Login In
1998 Volume 9 Issue 1
1998, 9(1): 1-4
Abstract:
Under microwave irradiation, boron trifluoride has been found to mediate a novel condensation reaction of alkyl aryl ketone with ethyl ortho-formate to give a series of new condensa-tion products (5,6,7,8). Their structures were determined by IR, 1H-/13C-NMR, MS spectra, and the crystal structure of 8 was further defined by X-ray diffraction.
Under microwave irradiation, boron trifluoride has been found to mediate a novel condensation reaction of alkyl aryl ketone with ethyl ortho-formate to give a series of new condensa-tion products (5,6,7,8). Their structures were determined by IR, 1H-/13C-NMR, MS spectra, and the crystal structure of 8 was further defined by X-ray diffraction.
1998, 9(1): 5-6
Abstract:
In the presence of chlorotrimethylsilane, zinc-mediated addition of bromoacetonitrile to aldimines gives β-aminonitriles in THF with good yields.
In the presence of chlorotrimethylsilane, zinc-mediated addition of bromoacetonitrile to aldimines gives β-aminonitriles in THF with good yields.
1998, 9(1): 7-9
Abstract:
Aromatic ethers were conveniently brominated with quaternary ammonium bromide and iodosylbenzene in glacial acetic acid under mild conditions to give the corresponding monobromo-aromatic ethers in nearly quantitative yields.
Aromatic ethers were conveniently brominated with quaternary ammonium bromide and iodosylbenzene in glacial acetic acid under mild conditions to give the corresponding monobromo-aromatic ethers in nearly quantitative yields.
1998, 9(1): 10-12
Abstract:
A simple and direct method for preparation of N-substituted spirocyclic diester of □-amino phosphonic acid (4) in high yield is introduced. The reaction consists of the three-component reaction of phenylurea (1), an aromatic aldehyde (2), and 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5] undecane (3) in anhydrous benzene.
A simple and direct method for preparation of N-substituted spirocyclic diester of □-amino phosphonic acid (4) in high yield is introduced. The reaction consists of the three-component reaction of phenylurea (1), an aromatic aldehyde (2), and 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5] undecane (3) in anhydrous benzene.
1998, 9(1): 13-16
Abstract:
Mono 3-deoxy-(N'-benzoyl-ethylenediamino)-P-CD, mono 3-deoxy-(N'-benzimidoy 1-ethylamino)-β-CD, and mono S-deoxy-(N'-salicylidene-ethylenediamino)-β-CD, each of which has a flexible chain that bonds the aryl moiety on the secondary side of β-CD, were prepared in this research. The reaction processes might involve the formation of mono(2,3-manno-epoxide)-p-CD as an intermediate in our reaction conditions.
Mono 3-deoxy-(N'-benzoyl-ethylenediamino)-P-CD, mono 3-deoxy-(N'-benzimidoy 1-ethylamino)-β-CD, and mono S-deoxy-(N'-salicylidene-ethylenediamino)-β-CD, each of which has a flexible chain that bonds the aryl moiety on the secondary side of β-CD, were prepared in this research. The reaction processes might involve the formation of mono(2,3-manno-epoxide)-p-CD as an intermediate in our reaction conditions.
1998, 9(1): 17-20
Abstract:
Two types of N-phenyl and N,N'-diphenyl azathiacrowii ether analogs, which contain two sulfur atoms, one or two oxygen atoms, and one or two nitrogen atoms, were synthesized by the reaction of an appropriate halide with a corresponding a,ω-dithiol. They were further deter-mined by IR, 1HNMR, and MS.
Two types of N-phenyl and N,N'-diphenyl azathiacrowii ether analogs, which contain two sulfur atoms, one or two oxygen atoms, and one or two nitrogen atoms, were synthesized by the reaction of an appropriate halide with a corresponding a,ω-dithiol. They were further deter-mined by IR, 1HNMR, and MS.
1998, 9(1): 21-22
Abstract:
Under esterification conditions, 2-(1,2-ethylenedithio) methylene-3-oxo-5-aryl-4-pentenoic acid 3 afforded the decarboxylated products 4. The triphenyltin 2-(1, 2-ethylenedithio) methylene-3-oxo-5-aryl-4-pentenoates 5 were obtained in high yields when 3 reacted with triphenyltin hydroxide.
Under esterification conditions, 2-(1,2-ethylenedithio) methylene-3-oxo-5-aryl-4-pentenoic acid 3 afforded the decarboxylated products 4. The triphenyltin 2-(1, 2-ethylenedithio) methylene-3-oxo-5-aryl-4-pentenoates 5 were obtained in high yields when 3 reacted with triphenyltin hydroxide.
