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2017 Volume 37 Issue 1
2017, 37(1): 1-19
doi: 10.6023/cjoc201607040
Abstract:
The tertiary amine motif is an important structure component of multitudinous natural products and drug molecules.Visible light promoted C-H functionalization of tertiary amines has recently received much attention and facilitated the synthesis of alkaloids and drug molecules.Based on photoredox catalysis, visible light is able to induce the formation of iminium cations or α-amino carbon radicals through single electron transfer process which can participate in multitudinous type of organic reactions and complete C-H functionalization of tertiary amines.In this review, the research progress of photoredox catalytic C-H func-tionalization was categorized and summarized.
The tertiary amine motif is an important structure component of multitudinous natural products and drug molecules.Visible light promoted C-H functionalization of tertiary amines has recently received much attention and facilitated the synthesis of alkaloids and drug molecules.Based on photoredox catalysis, visible light is able to induce the formation of iminium cations or α-amino carbon radicals through single electron transfer process which can participate in multitudinous type of organic reactions and complete C-H functionalization of tertiary amines.In this review, the research progress of photoredox catalytic C-H func-tionalization was categorized and summarized.
2017, 37(1): 20-30
doi: 10.6023/cjoc201607017
Abstract:
Phenol oxidation and the induced transformations can construct various core skeletons of bioactive molecules.Due to the extensive existence of dihydrobenzofuran core, which could be generated from the oxidative cycloaddtion reaction of phenols and olefins in bioactive neolignans and resveratrol oligomers, the oxidative cycloaddition reaction of phenols and olefins catched broad attention from organic chemists.Herein, the progress of oxidative cycloadditon reactions of phenols and olefins in recent years is reviewed according to the difference of reaction conditions, and the corresponding reaction mechanisms are discussed.
Phenol oxidation and the induced transformations can construct various core skeletons of bioactive molecules.Due to the extensive existence of dihydrobenzofuran core, which could be generated from the oxidative cycloaddtion reaction of phenols and olefins in bioactive neolignans and resveratrol oligomers, the oxidative cycloaddition reaction of phenols and olefins catched broad attention from organic chemists.Herein, the progress of oxidative cycloadditon reactions of phenols and olefins in recent years is reviewed according to the difference of reaction conditions, and the corresponding reaction mechanisms are discussed.
2017, 37(1): 31-39
doi: 10.6023/cjoc201607003
Abstract:
Developing simple and concise methods to construct azoarene derivatives has aroused wide concerns due to that these compounds are widely used in the fields of organic dyes, medicines, protein probe and functional materials.As a highly atom-and step-economical approach to making these compounds, transition metal-catalyzed azo group-directed C (sp2)-H bond functionalization provides an efficient synthetic method to regioselectively assemble azoarenes.The reaction types about diverse C (sp2)-H bond functionalzation of azoarenes were summarized in this paper.
Developing simple and concise methods to construct azoarene derivatives has aroused wide concerns due to that these compounds are widely used in the fields of organic dyes, medicines, protein probe and functional materials.As a highly atom-and step-economical approach to making these compounds, transition metal-catalyzed azo group-directed C (sp2)-H bond functionalization provides an efficient synthetic method to regioselectively assemble azoarenes.The reaction types about diverse C (sp2)-H bond functionalzation of azoarenes were summarized in this paper.
2017, 37(1): 40-46
doi: 10.6023/cjoc201607026
Abstract:
Recently, catalytic transformation of biobased 5-hydroxymethylfurfural (5-HMF) has been paid much more attentions.1-Hydroxyhexane-2, 5-dione (HHD) is a potential feedstock to synthesize valuable chemicals.The recent remarkable progress of HHD preparation, which utilized 5-HMF as a starting material, is a green and atom economic method.In this review, the approaches of HHD preparation from 5-HMF are summarized based on the homogeneous and heterogeneous catalysis.
Recently, catalytic transformation of biobased 5-hydroxymethylfurfural (5-HMF) has been paid much more attentions.1-Hydroxyhexane-2, 5-dione (HHD) is a potential feedstock to synthesize valuable chemicals.The recent remarkable progress of HHD preparation, which utilized 5-HMF as a starting material, is a green and atom economic method.In this review, the approaches of HHD preparation from 5-HMF are summarized based on the homogeneous and heterogeneous catalysis.
2017, 37(1): 47-78
doi: 10.6023/cjoc201606024
Abstract:
Chiral 2, 2'-bis (diphenylphosphino)-1, 1'-binapthyl (Binap) ligand consists of a pair of 2-diphenylphosphinonaphthyl groups connected at the 1 and 1'positions, being of the nature of the C2-axial chirality with optical activity of ±234°.The Binap can coordinate with many transitional metals to form stable chelation complexes, effecting the chirality transfer to the metal center for function in asymmetrically catalytic reactions.This contribution is focused on the Binap-Ru (Ⅱ) catalytic system that covers the various substrates, reaction conditions, enantioselectivity of the products, reaction mechanism, and others on the basis of the prepared stable Binap-Ru (Ⅱ) complexes as the clue in the text.This study will give a deep understanding of this system especially concerning the applied catalytic synthesis of the useful organic molecules.
Chiral 2, 2'-bis (diphenylphosphino)-1, 1'-binapthyl (Binap) ligand consists of a pair of 2-diphenylphosphinonaphthyl groups connected at the 1 and 1'positions, being of the nature of the C2-axial chirality with optical activity of ±234°.The Binap can coordinate with many transitional metals to form stable chelation complexes, effecting the chirality transfer to the metal center for function in asymmetrically catalytic reactions.This contribution is focused on the Binap-Ru (Ⅱ) catalytic system that covers the various substrates, reaction conditions, enantioselectivity of the products, reaction mechanism, and others on the basis of the prepared stable Binap-Ru (Ⅱ) complexes as the clue in the text.This study will give a deep understanding of this system especially concerning the applied catalytic synthesis of the useful organic molecules.
