GB667199A - Process for stabilizing photographic emulsions - Google Patents

Abstract

<FORM:0667199/IV (b)/1> <FORM:0667199/IV (b)/2> <FORM:0667199/IV (b)/3> Compounds of the general formula of Fig. 1, wherein D represents the atoms to complete an iminazole, iminazoline, or arylene iminazoline nucleus, R1 is H, alkyl, or aryl, R2 is an ester, nitrile, or carboxyl group, and R3 is OH or NH2, are prepared by reacting an amine of the formula of Fig. 2 with a compound of the formula of Fig. 3, wherein R4 has the same significance as R2 and R5 is a substituted or unsubstituted alkoxy group. 5 - Hydroxy - 6 - carbethoxy - 1 : 2 - benz - 3 : 4 - diazaindolizine is prepared by boiling together 2-aminobenziminazole and diethyl ethoxymethylenemalonate in acetic acid. The following derivatives of 1 : 2-benz-3 : 4-diazaindoline are similarly prepared: 5-amino-9-carbethoxy-, 5 - amino - 6 - cyano-, 5 - hydroxy - 6 - carbethoxy - x - chloro -, 5 - hydroxy - 6 - carbethoxy - 7 - methyl -, 5 - amino - 6 - carbethoxy - 7 - methyl-, and 5 - hydroxy - 6 - carbethoxy - 7 - phenyl. 5 - Amino - 6 - carbethoxy - 7 - methyl - 1 : 2 - di-hydroxy - 3 : 4 - diazaindolizine and 5 - hydroxy - 6 - carbethoxy - 1 : 2 : 11 : 21 - naphtha - 3 : 4 - diazaindolizine are also similarly prepared. 5 - Hydroxy - 6 - carboxy - 1 : 2 - benz - 3 : 4 - diazaindolizine is prepared by the saponification of 5 - hydroxy - 6 - carbethoxy - 1 : 2 - benz - 3 : 4-diazaindolizine in 10 per cent sodium hydroxide solution. According to the Provisional Specification, R2 may be H or any electronegative group (e.g. an amide group), and R5 may be a substituted or unsubstituted amino group.