Synthesis of Di- and Tri-Substituted Imidazole-4-carboxylates via PBu3-Mediated [3 + 2] Cycloaddition
摘要:
Some new di- and trisubstituted imidazole-4-carboxylates were prepared from amidoacetic acids 3 in the present report. The key step to establish such imidazole-4-carboxylates stemmed from the PBu3-mediated [3+2] cycloaddition between in situ-generated 2-oxazolinone 4 and ethyl cyanoformate6. Our results indicated that trisubstituted imidazoles 7-20 were afforded in better yields than those of disubstituted imidazoles 21-27. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications (R) to view the free supplemental file.