Codeine violet

Marquis reagent (gives a purple-red coloration, then violet, then blue with morphine, codeine, dionine, and heroine) mix 3 mL of concentrated H2SO4 with 3 drops of a 35% formaldehyde solution. 

Chlorpheniramine produces purple zones and codeine bluish-gray zones on a light background [1]. Adamexine and bromexine produce pinkish-violet zones, that are stable for ca 24 h in the dark, on a yellowish-white background [2]. 

Narceine (h/ f 1-5) yielded red-brown, morphine (h/ f 5-10), codeine (h/Jf 15-20) and thebaine (h/ j 35-40) brown-violet, papaverine (h/ f 60-65) light brown and narcotine red chromatogram zones on a colorless background. Since the colors fade in the air it is recommended that the chromatogram be covered with a glass plate. 

This procedure yielded a colorless background, on which the colors of the alkaloid zones became pale brown (narceine), blue (morphine) or violet (codeine, papaverine, narcotine) (Fig. 2B). 

Acepromazine (- red), adiphenine (-> blue), benorylate, bephenium hydroxynaphthoate, bibenzonium, buclosamide (blue rim), bunamidine, chlorpromazine (-> violet), clefamide (— brown), codeine, colchicine, cyclazocine, cyclomethycaine (— brown), debrisoquine, diaveridine, dibenzepin, diethazine (— violet with excess reagent), diethylthiambutene (-> green-blue), dimethindene, dimethoxanate (— brown), dimoxyline, dipipanone (— blue), dothiepin, doxorubicin, doxycycline (-> yellow), ethopropazine violet), fenpiprane,... 

The absorption spectrum of morphine has been determined by Hartley [594], Mayer (in sulphuric-nitric acid) [595], and Kitasato [596], and the ultra-violet absorption spectrum (shown in comparison with that of codeine in Chap. IV) by other workers [597-602],... 

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]. 

N ic opine was first isolated by Dobbie and Lauder from the last mother liquors from the processing of the opium alkaloids after all other bases had been eliminated [1], This remains the only source of the base. The method of isolation has since been improved and the alkaloid can ho separated from codeine through the sulphates [2], The base was first allotted the formula C18H2404N and the name hydroxycodeine it was shown to contain one —OMe, one —NMe, and to be a tertiary base. Its colour reactions and ultra-violet absorption spectrum are practically idontical with those of codeine [1]. 

Thebainone-B [xm] is best prepared as its hydrobromide by the hydrolysis of dihydrothebaine- [iv] with alcoholic hydrobromic acid [13], but it is also formed by the hydrolysis of the same base with mineral acid in aqueous solution [13], a reaction first reported to give an ill-defined substance, isocodeine [18], and later said to give a coloured, varnish-like substance [3]. Thebainone-B appears to be stable only as its salts in the dry state, the damp salts and free base readily degenerating to brown tars [13]. The ultra-violet spectra of thebainone-A, /3-thebainone-A, and thebainone-B closely resemble those of dihydrothebaine- and codeine, whilst that of thebainone-C is widely different (Fig. 8) and the frequencies of the carbonyl-absorption in the infra-red indicate that whereas thebainone-A and /3-thebainone-A are a /3-unsaturated ketones, the unsaturation is /3 y- in thebainone-B and thebainone-C [13]. On this evidence thebainone-B is allotted the structure [xm]. It can be catalytically reduced to dihydrothebainone [ix], in which the configuration at C-14 is the same as in codeine [13] (cf. the production of dihydrocodeine on reduction of neopine [xiv] [19]). 

Codeine dihydromethine [xn] has now been prepared by the sodium-ammonia reduction of codeine methiodide, together with dihydrodesoxy-codeine-C dihydromethine [xiii]. Both [xii] and [xni] result from the sodium and liquid ammonia reduction of a-codeimethine [xiv] [2] (cf. p. 106). The sodium and liquid ammonia reduction of dihydrocodeine methiodide affords a-tetrahydrocodeimethine, and the reduction of /3-codeimethine [xv] yields neopine dihydromethine [xvi]. When the methiodide of the latter is heated with sodium cyciohexyloxide in cyciohexanol a mixture of methyl-morphenol [xvn] and (-f-)-6-hydroxy-3-methoxy-5 6 7 8 9 10-hexahydro-phenanthrylene-4 5-oxide [xviii] is obtained. The latter structure is assigned to the product on account of the close resemblance of its ultra-violet absorption spectrum to that of a-codeimethine. This represents a new type of degradation with hydrolytic scission of the side-chain [2]. Metathebainone methine has also been degraded in this way [2]. 

D With Marquis reagent the alkaloid.s morphine and codeine are immediately stained typically violet. 

The standard method was used on silica gel GF254 layers, with uniform external conditions. The fluorescence-quenching zones of the six best known opium alkaloids could be visualised with concentrated sulphuric acid, which yielded differentiating, colours. Thebaine alone was visible in the cold, as a yellow spot. 10 jxg amounts on heating 10 min at 150° C gave the colours morphine, violet narceine, brown violet codeine, reddish blue thebaine, light violet papaverine, grey and narcotine, pale red. 

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