BASIC AZO DYES FREE FROM SULPHONIC ACID GROUPS THEIR PRODUCTION AND USE

1332477 Substituted dihydropyridine derivatives SANDOZ Ltd 2 Nov 1970 [7 Nov 1969 23 Dec 1969 13 Aug 1970 18 Aug 1970] 52077/70 Addition to 1273748 Heading C2C [Also in Division C4] Compounds of formula wherein R is H or an organic radical, R 1 is H or a hydrocarbon radical, a heterocyclic radical or an amino group, which radical or group may be substituted, A is an anion and Z represents the atoms needed to complete a ring of aromatic character which may contain one or more further hetero atoms and may be substituted and on which one or more further rings may be condensed are used in the preparation of azo dyes (see Divisions C4-C5) and are prepared by condensing a salt of an acetamide bearing a group of formula with an acylacetic acid ester in an organic solvent in the presence of a basic catalyst. In Examples: (1) N-carbamoylmethyl-pyridinium chloride is reacted with methyl acetoacetate in methanolic NaOH to give 2-keto-3-pyridinium chloride - 4 - methyl - 6 - hydroxy - 1,2 - dihydropyridine; (3-7(a)) 1,21,4-trimethyl-2- keto - 3 - pyridinium chloride - 6 - hydroxy - 1, 2 - dihydropyridine, 1 - (2<SP>11</SP> - ethyl) - hexyl - 2. keto - 3 - quinolinium chloride - 4 - methyl - 6- hydroxy - 1,2 - dihydropyridine, 1 - phenyl - 2- keto - 3 - pyridinium chloride - 4 - methyl - 6- hydroxy - 1,2 - dihydropyridine, 1 - dimethylamino - 2 - keto - 3 - pyridinium chloride - 4- methyl - 6 - hydroxy - 1,2 - dihydropyridine and 2 - keto - 3 - pyridinium chloride - 4 - ethoxycarbonyl - 6 - hydroxy - 1,2 - dihydropyridine are similarly prepared; (7(b)) 2-keto-3- pyridinium chloride - 4 - N<SP>11</SP>,N<SP>11</SP> - dimethylcarbamoyl - 6 - hydroxy - 1,2 - dihydropyridine is prepared by reacting the 4-ethoxycarbonyl compound with dimethylamine. Many similar compounds are listed.