Dyes, xxii

G. M. Wyman, W. R. Brode, The relation between the absorption spectra and the chemical constitution of dyes, XXII. Cis-trans isomerism in thioindigo dyes, J. Am. Chem. Soc. 73(1951) 1487. 

Scheme 13 Chemical structure of poly(L-glutamic acid) containing triphenylmethane dyes in the side chains (XXII, Y =-OH and...

Constituents (See also table II) Relbun roots contain galiosin as the pricipal dye, but pseudopurpurin (XXII) and purpurin (which may have been formed from pseudopurpurin by decarboxylation) may also be present (48). Alizarin has not been found in relbun roots (49). 

Constituents (See also table II) The dyes contained in the roots of these two plants are pseudopurpurin (XXII), its primveroside galiosin, purpurin (XXI) (formed in some cases from pseudopurpurin by decarboxylation), rubiadin (III), its 3-B-primveroside, lucidin (V) (jpartly as glycoside), purpuroxanthin (II), and alizarin (I) (partly as glycoside) (51). 

Table XXII. Color Difference Values for Series VI Dyeings on Textured Yarn...

The diimine (XXII) has been described as a vital intermediate in oxidative hair dyeing [23]. More recently, Corbett [3] has described the protonated diimine (IX) as the reactive species that actually attacks dye-coupUng agents, ultimately forming indo dyes. 

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