5302-74-9Relevant articles and documents
Synthesis of the Calophyllum coumarins. Part 2
Palmer, Christopher,Josephs, Jonathan
, p. 3135 - 3152 (2007/10/03)
Synthetic routes leading to the synthesis of the natural 4-phenyl, 4-propyl and 4-methyl coumarins isolated from Calophyllum sp. are presented. 4-Aryl or -alkyl, 8- and 6-acyl 5,7-dihydroxy coumarins were chromenylated and then methylated at the 5 or 7 positions.A 4-step hydrobromination-bromination-double dehydrobromination sequence converted the 2-methylbutanoyl side chain into the (E)-2-methylbut-2-enoyl (tigloyl) group to give calophyllolide, oblongulide, their natural 4-propyl analogue and the corresponding regioisomers.Demethylation and cyclisation of the tigloyl group gave inophyllums C and E, tomentolides A and B, and calanolide D.Sodium boranuide reduction of the 2,3-dimethylchromanone ring afforded inophyllums A, B, D and P, soulattrolide, calanolides A-C, costatolide, and cordatolides A and B.The structures of calanolides C and D, oblongulide and apetatolide have been reassigned.The previously unknown stereochemistry about the 2,3-dimethylchromanone ring of tomentolides A and B has been established as trans.
Synthesis of Mammea Coumarins. Part 1. The Coumarins of the Mammea A, B, and C Series
Crombie, Leslie,Jones, Raymond C. F.,Palmer, Christopher J.
, p. 317 - 332 (2007/10/02)
The naturally-occuring Mammea coumarins of the 4-phenyl-(mammea A), propyl-(mammea B), and 4-pentyl-(mammea C) series have been prepared by Pechmann condensation of an acylphloroglucinol (3-methylbutyryl-, 2-methylbutyryl-, butyryl-, or 2-methylpropionyl-) with the appropriate β-ketoester to give a mixture of 6- and 8-acyl-5,7-dihydroxycoumarins that could be separated.C-Alkylation with 3-methylbut-2-enyl bromide, or 3,7-dimethylocta-2,6-dienyl chloride, in aqueous potassium hydroxide completed the synthesis of the Mammea coumarins having unmodified prenyl or geranyl substituents; oxidative modification of the prenyl group led to the mammea cyclo E and cyclo F coumarins.Some mammea cyclo D (chromeno) coumarins were synthesized by reaction of acylcoumarins with 1,1-dimethoxy-3-methylbutan-3-ol.