Synthesis of melodienone and 7-hydroxy-6-hydromelodienone, two heptenes from Melodorum fruticosum.

✍ Scribed by Achille Barco; Simonetta Benetti; Carmela De Risi; Gian P. Pollini; Romeo Romagnoli; Vinicio Zanirato

• Publisher: Elsevier Science
• Year: 1994
• Tongue: French
• Weight: 430 KB
• Volume: 50
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(01)89589-2

✦ Synopsis

AbsWct: An unified approach to the construction of the seven carbon atom framework of the title compotmds. having a y-oxoacxylate moiety as common stnlcmml feature, utilitig an int-lecallar [3+2] cydo&ition of the nitrile oxide generated from a m&c acid derived C-4 aldehyde fragment with methyl aaylate. is desaibed. Recently, McLaughlin et al.12 have isolated from Meloaimmfruticosum Lour.(Annonacee) several new bioactive compounds with slight to significant cytotoxic activity to human tumor cell lines, which were named heptenes, owing to their novel seven-carbon atom skeleton.

Interestingly, the examination of the structures of two members of this family, trivially named melodienone 1 and 7-hydroxy-6-hydromelodienone 2, revealed common structural similarities, including a C( 1)-C(4) fragment of their skeleton incorporated into a y-oxoacrylate moiety and a primary hydroxyl group at C(7) esterified with a benzoic acid residue, which seems to be of crucial importance for the integrity of these structures.

In fact, the free primary hydroxyl group is suitably located for intramolecular addition to the carbonyl group to produce the corresponding hemiketal, which may in turn give rise to the corresponding 3-(2-fury&acrylic acid ester by dehydration3 as outlined in the Scheme I.