New cyanine salt - and merocyanine - sensitizing dyes

摘要

1300641 Pyrido-benzimidazoles MINNESOTA MIN3G & MFG CO 20 Jan 1970 [22 Jan 1969] 2775/70 Heading C2C [Also in Divisions C4 and G2] 5-Aminobenzimidazoles are reacted with methyl vinyl ketone to give a compound of formula (in which R and R 1 are each H or optionally substituted alkyl) which is then converted to a quaternary salt. In an example, a compound in which RSP11/SP is CH 3 and R 1 is C 2 H 5 is prepared by heating 5 - amino - 1 - ethyl - 2 - methylbenz. imidazole, methyl vinyl ketone, FeCl 3 .6H 2 O and ZnCl 2 in ethanol and treating with NaOH; the compound is then quaternized with C 2 H 5 I.