METHOD FOR OBTAINING PRAZIQUANTEL AND ITS INTERMEDIATE COMPOUNDS Russian patent published in 2018 - IPC C07D471/04 C07C231/04 C07C231/14 C07C237/22 

FIELD: biotechnology.

SUBSTANCE: invention relates to a process for the preparation of Praziquantel. Method includes the following steps: 1) β-phenethylamine and chloroacetyl chloride are condensed in the presence of an alkaline substance to give a compound of formula II;

2) compound of formula II and ethanolamine are subjected to a substitution reaction to obtain a compound of formula III; 3) compound of formula III and cyclohexanecarbonyl chloride are subjected to an acylation reaction in the presence of an alkaline substance to give a compound of formula IV; 4) compound of formula IV is subjected to an oxidation reaction in the presence of an oxidizing agent to obtain a compound of formula V; and 5) compound of formula V is cyclized in the presence of a cyclizing agent to obtain Praziquantel as a compound of formula I. Formulas I, II, III, IV and V are given in the claims. Step 2) is carried out without a solvent. Step 1), step 3), step 4) or step 5) is carried out with at least one aprotic organic solvent as the solvent. Reaction temperature of step 1), step 2), step 3), step 4) or step 5) is from -10 °C to 100 °C. Intermediates, methods for their preparation and use are also provided.

EFFECT: invention provides a simple, cost-effective and environmentally friendly method for the preparation of Praziquantel in high yield and purity.

20 cl, 25 ex