Improved Synthesis and Efficient Chemoselective Reduction of Fused Tetrazoles under Phase-Transfer Conditions

Abstract Liquid-liquid phase-transfer conditions were employed in an improved synthesis of 7,9-substituted 7H-pyrrolo[3,2-E]tetrazolo[1,5-C]pyrimidines and 5,7-substituted 4-amino-7H-pyrrolo[2,3-D]pyrimidines. The latter were obtained either by reductive ring cleavage of the former, or by one-pot synthesis from 5,7-substituted 4-chloro-7H-pyrrolo[2,3-D]pyrimidines.