Reduced graphene oxide as a recyclable catalyst for dehydrogenation of hydrazo compounds
摘要:
Reduced graphene oxide served as a reusable and efficient carbocatalyst for aerobic oxidative dehydrogenation of hydrazo compounds. Azo compounds were obtained in high yields under mild reaction conditions. (C) 2014 Elsevier Ltd. All rights reserved.
Reaction of 1-(4-benzyloxyphenyl)-2-phenylhydrazine with dimethyl acetylenedicarboxylate (DMAD) gave dimethyl 5-benzyloxyindole-2,3-dicarboxylate and dimethyl indole-2,3-dicarboxylate. However, treatment of 1-(2-bromophenyl)2-phenylhydrazine with DMAD afforded dimethyl 7-bromoindole-2,3-dicarboxylate, exclusively. In a similar manner, dimethyl 7-bromo-5-methoxyindole-2,3-dicarboxylate was also obtained from 1-(2-bromo-4-methoxyphenyl)-2phenylhydrazine. The bromo group of dimethyl 7-bromoindole-2,3-dicarboxylate was converted to an 1-ethoxyvinyl or vinyl group by treatment with tributyl-(1-ethoxyvinyl)tin or tributyl(vinyl)tin in the presence of a Pd(O) catalyst.