Desoxycodeine methine

Desoxycodeine-A is phenolic, being soluble in alkali, giving a colour with ferric chloride and forming a methyl ether [1]. The phenol may be degraded to a methine base [vi, R = H], which oxidizes rapidly in air, and the methyl ether to [vi, R = Me], which decomposes spontaneously to an amine and dimethylmorphol [vn] [1],... 

Dihydrodesoxycodeine-A was originally thought to be a definite compound, but is now known to be a mixture of two bases. It is obtained by the sodium and alcohol reduction of desoxycodeine-A [m], a-chlorocodide [iv] [1, 3, 10, 22], and desoxycodeine-C [ix] [3, 10], and can be further reduced catalytically to tetrahydrodesoxycodeine [xiv] [3], It was first stated to yield on degradation a methine base that absorbed two moles of hydrogen on reduction, giving tetrahydrodesoxycodeine dihydromethine (see below) [21], but later attempts to isolate the methine base from the products of degradation were unsuccessful [23]. 

Dihydrodesoxycodeine-D [xm], the only non-phenolic dihydro-desoxycodeine, can be prepared by the catalytic hydrogenation of a-chlorocodide [rv] [29], /3-chlorocodide [v, It = Cl] [7, 29], bromocodide [v, R = Br] [29], and desoxycodeine-C [ix] hydrochloride [6], It has also been reported to be formed by catalytic reduction of codeinone oxime [xlii] hydrochloride [30]. Dihydrodesoxycodeine-D methine [xlhi] results from Hofmann degradation of the methiodide [7], and a substance that is presumably the dihydromethine [xliv] is obtained by catalytic reduction of a-chlorocodeimethine [xlv] [26]. 

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