 3-b]indol-8(8aH)-yl)ethanone-3-(2-naphthylmethyl)-5, 6-dimethyl-1H-benzo[d]imidazol-3-ium bromide (22) exhibited higher inhibitory activity selectively against SMMC-7721, MCF-7 and SW480 cell lines compared with DDP. In particular, 1-((3aR, 8aS)-3, 3a-dihydro-3a-hydroxy-2H-furo[2, 3-b]indol-8(8aH)-yl)ethanone-3-(2-bromobenzyl)-5, 6-dimethyl-1H-benzo[d]imidazol-3-ium bromide (24) was more selective to SW-480 cell lines with IC50 values 2.0-fold lower than DDP.
2017, 37(6): 1516-1522
doi: 10.6023/cjoc201612012
Abstract:
As the active component in visci herba of traditional Chinese medicine, homoeriodictyol-7-O-β-D-glycoside has been widely studied for years. In this paper, the first synthesis of homoeriodictyol-7-O-β-D-glycoside and its diastereoisomer has been achieved, which was carried out using phloroglucinol and D-glucose as the starting materials through Friedel-Crafts acylation, selective hydroxy protecting, aldol condensation, glycosylation under phase transfer catalytic condition and other reactions. Our work laid the foundation for large scale preparation of homoeriodictyol-7-O-β-D-glycoside instead of inefficient extration, and provided material baisis for furthur pharmaceutical investigation. The structures of synthetic compounds were confirmed by 1H NMR, 13C NMR and HRMS spectra.
As the active component in visci herba of traditional Chinese medicine, homoeriodictyol-7-O-β-D-glycoside has been widely studied for years. In this paper, the first synthesis of homoeriodictyol-7-O-β-D-glycoside and its diastereoisomer has been achieved, which was carried out using phloroglucinol and D-glucose as the starting materials through Friedel-Crafts acylation, selective hydroxy protecting, aldol condensation, glycosylation under phase transfer catalytic condition and other reactions. Our work laid the foundation for large scale preparation of homoeriodictyol-7-O-β-D-glycoside instead of inefficient extration, and provided material baisis for furthur pharmaceutical investigation. The structures of synthetic compounds were confirmed by 1H NMR, 13C NMR and HRMS spectra.
2017, 37(6): 1398-1406
doi: 10.6023/cjoc201701020
Abstract:
A chiral prosthetic group induced heterogeneous diastereoselective asymmetric hydrogenation of β-dehydroamino esters, catalyzed by Pt/Al2O3, has been developed. A series of β-dehydroamino esters were successfully hydrogenated in high yields with good diastereoselectivities (dr up to 5.2:94.8). This method provides a convenient and efficient synthetic way for the preparation of chiral β-amino acid derivatives, which are key intermediates for bioactive compounds and pharmaceuticals.
A chiral prosthetic group induced heterogeneous diastereoselective asymmetric hydrogenation of β-dehydroamino esters, catalyzed by Pt/Al2O3, has been developed. A series of β-dehydroamino esters were successfully hydrogenated in high yields with good diastereoselectivities (dr up to 5.2:94.8). This method provides a convenient and efficient synthetic way for the preparation of chiral β-amino acid derivatives, which are key intermediates for bioactive compounds and pharmaceuticals.
2017, 37(6): 1523-1529
doi: 10.6023/cjoc201704018
Abstract:
Acute myelogenous leukemia is a malignant disease of the hemopoietic tissue, which causes great harm to human health, and there is no therapeutic drugs with low toxicity and high efficiency. Indirubin is the active constituent of the traditional chinese medicine qingdai, which has potential anti-leukemia activity. However, poor water solubility and low bioavailability have limited its clinical treatment. To improve the water solubility and anti-leukemia activity of indirubin, hydrophilic amino side chain was linked to the indirubin, and five novel indirubin derivatives were synthesized, which were identified by HRMS, 1H NMR and 13C NMR. Meanwhile, the effects of target molecules on the proliferation of acute myeloblastic leukemia HL-60 cells were evaluated using CCK-8 assay. The results showed that four derivatives displayed potent antiproliferative activity against HL-60 cells. Notably, N1-(2-dimethylaminoethyl)indirubin (5a) exhibited the best anticacner activity with an IC50 value of (3.564±0.211) μmol/L. Flow cytometry and Hoechst 33342 staining indicated that compound 5a could significantly trigger cell cycle arrest and induce apoptosis of HL-60 cells. Finally, compound 5a could regulate the levels of cell cycle arrest-and apoptosis-related proteins. Together, these findings revealed that compound 5a maybe be a promising lead candidate for the treatment of leukemia.
