FIELD: chemistry.SUBSTANCE: invention relates to polymorph of inner salt 1-[(2-chlor-5-thiazolyl)methyl]-3-(3,5-dichlorophenyl)-2-hydroxy-9-methyl-4-oxo-4N-pyrido[1,2-a]pyrimidine designated as form A, characterized by powder diffraction roentgenogram taken with the use of Cu(Kα1) radiation at room temperature, having, at least, the position of reflections 2θ: 8.036, 9.592, 13.719, 14.453, 17.07, 23.092, 24.027, 24.481, 29.743, 31.831. Polymorphic form A is produced by the formation of a suspension of toluene with one or more solid forms of the inner salt 1-[(2-chlor-5-thiazolyl) methyl]-3-(3,5-dichlorophenyl)-2-hydroxy-9-methyl-4-oxo-4N-pyrido[1,2-a]pyrimidine selected from the group: (i) polymorphic form B of the inner salt 1-[(2-chlor-5-thiazolyl) methyl]-3-(3,5-dichlorophenyl)-2-hydroxy-9-methyl-4-oxo-4N-pyrido[1,2-a]pyrimidine characterized by the powder diffraction roentgenogram taken with the use of Cu(Kα1) radiation at room temperature, having, at least, the position of reflections 2θ: 6.654, 9.41, 10.983, 11.986, 15.513, 21.225, 22.012, 25.638, and 28.545 40.244, and (ii) a mixture of (i) polymorphic form A of the inner salt 1-[(2-chlor-5-thiazolyl)methyl]-3-(3,5-dichlorophenyl)-2-hydroxy-9-methyl-4-oxo-4N-pyrido[1,2-a]pyrimidine. The resulting slurry is cured and optionally, if necessary, seed crystals of the polymorphic form A are added according to cl. 1, and/or the slurry is mixed and heated to a temperature of 90°C to 110°C, while the transformation of the solid forms of the inner salt of 1-[(2-chloro-5-thiazolyl)methyl]-3-(3,5-dichlorophenyl)-2-hydroxy-9-methyl-4-oxo-4N-pirido[1,2-a]pyrimidine in polymorphic form A. Also, the versions of the method of producing polymorphic form A of the invention are proposed. The polymorphic form A of the invention is intended to control insect pests.EFFECT: polymorphic form of the inner salt has improved stability properties, filterability, solubility.9 cl, 2 dwg, 16 tbl, 18 exИзобретение относится к полиморфу внутр
