The synthesis of some new thiophenyl-derivatized
and furanyl-derivatized phenothiazine
and phenoxazine dyestuffs is described. This was achieved by two methods after the synthesis of
6-chloro-5H-benzo[a]phenothiazin-5-one,
6-chloro-5H-benzo[a]phenoxazin-5-one,
and 6-chloro-5H-naphtho[2,1-b]pyrido[2,3-e][1,4]oxazin-5-one intermediates via anhydrous base
condensation reaction of
2,3-dichloro-1,4-naphthoquinone with
2-aminothiophenol,
2-aminophenol,
and 2-aminopyridinol, respectively. The first method involved treatment of tributyl(thien-2-yl) or
tributyl(furan-2-yl) stannane with chlorophenothiazine/chlorophenoxazine under mild basic chemical formula (CsF)
and 1,4-dioxane or toluene solvent at 80°C to supply dazzling yellow solid in high yields. In the second method, the catalytic system was pre-activated in acetonitrile, followed by addition of coupling partners
and K
3PO
4 to obtain high melting
and variety of highly colored products in moderate to high yields. The reaction conditions were compatible with unprotected N–H
and carbonyl functional groups. The intense colors of these dyes
and their ease of re-oxidation of Na
2S
2O
4-reduced derivatives make them suitable as
vat dyes. Also, they were found to be good colorants for textiles, papers, paint, ink, soap, polish, c
andle,
and plastic materials.