ChemInform Abstract: STUDIES IN 4‐PHENYLCOUMARINS, SOME UNUSUAL OBSERVATIONS

Ahluwalia, V. K.; Kumar, Devendra; Sunita, Sunita

doi:10.1002/chin.197537232

Cited by 1 publication

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“…It was reported that 5,7-diacetoxy-4-phenylcoumarin underwent Fries rearrangement to form 6,8-diacetyl-5,7-dihydroxy-4-phenylcoumarin. 48 The same was observed for the 5,7-diester 10. In refluxing triglyme, 5,7-diester 10 was decomposed into the starting coumarin in the presence of AlCl 3 .…”

Section: Chemistrysupporting

confidence: 58%

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Synthesis, Chromatographic Resolution, and Anti-Human Immunodeficiency Virus Activity of (±)-Calanolide A and Its Enantiomers

et al. 1996

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The anti-HIV agent (+/-)-calanolide A (1) has been synthesized in a five-step approach starting with phloroglucinol [-->5-->6-->11-->18-->(+/-)-1], which includes Pechmann reaction, Friedel-Crafts acylation, chromenylation with 4,4-dimethoxy-2-methylbutan-2-ol, cyclization, and Luche reduction. Cyclization of chromene 11 to chromanone 18 was achieved by employing either acetaldehyde diethyl acetal or paraldehyde in the presence of trifluoroacetic acid and pyridine or PPTS. Luche reduction of chromanone 18 at lower temperature preferably yielded (+/-)-1. Reduction of chromone 12, synthesized by Kostanecki-Robinson reaction from chromene 11, failed to afford (+/-)-1. The synthetic (+/-)-1 has been chromatographically resolved into its optically active forms, (+)- and (-)-1. The anti-HIV activities for synthetic (+/-)-1, as well as resultant (+)- and (-)-1, have been determined. Only (+)-1 accounted for anti-HIV activity, which was similar to the data reported for the natural product, and (-)-1 was inactive.

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Section: Chemistrysupporting

confidence: 58%

“…Attempts to convert both 9 and 10 under Fries conditions into the corresponding 8-acylated coumarin 6 were unsuccessful. It was reported that 5,7-diacetoxy-4-phenylcoumarin underwent Fries rearrangement to form 6,8-diacetyl-5,7-dihydroxy-4-phenylcoumarin …”

Section: Chemistrymentioning

confidence: 99%