Acute myelogenous leukemia is a malignant disease of the hemopoietic tissue, which causes great harm to human health, and there is no therapeutic drugs with low toxicity and high efficiency. Indirubin is the active constituent of the traditional chinese medicine qingdai, which has potential anti-leukemia activity. However, poor water solubility and low bioavailability have limited its clinical treatment. To improve the water solubility and anti-leukemia activity of indirubin, hydrophilic amino side chain was linked to the indirubin, and five novel indirubin derivatives were synthesized, which were identified by HRMS, 1H NMR and 13C NMR. Meanwhile, the effects of target molecules on the proliferation of acute myeloblastic leukemia HL-60 cells were evaluated using CCK-8 assay. The results showed that four derivatives displayed potent antiproliferative activity against HL-60 cells. Notably, N1-(2-dimethylaminoethyl)indirubin (5a) exhibited the best anticacner activity with an IC50 value of (3.564±0.211) μmol/L. Flow cytometry and Hoechst 33342 staining indicated that compound 5a could significantly trigger cell cycle arrest and induce apoptosis of HL-60 cells. Finally, compound 5a could regulate the levels of cell cycle arrest-and apoptosis-related proteins. Together, these findings revealed that compound 5a maybe be a promising lead candidate for the treatment of leukemia.
2017, 37(6): 1530-1536
doi: 10.6023/cjoc201703006
Abstract:
Pseudoginsenoside HQ[PHQ, 3β-O-β-D-glucopyranosyl-(20S, 24S)-epoxydammarane-12β, 25-diol] is the main in vivo metabolite of 20(S)-ginsenoside Rh2 which has high biological activities, with potential medicinal value. The reported chemical synthesis of PHQ suffered complex synthetic route and low overall yield because the rational protecting group strategies were required for the key glycosylation on C-3 position of sapogenins. In this paper, the glycosylation conditions on C-3 position of ocotillol type sapogenins were investigated, and it was found that it could realize the selective glycosylation on C-3-position of sapogenins to prepare PHQ under the Ag2CO3 promoter without the protecting group strategy. A new synthesis of PHQ was achieved in three steps via epoxidation, selective glycosylation and debenzoylation reaction of glycon using commercially available 20(S)-protopanoxadiol as the starting material. This method provides a simple and efficient way for the preparation of PHQ and its derivatives.
Pseudoginsenoside HQ[PHQ, 3β-O-β-D-glucopyranosyl-(20S, 24S)-epoxydammarane-12β, 25-diol] is the main in vivo metabolite of 20(S)-ginsenoside Rh2 which has high biological activities, with potential medicinal value. The reported chemical synthesis of PHQ suffered complex synthetic route and low overall yield because the rational protecting group strategies were required for the key glycosylation on C-3 position of sapogenins. In this paper, the glycosylation conditions on C-3 position of ocotillol type sapogenins were investigated, and it was found that it could realize the selective glycosylation on C-3-position of sapogenins to prepare PHQ under the Ag2CO3 promoter without the protecting group strategy. A new synthesis of PHQ was achieved in three steps via epoxidation, selective glycosylation and debenzoylation reaction of glycon using commercially available 20(S)-protopanoxadiol as the starting material. This method provides a simple and efficient way for the preparation of PHQ and its derivatives.
2017, 37(6): 1537-1541
doi: 10.6023/cjoc201701009
Abstract:
To search for the pyridine pesticide lead compound with high antigungal activity, a series of novel 3-phenyl propan-1-one oxime ethers bearing pyridine moiety were synthesized using 3-acetypyridine, benzaldehyde, substituted anilines and alkoxyamine hydrochlorides as starting materials. The structures of target compounds were determined by IR, 1H NMR, 13C NMR and elemental analysis. Meanwhile, the target compounds were evaluated for their antifungal activities against S. sclerotiorum and B. cinerea by the mycelium growth rate method. The results indicated that some compounds displayed high antifungal activity to the two kinds of pathogenic fungi, and their activities were even higher than that of the positive control, chlorothalonil.