2017, 37(1): 79-85
doi: 10.6023/cjoc201606031
Abstract:
Mn (OAc)3-mediated reaction of dialkyl phosphites with α, β-unsaturated sulfones to form α, β-unsaturated phosphonates is described.This reaction proceeded in acetic acid at 80℃ for 2 h to afford selective (E)-2-alkenyl phosphonates in 40%~72% yields.
Mn (OAc)3-mediated reaction of dialkyl phosphites with α, β-unsaturated sulfones to form α, β-unsaturated phosphonates is described.This reaction proceeded in acetic acid at 80℃ for 2 h to afford selective (E)-2-alkenyl phosphonates in 40%~72% yields.
2017, 37(1): 86-91
doi: 10.6023/cjoc201608019
Abstract:
Using (R, R)-4, 6-dibenzofurandiyl-2, 2'-bis (4-phenyloxazoline)-Ni (Ni-DBFOX) as the catalyst, asymmetric catalytic 3-dipolar cycloaddition reactions between N-α, β-unsaturated acylpyrazoles and C, N-diarylnitrone have been developed with 95% regioselectivity and an endo/exo ratio of 99:1 with >90% ee of the endo-diastereomer.Influence of olefins, nitrone structure, metal type and amount of catalyst on the reaction stereoselectivity was also carefully discussed.
Using (R, R)-4, 6-dibenzofurandiyl-2, 2'-bis (4-phenyloxazoline)-Ni (Ni-DBFOX) as the catalyst, asymmetric catalytic 3-dipolar cycloaddition reactions between N-α, β-unsaturated acylpyrazoles and C, N-diarylnitrone have been developed with 95% regioselectivity and an endo/exo ratio of 99:1 with >90% ee of the endo-diastereomer.Influence of olefins, nitrone structure, metal type and amount of catalyst on the reaction stereoselectivity was also carefully discussed.
2017, 37(1): 92-96
doi: 10.6023/cjoc201607034
Abstract:
A reaction-based probe 8-(2, 4-dinitrophenoxy) pyrene-1-carbaldehyde (PCNP) for H2S detection was designed and synthesized by utilizing 8-hydroxypyrene-1-carbaldehyde and dinitrophenyl ether as the reporting chromophore and the recognition unit, respectively.The probe was dissolved in phosphate buffer saline (PBS) with cetyltrimethyl ammonium bromide (CTAB), and the sensing ability toward H2S was investigated with steady-state spectroscopy.The emission of PCNP was quenched by photoinduced electron transfer without H2S.The fluorescence of PCNP was boosted after thiolysis reaction in the presence of H2S, showing orange red emission.The fluorescence response was rapid and reached a maximum enhancement of about 260 times in the presence of 0.1 mmol·L-1 H2S, giving a reaction rate constant of 0.20 min-1.The limit of detection of PCNP is estimated to be 0.10 μmol·L-1.The results demonstrate that PCNP is capable of detecting H2S rapidly, sensitively and selectively.
A reaction-based probe 8-(2, 4-dinitrophenoxy) pyrene-1-carbaldehyde (PCNP) for H2S detection was designed and synthesized by utilizing 8-hydroxypyrene-1-carbaldehyde and dinitrophenyl ether as the reporting chromophore and the recognition unit, respectively.The probe was dissolved in phosphate buffer saline (PBS) with cetyltrimethyl ammonium bromide (CTAB), and the sensing ability toward H2S was investigated with steady-state spectroscopy.The emission of PCNP was quenched by photoinduced electron transfer without H2S.The fluorescence of PCNP was boosted after thiolysis reaction in the presence of H2S, showing orange red emission.The fluorescence response was rapid and reached a maximum enhancement of about 260 times in the presence of 0.1 mmol·L-1 H2S, giving a reaction rate constant of 0.20 min-1.The limit of detection of PCNP is estimated to be 0.10 μmol·L-1.The results demonstrate that PCNP is capable of detecting H2S rapidly, sensitively and selectively.
2017, 37(1): 97-102
doi: 10.6023/cjoc201605045
Abstract:
A novel synthesis of aromatic aldehyde from arylmethyl azides has been explored via base-mediated N2-extrusion and hydrolyzation. The effects of bases, hydrolysis conditions and the amount of base used on the reaction were also investigated. Benzaldehyde was isolated in the best yield of 83%, when the reaction was carried in N, N-dimethylformamide (DMF) and catalyzed by t-BuOK. Meanwhile, a variety of azides were investigated, and it was found that substituted benzyl azides could give the corresponding aromatic aldehydes in the yield of 38%~87%. The reaction of heteoaryl methyl azides was less efficient. According to the controlling experiments, the mechanism has been quitted.
A novel synthesis of aromatic aldehyde from arylmethyl azides has been explored via base-mediated N2-extrusion and hydrolyzation. The effects of bases, hydrolysis conditions and the amount of base used on the reaction were also investigated. Benzaldehyde was isolated in the best yield of 83%, when the reaction was carried in N, N-dimethylformamide (DMF) and catalyzed by t-BuOK. Meanwhile, a variety of azides were investigated, and it was found that substituted benzyl azides could give the corresponding aromatic aldehydes in the yield of 38%~87%. The reaction of heteoaryl methyl azides was less efficient. According to the controlling experiments, the mechanism has been quitted.
