Patent GB-377132-A (GB)
Title: Manufacture of double compounds of the pyridine series
IPC: C07D213/79
Filed: 1932-03-05
Abstract: Double compounds are prepared by interaction of a pyridine carboxylic acid or a derivative substituted in the carboxyl group (except an acid anhydride) or a substitution product thereof with an alkaline earth metal halide or sulphocyanide.  The products are molecular, usually containing one or two molecular proportions of the pyridine compound for each molecular proportion of the alkaline earth metal salt.  The reaction may be effected in solution or merely by mixing. Examples are given of the formation of double compounds of (1) calcium chloride with nicotinic acid, picolinic acid, a -oxypyridine-b -carboxylic acid, nicotinic acid chloride, ethyl ester, amide and diethylamide; (2) calcium bromide and iodide, and magnesium and strontium chlorides, with nicotinic acid diethylamide; (3) calcium sulphocyanide with nicotinic acid diethylamide, nicotinic acid methyl-n-propylamide, picolinic acid diethylamide and 2 : 4 : 6-trimethylpyridine-3 : 5-dicarboxylic acid diethyl ester.  The description of the preparation of the samples, comprising double compounds of calcium sulphocyanide with a -chloronicotinic acid diethylamide and calcium picolinate, is included in the Specification.  The Specification as open to inspection under Sect. 91 (3) (a) describes also the use of the anhydrides of pyridine carboxylic acids and their substitution products.  This subject-matter does not appear in the Specification as accepted.ALSO:Double compounds are prepared by interaction of a pyridine carboxylic acid or a derivative substituted in the carboxyl group (except an acid anhydride) or a substitution product thereof with a water-soluble salt of an alkaline earth metal.  The pyridinic starting material may comprise nicotinic acid, picolinic acid, the oxy-, halogen- or amino-pyridine carboxylic acids, and their esters, halides, amides or salts; as salts of the alkaline earth metals may be used the halides and sulphocyanides, as well as the salts of organic acids, e.g. benzoates, salicylates and aromatic sulphonates. The products are molecular, usually containing one p  or two molecular proportions of the pyridine compound for each molecular proportion of the alkaline earth metal salt.  The interaction may be effected in solution and merely by mixing.  The double compounds are useful therapeutically, or may serve for the isolation and purification of the pyridine compounds.  Examples are given of the formation of double compounds of (1) calcium chloride with nicotinic acid, picolinic acid, a -oxypyridine-b -carboxylic acid, nicotinic acid chloride, nicotinic acid ethyl ester, nicotinic acid amide, and nicotinic acid diethylamide; (2) calcium bromide and iodide with nicotinic acid diethylamide; (3) magnesium and strontium chlorides with nicotinic acid diethylamide; (4) calcium sulphocyanide with nicotinic acid diethylamide, nicotinic acid methyl-n-propylamide, picolinic acid diethylamide (prepared from picolinic acid chloride and diethylamine), and 2 : 4 : 6-trimethylpyridine-3 : 5-dicarboxylic acid diethyl ester; (5) calcium salicylate with nicotinic acid diethylamide.  The description of the preparation of the samples, comprising double compounds of calcium sulphocyanide with a -chloronicotinic acid diethylamide (prepared from a -chloro-nicotinic acid chloride described in Specification 355,017 and diethylamine) and calcium picolinate, is included in the Specification.  The Specification as open to inspection under Sect. 91 (3) (a) describes also the use of the anhydrides of pyridine carboxylic acids and their substitution products, as well as of alkaline earth metal salts in general.  This subject-matter does not appear in the Specification as accepted.