METHOD OF PREPARING 1-HYDROXY-PYRID-2-ONES

FIELD: organic chemistry. SUBSTANCE: described is method of preparing compounds of formula I: which are well known for their bacterial and antifungal activities wherein R1 is branched or unbranched alkyl having 1 to 17 carbon atoms, branched or unbranched alkyl having 2 to 17 carbon toms, cycloalkyl having 3-8 carbon atoms in the ring, said cycloalkyl residue being not substituted or substituted by means of 1-3 alkyl residues each, depending on circumstances, with 1-3 carbon atoms, phenyl, phenyloxy (C1-C4) alkyl or phenyl-(C1-C4) alkyl, phenyl, phenyloxy-(C1-C4) alkyl and phenyl-(C1-C4) alkyl residues being not substituted or substituted in the aromatic ring with by means of 1-3 (C1-C6) alkyl, benzyl, (C1-C6) alkoxy, phenoxy or halide residues, said cycloalkyl, phenyl, phenyloxy (C1-C4) alkyl residues being connected directly or through methylene or ethylene group with pirydone ring; and R2 is hydrogen atom, alkyl having 1-6 carbon atoms, alkenyl having 2-6 carbon atoms or benzyl residue by reacting pyrone of formula II: , residues R1 and R2 are as defined in formula I for corresponding residues R1 and R2, with hydroxyammonium salt in solvent and in the presence of alkali metal carbonate and/or alkali metal hydrocarbonate in amount of 0.8-5 equivalents calculated for hydroxyammonium salt, and reaction is carried out in the presence or organic acid or salt thereof. Method makes it possible to make process more profitable. EFFECT: more efficient preparation method. 10 cl, 30 ex, 3 tbl