1998, 9(1): 23-24
Abstract:
The synthesis of carboxymethyl cellulose (CMC)-multipeptide conjugate is reported in the present paper. This new type of peptide-polymer surrogate possesses some merits, such as ease of synthesis, high density of peptide, and the possibility of increased bioavailability, and seems to have promising uses in drug development.
The synthesis of carboxymethyl cellulose (CMC)-multipeptide conjugate is reported in the present paper. This new type of peptide-polymer surrogate possesses some merits, such as ease of synthesis, high density of peptide, and the possibility of increased bioavailability, and seems to have promising uses in drug development.
1998, 9(1): 25-27
Abstract:
Phenylthiotrimethylsilane is reduced by samarium diiodide to yield samarium phenylthiolate. This new thiolate anion species reacts with acyl chlorides mildly to give thiolesters in good yields.
Phenylthiotrimethylsilane is reduced by samarium diiodide to yield samarium phenylthiolate. This new thiolate anion species reacts with acyl chlorides mildly to give thiolesters in good yields.
1998, 9(1): 29-33
Abstract:
Two rearranged products, dienone 4 and 10-oxo product 5 were obtained upon at-tempted 10p-OSO2CF3 formation from 3. The formation of compound 5 can be explained by an-chimeric assistance of 7α-OH. Reduction of 4 yielding a 4-deacetyl product (12) also involves neighboring group participation.
Two rearranged products, dienone 4 and 10-oxo product 5 were obtained upon at-tempted 10p-OSO2CF3 formation from 3. The formation of compound 5 can be explained by an-chimeric assistance of 7α-OH. Reduction of 4 yielding a 4-deacetyl product (12) also involves neighboring group participation.
1998, 9(1): 35-38
Abstract:
A chiral synthesis of the C11-16+C27 segment of epothilone A is described using inex-pensive L-(-)-malic acid as starting materinal and using Sharpless asymmetric epoxidation for in-troduction of the desired 12,13 epoxide.
A chiral synthesis of the C11-16+C27 segment of epothilone A is described using inex-pensive L-(-)-malic acid as starting materinal and using Sharpless asymmetric epoxidation for in-troduction of the desired 12,13 epoxide.
1998, 9(1): 39-43
Abstract:
Microbial transformation of taxoids was investigated:taxoid 2 was transformed into 1β and 14β hydroxylated derivatives 3 and 4; unnatural taxoid 6 was transformed into 1β-hydroxy derivative 7 and 11(15→1) abeotaxane 8. Taxoids with an oxetane ring, 11-13 were synthesized from 1 via chemical reactions.
Microbial transformation of taxoids was investigated:taxoid 2 was transformed into 1β and 14β hydroxylated derivatives 3 and 4; unnatural taxoid 6 was transformed into 1β-hydroxy derivative 7 and 11(15→1) abeotaxane 8. Taxoids with an oxetane ring, 11-13 were synthesized from 1 via chemical reactions.
1998, 9(1): 45-49
Abstract:
Two new taxane diterpenoids, 2-deacetoxy-7,9-dideacetyltaxinine J (1) and 2-deacetoxy-taxinine B (3), were isolated from the barks of Taxus chinensis. Their structures were elucidated by spectroscopic methods.
Two new taxane diterpenoids, 2-deacetoxy-7,9-dideacetyltaxinine J (1) and 2-deacetoxy-taxinine B (3), were isolated from the barks of Taxus chinensis. Their structures were elucidated by spectroscopic methods.
1998, 9(1): 51-55
Abstract:
Three new compounds, suspenolic acid (1),forsythenside A (2),and forsythenside B (3) have been isolated from the fruits of Forsythia suspensa. Their structures were elucidated by spectral methods including IR, 1H-and 13C-NMR, DEPT, 1H-1H COSY, 1H-13C COSY, NOE difference, HMBC, FABMS, CIMS, and chemical reactions.
Three new compounds, suspenolic acid (1),forsythenside A (2),and forsythenside B (3) have been isolated from the fruits of Forsythia suspensa. Their structures were elucidated by spectral methods including IR, 1H-and 13C-NMR, DEPT, 1H-1H COSY, 1H-13C COSY, NOE difference, HMBC, FABMS, CIMS, and chemical reactions.
1998, 9(1): 57-59
Abstract:
Two new norditerpenoid alkaloids, souline A and souline B, were isolated from Delphinium souliei Franch, and their structures were elucidated by spectroscopic methods.
Two new norditerpenoid alkaloids, souline A and souline B, were isolated from Delphinium souliei Franch, and their structures were elucidated by spectroscopic methods.