To search for the pyridine pesticide lead compound with high antigungal activity, a series of novel 3-phenyl propan-1-one oxime ethers bearing pyridine moiety were synthesized using 3-acetypyridine, benzaldehyde, substituted anilines and alkoxyamine hydrochlorides as starting materials. The structures of target compounds were determined by IR, 1H NMR, 13C NMR and elemental analysis. Meanwhile, the target compounds were evaluated for their antifungal activities against S. sclerotiorum and B. cinerea by the mycelium growth rate method. The results indicated that some compounds displayed high antifungal activity to the two kinds of pathogenic fungi, and their activities were even higher than that of the positive control, chlorothalonil.
2017, 37(6): 1542-1547
doi: 10.6023/cjoc201701042
Abstract:
In order to explore novel pyrazole derivatives with good biological activities, a series of novel pyrazole oxime ester compounds containing pyridyl moiety were designed and synthesized according to the method of active substructure combination. The structures of the target compounds were determined by 1H NMR, 13C NMR and elemental analysis. Preliminary bioassay data indicated that some of the title compounds showed certain insecticidal activities. At a concentration of 500 μg/mL, seven compounds exhibited insecticidal activity against Oriental armyworm with 50%~90%, and six compounds exhibited insecticidal activity against Aphis medicaginis with 50%~90%. When the dosage was lowered to 100 μg/mL, 1, 3-dimethyl-5-(4-chlorophenoxy)pyrazole-4-formyl-O-(2-chloropyridin-3-formyl)oxime (5f) and 1, 3-dimethyl-5-(4-methylphenoxy)pyra-zole-4-formyl-O-(2-chloropyridin-3-formyl)oxime (5j) were still active against Aphis medicaginis with inhibitory values of 50% and 50%, respectively. Insecticidal activities against Nilaparvata lugens of 1, 3-dimethyl-5-(3-fluorophenoxy)pyrazole-4-formyl-O-(2-chloropyridin-3-formyl)oxime (5b) and 5f were both 100% at 500 μg/mL. Additionally, 1, 3-dimethyl-5-(4-fluorophenoxy)pyrazole-4-formyl-O-(2-chloropyridin-3-formyl)oxime (5c), 1, 3-dimethyl-5-(3-chlorophenoxy)-pyrazole-4-for-myl-O-(2-chloropyridin-3-formyl)oxime (5e), 1, 3-dimethyl-5-(4-trifluoromethoxyphenoxy)pyrazole-4-formyl-O-(2-chloro-pyridin-3-formyl)oxime (5i) and 5j displayed good anti-tumor activity against HepG2 cells with IC50 values of 2.6, 4.6, 1.8和1.1 μmol/L, respectively.
In order to explore novel pyrazole derivatives with good biological activities, a series of novel pyrazole oxime ester compounds containing pyridyl moiety were designed and synthesized according to the method of active substructure combination. The structures of the target compounds were determined by 1H NMR, 13C NMR and elemental analysis. Preliminary bioassay data indicated that some of the title compounds showed certain insecticidal activities. At a concentration of 500 μg/mL, seven compounds exhibited insecticidal activity against Oriental armyworm with 50%~90%, and six compounds exhibited insecticidal activity against Aphis medicaginis with 50%~90%. When the dosage was lowered to 100 μg/mL, 1, 3-dimethyl-5-(4-chlorophenoxy)pyrazole-4-formyl-O-(2-chloropyridin-3-formyl)oxime (5f) and 1, 3-dimethyl-5-(4-methylphenoxy)pyra-zole-4-formyl-O-(2-chloropyridin-3-formyl)oxime (5j) were still active against Aphis medicaginis with inhibitory values of 50% and 50%, respectively. Insecticidal activities against Nilaparvata lugens of 1, 3-dimethyl-5-(3-fluorophenoxy)pyrazole-4-formyl-O-(2-chloropyridin-3-formyl)oxime (5b) and 5f were both 100% at 500 μg/mL. Additionally, 1, 3-dimethyl-5-(4-fluorophenoxy)pyrazole-4-formyl-O-(2-chloropyridin-3-formyl)oxime (5c), 1, 3-dimethyl-5-(3-chlorophenoxy)-pyrazole-4-for-myl-O-(2-chloropyridin-3-formyl)oxime (5e), 1, 3-dimethyl-5-(4-trifluoromethoxyphenoxy)pyrazole-4-formyl-O-(2-chloro-pyridin-3-formyl)oxime (5i) and 5j displayed good anti-tumor activity against HepG2 cells with IC50 values of 2.6, 4.6, 1.8和1.1 μmol/L, respectively.
