GB485266A - Process for the preparation of bisulphite addition compounds of etherified derivatives of pentahydroxy-fuchsone - Google Patents

Abstract

Partly or completely etherified derivatives of hexahydroxytriphenylmethanes containing two hydroxy groups in each benzene nucleus are oxidized, and the resulting fuchsones converted into addition compounds with bisulphites. The triphenylmethanes may be prepared by the customary reactions and the oxidation simultaneously effected. Alkyl, halogen and sulpho groups may be present. In examples: (1) 3 : 31 - 311-trimethoxy-4 : 41 : 411-trihydroxytriphenylmethane is treated with amylnitrite and the fuchsone isolated by treatment with absolute alcohol and dry hydrogen chloride; the resulting crystals are washed with sodium acetate solution and water and reacted with aqueous sodium bisulphite to obtain the sodium bisulphite compound of trimethoxydihydroxyfuchsone: trihydroxydimethoxyfuchsone and monomethoxy tetrahydroxyfuchsone may similarly be isolated in the form of their sodium bisulphite compounds; (2) the hydrochloride of 3 : 31-dimethoxy - 311 : 411 - methylenedioxy - 41-hydroxyfuchsone is obtained by oxidizing with amylnitrite the triphenylmethanehydrochloride obtained by condensing piperonal with guaiacol in the presence of hydrochloric acid; the fuchsone is finally treated with aqueous sodium or ammonium bisulphite; (3) 3 : 31 : 311-trimethoxy - 4 : 41 : 411-trihydroxy - 5 - bromtriphenyl methane, obtained from 5-bromvanillin and guaiacol, is oxidized in ethylacetate with amylnitrite and the resulting fuchsone converted into the bisulphite compound; (4) guaiacol is condensed with iodoform, the volatile products removed by distilling on a water bath and the residue dissolved in sodium carbonate; the product obtained by precipitating with acetic acid is extracted with sodium bisulphite solution, decomposed with hydrochloric acid and, after addition of sodium acetate extracted with ethylacetate; by saturating with dry hydrochloric acid, the hydrochloride of trimethoxydihydroxyfuchsone is obtained, which is converted into the bisulphite compound; (5) the calcium salt of m-trimethoxy-p-dihydroxyfuchsone-m-sulphonic acid is obtained either by oxidizing 3 : 31 : 311-trimethoxy-4 : 41 : 411-trihydroxytriphenylmethane-5-sulphonic acid (prepared from guaiacol and 3-methoxy-4-hydroxybenzaldehyde-5-sulphonic acid) or directly by the interaction of amylnitrite, guaiacol and the calcium salt of 3-methoxy-4-hydroxybenzaldehyde-5-sulphonic acid.