4-Phenyl derivatives of spinaceamine and spinacine undergo mild catalytic hydrogenation under atmospheric pressure with cleavage of the C-4-N-5 bond to give 5-benzyl-substituted histamines and histidines. The process is likely to be facilitated by the double benzylic effect on the C-N bond of the imidazole and benzene rings.
4-Phenyl derivatives of spinaceamine and spinacine undergo mild catalytic hydrogenation under atmospheric pressure with cleavage of the C-4-N-5 bond to give 5-benzyl-substituted histamines and histidines. The process is likely to be facilitated by the double benzylic effect on the C-N bond of the imidazole and benzene rings.
An efficient two-step synthesis of 4(5)-benzyl-L-histidine from L-histidine was developed. A Pictet-Spengler reaction between L-histidine and benzaldehyde in the presence of excess strong base yielded 4-L-phenylspinacine within one hour. Catalytic transfer hydrogenolysis in methanol at reflux using ammonium formate rapidly converted 4-L-phenylspinacine to 4(5)-benzyl-L-histidine within five minutes. No racemization of the final product 4(5)-benzyl-L-histidine was observed using the Marfey reagent. To show the utility of this method, a series of fluorinated benzylhistidines were prepared.
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作者:Yu. M. Yutilov、M. G. Abramyants、N. N. Smolyar
DOI:10.1023/a:1012346021943
日期:——
4-Phenyl derivatives of spinaceamine and spinacine undergo mild catalytic hydrogenation under atmospheric pressure with cleavage of the C-4-N-5 bond to give 5-benzyl-substituted histamines and histidines. The process is likely to be facilitated by the double benzylic effect on the C-N bond of the imidazole and benzene rings.