H. Yamaguchi, F. Ishikawa
Jan 25, 1982
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Journal
Chemical & Pharmaceutical Bulletin
Abstract
Methylation of 2-chloro-3, 4, 5, 6, 7, 8-hexahydro [1] benzothieno [2, 3-d] pyrimidine (1) gave the 3-methyl derivative as a major product, but benzylation predominantly afforded the 1-substituted product. On the other hand, alkylation of 1 with an α-carbonylalkyl halide predominantly occurred at position 3. The 2-chloro-1-or 3-alkylated compounds were easily hydrolyzed to give the corresponding 1-alkyl-2 (1H)-or 3-alkyl-2 (1H)-one derivatives, which were readily oxidized to the corresponding 3, 4-or 1, 4-dehydrogenated compounds, respectively. The 2-chloro-3-substituted compounds were used for the synthesis of new heterocycles, imidazo [1, 2-a] thieno [2, 3-d] pyrimidine and 2, 3-dihydro-5H-oxazolo [3, 2-a] thieno [2, 3-d]-pyrimidine.