摘要:

At 95–115°, paraformaldehyde and hydriodic acid completelyC-methylate aromatics such as benzene and phenol. Pyrroles areC-methylated similarly, carbethoxy and acetyl groups being lost. In hydriodic acid at 15–45°, typical pyrroles retain these groups and all free positions areC-alkylated, methylated by paraformaldehyde, or otherwise alkylated by the appropriate carbonyl compound. The alkylation of a 2-free- by a 2-formylpyrrole led to a dipyrrylmethane. With pyrroles, hydriodic acid may be replaced by another strong acid and a reducing agent. This was necessary when a β-free pyrrole gave the iodo–alkyl derivative rather than the expected product.

ISSN:0008-4042    

DOI:10.1139/v68-545

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Secondary kinetic isotope effects on four deuterated 1-pyrazolines support the formation of a trimethylene intermediate during gas phase thermolysis. Calculation of cyclization relative rate constants for the trimethylene intermediates reveals that substitution of hydrogen by deuterium has no effect when the terminal methylenes are substituted, but the rate constants are decreased when the central methylene's hydrogens are substituted. Explanations are advanced for all of the observed effects.

ISSN:0008-4042    

DOI:10.1139/v68-546

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

The direct and photosensitized photolysis of six methylated-1-pyrazolines is described. Examination of the products suggests that direct photolysis leads to an excited singlet trimethylene, whereas a triplet is produced on benzophenone photosensitization. The trimethylene produced from4and5is related to the intermediates produced on addition of triplet methylenes tocis- andtrans-2-butene. Evidence is presented to support the claim that no intermediate is involved in the addition of singlet methylene tocis-andtrans-2-butene.

ISSN:0008-4042    

DOI:10.1139/v68-547

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

A series of dideuterated primary phenylalkyl chlorides 1-chloro-3-phenylpropane-2,2-d2(4), 1-chloro-3-phenylpropane-1,1-d2(9), 1-chloro-4-phenylbutane-2,2-d2(8), 1-chloro-5-phenylpentane-4,4-d2(5), 1-chloro-5-phenylpentane-3,3-d2(6), and 1-chloro-5-phenylpentane-2,2-d2(7) were synthesized by alkylations of malonic ester with phenylalkyl chlorides. Deuterium was introduced by exchange of the sodium salt of the alkylated malonic ester with D2O, followed by hydrolysis and decarboxylation. The resulting acids were reduced by hydride to primary alcohols and these were converted to the dideuterated primary chlorides by decomposition of the intermediate chlorosulfite esters. Nuclear magnetic resonance (n.m.r.) spectra confirmed the position of the deuterium in the chlorides. Friedel–Crafts cyclialkylation of the deuterated phenylpentyl chlorides yielded labelled 1-methyltetralins in which the label was located by n.m.r. and mass spectroscopy. The results demonstrated that rearrangement precedes cyclialkylation of 1-chloro-5-phenylpentane. Extensive deuterium scrambling between C-1, C-2, and C-3 accompanied the cyclialkylation of5but not that of8. Reaction mechanisms are suggested to account for these results.

ISSN:0008-4042    

DOI:10.1139/v68-548

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

A number of phenylalkyl chlorides were synthesized for a comparative study of Friedel–Crafts cyclialkylations and competing reactions involving hydride exchange. The synthetic work showed that phenylbutyl alcohols, especially a tertiary alcohol, may cyclize directly with chlorinating agents to yield tetralins. Cyclialkylation products from phenylpentyl chloride include 1-methyltetralin (4),n-pentylbenzene, 1-methyl-3,4-dihydronaphthalene, and methylnaphthalene. A reaction sequence is given involving dealkylation of4and hydride transfers. Phenylbutyl chloride yielded tetralin,n-butylbenzene, and naphthalene. 1-Chloro-4-methyl-4-phenylpentane yielded 1,1-dimethyltetralin (10), 2-methyl-5-phenylpentane (11), and a small amount of 2-methyl-2-phenylpentane (12). Hydrocarbon11formed from10after cyclialkylation, while12formed by hydride transfer preceding cyclization. Phenylpropyl chloride yielded mainly a hydride transfer product (propylbenzene) and not indane. Treatment of this chloride containing deuterium labels at C-1 and C-2 showed that the hydride ion rearranges from the carbon adjacent to the halogen. 1-Chloro-3-methyl-3-phenylbutane yielded a complex mixture includingt-pentylbenzene, 2-phenyl-3-methylbutane, and products of higher molecular weight.