2017, 37(1): 103-109
doi: 10.6023/cjoc201606034
Abstract:
Selective trifluoromethylation of α-oxo-Weinreb amides was explored using trimethyl (trifluoromethyl) silane as fluorinating reagent. A series of α-trifluoromethyl-α-hydroxyl Weinreb amides were successfully synthesized and their reaction with organometallic reagents was investigated.
Selective trifluoromethylation of α-oxo-Weinreb amides was explored using trimethyl (trifluoromethyl) silane as fluorinating reagent. A series of α-trifluoromethyl-α-hydroxyl Weinreb amides were successfully synthesized and their reaction with organometallic reagents was investigated.
2017, 37(1): 110-115
doi: 10.6023/cjoc201607008
Abstract:
Seven kinds of ferrocenyl-benzoyl-thiadiazole compounds FcL1~FcL7 were synthesized by using 4-ferrocenyl-benzoic and 2-amino-5-aryl-1, 3, 4-thiadiazole as raw materials. These compounds were characterized by IR, 1H NMR and elemental analysis. The crystal structure of FcL4 was determined by X-ray diffraction analysis. The electrochemical research showed that the redox reaction on the surface of electrode was reversible with single electron, and FcL1~FcL7 have a certain redox response to Pb2+and Zn2+. The antibacterial activity tests indicated that FcL1~FcL7 presented significant activity and selectivity against Fusarium graminearum. FcL5~FcL7 exhibited good inhibition against human esophageal cancer cells in the anticancer activity tests.
Seven kinds of ferrocenyl-benzoyl-thiadiazole compounds FcL1~FcL7 were synthesized by using 4-ferrocenyl-benzoic and 2-amino-5-aryl-1, 3, 4-thiadiazole as raw materials. These compounds were characterized by IR, 1H NMR and elemental analysis. The crystal structure of FcL4 was determined by X-ray diffraction analysis. The electrochemical research showed that the redox reaction on the surface of electrode was reversible with single electron, and FcL1~FcL7 have a certain redox response to Pb2+and Zn2+. The antibacterial activity tests indicated that FcL1~FcL7 presented significant activity and selectivity against Fusarium graminearum. FcL5~FcL7 exhibited good inhibition against human esophageal cancer cells in the anticancer activity tests.
2017, 37(1): 116-121
doi: 10.6023/cjoc201606005
Abstract:
The method of oxidation of N-sulfonylimines to N-sulfonyloxaziridines with m-chloroperbenzoic acid catalyzed by ammonium halides was systematically investigated for the first time. Tetraethylammonium halides (Et4NI or Et4NCl) and tetramethylammonium halides (Me4NI, Me4NBr or Me4NCl) were firstly used to catalyze the oxidation of a series of N-sulfonylimines to the corresponding N-sulfonyloxaziridines in excellent yields. The experimental results showed that the alkyl group of the ammonium had significant influence on the reaction, whereas the halide ions had lesser influence on the reaction. Thus the research has provided a simple procedure for the preparation of oxaziradine with excellent yields.
The method of oxidation of N-sulfonylimines to N-sulfonyloxaziridines with m-chloroperbenzoic acid catalyzed by ammonium halides was systematically investigated for the first time. Tetraethylammonium halides (Et4NI or Et4NCl) and tetramethylammonium halides (Me4NI, Me4NBr or Me4NCl) were firstly used to catalyze the oxidation of a series of N-sulfonylimines to the corresponding N-sulfonyloxaziridines in excellent yields. The experimental results showed that the alkyl group of the ammonium had significant influence on the reaction, whereas the halide ions had lesser influence on the reaction. Thus the research has provided a simple procedure for the preparation of oxaziradine with excellent yields.
2017, 37(1): 122-132
doi: 10.6023/cjoc201607020
Abstract:
20 novel rhein-amino acid conjugates were designed and synthesized from the rhein via esterification, etherification, hydrolysis, condensation and salification. Their structures were confirmed by 1H NMR, 13C NMR and HRMS. All the target compounds were tested for cytotoxic activity against five cancer cell lines including Hela, MCF-7, HepG2, KB and HEK293T by methyl thiazolyl tetrazolium (MTT) method in vitro. The results showed that sodium (4, 5-bis (benzyloxy)-9, 10-dioxo-9, 10-dihydroanthracene-2-carbonyl) leucinate (6eb) demonstrated moderate cytotoxic activities (IC50 < 50 µmol•L-1). The fluorescence of compounds sodium (4, 5-dibutoxy-9, 10-dioxo-9, 10-dihydroanthracene-2-carbonyl) leucinate (6db) and 6eb could be both quenched by DNA. It was speculated that compound 6db interacted with DNA by the static attraction or was partially embedded into DNA.
20 novel rhein-amino acid conjugates were designed and synthesized from the rhein via esterification, etherification, hydrolysis, condensation and salification. Their structures were confirmed by 1H NMR, 13C NMR and HRMS. All the target compounds were tested for cytotoxic activity against five cancer cell lines including Hela, MCF-7, HepG2, KB and HEK293T by methyl thiazolyl tetrazolium (MTT) method in vitro. The results showed that sodium (4, 5-bis (benzyloxy)-9, 10-dioxo-9, 10-dihydroanthracene-2-carbonyl) leucinate (6eb) demonstrated moderate cytotoxic activities (IC50 < 50 µmol•L-1). The fluorescence of compounds sodium (4, 5-dibutoxy-9, 10-dioxo-9, 10-dihydroanthracene-2-carbonyl) leucinate (6db) and 6eb could be both quenched by DNA. It was speculated that compound 6db interacted with DNA by the static attraction or was partially embedded into DNA.
