抄録
The synthesis and sodium borohydride reduction of 4-chloro-(1) and 4-unsubstituted-(3) 5, 6, 7, 8-tetrahydro [1] benzothieno [2, 3-d] pyrimidines, substituted with various groups, such as chloro, hydrogen, methyl, phenyl, amino, ethoxy, methylthio, methylsulfinyl and mesyl, at position 2, are described. In the reduction of 1, the 2-chloro and 2-methyl-sulfinyl derivatives only gave the corresponding 3, 4-dihydro derivatives. The compounds 3, except for the 2-phenyl, 2-amino and 2-ethoxy derivatives, were reduced to give the corresponding 3, 4-dihydro derivatives. The reduction was promoted by the presence of an electron withdrawing group at position 2. A 2-or 4-mesyl group was eliminated in the course of the 3, 4-dihydrogenation.
