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The reactions of ethyl 3,4‐dihydro‐4‐quinazolylacetate and its derivatives with cyclopentanone. An attempt at the synthesis of the 6,8‐diazasteroid system VII
Author(s) -
Yamazaki Takao,
Matoba Katsuhide,
Shirokawa Atsuko,
Castle Raymond N.
Publication year - 1978
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.5570150319
Subject(s) - cyclopentanone , chemistry , yield (engineering) , trifluoroacetic anhydride , trifluoroacetic acid , decomposition , ethyl ester , organic chemistry , thermal decomposition , medicinal chemistry , catalysis , metallurgy , materials science
The reaction of ethyl 3,4‐dihydro‐4‐quinazolylacetate ( 1a ) with cyclopentanone in the presence of trifluoroacetic acid gave mainly two decomposition products, carbostyril (VIII) and ethyl 2‐aminocinnamate (IX). Two compounds which are suggested to have the 6,8‐diazasteroid skeleton were also obtained in poor yield. Ethyl 3,4‐dihydro‐2‐ p ‐methoxyphenyl‐4‐quinazolylacetate (1b), however, gave 2‐ p ‐methoxyphenylquinazoline (XII) as a decomposition product and did not condense with cyclopentanone. Furthermore, two ethyl 3,4‐dihydroquinazolylacetates substituted at the 2‐position with cyclohexyl (1c) and methyl (1d) groups could not be converted to the expected diazasteroid system.