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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
Author(s) -
Phillips Steven D.,
Castle Raymond N.
Publication year - 1980
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570170805
Subject(s) - chemistry , triethyl orthoformate , acetic anhydride , carbon disulfide , quinazoline , methyl iodide , benzoyl chloride , thio , medicinal chemistry , quinoline , pyridine , phenacyl bromide , organic chemistry , catalysis
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.