Synthesis of asperenone, a new pigment from aspergillus niger and aspergillus awamori

✍ Scribed by Gerald Pattenden

• Publisher: Elsevier Science
• Year: 1969
• Tongue: French
• Weight: 194 KB
• Volume: 10
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)88611-1

✦ Synopsis

Asperencne is the name proposed' ('asperyellcne' has also been suggested2) for a new yellow pigment isolated from Aspernillus niger and Aspergillus awamcri.

The pigment was 132 isolated and characterised independently in two laboratories.

Chemical and spectroscopic studies indicate that the piwent is a methyl derivative of 13-phenyltrideca-4,6,8,10,12pentaen-3-one, with the methyl group located somewhere on the side chain. The exact location of the methyl group is not known, but n.m.r. deuteration' and decoupling2 experiments on the decahydrc derivative; show that it is not located on carbon atoms 4,5,12 or 13. Examination of the relative abundances of hydrocarbon fraeents in the mass spectrum of asperenone led Yu et? to assign two structures for the pigment, the methyl group bein located on either C-7 (4a) or C-6 (4b); of these two structures the Japanese authors favcur (4a). Jefferson? however, on the basis of similar mass spectral analysis, suggests the methyl group is most likely located on c-8 (10). This communication describes unambiguous syntheses of the three structures (4a), (4b) and (10) put forward for asperenone.

Comparison with the natural material confirms structure (in) for asperenone.

Reaction of benzaldehyde with the Grignard reagent derived from l-methcxybut-1-en-j-yne