2017, 37(1): 133-140
doi: 10.6023/cjoc201608002
Abstract:
Eight novel quercetin conjugates 20~27 were successfully synthesized through a concise procedure with 15%~46% overall yields by using Rutin as the starting material. After O-benzylation, glycoside hydrolysis and O-propargylation, rutin was converted to the key intermediate 5, 7, 3', 4'-tetrabenzyloxy-3-O-propargylquercetin, which subsequently 'clicked' with azido containing glycosides, poly (ethylene glycol) (PEG) or oligo (ethylene glycol) (OEG) to provide the fully protected quercetin conjugates 12~19. After global deprotection, the resulting quercetin conjugates were evaluated on hypoglycemic activities at 3T3-L1 adipocyte level. The results showed that conjugates 24, 26 and 27 exhibited good hypoglycemic effects.
Eight novel quercetin conjugates 20~27 were successfully synthesized through a concise procedure with 15%~46% overall yields by using Rutin as the starting material. After O-benzylation, glycoside hydrolysis and O-propargylation, rutin was converted to the key intermediate 5, 7, 3', 4'-tetrabenzyloxy-3-O-propargylquercetin, which subsequently 'clicked' with azido containing glycosides, poly (ethylene glycol) (PEG) or oligo (ethylene glycol) (OEG) to provide the fully protected quercetin conjugates 12~19. After global deprotection, the resulting quercetin conjugates were evaluated on hypoglycemic activities at 3T3-L1 adipocyte level. The results showed that conjugates 24, 26 and 27 exhibited good hypoglycemic effects.
2017, 37(1): 141-148
doi: 10.6023/cjoc201607028
Abstract:
Jaspine B is a natural product with significant antitumor activity, which was isolated from the marine sponge Pachastrissa sp.In order to find new antitumor compounds with high efficiency and succinct synthetic methods, a series of 3-epi-jaspine B analogues were designed and synthesized.16 compounds were synthesized and all of them were unknown in the literature.Their structures were determined by 1H NMR, 13C NMR and HRMS.The antitumor activity of these compounds against four tumor cell lines B16-F10, A-549, MCF-7 and PC-3 was assayed using thiazolyl blue (MTT) assay, and some compounds showed potent inhibitory effect on tumor cells.Compounds 8f and 11 were more potent against A-549 with IC50 of (9.646±0.984) and (7.144±0.854)μg/mL.
Jaspine B is a natural product with significant antitumor activity, which was isolated from the marine sponge Pachastrissa sp.In order to find new antitumor compounds with high efficiency and succinct synthetic methods, a series of 3-epi-jaspine B analogues were designed and synthesized.16 compounds were synthesized and all of them were unknown in the literature.Their structures were determined by 1H NMR, 13C NMR and HRMS.The antitumor activity of these compounds against four tumor cell lines B16-F10, A-549, MCF-7 and PC-3 was assayed using thiazolyl blue (MTT) assay, and some compounds showed potent inhibitory effect on tumor cells.Compounds 8f and 11 were more potent against A-549 with IC50 of (9.646±0.984) and (7.144±0.854)μg/mL.
2017, 37(1): 149-156
doi: 10.6023/cjoc201607041
Abstract:
Eighteen N-(thiazol-2-yl)-2-(4-aryloxyphenoxy) propionamides were synthesized by reaction of (R)-(+)-2-(4-hy-droxyphenoxy) propanoyl chlorides with 2-aminothiazole derivatives.Their structures were confirmed by 1H NMR, 13C NMR, elemental analysis, EI-MS and optical rotation.The crystal structure of (R)-N-(4-trifluoromethyl-5-ethoxycarbonylthiazole-2-yl)-2-[4-(3-fluoro-5-chloropyridin-2-yl) oxy) phenoxy) propionamide was determined by X-ray diffraction analysis.The crystal belonged to the tetragonal system, space group P41212 with a=14.45502(18)Å, b=14.45502(18)Å, c=21.7813(5)Å;Z=8, V=4551.14(15)Å3, Dc=1.558 Mg/m3, F(000)=2176, μ=3.013 mm-1, and the final R=0.0302, wR=0.0687.The bioassay results indicated that most of title compounds displayed moderate to excellent herbicidal activity against crabgrass (Digitaria sanguinalis) and barnyard grass (Echinochloa crusgalli) at the dose of 1500 g/hm2.Some compounds showed 100% inhibition against the growth of the crabgrass and barnyard grass when applied at the pre-emergence and post-emergence treatment.
Eighteen N-(thiazol-2-yl)-2-(4-aryloxyphenoxy) propionamides were synthesized by reaction of (R)-(+)-2-(4-hy-droxyphenoxy) propanoyl chlorides with 2-aminothiazole derivatives.Their structures were confirmed by 1H NMR, 13C NMR, elemental analysis, EI-MS and optical rotation.The crystal structure of (R)-N-(4-trifluoromethyl-5-ethoxycarbonylthiazole-2-yl)-2-[4-(3-fluoro-5-chloropyridin-2-yl) oxy) phenoxy) propionamide was determined by X-ray diffraction analysis.The crystal belonged to the tetragonal system, space group P41212 with a=14.45502(18)Å, b=14.45502(18)Å, c=21.7813(5)Å;Z=8, V=4551.14(15)Å3, Dc=1.558 Mg/m3, F(000)=2176, μ=3.013 mm-1, and the final R=0.0302, wR=0.0687.The bioassay results indicated that most of title compounds displayed moderate to excellent herbicidal activity against crabgrass (Digitaria sanguinalis) and barnyard grass (Echinochloa crusgalli) at the dose of 1500 g/hm2.Some compounds showed 100% inhibition against the growth of the crabgrass and barnyard grass when applied at the pre-emergence and post-emergence treatment.
