Thebaine ultra-violet spectrum

The ultra-violet spectrum of morphothebaine has been determined by Girardet [26], It is shown in comparison with that of thebaine in Fig. 16. 

Thermochemical studies have been made by Leroy [394-5], The absorption spectrum of codeine in the visible [396-7] and in the ultraviolet [398-9] has been determined. The ultra-violet absorption curve, compared with those of morphine and thebaine is given in Mg. 1. That of ethylmorphine is closely similar [400]. 

Thermochemical studies of thebaine have been made by Leroy [118-19]. The absorption spectrum of the alkaloid has been determined by Hartley [120] and the ultra-violet absorption spectrum (Eig. 4) by Girardet [121], Steiner [122], and Kitasato [123]. 

Examination of the infra-red and ultra-violet absorption spectrum of /3-dihydrothebaine indicated that it has in fact the structure [n] initially allotted to dihydrothebaine- [6]. Such a conjugated diene would be expected to imdergo 1 4-addition of hydrogen with final production of [vm], a reduction parallel to the production of tetrahydrothebaine from thebaine (see below). 

Reduction of the orange-red solution of thebaine in concentrated hydrochloric acid with zinc affords a yellow phenolic base about which little is yet known beyond the facts that it is dimolecular and contains no carbonyl group. Its ultra-violet absorption spectrum contains a band at about 3,800 A, apparently indicating the presence of a highly conjugated system of double bonds such as... 

This isomer is obtained in erratic yield by the hydrolysis of dihydro-thebaine- by sulphurous acid. It was initially allotted the structure [xm] [3], but has since been shown to have the structure [xxv], which is allotted to the base on account of the ultra-violet absorption spectrum, which indicates a highly conjugated system (Figs. 8 and 9), and the infra-red absorption, which indicates that the compound is a /3 y-unsaturated ketone [13]. It is apparently formed during the hydrolysis... 

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