Synthesis of 2‐phenyl‐3,4‐dihydro‐2H‐ and ‐3,4,5,6‐tetrahydro‐2H‐1,6‐benzothiazocine derivatives

The resynthesis of 2-phenyl-3,4-dihydro-2H-benzothiazocin-5(6H)-one (1) was investigated in order to prepare derivatives with potential CNS activity. Lactam 1 could be converted to amidine derivatives 6a-e via the intermediacy of the thioether 5a. Reduction of 1 with lithium aluminum hydride gave amine 8a. Reductive alkylation of 8a gave 9a and 9b while acylation of 8a gave derivatives 10a-d. No interesting biological properties were found for these compounds.