Abstract
In the cyclization of acyl-β-phenethylamides (I) by the Bischler-Napieralski-Perkin method in the presence of metallic tin or zinc, it has been found that the presence of these metals, especially that of tin, gave better yields and a high purity in the formation of 3, 4-dihydroisoquinolines (II). The solvent of hydrocarbons of benzene series used for cyclization was supplemented by dioxane, tetraline and decaline, and experiments were conducted with N-anisoyl-β- (3, 4-methylenedioxyphenyl) -α-methylethylamide (I) and various acid amides (I), with and without the use of tin. Without the use of tin, dioxane was found to be an excellent solvent, the yield of isoquinoline derivatives (II) being large and the purity high. On the other hand, in the presence of the metal, benzene was fund to give the best result. The use of tetraline or decaline results in a poor yield.
