STUDIES ON THE CHEMISTRY OF THIENOANELLATED O,N-CONTAINING AND S,N-CONTAINING HETEROCYCLES .10. SYNTHESIS OF 2-SUBSTITUTED THIENO-DILTIAZEM DERIVATIVES

The syntheses of 2-acetyl-, 2-benzyl-, and 2-ethyl-thieno-diltiazem derivatives are described starting from the corresponding 5-substituted 3-nitro-2-thiophenthiol via reaction with racemic methyl trans-3-(4-methoxyphenyl)-glycidate under different conditions (solvent, catalyst, temperature) to obtain pure three or erythro products. The nitro groups of these products were reduced and the resulting amino esters cyclized. The thieno[2,3-b][1,4]thiazepin-5(4H)-ones were N-alkylated and acetylated in position 3. The desired 2-substituted 4-(2-dimethylaminoethyl)-4,5,6,7-tetrahyro-7-(4-methoxyphenyl)-5-oxothieno[2,3-b][1,4]thiazepin-6-yl acetates were isolated in good yields.