1998, 9(1): 61-64
Abstract:
Four new eremophilane type sesquiterpenes were isolated from the roots of Cacalia roborowskii (Maxim) Ling. Their structures were established as 8-oxo-eremophila-6, 9-dien-12-oic acid (1), 3β-acetoxyl-8-oxo-eremophila-6, 9-dien-12-oic acid (2), 3β-aiigeloyoxyl-8-oxo-eremophila-6, 9-dien-12-oic acid (3) and 3β-(2-methylbutyryloxyl)-8-oxo-eremophila-6, 9-dien-12-oic acid (4) by means of ID and 2D NMR spectroscopy.
Four new eremophilane type sesquiterpenes were isolated from the roots of Cacalia roborowskii (Maxim) Ling. Their structures were established as 8-oxo-eremophila-6, 9-dien-12-oic acid (1), 3β-acetoxyl-8-oxo-eremophila-6, 9-dien-12-oic acid (2), 3β-aiigeloyoxyl-8-oxo-eremophila-6, 9-dien-12-oic acid (3) and 3β-(2-methylbutyryloxyl)-8-oxo-eremophila-6, 9-dien-12-oic acid (4) by means of ID and 2D NMR spectroscopy.
1998, 9(1): 65-68
Abstract:
From the extracts of the roots of Cacalia roborowskii (Maxim) Ling, five new eremo-philenolides were isolated and their structures identified as 8β, 10β-dihydroxy-6β-methoxyleremophilenolide (1), 3β-acetoxyl-8β, 10β-dihydroxy-6p-methoxyeremophilenolide (2), 3β-angeloyloxy-8β-, 10β-dihydroxy-6p-methoxyeremophilenolide (3), 3β-(2-methylbutyryloxy)-8β, 10β-dihydroxy-6β-methoxyeremophilenolide (4), and 8β-hydroxy-6β-methoxyeremophil-7(11), 9-dien-8, 12-olide (5), based on ID and 2D NMR experiments.
From the extracts of the roots of Cacalia roborowskii (Maxim) Ling, five new eremo-philenolides were isolated and their structures identified as 8β, 10β-dihydroxy-6β-methoxyleremophilenolide (1), 3β-acetoxyl-8β, 10β-dihydroxy-6p-methoxyeremophilenolide (2), 3β-angeloyloxy-8β-, 10β-dihydroxy-6p-methoxyeremophilenolide (3), 3β-(2-methylbutyryloxy)-8β, 10β-dihydroxy-6β-methoxyeremophilenolide (4), and 8β-hydroxy-6β-methoxyeremophil-7(11), 9-dien-8, 12-olide (5), based on ID and 2D NMR experiments.
1998, 9(1): 69-70
Abstract:
A new chromone glycoside, saikochromoside A(1), was isolated from the roots of Bupleurum chinense DC. Its structure was determined on the bases of chemical and spectral analyses.
A new chromone glycoside, saikochromoside A(1), was isolated from the roots of Bupleurum chinense DC. Its structure was determined on the bases of chemical and spectral analyses.
1998, 9(1): 71-73
Abstract:
A new isoflavonoside, 7-hydroxy-4'-methoxy-isoflavonone-7-0-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside was isolated from roots of Bupleurum scorzonerifolium Willd., and named as saikoisoflavonoside A. The structure was determined by spectroscopic methods.
A new isoflavonoside, 7-hydroxy-4'-methoxy-isoflavonone-7-0-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside was isolated from roots of Bupleurum scorzonerifolium Willd., and named as saikoisoflavonoside A. The structure was determined by spectroscopic methods.
1998, 9(1): 75-77
Abstract:
A series of soluble poly(p-phenylene vinylene) (PPV) derivatives were synthesized through dehydrochlorination with the p-methoxy phenol as starting materials. The electronic characteristics of PPV derivatives were studied.
A series of soluble poly(p-phenylene vinylene) (PPV) derivatives were synthesized through dehydrochlorination with the p-methoxy phenol as starting materials. The electronic characteristics of PPV derivatives were studied.
1998, 9(1): 79-81
Abstract:
Appling the dehydrochlorination reaction, the copolymerization of 1, 4-bis(chloromethyl)-2, 5-dimethyl benzene and 1,4-bis(chloromethyl)-2-methoxy-5-hexyloxyl benzene was studied. The solubility of the copolymer was determined by the structure and molar ratio of two monomers. The structure of the copolymer was identified by UV, IR, and 1H NMR analyses.
Appling the dehydrochlorination reaction, the copolymerization of 1, 4-bis(chloromethyl)-2, 5-dimethyl benzene and 1,4-bis(chloromethyl)-2-methoxy-5-hexyloxyl benzene was studied. The solubility of the copolymer was determined by the structure and molar ratio of two monomers. The structure of the copolymer was identified by UV, IR, and 1H NMR analyses.
