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The experimental conditions for <jats:italic>trans<\/jats:italic>\u2010<jats:italic>cis<\/jats:italic>\u2010isomerization of the cinnamic\u2010acid derivative <jats:bold>3<\/jats:bold> and subsequent non\u2010enzymatic cyclization were described. The photoperiod and the presence of air and iron\u2010chelate catalyst are shown to be important parameters that markedly affect yields. The reactions probably occur by a free\u2010radical mechanism involving a photo\u2010initiated one\u2010electron redox process (<jats:italic>Scheme 2<\/jats:italic>).<\/jats:p>","DOI":"10.1002\/hlca.19920750409","type":"journal-article","created":{"date-parts":[[2004,12,26]],"date-time":"2004-12-26T23:11:48Z","timestamp":1104102708000},"page":"1061-1068","source":"Crossref","is-referenced-by-count":12,"title":["Synthesis of Coumarins and Derivatives. Part 1. Biomimetic synthesis of esculetin and halogenated derivatives"],"prefix":"10.1002","volume":"75","author":[{"given":"Fernanda","family":"Borges","sequence":"first","affiliation":[]},{"given":"Madalena","family":"Pinto","sequence":"additional","affiliation":[]}],"member":"311","published-online":{"date-parts":[[2004,10,25]]},"reference":[{"key":"e_1_2_1_2_2","doi-asserted-by":"publisher","DOI":"10.1007\/BF00594814"},{"key":"e_1_2_1_3_2","doi-asserted-by":"publisher","DOI":"10.1002\/anie.197904291"},{"key":"e_1_2_1_4_2","doi-asserted-by":"publisher","DOI":"10.1016\/0031-9422(91)85057-7"},{"key":"e_1_2_1_5_2","doi-asserted-by":"publisher","DOI":"10.1021\/ed066p781"},{"key":"e_1_2_1_6_2","doi-asserted-by":"publisher","DOI":"10.1002\/hlca.19860690118"},{"key":"e_1_2_1_7_2","first-page":"163","volume-title":"The Natural Coumarins \u2013 Occurrence, Chemistry, and Biochemistry","author":"Murray R. D. 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