Das allenische Carotinoid Deepoxineoxanthin/ The Allenic Carotenoid Deepoxineoxanthin

Abstract

Deepoxineoxanthin, the epoxide-free homologue of neoxanthin, is synthesised in the petals of Mimulus guttatus (Monkey flower). The pigment is esterified with various fatty acids. The free pigment has the structure of 6′,7′-didehydro-5′,6′-hydro-β,β^-carotene-3,3′,5′-triol. These structural conclusions were borne out by the formation of a diacetate (2-sec OH), a mono-silanate of the diacetate (1-tert OH) and a mono-ether of the diacetate and the free pigment (allylic tert OH). PMR, mass and IR spectra supported the proposed structure, which was confirmed by the trans­ formation of deepoxineoxanthin into diatoxanthin with acidified acetone (allene-acetylene trans­formation) and its oxidation to neoxanthin with monoperphthalic acid.