FIELD: organic chemistry, chemical technology. SUBSTANCE: invention relates to method of synthesis of compound of the formula (7): 
where R1 means optionally substituted cycloalkyl group, optionally substituted aryl group or optionally substituted heterocyclic group; R2 means lower alkyl or halogenated lower alkyl and R3 means halogen or hydrogen atom. Method involves reaction of compound (1) 
with thionyl chloride and synthesized compound (2) 
interacts with compound (3) 
where X means halogen being reaction is performed in ethyl acetate medium in the presence of magnesium salt and a base and forming compound (4) 
is subjected for hydrolysis and decarboxylation and synthesized compound (5) 
is converted to compound (6) 
by cyclization, sulfonation with sulfonating agent and chlorination with thionyl chloride followed by amidation of (6) with aqueous ammonia in ethyl acetate medium that results to the end product preparing. Invention relates also to method of synthesis of acetophenone derivative (5) and to preparing the end oxazole compound from compound (5). Proposed methods show less labor intensity and ensures to use intermediate products without their isolation and purification that provide good yield of the end product (above 80%). Said methods can be used in industrial synthesis of the end product. EFFECT: improved method of synthesis, significantly simplified process. 9 cl
