- The Effect of Ring-Size on the Anodic Oxidation of 'Cyclic Amides' in Methanol
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The anodic oxidation of three 'cyclic amides' of type N-acylazacycloalkanes [5- (I), 6- (II) and 7-membered (III) rings] has been studied in methanol under constant current electrolysis, at C anodes and in the presence of various supporting electrolytes, and different concentrations of substrates. Four major products were formed in good yields by all three substrates, namely N-acyl, α-azacycloalkenes, N-acyl, α-methoxyazacycloalkanes, N-acyl, α-methoxy, α'-azacycloalkenes and N-acyl, α,α′-dimethoxyazacycloalkanes. The relative ratios among products and selectivity were found to be highly dependent on the nature of the electrolyte used, and to a lesser extent on substrate concentration. In terms of ring-size effect it was found that the rate of oxidation and current efficiency (yield) was in the order: I > II > III. Also the latter two behaved similarly (but different from I) when various supporting electrolytes were used.
- Golub, Tatiana,Becker, James Y.
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p. 207 - 214
(2016/05/24)
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- Resolved pyrrolidine, piperidine, and perhydroazepine analogues of the muscarinic agent N-methyl-N-(1-methyl-4-pyrrolidino-2-butynyl)acetamide
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A series of conformationally restricted analogues of the partial muscarinic agonist N-methyl-N-(1-methyl-4-pyrrolidino-2-butynyl)acetamide (BM 5; 1) was synthesized. Three of the racemic derivatives were resolved into the enantiomers. The compounds were investigated for muscarinic and antimuscarinic activity in the isolated guinea pig ileum. They were found to be fairly potent muscarinic antagonists or weak partial agonists. The new compounds were either equally or less potent than 1 in inhibiting (-)-[3H]-N-methylscopolamine binding in homogenates of the rat cerebral cortex. Thus, structural modifications to 1 in which the amide moiety and the methyl group in the butynyl chain have been joined to form a six- or seven-membered ring preserve affinity but abolish efficacy. The R enantiomers were found to have 14-79 times higher affinity to ileal muscarinic receptors than the respective antipodes. The enantiomeric affinity ratios were nearly identical in both preparations studied. As suggested by molecular mechanics calculations, the difference in affinity between the five-membered and the six- and seven-membered ring analogues may be rationalized in conformational terms.
- Lundkvist,Vargas,Caldirola,Ringdahl,Hacksell
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p. 3182 - 3189
(2007/10/02)
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- Electro-organic Reactions. Part 23. Regioselectivity and the Stereochemistry of Anodic Methoxylation of N-Acylpiperidines and N-Acylmorpholines
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Anodic methoxylation of conformationally biassed N-acylpiperidines has been shown to give axial substitution due to steric constraints imposed by relatively slow rotation of the planar N-acyl groups.These steric constraints also account for the regioselec
- Palasz, Peter D.,Utley, James H. P.,Hardstone, J. David
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p. 807 - 814
(2007/10/02)
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- Electroorganic Chemistry. 60. Electroorganic Synthesis of Enamides and Enecarbamates and Their Utilization in Organic Synthesis.
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A variety of enecarbamates and enamides were synthesized from α-methoxy carbamates and α-methoxy amides prepared by anodic methoxylation of amine derivatives.Some new carbon-carbon bond-forming reactions and hydroxylation at the β position of amines have been accomplished by using these enecarbamates and enamides as key intermediates.Also, new synthetic routes of nicotinaldehyde and pyrrole derivatives have been exploited by utilizing anodic dimethoxylation of carbamates of piperidine and pyrrolidine, respectively.
- Shono, Tatsuya,Matsumura, Yoshihiro,Tsubata, Kenji,Sugihara, Yoshihiro,Yamane, Shin-ichiro,et. al.
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p. 6697 - 6703
(2007/10/02)
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