摘要:

A comparison of the infrared spectra of natural 2-pyridone with that of the oxygen-18 labelled compound indicated modest shifts not only for the CO stretching mode (8.3−17.8 cm−1) for the various species in solution, but also for ring modes (0−13 cm−1) indicating a considerable mixing of the vibrations. The infrared spectrum of 2-pyridone at high concentrations revealed a new absorption band in chloroform solutions at 1685.0 and 1667.2 cm−1for the unlabelled and labelled compound, respectively. In addition, absorption at 1614.9 cm−1in the spectrum of 2-pyridone-18O in chloroform was found to be concentration dependent.

ISSN:0008-4042    

DOI:10.1139/v68-406

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Treatment ofD-lyxose with nitromethane in the presence of sodium methoxide gave 1-deoxy-1-nitro-D-galactitol which, after conversion to 2,3,4,5,6-penta-O-acetyl-1-deoxy-1-nitro-D-galactitol, reacted with saturated methanolic ammonia solution to yield 2-acetamido-1,2-dideoxy-1-nitro-D-talitol and 2-acetamido-1,2-dideoxy-1-nitro-D-galactitol. 2-Acetamido-1,2-dideoxy-1-nitro-D-talitol and 2-acetamido-1,2-dideoxy-1-nitro-D-galactitol were converted by a modified Nef reaction to 2-acetamido-2-deoxy-D-talose and 2-acetamido-2-deoxy-D-galactose which on hydrolysis with hydrochloric acid afforded 2-amino-2-deoxy-D-talose hydrochloride and 2-amino-2-deoxy-D-galactose hydrochloride. The properties and derivatives of the aminoglycoses are described.

ISSN:0008-4042    

DOI:10.1139/v68-407

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

The synthesis of ten new partially acylated derivatives of methyl β-D-glucopyranoside, all with an acyl group at C-6, is described. The nuclear magnetic resonance spectra of these compounds, and of a number of related derivatives, have been measured using pyridine, acetone-d6, and deuteriochloroform as solvents. When OH-4 is acylated, the H-6 signals are at higher field (by 0.1–0.3 p.p.m.) than when OH-4 is not acylated, but this effect is not observed when OH-3 is acylated. When a trimethylsilyl ether group is introduced at C-4 the difference between the chemical shifts of the H-6 protons (δA –δB) increases markedly. Estimation ofJBXandJAX(where B is the H-6 proton at higher field and X is H-5), from spectra obtained using acetone-d6and pyridine as solvents, shows thatJBX < JAXwhen there is an acyl group at C-4 butJBX > JAXwhen there is no acyl group at C-4.

ISSN:0008-4042    

DOI:10.1139/v68-408

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

The products from the reaction of 4-hydroxycoumarin with phosphorous oxychloride are the reported 4-chlorocoumarin and an additional compound of high molecular weight. This latter compound was characterized by substitution, degradation, and deuteration reactions as 4-chloro-3,4′;3′,4″-tercoumarin, a trimer corresponding to condensations between three coumarin molecules.

ISSN:0008-4042    

DOI:10.1139/v68-409

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

The mass spectra and the proton magnetic resonance spectra of tetrahydroprotoberberine alkaloids, oxygenated at the 9- and 10-positions, show marked differences from the spectra of those oxygenated at the 10- and 11-positions. These differences may be useful in structural studies on new members of this group of alkaloids.

ISSN:0008-4042    

DOI:10.1139/v68-410

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

It was shown that many silicon–carbon bonds were readily broken by lithium aluminium hydride in refluxing tetrahydrofuran. The rate of cleavage was dependent upon the nature of the leaving group and of the other groups present on the silicon. Carbon–tin bonds were cleaved more readily than carbon–silicon bonds while carbon–germanium bonds were not cleaved.

