CONVENIENT SYNTHESIS OF IMIDAZO[1,5- a ]PYRIMIDINE DERIVATIVES AND THEIR UNUSUAL RECYCLIZATION INTO 3 H -IMIDAZO[4,5- b ]PYRIDINE DERIVATIVES

Valery S. Tolkunov; Andrew S. Tolkunov; Olga V. Smirnova; Sergei V. Tolkunov

doi:10.1007/5988

CONVENIENT SYNTHESIS OF IMIDAZO[1,5-a]PYRIMIDINE DERIVATIVES AND THEIR UNUSUAL RECYCLIZATION INTO 3H-IMIDAZO[4,5-b]PYRIDINE DERIVATIVES

Valery S. Tolkunov, Andrew S. Tolkunov, Olga V. Smirnova, Sergei V. Tolkunov

Abstract

New derivatives of imidazo[1,5-a]pyrimidine have been synthesized by cyclization of in situ generated 1H-imidazol-4(5)-amine with 1,3-diketones or malondialdehyde derivatives. Utilization of asymmetrical 1,3-diketones leads to the formation of a mixture of regioisomers. The discovered conversion of imidazo[1,5-a]pyrimidine core into 3H-imidazo[4,5-b]pyridine that takes place only under acidic conditions can be considered as a new version of Dimroth rearrangement involving cleavage of C–N bond and formation of C–C bond.

Keywords

1,3-diketones, 1H-imidazol-4(5)-amine; imidazo[4,5-b]pyridines; imidazo[1,5-a]pyrimidines; trifluoroacetic acid; carbonylation; Dimroth rearrangement.

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Supplementary File(s): None

Latvian Institute of Organic Synthesis - Aizkraukles iela, 21, Riga, LV-1006, Latvia - hgs@osi.lv

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