mode cyclization of the N-(2-ethynylphenyl)thioureas, which were easily obtained from the o-ethynylphenyl isothiocyanates and the primary amines, to provide the 2-imino-4-methylidene-1H-benzo[d][1,3]thiazines as the sole product in excellent yields. The secondary amines reacted with the o-ethynylphenyl isothiocyanates to give both the 6-exo and 5-endo-dig mode cyclization products under the same conditions
三氟甲磺酸银促进了N-(2-
乙炔基苯基)
硫脲的6-exo-dig模式环化反应,这是很容易从邻
乙炔基苯基异
硫氰酸酯和
伯胺获得的,从而提供了2-亚
氨基-4-亚甲基-1 H作为唯一产品的-苯并[ d ] [1,3]
噻嗪具有极好的收率。仲胺与邻
乙炔基苯基异
硫氰酸酯在相同条件下反应,生成6-exo和5-endo-dig模式环化产物。