ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
On ultraviolet irradiation O-acetyljervine (1) is subjected to several parallel fragmentations. From the complex reaction mixtures obtained in a variety of solvents (dioxan, tetrahydrofuran, acetonitrile, iso-octane, benzene) the major alicyclic products 6-8 and the heterocyclic compounds 12-16 have been isolated. Products 6-8 undergo further photochemical changes, e.g., decarbonylation of 7 to 9 and hydrolytic cleavage of 8 to 10.These photofragmentations are initiated almost specifically upon selective π → π* excitation at 2537 Å with a quantum yield of Φ2537 = 0.145 for conversion of starting material. Reaction upon irradiation in the long-wavelength n → π* absorption band is very much less efficient (Φ3660 = 0.611 · 10-3, both determinations for O-trimethylsilyl-jervine (2) in tetrahydrofuran). A high degree of photostability is observed also at 2537 Å on N-protonation of O-acetyljervine (1) in acetic acid. Furthermore, reactivity is greatly reduced for the N-methyl (3) and N-acetyl (4) derivatives in neutral solvents at 2537 Å. N-Chloro-O-acetyljervine (5) in dioxan at 2537 Å gave preferentially O-acetyljervine hydrochloride.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19710540202
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