94002-01-4Relevant academic research and scientific papers
Synthesis of 3,4-Dimethylpsoralene, Angelicin and Their Derivatives
Ahluwalia, V. K.,Khanduri, C. H.,Sharma, N. D.
, p. 748 - 751 (2007/10/02)
7-Hydroxy-3,4-dimethyl-2H-1-benzopyran-2-one (1) on alkylation followed by Claisen migration of the intermediate allyloxycoumarin 2 gives 8-allyl-7-hydroxy-3,4-dimethyl-2H-1-benzopyran-2-one (3) which on oxidation with OsO4-KIO4 and subsequent cyclodehydration with PPA yields 6,7-dimethyl-5H-furobenzopyran-5-one (4).However, the allylcoumarin 3 on cyclisation with sulphuric acid followed by DDQ affords 2,6,7-trimethyl-5H-furobenzopyran-5-one (6).The isomeric 5,6-dimethyl-7H-furobenzopyran-7-one (10) and 2,5,6-trimethyl-7H-furobenzopyran-7-one (12) have been synthesised starting from 7-hydroxy-8-iodo-3,4-dimethyl-2H-1-benzopyran-2-one (7).Similarly, 5,6,9-trimethyl-7H-furobenzopyran-7-one (16) and 2,5,6,9-tetramethyl-7H-furobenzopyran-7-one (18), and 4,8,9-trimethyl-7H-furobenzopyran-7-one (22) and 2,4,8,9-tetramethyl-7H-furobenzopyran-7-one (24) have been synthesised starting from the appropriate benzopyran-2-ones (13 and 19).