2017, 37(1): 157-165
doi: 10.6023/cjoc201608006
Abstract:
Based on benalaxyl pesticide metabolite structure framework, fourteen novel diamide derivatives were synthesized by the reaction of amine and N2-carboxyacetyl-N1-(2, 6-dimethylphenyl) alanine methyl ester.Their structures were identified by 1H NMR, 13C NMR spectra and HRMS.The results of bioassay indicated that some compounds possess potential fungicidal activities against 8 kinds of bacteria, and the antibacterial activity of some compounds was better than that of benalaxyl.At a dosage of 5.0×10-5 g/mL, compound 7d displayed 94.2% antifungal activities against Rhizoctonia solani.Compound 8f displayed 87.1% and 88.9% antifungal activities against Phytophthora capsici and Rhizoctonia solani.
Based on benalaxyl pesticide metabolite structure framework, fourteen novel diamide derivatives were synthesized by the reaction of amine and N2-carboxyacetyl-N1-(2, 6-dimethylphenyl) alanine methyl ester.Their structures were identified by 1H NMR, 13C NMR spectra and HRMS.The results of bioassay indicated that some compounds possess potential fungicidal activities against 8 kinds of bacteria, and the antibacterial activity of some compounds was better than that of benalaxyl.At a dosage of 5.0×10-5 g/mL, compound 7d displayed 94.2% antifungal activities against Rhizoctonia solani.Compound 8f displayed 87.1% and 88.9% antifungal activities against Phytophthora capsici and Rhizoctonia solani.
2017, 37(1): 166-175
doi: 10.6023/cjoc201607002
Abstract:
In this paper, a concise protocol for synthesis of possess potential pharmacological active amide class heterocyclic ketene aminals (HKAs) has been developed, which based on the six or seven-membered HKAs 1~2, using aryl isocyanate 4 as acylation agent.The regioselective acylation reaction of HKAs in 1, 4-dioxane at room temperature gave compounds 5~6 with 90%~98% yields.However, the five-membered HKAs 3 and aryl isocyanate 4 reacted in 1, 4-dioxane catalyzed by Cs2CO3 at room temperature to obtain compounds 7 in 78%~93% yields.
In this paper, a concise protocol for synthesis of possess potential pharmacological active amide class heterocyclic ketene aminals (HKAs) has been developed, which based on the six or seven-membered HKAs 1~2, using aryl isocyanate 4 as acylation agent.The regioselective acylation reaction of HKAs in 1, 4-dioxane at room temperature gave compounds 5~6 with 90%~98% yields.However, the five-membered HKAs 3 and aryl isocyanate 4 reacted in 1, 4-dioxane catalyzed by Cs2CO3 at room temperature to obtain compounds 7 in 78%~93% yields.
2017, 37(1): 176-184
doi: 10.6023/cjoc201608013
Abstract:
Reactions of the simple osmium precursors OsHCl (PPh3)3(1) or OsCl2(PPh3)3(2) with 3-chloro-3-methylbut-1-yne afforded OsHCl2(≡CCH=CMe2)(PPh3)2(3) or OsCl3(≡CCH=CMe2)(PPh3)2(4), respectively.Treatment of 3 with Ph2PC≡CPh led to the formation of the tris-diphenyl (phenylethynyl) phosphine alkenylcarbene complex OsCl2(=CHCH=CMe2)(Ph2PC≡CPh)3(5), while complex 4 underwent simple phosphine ligand substitution with Ph2PC≡CPh to give OsCl3(≡CCH=CMe2)(Ph2PC≡CPh)2(6).Presumably, upon the phosphine ligand substitution of PPh3 in 3 by Ph2PC≡CPh, the relatively electron-poor nature of the later decreased the electron density of the osmium center, and thus promoted the transformation of the hydride-carbyne to carbene via the 1, 2-shift of the hydride ligand from Os to the carbyne carbon, which was then further facilitated by the coordination of a third less bulky Ph2PC≡CPh ligand to the osmium center to give the stable 18e product 5.
Reactions of the simple osmium precursors OsHCl (PPh3)3(1) or OsCl2(PPh3)3(2) with 3-chloro-3-methylbut-1-yne afforded OsHCl2(≡CCH=CMe2)(PPh3)2(3) or OsCl3(≡CCH=CMe2)(PPh3)2(4), respectively.Treatment of 3 with Ph2PC≡CPh led to the formation of the tris-diphenyl (phenylethynyl) phosphine alkenylcarbene complex OsCl2(=CHCH=CMe2)(Ph2PC≡CPh)3(5), while complex 4 underwent simple phosphine ligand substitution with Ph2PC≡CPh to give OsCl3(≡CCH=CMe2)(Ph2PC≡CPh)2(6).Presumably, upon the phosphine ligand substitution of PPh3 in 3 by Ph2PC≡CPh, the relatively electron-poor nature of the later decreased the electron density of the osmium center, and thus promoted the transformation of the hydride-carbyne to carbene via the 1, 2-shift of the hydride ligand from Os to the carbyne carbon, which was then further facilitated by the coordination of a third less bulky Ph2PC≡CPh ligand to the osmium center to give the stable 18e product 5.