ISSN:0008-4042    

DOI:10.1139/v68-549

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Carbethoxynitrene (1) generated thermally from ethyl azidoformate adds stereospecifically totrans- andcis-propenylbenzene. Ring-opening of the aziridines thus produced, proceeds with inversion at the phenyl-substituted carbon in dry acetic acid, while the reaction in aqueous acetic acid occurs with no stereospecificity.

ISSN:0008-4042    

DOI:10.1139/v68-550

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

The complete structures of the major components of the mixture of lactonic and acidic sophorosides of 17-L-hydroxyoctadecanoic acid, which is produced by a yeast of the genusTorulopsis, have been determined. The principal lactonic component (1) (41%) has acetate groups at the 6′- and 6″-positions and the fatty acid carboxyl group is linked to the 4″-position to form a macrocyclic lactone ring. The other lactonic component (2) (8%) differs from the first only in the absence of the acetate group at the 6′-position. The principal acidic component (5) (31%) also has acetate groups at the 6′- and 6″-positions but the fatty acid carboxyl group is free. The structures were deduced by a combination of glycol cleavage and nuclear magnetic resonance studies and by examination of the products of acetobrominolysis of the acetylated lactones and acid.The 2″,3″-glycol group of the lactones is resistant to oxidation by periodate and by lead tetraacetate in acetic acid. Studies of the rate of glycol cleavage of methyl 4,6-di-O-acyl-β-D-glucopyranosides showed that though an acyl group at C-4 retarded the oxidation of the 2,3-diol it did not stop it completely. The conformation of the lactone ring is probably responsible for the unreactivity of the 2″,3″-glycol group. The lactone ring, however, considerably increases the rate of acetobrominolysis of the fully acetylated lactone compared to that of the acetylated sophorosyl acid methyl ester.

ISSN:0008-4042    

DOI:10.1139/v68-551

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

D-Glucose,D-galactose, andD-mannuronic acid in equimolar proportions constitute 75% of the weight of the polysaccharide elaborated byArthrobacterviscosusNRRL B-1973.O-Acetyl groups account for the remaining 25% of the weight; 50% of the hydroxyl groups are acetylated. Acid hydrolysis of the polysaccharide revealed that theD-mannopyranosyluronic acid bonds hydrolyzed with unexpected ease. Controlled acid hydrolysis afforded three oligosaccharides identified as 4-O-β-D-glucopyranosyl-D-galactose; 4-O-β-D-mannopyranosyluronic acid-D-glucose; andO-β-D-mannopyranosyluronic acid-(1 → 4)-O-β-D-glucopyranosyl-(1 → 4)-D-galactose. The native polysaccharide was oxidized slowly by sodium metaperiodate and consumed 0.42 mole per sugar residue in 340 h at 4°. The deacetylated polysaccharide consumed 0.67 mole of periodate per sugar residue and produced 1 mole of acid per 160 to 165 sugar residues in 170 h at 4°. At 20° the deacetylated polysaccharide was oxidized excessively by periodate, 1.5 moles of oxidant was consumed, and 0.4 mole of acid was produced per sugar residue in 340 h. However, only 20% of the C4-substitutedD-glucose residues in the polysaccharide was cleaved by periodate in spite of the excessive oxidation at 20°.The polysaccharide has a linear structure and consists predominantly of repeating trisaccharide units,O-β-D-mannopyranosyluronic acid-(1 → 4)-O-β-D-glucopyranosyl-(1 → 4)-D-galactose.

ISSN:0008-4042    

DOI:10.1139/v68-552

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

not available

ISSN:0008-4042    

DOI:10.1139/v68-553

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

The mechanism of the Schmidt rearrangement has been examined in the conversion of chromanones to 1,4- and 1,5-benzoxazepinones. With substituents in the 6-, 7-, or 8-position, only electronic effects prevail resulting in the exclusive formation of 1,4-benzoxazepinones. Steric effects come into play with increasing bulk of substituents in the 5-position of the chromanone. Results now presented favor more than one pathway for the products to arise. Nuclear magnetic resonance spectra have been used to distinguish between the isomeric 1,4- and 1,5-benzoxazepinones.Several new chromanones have been synthesized.

ISSN:0008-4042    

DOI:10.1139/v68-554

出版商:NRC Research Press    

年代:1968

数据来源: NRC