METHOD FOR PREPARING 6-ALKYLIDENEPENEM DERIVATIVES Russian patent published in 2008 - IPC C07D499/88 C07D519/00 

FIELD: organic chemistry, chemical technology, antibiotics.

SUBSTANCE: invention relates to a method for synthesis of compounds of the formula (I): wherein one of substitutes A or B means hydrogen atom (H) and another one means aryl substituted optionally with one or two R₂, heteroaryl substituted optionally with one or two R₂, and so on; R represents H, (C₁-C₆)-alkyl, (C₅-C₆)-cycloalkyl or -CHR₃-OCO-(C₁-C₆)-alkyl or salt; R₂ represents hydrogen atom, optionally substituted (C₁-C₆)-alkyl, optionally substituted (C₂-C₆)-alkenyl, and so on; R₃ represents hydrogen atom, (C₁-C₆)-alkyl, (C₅-C₆)-cycloalkyl, optionally substituted aryl, optionally substituted heteroaryl. Method for synthesis of these compounds involves the following steps: (a) condensation of substituted aldehyde of the formula: (A'-CHO) (17) wherein A' represents A, such as given above when B represents hydrogen atom; or B, such as given above when A represents hydrogen with derivative of 6-bromopenem of the formula (16): wherein R represents p-nitrobenzyl in the presence of Lewis acid and a weak base at low temperature that results to formation of intermediate aldol product of the formula (18): ; (b) interaction of intermediate compound of the formula (18) with chloroanhydride or acid anhydride of the formula: (R₈)Cl or (R₈)₂O or with tetrahalogen methane of the formula: C(X₁)₄ and triphenylphosphine wherein R₈ represents alkyl-SO₂, aryl-SO₂, alkyl-CO or aryl-CO; X₁ represents Br, J or Cl atoms to form intermediate compound of the formula (19): wherein R₉ represents X₁ or -OR₈, and conversion of intermediate compound of the formula (19) to the end compound of the formula (I). Also, invention relates to 4-nitrobenzyl-(5R,6S)-6-bromopenem-3-carboxylate of the formula (16) and to a method for its synthesis. Method involves the following steps: (A) (i) interaction of 6-aminopenicillanic acid with hydrobromic acid in organic solvent and water to form 6-bromopenicillanic acid of the formula (21): and its conversion to p-nitrobenzyl-6-bromopenicillanate of the formula (22): wherein R represents p-nitrobenzyl by interaction with 4-nitrobenzyl bromide in the presence of a base in organic solvent; (B) oxidation of compound of the formula (22) to form p-nitrobenzyl-6-bromopenicillanate-1-oxide of the formula (23) given in the invention description; (C) boiling compound of the formula (23) with 2-mercaptobenzothiazole in aromatic solvent to form 4-nirobenzyl-(2R)-2-[(3S,4R)-4-(benzothiazol-2-yldithio)-3-bromo-2-oxoazethidin-1-yl]-3-methylbut-3-enoate of the formula (24) given in the invention description; (D) dissolving compound of the formula (24) in organic solvent and interaction with an organic tertiary base to form 4-nitrobenzyl-2-[(3S,4R)-4-(benzothiazol-2-yldithio)-3-bromo-2-oxoazethidin-1-yl]-3-methylbut-2-enoate of the formula (25) given in the invention description; (E) conversion of compound of the formula (25) to 4-nitrobenzyl-2-[(3S,4R)-3-bromo-4-formylthio-2-oxoazethidin-1-yl]-3-methylbut-2-enoate of the formula (26) given in the invention description as result of interaction of with organic acid in aromatic organic medium in the presence of a mixture acetic anhydride/organic tertiary base and trialkyl- or triarylphosphine in the range of temperature from about -10°C to about -30°C, and (F) passing ozonized oxygen through solution of compound of the formula (26) in organic solvent for 3-4 h at temperature from -70°C to -90°C and the following the intramolecular cyclization reaction using a phosphite reagent. Invention provides the increased yield and economy method for synthesis of derivatives of 6-alkylidenepenem.

EFFECT: improved method of synthesis.

41 cl, 2 tbl, 42 ex