1998, 9(1): 83-85
Abstract:
The effects of adding Al(i-C4H9)3 (TEA) to rac-Me2Si(Ind)2ZrCl2/MAO catalyzed propylene-1-octene copolymerization were studied. At TBA/MAO(Al/Al mole ratio) of about 0.6, the polymerization activity was found to be much higher than the system without TBA. In-creases of polymer molecular weight and 1-octene content from addition of TBA were also ob-served.
The effects of adding Al(i-C4H9)3 (TEA) to rac-Me2Si(Ind)2ZrCl2/MAO catalyzed propylene-1-octene copolymerization were studied. At TBA/MAO(Al/Al mole ratio) of about 0.6, the polymerization activity was found to be much higher than the system without TBA. In-creases of polymer molecular weight and 1-octene content from addition of TBA were also ob-served.
1998, 9(1): 87-91
Abstract:
It was shown that in capillary electrophoresis (CE) the addition of boric acid as a complexing agent in phosphate buffer can modulate the separation selectivity of phenolic acids.
It was shown that in capillary electrophoresis (CE) the addition of boric acid as a complexing agent in phosphate buffer can modulate the separation selectivity of phenolic acids.
1998, 9(1): 93-97
Abstract:
It is reported that two kinds of specific mass spectrometric fragmentations are generated from dissociations of the intermediates of both the ion-neutral complex and the proton-bound complex. Collision-induced dissociation, isotopic labelling, and semi-empirical AMI calculations were used to investigate the formation mechanism of the ion of m/z 139 from ionized tetrahydroimi-dazole-substituted methylene β-diketones and the unimolecular fragmentations pathway of 3-phenyl-1-butyn-3-ol upon electron impact.
It is reported that two kinds of specific mass spectrometric fragmentations are generated from dissociations of the intermediates of both the ion-neutral complex and the proton-bound complex. Collision-induced dissociation, isotopic labelling, and semi-empirical AMI calculations were used to investigate the formation mechanism of the ion of m/z 139 from ionized tetrahydroimi-dazole-substituted methylene β-diketones and the unimolecular fragmentations pathway of 3-phenyl-1-butyn-3-ol upon electron impact.
1998, 9(1): 99-101
Abstract:
The electrochemical properties of a new derivative of C60 were investigated by cyclic voltammetry. It was found that the derivative was reduced at a more positive potential than C60, reflecting its significance to accept electron easily. Its NIR characteristic absorption bands of monoanion and dianion were also obtained.
The electrochemical properties of a new derivative of C60 were investigated by cyclic voltammetry. It was found that the derivative was reduced at a more positive potential than C60, reflecting its significance to accept electron easily. Its NIR characteristic absorption bands of monoanion and dianion were also obtained.
1998, 9(1): 103-106
Abstract:
In the present paper, the electrochemical behavior of ergosterol has been investigated by in situ circular dichroism (CD) spectroelectrochemistry with long path-length thin layer cell. E0(1.02V), αnα(0.302) of the electroxidation process of ergosterol were obtained from the CD spec-troelectrochemical data. The mechanism of the electroxidation process of ergosterol is suggested.
In the present paper, the electrochemical behavior of ergosterol has been investigated by in situ circular dichroism (CD) spectroelectrochemistry with long path-length thin layer cell. E0(1.02V), αnα(0.302) of the electroxidation process of ergosterol were obtained from the CD spec-troelectrochemical data. The mechanism of the electroxidation process of ergosterol is suggested.
1998, 9(1): 107-110
Abstract:
In this paper, direct photooxidation of benzothiazolone cyanine dye in acetonitrile was studied. The photoproducts had been identified by 1HNMR and fast atom bombardment (FAB) mass spectrometry. The results showed that the N-ethylbeiizothiazolone (Ⅰ), the ionic acid (Ⅱ), and ionic aldehyde (Ⅲ) are the principal photoproducts.
In this paper, direct photooxidation of benzothiazolone cyanine dye in acetonitrile was studied. The photoproducts had been identified by 1HNMR and fast atom bombardment (FAB) mass spectrometry. The results showed that the N-ethylbeiizothiazolone (Ⅰ), the ionic acid (Ⅱ), and ionic aldehyde (Ⅲ) are the principal photoproducts.
1998, 9(1): 111-112
Abstract:
The first reported X-ray crystal structure of a new (2:2) macrocyclic thiocarbohydrazone, effectively derived from thiocarbohydrazide and di(2-formylphenoxy)ethylene is shown.
The first reported X-ray crystal structure of a new (2:2) macrocyclic thiocarbohydrazone, effectively derived from thiocarbohydrazide and di(2-formylphenoxy)ethylene is shown.
