Nuclear magnetic resonance and UV spectral probe of photochemical steady states of vitamin K1

✍ Scribed by R.P. Gandhi; M.P.S. Ishar; Rashmi Srivastava; Rita Sarin

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 669 KB
• Volume: 78
• Category: Article
• ISSN: 1010-6030
• DOI: 10.1016/1010-6030(94)80060-x

✦ Synopsis

Steady state photochemistry

of vitamin K1 has been examined using a 'H nuclear magnetic resonance probe on solutions in CDCl,, acetone-d,, benzene-d, and acetonitriled,, and a UV probe on solutions in acetone, pentane and ethanol. A rationale for formation of the major photoproduct, i.e. chromenol (l), based on electron transfer from the side-chain olefinic bond to the naphthoquinone moiety in vitamin K1, has been suggested. The new mechanistic scheme implicates, inter alia, quinone methide ( 6) as the precursor of 1. Attempted separation of pbotolysis mixture using flash chromatography has led to isolation of 9 and an oxygen adduct 10 of chromenol (1). The photoconversion of the vitamin is accelerated with catalytic amounts of triethylamine.