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Quino[1,2‐ c ]quinazolines. II. Synthesis of 12,13‐dihydro‐11 b H ‐quino‐[1,2‐ c ]quinazolines via the versatile intermediates 2‐(2‐amino‐4,5‐dimethoxyphenyl)‐6,7‐disubstituted‐1,2,3,4‐tetrahydroquinolines

1980; Wiley; Volume: 17; Issue: 8 Linguagem: Inglês

10.1002/jhet.5570170805

1943-5193

Steven Phillips, Raymond N. Castle,

Synthesis and Biological Evaluation

Abstract The versatile intermediates 2‐(2‐amino‐4,5‐dimethoxyphenyl)‐6,7‐dimethoxy‐1,2,3,4‐tetrahydroquinoline ( 2a ) and 6‐(2‐amino‐4,5‐dimethoxyphenyl)‐5,6,7,8‐tetrahydro[1,3]dioxolo[4,5‐ g ]quinoline ( 2b ) were used in the preparation of a wide variety of 12,13‐dihydro‐11 b H ‐quino[1,2‐ c ]quinazolines by reaction with triethyl orthoformate, cyanogen bromide, urea and carbon disulfide in pyridine. Reaction of the thio and keto products with methyl iodide and phosphorus oxychloride, respectively, gave the requisite methylthio and chloro derivatives. Novel Reissert type reactions occurred when the intermediates 2a,b were reacted with acetic anhydride or benzoyl chloride. The attempted dehydrogenation of 12,13‐dihydro‐2,3,9,10‐tetramethoxy‐11 b H ‐quino[1,2‐ c ]quinazoline ( 3a ) is also reported.