SYNTHESIS OF 3-METHYL-1,2,4-THIADIAZOLE-5-CARBOHYDRAZIDE OR ITS METHYL-d DUTERATED FORM Russian patent published in 2023 - IPC C07D285/08 C07B43/00 

FIELD: pharmaceuticals.

SUBSTANCE: invention relates to a process for the synthesis of 3-methyl-1,2,4-thiadiazole-5-carbohydrazide or its methyl-d ₃ deuterated form of formula (I) wherein R¹ is methyl or methyl-d₃. The said method comprises the following steps: a) carrying out an alkoxycarbonylation reaction of a compound of formula (III), where X is halogen, R¹ is either methyl or methyl-d₃, to obtain a compound of formula (II), where R¹ is either methyl or methyl-d₃, R² means either alkyl or arylalkyl; and b) preparing a compound of formula (I) by reacting a compound of formula (II) with hydrazine monohydrate. The compounds obtained by the claimed method are applicable as key intermediates in the synthesis of pharmaceutical compounds, in particular phesolinetant and deuterated phesolinetant.

EFFECT: technical result of the invention is a safer, more reliable, scalable and more efficient synthesis of the intermediate compound of formula (I).

15 cl, 10 ex