2017, 37(6): 1548-1555
doi: 10.6023/cjoc201612001
Abstract:
An efficient method for the synthesis of pyrano[3, 2-c]quinoline-4, 5-dione derivatives via iodine promoted intramolecular cyclization of 1-methyl-3-cinnamoyl-4-hydroxyquinolin-2-one, synthesized from aldol condensation of 1-methyl-3-acetyl-4-hydroxyquinolin-2-one with aromatic aldehydes in the presence of pyridine and PEG-400 under ultrasound irradiation, has been described. This method offers the advantages of a green approach, easy work-up, mild conditions and good yields.
An efficient method for the synthesis of pyrano[3, 2-c]quinoline-4, 5-dione derivatives via iodine promoted intramolecular cyclization of 1-methyl-3-cinnamoyl-4-hydroxyquinolin-2-one, synthesized from aldol condensation of 1-methyl-3-acetyl-4-hydroxyquinolin-2-one with aromatic aldehydes in the presence of pyridine and PEG-400 under ultrasound irradiation, has been described. This method offers the advantages of a green approach, easy work-up, mild conditions and good yields.
2017, 37(6): 1560-1564
doi: 10.6023/cjoc201612044
Abstract:
Six kinds of 5, 5-(phenylmethylene)bis(2, 2-dimethyl-1, 3-dioxane-4, 6-dione) derivatives were synthesized by the reaction of aromatic aldehydes and 2, 2-dimethyl-1, 3-dioxane-4, 6-dione in biobased gluconic acid aqueous solution at 40 ℃. The reaction has the advantages of high yields (81%~92%), mild conditions, simple operation and environmental friendliness. Furthermore, GAAS can be reused for several times.
Six kinds of 5, 5-(phenylmethylene)bis(2, 2-dimethyl-1, 3-dioxane-4, 6-dione) derivatives were synthesized by the reaction of aromatic aldehydes and 2, 2-dimethyl-1, 3-dioxane-4, 6-dione in biobased gluconic acid aqueous solution at 40 ℃. The reaction has the advantages of high yields (81%~92%), mild conditions, simple operation and environmental friendliness. Furthermore, GAAS can be reused for several times.
2017, 37(6): 1565-1570
doi: 10.6023/cjoc201608020
Abstract:
A series of 11-aryl-8, 11-dihydrofuro[3', 4':5, 6]pyrido[3, 2-f]quinoxalin-10(7H)-one derivatives were obtained via a one-pot and three-component reaction of aromatic aldehydes, 6-aminoquinoxaline and tetronic acid in EtOH. The structure of 11-(4-nitrophenyl)-8, 11-dihydrofuro[3', 4':5, 6]pyrido[3, 2-f]quinoxalin-10(7H)-one (4g) was confirmed by X-ray diffraction analysis. This procedure had the advantages of operation simplicity, catalyst-free and without isolating intermediates, and provided a good method for the synthesis of fused tetracyclic heterocycles containing furan, pyridine and quinoxaline moieties at the same time.
