METHOD FOR PREPARING PENAM DERIVATIVES FROM DERIVATIVES OF CEPHAM Russian patent published in 2006 - IPC C07D499/04 

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to a method for synthesis of 2β-heterocyclylmethylpenam-derivatives of the formula (I):

wherein R₁ means hydrogen atom, protecting group for carboxyl group that forms, for example, ester or pharmaceutically acceptable salt; R₂ and R₃ can be similar or different and mean independently hydrogen, halogen atom, -NH₂, acylamino-, phthalimido-group under condition that both R₂ and R₃ don't mean -NH₂, acylamino-, phthalimido-groups; Het means 5-membered heterocyclic system comprising -NH and comprising one or some of nitrogen atoms (N) as a heteroatom. Method involves carrying out the following steps: (i) interaction of compound of the formula (VII):

wherein L means a leaving group and all other substitutes are determine above with compound of the formula (VIII): Het-H (VIII) wherein Het is determined above in the presence of a solvent and a base at temperature range from -10°C to 110°C to yield compound of the formula (IX):

wherein all substitutes are determined above; (ii) oxidation of compound of the formula (IX) with conventional oxidizing agents in the presence of water-soluble solvent and organic acid at temperature from -30°C to +50°C to yield compound of the formula (I), and if necessary (iii) desterification of compound of the formula (I) wherein R₁ means carboxy-protective group to yield compound of the formula (I) wherein R₁ means hydrogen atom by using metallic catalyst in the presence of a base and water-mixing solvent.

EFFECT: improved method of synthesis.

12 cl, 3 ex