SYNTHESIS OF COUMARINS AND DERIVATIVES .1. BIOMIMETIC SYNTHESIS OF ESCULETIN AND HALOGENATED DERIVATIVES

• Type: Article in International Scientific Journal
• Date: 1992

Authors

BORGES, F (Author) FFUP; PINTO, M (Author) FFUP

Journal

Title: Helvetica Chimica Acta

Vol. 75

ISSN: 0018-019X

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 9 Citations

Scopus - 12 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-001-Q1S

Abstract (EN): Esculetin (1) and the novel compounds 5-chloroesculetin (5) and 5-bromoesculetin (6) were obtained from a light-induced cyclization of trans-caffeic acid (3) catalyzed by [FeNa(edta)] and/or H2SO4, HCl, or HBr (Scheme 1). The experimental conditions for trans-cis-isomerization of the cinnamic-acid derivative 3 and subsequent nonenzymatic cyclization were described. The photoperiod and the presence of air and iron-chelate catalyst are shown to be important parameters that markedly affect yields. The reactions probably occur by a free-radical mechanism involving a photo-initiated one-electron redox process (Scheme 2).

Language: English

Type (Professor's evaluation): Scientific