A series of 11-aryl-8, 11-dihydrofuro[3', 4':5, 6]pyrido[3, 2-f]quinoxalin-10(7H)-one derivatives were obtained via a one-pot and three-component reaction of aromatic aldehydes, 6-aminoquinoxaline and tetronic acid in EtOH. The structure of 11-(4-nitrophenyl)-8, 11-dihydrofuro[3', 4':5, 6]pyrido[3, 2-f]quinoxalin-10(7H)-one (4g) was confirmed by X-ray diffraction analysis. This procedure had the advantages of operation simplicity, catalyst-free and without isolating intermediates, and provided a good method for the synthesis of fused tetracyclic heterocycles containing furan, pyridine and quinoxaline moieties at the same time.
2017, 37(6): 1571-1576
doi: 10.6023/cjoc201611018
Abstract:
A useful strategy for the synthesis of enol phosphates from β-keto esters via Atherton-Atodd reaction was developed. A variety of enol phosphates can be quickly and readily prepared with broad substrate scope and moderate yields under mild conditions. This method provides a low cost and practical way to synthesize enol phosphates from β-keto esters.
A useful strategy for the synthesis of enol phosphates from β-keto esters via Atherton-Atodd reaction was developed. A variety of enol phosphates can be quickly and readily prepared with broad substrate scope and moderate yields under mild conditions. This method provides a low cost and practical way to synthesize enol phosphates from β-keto esters.
2017, 37(6): 1556-1559
doi: 10.6023/cjoc201612003
Abstract:
The C—S cross-coupling of aryl halides with alkyl thiols under transition metal-free conditions was investigated. Good to excellent yields can be obtained for a variety of electron-poor aryl halides with alkyl thiols in the presence of KOtBu even at room temperature. The mechanisms for transition metal-free coupling reactions are discussed.
The C—S cross-coupling of aryl halides with alkyl thiols under transition metal-free conditions was investigated. Good to excellent yields can be obtained for a variety of electron-poor aryl halides with alkyl thiols in the presence of KOtBu even at room temperature. The mechanisms for transition metal-free coupling reactions are discussed.
2017, 37(6): 1577-1581
doi: 10.6023/cjoc201701016
Abstract:
Four new closely related vicinal diols, (1R, 2R)-1-(5-(pent-4-en-1-yl)furan-2-yl)propane-1, 2-diol (1), (1S, 2R)-1-(5-(pent-4-en-1-yl)furan-2-yl)propane-1, 2-diol (2), (1R, 2R)-1-(5-pentylfuran-2-yl)propane-1, 2-diol (3) and (1R, 2S)-1-(5-pen-tylfuran-2-yl)propane-1, 2-diol (4), were isolated from the cultures of the fungus Ceriporia alachuana. Their structures and absolute configurations were totally determined by spectroscopic means, chemical method (forming di-O-isopropylidene derivative) and Mo2(OAc)4 induced circular dichroism (ICD) experiments.
Four new closely related vicinal diols, (1R, 2R)-1-(5-(pent-4-en-1-yl)furan-2-yl)propane-1, 2-diol (1), (1S, 2R)-1-(5-(pent-4-en-1-yl)furan-2-yl)propane-1, 2-diol (2), (1R, 2R)-1-(5-pentylfuran-2-yl)propane-1, 2-diol (3) and (1R, 2S)-1-(5-pen-tylfuran-2-yl)propane-1, 2-diol (4), were isolated from the cultures of the fungus Ceriporia alachuana. Their structures and absolute configurations were totally determined by spectroscopic means, chemical method (forming di-O-isopropylidene derivative) and Mo2(OAc)4 induced circular dichroism (ICD) experiments.
2017, 37(6): 1582-1584
doi: 10.6023/cjoc201701035
Abstract:
A practical synthesis of trifluoromethanesulfonate esters by reaction of orthoformate esters with triflic anhydride is described. The solvent-free method featured mild condition, short time, high yield, simple operation and broad substrate scope. The in situ generated trifluoromethanesulfonate ester is highly reactive alkylating agent, providing triflate ionic liquid in excellent yield via a one-pot procedure.
A practical synthesis of trifluoromethanesulfonate esters by reaction of orthoformate esters with triflic anhydride is described. The solvent-free method featured mild condition, short time, high yield, simple operation and broad substrate scope. The in situ generated trifluoromethanesulfonate ester is highly reactive alkylating agent, providing triflate ionic liquid in excellent yield via a one-pot procedure.
