Stereoselective synthesis of the imidazole alkaloids (+)-pilocarpine and (+)-isopilocarpine. (Imidazole chemistry, Part IX)
作者:A. Noordam、L. Maat、H. C. Beyerman
DOI:10.1002/recl.19811001202
日期:——
A novel synthesis of (+)-pilocarpine (10a) is described. L-Histidine is converted into methyl (R)-2-bromo-3-(l-methyl-5-imidazolyl)propionate (5) in which the configuration has been inverted. Alkylation of dibenzyl ethylmalonate with 5 yields the imidazole compound 6, again with inversion. Finally, 6 is converted into a mixture of (+)-pilocarpine (10a) and (+)-isopilocarpine (10b), the separation of
Asymmetric Total Synthesis of <i>ent</i>-Cyclooroidin
作者:Sabuj Mukherjee、Rasapalli Sivappa、Muhammed Yousufuddin、Carl J. Lovely
DOI:10.1021/ol1020916
日期:2010.11.5
An enantiospecific total synthesis of the pyrrole-imidazole natural product cyclooroidin from histidine is described. The key N1-C9 bond is constructed through an intramolecular SN2-type of reaction of a chloro ester. Subsequent imidazole azidation at the 2-position, pyrrole bromination, azide reduction, and deprotection leads to the completion of the synthesis.