METHODS FOR PREPARING 5-(1-PIPERAZINYL)-BENZOFURAN-2-CARBOXAMIDE AND INTERMEDIATE COMPOUNDS

FIELD: organic chemistry, chemical technology, pharmacy. ^ SUBSTANCE: invention relates to a method for preparing 5-(1-piperazinyl)-benzofuran-2-carboxamide. Method involves reaction of bromosalicylic aldehyde with compound of the formula (I): L-CH2-COOR1 (I) wherein L represents Cl, Br or J atoms, or reactive esterified group -OH; R1 means (C1-C6)-alkyl or benzyl followed by reaction with formamide to yield 5-L-benzofuran-2-carboxamide (II) and the following its amination with R2-piperazine wherein R2 represents hydrogen atom (H) or amino-protecting group in the presence of a catalyst based on transient metals; in case if R2 is not H then R2 is removed, and/or prepared 5-(1-piperazinyl)-benzofuran-2-carboxamide is converted to one of its salts by treatment with acid. Except for, the invention proposes two additional methods for preparing 5-(1-piperazinyl)-benzofuran-2-carboxamide and intermediate compounds of the formula (V): wherein R2 represents H or amino-protected group; R3 means H or -CH2R6; R4 and R5 in common represent carbonyl; R6 means -CN, -COOH, -COOR7 or -CONH2; R7 means (C1-C6)-alkyl, and also their salts and solvates. Invention provides a new method for preparing the valuable intermediate compound used in preparing pharmaceutical preparations and increase of the yield of the end compound. ^ EFFECT: improved preparing methods. ^ 6 cl, 10 ex