Download PDF
Synthesis 2002(1): 0121-0125
DOI: 10.1055/s-2002-19309
PAPER
© Georg Thieme Verlag Stuttgart · New York

Synthesis of Bioactive Heterocycles: Aza-Claisen Rearrangement of 4-N-(4"-Aryloxybut-2"-ynyl),N- methylamino[1]benzothiopyran-2-ones

K. C. Majumdar*, S. K. Samanta
Department of Chemistry, University of Kalyani, Kalyani-741 235, India
e-Mail: kcm@klyuniv.ernet.in;
Further Information

Publication History

Received 20 July 2001
Publication Date:
04 August 2004 (online)

    Permissions and Reprints All articles of this category

Abstract

The hitherto unreported 4-(aryloxymethylene-1-methyl-1,2,3-trihydropyrido[3,2-c]benzothiopyran-5-ones are synthesized in 60-90% yield by the thermal aza-Claisen rearrangement of 4-N-(4"-aryloxybut-2"-ynyl),N-methylamino[1]benzothiopyran-2-ones in refluxing 1,2-dichlorobenzene. 4-N-(4"-Aryloxybut-2"-ynyl),N-methylamino[1]benzothiopyran-2-ones were prepared in 80-90% yields by the reaction of 4-chloro[1]benzothiopyan-2-one and appropriate 1-aryloxy-N-methylaminobut-2-ynes in refluxing ethanol. 4-Chloro[1]benzothiopyran-2-ones was in turn synthesised from 4-hydroxythiocoumarin by reaction with phosphorous oxychloride at 140 °C.

Key words

aza-Claisen rearrangement - sigmatropic rearrangement - heterocycles - pyrido[3,2-c][1]benzothiopyran-5-ones - 4-chlorothiocoumarin - 4-hydroxythiocoumarin