2017, 37(1): 185-189
doi: 10.6023/cjoc201606036
Abstract:
A new anthracene-containing tripodal triazole with 1, 3, 5-trisubstituted benzene core has been easily synthesized by "click reaction".Among various metal ions, 1 shows exclusive fluorescence turn-off sensing of Hg2+ in CH3CN-H2O (V:V=9:1) solution.The quenching ration is about 75%, and the detection limit for Hg2+ is 6.1×10-6 mol/L.The 1H NMR titrations results reveal that the N atoms of the three triazoles of 1 take part in binding with center ion with forming 1:1 1-Zn2+ complex.
A new anthracene-containing tripodal triazole with 1, 3, 5-trisubstituted benzene core has been easily synthesized by "click reaction".Among various metal ions, 1 shows exclusive fluorescence turn-off sensing of Hg2+ in CH3CN-H2O (V:V=9:1) solution.The quenching ration is about 75%, and the detection limit for Hg2+ is 6.1×10-6 mol/L.The 1H NMR titrations results reveal that the N atoms of the three triazoles of 1 take part in binding with center ion with forming 1:1 1-Zn2+ complex.
2017, 37(1): 190-195
doi: 10.6023/cjoc201607005
Abstract:
Computational studies were carried out to investigate the detailed mechanism of Pd (0) and benzoic acid co-catalyzed hydroamination of internal alkynes.In the presence of the benzoic acid, the formation of a hydridopalladium intermediate via the oxidative addition (OA) of the O-H bond of benzoic acid into the Pd (0) complex center might not be a favorable reaction pathway to start the reaction.Instead, after the coordination of benzoic acid with the Pd (0)-alkyne complex, a proton transfer process from the acid to carbon of alkyne is found to be a favorable pathway, leading to the alkenyl (PhCOO) Pd (Ⅱ) intermediate.Next, the resulting alkenyl (PhCOO) Pd (Ⅱ) species would produce phenylallene intermediate via a β-H elimination step assisted by the formed benzoate anion.Subsequently, the benzoic acid might undergo a second proton step to the phenylallene intermediate to produce the π-allylpalladium species.Finally, the amine substrate could undergo a nucleophilic addition to the terminal carbon of the π-allylpalladium species to produce the hydroamination product.
Computational studies were carried out to investigate the detailed mechanism of Pd (0) and benzoic acid co-catalyzed hydroamination of internal alkynes.In the presence of the benzoic acid, the formation of a hydridopalladium intermediate via the oxidative addition (OA) of the O-H bond of benzoic acid into the Pd (0) complex center might not be a favorable reaction pathway to start the reaction.Instead, after the coordination of benzoic acid with the Pd (0)-alkyne complex, a proton transfer process from the acid to carbon of alkyne is found to be a favorable pathway, leading to the alkenyl (PhCOO) Pd (Ⅱ) intermediate.Next, the resulting alkenyl (PhCOO) Pd (Ⅱ) species would produce phenylallene intermediate via a β-H elimination step assisted by the formed benzoate anion.Subsequently, the benzoic acid might undergo a second proton step to the phenylallene intermediate to produce the π-allylpalladium species.Finally, the amine substrate could undergo a nucleophilic addition to the terminal carbon of the π-allylpalladium species to produce the hydroamination product.
2017, 37(1): 196-202
doi: 10.6023/cjoc201608008
Abstract:
C-or O-benzylation of 1, 3-dicarbonyl compounds is one of the most fundamental methodologies for carbon-carbon or carbon-oxygen bond formation in organic synthesis.Perfluoroalkanosulfonyl fluoride (RfSO2F) is a class of excellent hy-droxyl-activating reagent, and has been extensively developed and used in the formation of C-F, C-O, C-N and C-S bonds in organic synthesis.In this work one-step C-or O-benzylation of 1, 3-dicarbonyl compounds (1, 3-diketones and β-ketonic esters) with benzyl alcohols promoted by RfSO2F in alkaline media was explored, and the corresponding C-or O-benzylation products were generated in medium to excellent yields.The optimized reaction conditions:1, 8-diazabicyclo[5.4.0]undec-7-ene (DBU) as base, CH2Cl2 as solvent, n-C4F9SO2F, room temperature and the molar ratio of n(1, 3-dicarbonyls):n(benzyl alco-hols):n(RfSO2F):n(DBU) is 1.0:1.0:1.0:2.2.A novel reagent system for the direct C-or O-benzylation of 1, 3-dicarbonyl compounds with benzyl alcohols was developed.The application scope of RfSO2F in organic synthesis was further broadened.
C-or O-benzylation of 1, 3-dicarbonyl compounds is one of the most fundamental methodologies for carbon-carbon or carbon-oxygen bond formation in organic synthesis.Perfluoroalkanosulfonyl fluoride (RfSO2F) is a class of excellent hy-droxyl-activating reagent, and has been extensively developed and used in the formation of C-F, C-O, C-N and C-S bonds in organic synthesis.In this work one-step C-or O-benzylation of 1, 3-dicarbonyl compounds (1, 3-diketones and β-ketonic esters) with benzyl alcohols promoted by RfSO2F in alkaline media was explored, and the corresponding C-or O-benzylation products were generated in medium to excellent yields.The optimized reaction conditions:1, 8-diazabicyclo[5.4.0]undec-7-ene (DBU) as base, CH2Cl2 as solvent, n-C4F9SO2F, room temperature and the molar ratio of n(1, 3-dicarbonyls):n(benzyl alco-hols):n(RfSO2F):n(DBU) is 1.0:1.0:1.0:2.2.A novel reagent system for the direct C-or O-benzylation of 1, 3-dicarbonyl compounds with benzyl alcohols was developed.The application scope of RfSO2F in organic synthesis was further broadened.