ISSN:0008-4042    

DOI:10.1139/v68-411

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

The reaction of methyl 2-O-acetyl-4,6-O-benzylidene-3-deoxy-3-nitro-β-D-glucopyranoside (1) or of methyl 4,6-O-benzylidene-2,3-dideoxy-3-nitro-β-D-erythro-hex-2-enopyranoside (2) with nitroalkanes led to branched-chain dinitro sugar derivatives, namely methyl 4,6-O-benzylidene-2,3-dideoxy-3-nitro-2-nitroalkyl-β-D-glucopyranosides (3). The nitroalkanes employed included nitromethane, nitroethane, 1-and 2-nitropropane, and methyl nitroacetate. The three first-mentioned nitroalkanes were added in similar fashion to methyl 4,6-O-benzylidene-2,3-dideoxy-3-nitro-β-D-threohex-2-enopyranoside (5) to give methyl 4,6-O-benzylidene-2,3-dideoxy-3-nitro-2-nitroalkyl-β-D-galactopyranosides (6). Analogous reactions of1and5with diethyl malonate produced the corresponding branched-chain glycosides7and8. The reactions appear to be highly stereoselective as far as the configurations at C-2 and C-3 in the products are concerned. However, there is evidence for the formation of side-chain epimers in three cases where the nitroalkyl side chain possesses an asymmetric carbon.

ISSN:0008-4042    

DOI:10.1139/v68-412

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Several substituted quinazolone hydrazides were synthesized to investigate their ability to inhibit rat liver mitochondrial monoamine oxidase. The monoamine oxidase activity was measured manometrically as oxygen uptake during oxidative deamination of tyramine. All quinazolone hydrazides, except 2-methyl-3-(3′-benzhydrazide)-4-quinazolone and 2-methyl-6,8-diiodo-3-(4′-phenylacetylhydrazide)-4-quinazolone, inhibited monoamine oxidase activity when used at a final concentration of 3 × 10−4 M. Substitution at position-6 or positions-6 and -8 of the quinazolone nucleus increased enzyme inhibitory power of quinazolone hydrazides. Monosubstituted quinazolone hydrazides exhibited maximum inhibitory effects while disubstitution resulted in a decrease in their ability to inhibit monoamine oxidase.

ISSN:0008-4042    

DOI:10.1139/v68-413

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

The fractionation of phlobaphenes from white spruce bark by column chromatography gave the non-crystalline stilbene glucosidetrans3,4′5-trihydroxy-3′-methoxystilbene-3-O-β-D-glucopyranoside (1). Purification was achieved through deacetylation of its hexaacetate (2). Compound1was cleaved with emulsin or dilute acid to the aglycone4, andD-glucose. The acetate, benzoate, and dihydro-derivatives of1, and the acetate, benzoate, methyl ether, and dihydro-derivatives of4were prepared. Oxidation of the benzoate derivative of1with chromic acid gave dibenzoyl-α-resorcylic acid. Similar oxidation of2gave acetylvanillic acid together with an uncharacterized acid which was hydrolyzed toD-glucose and β-resorcylic acid. The structure of1was therefore as shown, and its derivative2was synthesized. Vanillin was condensed with 3,5-dihydroxyphenylacetic acid and the product was decarboxylated and deacetylated. This compound was condensed with tetra-O-acetyl-α-D-glucopyranosyl bromide to yield a mixture of products which, after acetylation, were separated, using preparative thin-layer chromatography, to give the desired2.

ISSN:0008-4042    

DOI:10.1139/v68-414

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

An additivity scheme based on the changes in ortho, meta, and para proton coupling constants of benzene induced by a single substituent is applied to a number of trisubstituted benzenes. Ortho coupling constants are well reproduced (root mean square deviations = 0.05 c.p.s.) by the scheme but for meta and para couplings saturation effects are indicated. For the latter two couplings there are two substituents ortho to one of the protons involved. Measurements indicate that a temperature range of 100 °C has a negligible effect on the couplings but that polar solvents are to be avoided in obtaining data for the testing of additivity schemes.

ISSN:0008-4042    

DOI:10.1139/v68-415

出版商:NRC Research Press    

年代:1968

数据来源: NRC