RU1781216C - Process for producing monosubstituted 3-pyrimidylthiourreas - Google Patents

Abstract

Usage: in medical chemistry in the synthesis of biologically active compounds. SUMMARY OF THE INVENTION: a method for producing monosubstituted 2-pyrimidylthioureas of the general formula ngm-c-nn-cC sn, s m h where R, Ri-Alk, Ar, OH, CP3, by condensation of guanidylthiourea with / -dicarbonyl compounds their molar ratio 1: 2 to 1: 2.5 at a temperature of 80-120 ° C for 4-5 hours. 2 tablets. CO C

Description

The invention relates to the field of chemistry of pyrimidine, in particular to a method for half-training monosubstituted

2-pyrimidylthiourea, General formula I

./

VI //

„/

cn

Un-s-pl-s

s N: l

IR

where R, R is aryl, alkyl, OH, CH3.

Compounds of this formula can be used as intermediates in organic synthesis, in particular in the synthesis of herbicidal sulfonylureas. Monosubstituted 2-pyrimidyl derivatives of thioureas are difficult to access.

Known methods for producing thioureas of a pyrimidine series by treating the corresponding aminopyrimidines with alkyl and

arylisothiocyanates or acid hydrolysis of the corresponding cyanaminopyrimidines. However, these methods result in disubstituted thioureas.

Getting monosubstituted. containing structural fragments of pyrimidine derivatives described in. In particular, 4,6-dimethylpyrimidin-2-yl-urea was obtained by condensation of guanylurea with β-diketones, as well as by the interaction of nitroureas with aminopyrimidines.

The closest technical solution is the method for preparing 2-pyrimidylthiourea derivatives by reacting guanylthiourea with a carbonyl compound (e.g. acetylacetone by boiling the mixture) in an aqueous medium at a 1: 1 molar ratio of reactants for 1 hour (5). However

Vj 00

Yu

in this case, 4,6-dimethyl-2-pyrimyldiylthiourea is obtained with a low yield (-77%).

The aim of the described method is to increase the yield of the target products.

The goal is achieved in that the guanylthiourea is condensed with / -dicarbonyl compounds at a molar ratio of reactants from 1: 2 to 1: 2.5 at a temperature of 80-120 ° C for 4-5 hours.

Example 1. 0.02 mol of acetylacetone is added to 0.01 mol of guanylthiourea and heated for 4-5 hours at a temperature of 80-85 ° C. Then the precipitate is filtered off, washed with cold water and ether. The yield of 4,6-dimethylpyrimidin-2-thiourea is 85%. T.pl. 263-264 ° C,

Example 2. To 0.01 mol of guanylthiourea, 0.02 mol of acetoacetic ester was added and heated for 4-5 hours at a temperature of 110-120 ° C. Then the precipitate is filtered off, washed with cold water and ether. The yield of 4-hydroxy-b-methylpyrimidyl-2-thiourea is 90%. Mp 211-212 ° C.

The yield, melting point and elemental analysis data are presented in Table 1; in the synthesis of compound 5 according to the procedure for Example 1, malonic acid diethyl ether was used; compounds of 6-hexafluoro cetyl cetone.

The structure of the obtained products was confirmed by mass spectroscopy and IR spectroscopy.

Condensation at a reagent ratio of 1: 1 leads to a decrease in the yield of target products to 40-50%, and an increase in the ratio of more than 1: 2.5 leads to

to the appearance in the mass spectra of the synthesized compounds of by-products with a higher molecular weight. An example of the dependence of the yield of 4,6-dimethylpyrimidyl-2-thiourea on the ratio of reactants and reaction conditions is given in Table 2.

The implementation of the described method allows to increase the yield of the target products to 85-98% and expand the capabilities of the method due to the use of esters of / -oxocarboxylic and malonic acids in addition to guanylthiourea and / -diketones, which expands the range of products obtained.

Claims (1)

The claims The method of obtaining monosubstituted 2-pyrimidylthioureas of the General formula Jw-c NHj-C-NH-C CN where R, Ri-aryl, alkyl, OH, CPz, by condensation of guanidylthiourea with a ciL-dicarbonyl compound at an elevated temperature, characterized in that, in order to increase the yield of the target products, the process is carried out at a molar ratio of reactants from 1: 2 to 1: 2.5 at 80-120 ° C for 4-5 hours Ion-valuable 2-pyrimndylthione ureas Table T 517812166 Table 2 The dependence of the yield of 4,6-dimethylpyrimidyl-2-thiourea on the reaction conditions