2017, 37(1): 203-208
doi: 10.6023/cjoc201608016
Abstract:
A biodegradable poly (lactic-co-glycolic acid)/polyethylene glycol (PLGA-PEG) copolymer molecule was prepared by the simple and green coupling reaction between carboxyl group of poly (lactide-co-glycolide)-carboxylic acid endcap (PLGA-COOH) and amino group of poly (ethylene glycol) amine and carboxylic acid endcap (NH2-PEG-COOH) in the presence of 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS).The molecular structure of PLGA-PEG copolymer was characterized by 1H NMR spectroscopy, and the grafting yield of polyethylene glycol (PEG) on poly (lactic-co-glycolic acid)(PLGA) was calculated.Furthermore, pigment epithelium-derived factor (PEDF) was encapsulated in the PLGA-PEG copolymer to prepare a PLGA-PEG/PEDF emulsion for highly efficient inhibition on vascular endothelial growth gene expression (VEGF).The results showed that the obtained PLGA-PEG copolymer was bio-safety and the PLGA-PEG/PEDF emulsion was a good agent for effective inhibition VEGF expression under different conditions.Thus, the PLGA-PEG copolymer can be used as a bio-carrier and the PLGA-PEG/PEDF emulsion can be used as a good angiogenesis inhibitor, which has a potential application for some diseases by anti angiogenesis.
A biodegradable poly (lactic-co-glycolic acid)/polyethylene glycol (PLGA-PEG) copolymer molecule was prepared by the simple and green coupling reaction between carboxyl group of poly (lactide-co-glycolide)-carboxylic acid endcap (PLGA-COOH) and amino group of poly (ethylene glycol) amine and carboxylic acid endcap (NH2-PEG-COOH) in the presence of 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS).The molecular structure of PLGA-PEG copolymer was characterized by 1H NMR spectroscopy, and the grafting yield of polyethylene glycol (PEG) on poly (lactic-co-glycolic acid)(PLGA) was calculated.Furthermore, pigment epithelium-derived factor (PEDF) was encapsulated in the PLGA-PEG copolymer to prepare a PLGA-PEG/PEDF emulsion for highly efficient inhibition on vascular endothelial growth gene expression (VEGF).The results showed that the obtained PLGA-PEG copolymer was bio-safety and the PLGA-PEG/PEDF emulsion was a good agent for effective inhibition VEGF expression under different conditions.Thus, the PLGA-PEG copolymer can be used as a bio-carrier and the PLGA-PEG/PEDF emulsion can be used as a good angiogenesis inhibitor, which has a potential application for some diseases by anti angiogenesis.
2017, 37(1): 209-212
doi: 10.6023/cjoc201604045
Abstract:
The yield of Blaise reaction of trimethylsilyl protected (S)-4-chloro-3-hydroxyl but yronitrile with tert-butyl bromo zinc acetate is improved nearly 20% by using Cu+ or I2 as a single catalyst.Interestingly, when Cu+ and I2 were used as the co-catalyst, the reaction yield was further improved from 72.1% to 97.0%.These results, which were reasonably explained via the reaction mechanism, not only indicate that the Blaise reaction can be applied more widely, but also provide a simple route for the preparation of the side chain of rosuvastatin and atorvastatin.Moreover, this optimized Blaise reaction provides a new insight into the C-C bond formation.
The yield of Blaise reaction of trimethylsilyl protected (S)-4-chloro-3-hydroxyl but yronitrile with tert-butyl bromo zinc acetate is improved nearly 20% by using Cu+ or I2 as a single catalyst.Interestingly, when Cu+ and I2 were used as the co-catalyst, the reaction yield was further improved from 72.1% to 97.0%.These results, which were reasonably explained via the reaction mechanism, not only indicate that the Blaise reaction can be applied more widely, but also provide a simple route for the preparation of the side chain of rosuvastatin and atorvastatin.Moreover, this optimized Blaise reaction provides a new insight into the C-C bond formation.
2017, 37(1): 213-217
doi: 10.6023/cjoc201606021
Abstract:
The zwitterionic compounds 1-(diaminomethyleneammonio)(aryl) methyl-4, 4-dimethyl-2, 6-dioxocyclohexan-1-ides were synthesized from the reaction of dimedone, aromatic aldehydes and guanidine carbonate catalyzed by NaOH under solvent-free conditions.This is the new type azomethine ylide compound that has not been reported previously.The other advantages of this reaction were simple operation, short reaction time, and environmental friendly.The products were identified by 1H NMR, 13C NMR, IR and HRMS, and that of 4a was additionally confirmed by X-ray diffraction analysis.This reported approach is an effective way for the synthesis of azomethine ylide.
The zwitterionic compounds 1-(diaminomethyleneammonio)(aryl) methyl-4, 4-dimethyl-2, 6-dioxocyclohexan-1-ides were synthesized from the reaction of dimedone, aromatic aldehydes and guanidine carbonate catalyzed by NaOH under solvent-free conditions.This is the new type azomethine ylide compound that has not been reported previously.The other advantages of this reaction were simple operation, short reaction time, and environmental friendly.The products were identified by 1H NMR, 13C NMR, IR and HRMS, and that of 4a was additionally confirmed by X-ray diffraction analysis.This reported approach is an effective way for the synthesis of azomethine ylide.
