摘要:

The configuration of the Diels–Alder adduct (I) of furan and acetylene dicarboxylic acid was established by chemical and spectroscopic methods and found to beexo–exo(IIa).

ISSN:0008-4042    

DOI:10.1139/v66-185

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

The formation of 3-oxo-3,4-dihydro-2H-1,4-benzothiazine (IIIa) by cyclization of alkyl 2-haloacetamidophenyl sulfides (I) was investigated; it is proposed that the reaction proceeds via a six-membered sulfonium halide. The preparation of 4-alkyl derivatives of IIIaand of 4-alkyl and 4-acyl derivatives of its reduction product 3,4-dihydro-2H-1,4-benzothiazine (Va) is described. Acylation of Vawas shown to proceed without opening of the thiazine ring. Preparation of the O-benzoyl, N-benzoyl, and O,N-dibenzoyl derivatives of 2-(β-hydroxyethyl-mercapto)aniline (VIII) has permitted clarification of the confusion in the literature with respect to the derivatives of Vaand VIII. Compound XVIII, the 1,1-dioxide of IIIa, undergoes C-alkylation at the 2-position when treated with alkyl halides, rather than O-alkylation as previously suggested.

ISSN:0008-4042    

DOI:10.1139/v66-186

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

A very small amount of a new alkaloid, eschscholtzidine, present inE.californica, was shown to be eschscholtzine in which a methylenedioxy group is replaced by two methoxyls.

ISSN:0008-4042    

DOI:10.1139/v66-187

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Ionization constants at 25 °C have been determined by a spectrophotometric method for 17 substituted salicylic acids. These have been fitted to the simple Hammett relationship and to the extended one proposed by Jaffe, which takes into account the transmission of substituent effects by theo-hydroxy group. The results with Jaffe's equation show that substituent effects on acidity are transmitted only slightly, if at all, through the intramolecular hydrogen bond of a chelate ring. Possible interpretations of the results are discussed.

ISSN:0008-4042    

DOI:10.1139/v66-188

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

α-(9-Fluorenylidene) malononitrile (V) is obtained by the interaction of malononitrile and 9,9-(tetrachloro-o-phenylenedioxy) fluorene (II) in boilingn-butanol. Whereas fluorenone phenyl- or benzoyl-hydrazone is similarly obtained by the action of the corresponding hydrazine on II, the latter also undergoes reductive cleavage by hydrazine hydrate to give fluorene and tetrachlorocatechol. The heteropolar structures of methylene ethers are stressed.Methyl-, ethyl-, isopropyl-, and benzyl-magnesium halides react readily with V to give the 9-dicyanomethyl-9-alkylfluorenes (VIIb–VIIe), respectively, which give, upon oxidation with alkaline potassium permanganate, the corresponding 9-alkylfluorene-9-carboxylic acids.α-(9-Xanthenylidene) malononitrile (VIa) reacts similarly with alkylmagnesium halides to give the corresponding 9-xanthenylmalononitriles (VIIIb–VIIId). However, V and VI are reduced by isobutylmagnesium iodide to give 9-fluorenyl- (VIIa) and 9-xanthenyl-malononitrile (VIIIa), respectively.Whereas the infrared spectra of unsaturated malononitriles and cyanoesters show strong absorption in the 4.5 μ region, the spectra of the saturated analogues lack this absorption.

ISSN:0008-4042    

DOI:10.1139/v66-189

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Fractions of sunflower pectic acid containing 89.8%, 94.2%, and 91.4% ofD-galacturonic acid were carboxyl reduced as their methyl or ethylene glycol esters by potassium borohydride. Critical assessment of the effects of three different solvents (water, 80% aqueous dimethyl sulfoxide, and 80% aqueous methanol) on the efficiency of reduction showed that the latter solvent was best. The reductions caused a decrease in the degree of polymerization from 270 to 21. Measurement of the rates of hydrolysis of partially reduced pectic acids containing 90%, 41.6%, 19.9%, 11.0%, and 0.65% ofD-galacturonic acid showed that the rate of hydrolysis was directly related to the proportion of galacturonosidic linkages present. Methylation and hydrolysis of the carboxyl-reduced pectic acid fractions yielded 2,3,4,6-tetra-O-methyl-D-galactose and 2,3,6-tri-O-methyl-D-galactose in an approximate molar ratio of 1:20. Results of the periodate oxidation of the carboxyl-reduced pectic acid supported the conclusion inferred from the methylation results that the pectic acid was a linear polymer of 1 → 4 linked α-D-galacturonic acid units.

ISSN:0008-4042    

DOI:10.1139/v66-190

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Previously, reagents such as sodium borohydride – boron trifluoride were shown to be capable of reducing typical aliphatic esters and lactones to the corresponding ether derivatives. Under the same reaction conditions, a variety of benzoate esters (Ib, IIb, III, and V) were essentially unaffected. Resistance to attack was illustrated by conversion, with sodium borohydride – boron trifluoride, of 3-oxo-17β-benzoyloxy-5α-androstane (III) into 3β-hydroxy-17β-benzoyloxy-5α-androstane (IV) and of reserpine (V) into alcohol VI. With aryl–carbon–oxygen bonds of the ketone VII or alcohol IXatype, reaction with sodium borohydride– boron trifluoride was shown, in general, to cause reductive fission of the benzyl–oxygen linkage (e.g. X → XI). An exception was noted in the case of tertiary benzyl alcohols containing an available β-hydrogen (e.g. IXc). Here, dehydration to yield, for example, olefin XIIbappears to be the more favorable reaction course. The marked difference in the reactivity of sodium borohydride – boron trifluoride toward benzoyl–oxygen vs. benzyl–oxygen bonds has been demonstrated.

ISSN:0008-4042    

DOI:10.1139/v66-191

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Direct reduction of several pivalate esters to neopentyl ethers has been accomplished with boron trifluoride – sodium borohydride. The utility of the reduction reaction was illustrated with esters Ic, IIb, and IVa. Under the same conditions, a selection (Id, IId, and IVa) of carbonate esters was found to be relatively resistant to reduction. In this respect, the carbonate esters resembled benzoate esters, and selective reduction of a ketone (IId) or another ester (IVa → IVb) in their presence was possible. For comparison, one xanthate ester (Ie) was allowed to react with boron trifluoride – sodium borohydride, and only the corresponding alcohol (Ia) was isolated. Raney nickel desulfurization of xanthate Iawas shown to provide alcohol Iaand hydrocarbon Ifas principal products.

ISSN:0008-4042    

DOI:10.1139/v66-192

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

The configurations at the 3 positions of 3β-hydroxy-4-oxa-5α-estrane and of 3α, 17β-dihydroxy-4-oxa-5α-estrane were assigned from a study of the anomerizations of these compounds in aqueous tetrahydrofuran. 3α-Chloro-4-oxa-5α-estrane solvolyzed in alkaline methanol to give a mixture of 3α- and 3β-methoxy-4-oxa-5α-estrane, the former predominating. The difference in the solvolytic behavior of 3α-chloro-4-oxa-5α-steroids and of α-glycosyl halides is discussed.

ISSN:0008-4042    

DOI:10.1139/v66-193

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

The influence of the acidity of the solvent on the proportions of axial and equatorial alcohols obtained by hydrogenation of some steroidal ketones was investigated.

ISSN:0008-4042    

DOI:10.1139/v66-194

出版商:NRC Research Press    

年代:1966

数据来源: NRC