Synthesis of 3-alkoxymethylcoumarin from 3-cyanochromene via a novel intermediate 2-phenylimino-3-alkoxymethylchromene.
In this paper a concise, efficient, and environmentally benign method for the synthesis of 3-alkoxymethylcoumarin is described. From the reaction of 3-cyanochromene with an alkoxide and arylamine in THF, (Z)-2-phenylimino-3-alkoxymethylchromene was obtained as a novel intermediate via an isomerization of the double bond, a 1,2-addition of alkoxide, a Michael-type addition of aniline, an another isomerization of double bond and an elimination of ammonia. Subsequently, the intermediate was converted into the desired coumarin by treatment with 15% HCl in THF in good yield.
Tsai
Jui-Chi
JC
Faculty of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung City 807, Taiwan.
Li
Sie-Rong
SR
Chiang
Michael Y
MY
Chen
Lian-Yeu
LY
Chen
Po-Yuan
PY
Lo
Yi-Fang
YF
Wang
Chen-Hao
CH
Lin
Chun-Nan
CN
Wang
Eng-Chi
EC
D001578:Benzopyrans / Q000737:chemistry*; D003374:Coumarins / Q000138:chemical synthesis* / Q000737:chemistry; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D015394:Molecular Structure; D013237:Stereoisomerism
D001578:Benzopyrans; D003374:Coumarins