2017, 37(1): 218-225
doi: 10.6023/cjoc201606038
Abstract:
Novel pinanyl pyrazole derivatives were synthesized from nopinone and their bioactivities were also examined in this paper.The intermediate compounds 3-arylidenenopinones 2a~2g were synthesized by condensation of aromatic aldehydes and nopinone, and pinanyl pyrazole derivatives 3a~3g were subsequently obtained by cyclization and dehydroaromatization of compounds 2a~2g and hydrazine hydrate in the circumstance of N, N-dimethylformamide (DMT).The target compound pinanyl pyrazole acetamide derivatives 4a~4g were synthesized by alkylation using 2-chloroacetamide as the alkylating agent under the condition of base catalysis.The structures of synthesized compounds were characterized by 1H NMR, 13C NMR, IR, HRMS, and X-ray diffraction analysis.Biological activities evaluation of compounds 3a~3g and 4a~4g were performed including antibacterial and insecticidal activities on Tinocallis kahawaluokalani.Test results showed that compound 4g was a more potent bactericide and fungicide than others because of its good activities against bacteria and fungi; furthermore, compound 4g had shown the better insecticidal activity against Tinocallis kahawaluokalani than the others.
Novel pinanyl pyrazole derivatives were synthesized from nopinone and their bioactivities were also examined in this paper.The intermediate compounds 3-arylidenenopinones 2a~2g were synthesized by condensation of aromatic aldehydes and nopinone, and pinanyl pyrazole derivatives 3a~3g were subsequently obtained by cyclization and dehydroaromatization of compounds 2a~2g and hydrazine hydrate in the circumstance of N, N-dimethylformamide (DMT).The target compound pinanyl pyrazole acetamide derivatives 4a~4g were synthesized by alkylation using 2-chloroacetamide as the alkylating agent under the condition of base catalysis.The structures of synthesized compounds were characterized by 1H NMR, 13C NMR, IR, HRMS, and X-ray diffraction analysis.Biological activities evaluation of compounds 3a~3g and 4a~4g were performed including antibacterial and insecticidal activities on Tinocallis kahawaluokalani.Test results showed that compound 4g was a more potent bactericide and fungicide than others because of its good activities against bacteria and fungi; furthermore, compound 4g had shown the better insecticidal activity against Tinocallis kahawaluokalani than the others.
2017, 37(1): 226-231
doi: 10.6023/cjoc201607007
Abstract:
Aromatic azo compounds are widely used as organic dyes, biological medicines, food additives, radical initiators and so on.This paper describes an efficient protocol for the synthesis of aromatic azo compounds from anilines via Ag2CO3 mediated oxidative dehydrogenative coupling reactions in the presence of (CH3)3COK in PhCl.The yields are up to 92%, and this method is easy-operation and provides a practical process to synthesize aromatic azo compounds under mild conditions.
Aromatic azo compounds are widely used as organic dyes, biological medicines, food additives, radical initiators and so on.This paper describes an efficient protocol for the synthesis of aromatic azo compounds from anilines via Ag2CO3 mediated oxidative dehydrogenative coupling reactions in the presence of (CH3)3COK in PhCl.The yields are up to 92%, and this method is easy-operation and provides a practical process to synthesize aromatic azo compounds under mild conditions.
2017, 37(1): 232-236
doi: 10.6023/cjoc201607031
Abstract:
A series of novel 1, 2, 4-triazole derivatives were synthesized from ethyl trifluoroacetoacetate, triethyl orthoformate, methylhydrazine, phenyl isothiocyanate by multi-step reactions.Their structures were characterized by 1H NMR, 13C NMR, HRMS and X-ray diffraction.The target compounds were evaluated for their fungicidal activity and herbicidal activitiy.The results indicated that some of the title compounds displayed certain fungicidal activities against Colletotrichum orbiculare and herbicidal activity against dicotyledons.
A series of novel 1, 2, 4-triazole derivatives were synthesized from ethyl trifluoroacetoacetate, triethyl orthoformate, methylhydrazine, phenyl isothiocyanate by multi-step reactions.Their structures were characterized by 1H NMR, 13C NMR, HRMS and X-ray diffraction.The target compounds were evaluated for their fungicidal activity and herbicidal activitiy.The results indicated that some of the title compounds displayed certain fungicidal activities against Colletotrichum orbiculare and herbicidal activity against dicotyledons.
2017, 37(1): 237-241
doi: 10.6023/cjoc201605021
Abstract:
With the aim of developing new potent anticancer agents, a series of novel 4'-(N-substitued-1-piperazinyl) chalcone derivatives 3a~3j have been designed and synthesized based on the structure of the chalcone by molecular hybridization.The structures were characterized by 1H NMR, 13C NMR and HRMS.These derivatives were evaluated for their in vitro anti-tumor activity against a panel of human tumor cell lines (Hela, A549 and SGC7901) by the thiazolyl blue tetrazolium bromide (MTT) assay.The result indicated that compounds 3f, 3i and 3j were found to be the potent compounds against human tumor cell lines, which are to be lead compounds for further structural modifications and activity research.
With the aim of developing new potent anticancer agents, a series of novel 4'-(N-substitued-1-piperazinyl) chalcone derivatives 3a~3j have been designed and synthesized based on the structure of the chalcone by molecular hybridization.The structures were characterized by 1H NMR, 13C NMR and HRMS.These derivatives were evaluated for their in vitro anti-tumor activity against a panel of human tumor cell lines (Hela, A549 and SGC7901) by the thiazolyl blue tetrazolium bromide (MTT) assay.The result indicated that compounds 3f, 3i and 3j were found to be the potent compounds against human tumor cell lines, which are to be lead compounds for further structural modifications and activity research.
