ES427234A1 - A procedure for the preparation of a cefalosporine. (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

A process for the preparation of a cephalosporin of formula (I) or a pharmaceutically acceptable salt or an ester thereof: **(See formula)** where Y is oxygen or sulfur; R1 is an organic radical containing up to 20 carbon atoms; R2 is alkyl of 1 to 3 carbon atoms or benzyl; or R1 and R2 attached to the carbon and nitrogen atoms to which they are attached form a 5-, 6- or 7-membered ring; R3 is phenyl, phenyl substituted with one or more functional groups selected from the hydroxy, halogen, nitro, alkoxy groups of 1 to 3 carbon atoms and amino, 2- or 3-thienyl, cycloalkyl of 3 to 7 carbon atoms or alkyl from 1 to 4 carbon atoms; R4 is acetoxy or is a carbon, nitrogenous or sulfurized nucleophile; whose procedure consists of (a) reacting a compound of formula (II) or a salt, ester or silyl derivative thereof: **(See formula)** where the dotted line represents a bond at position 2 or 3, n is 0 or 1 and R4 is as defined when dealing with formula (I), with a reactive N-acylating derivative of an acid of formula (III): **(See formula)** where Y, R1, R2 and R3 are those defined in formula (I) and where any reactive group, such as amino and hydroxy groups, may be blocked or (b) react a compound of formula (IV) or a salt, ester or silyl derivative thereof: **(See formula)** where the dotted line represents a bond at position 2 or 3, R3 and R4 are those defined by dealing with formula (I), with a compound of formula (V) where Y, R1, R2 and R3 are those defined by try formula (I), or (c) in the case of compounds of formula (I) where R4 is a carbonated, sulfurized or nitrogen nucleophile, react a compound of formula (VI) or a salt, ester or derivative silyl thereof: **(See formula)** where the dotted line represents a bond at position 2 or 3, n is 0 or 1, and Y, R1, R2, and R3 are those defined in formula (I) and where any reactive group may be blocked, with a carbon nucleophile, sulfided or nitrogenous and, after reaction (a), (b), or (c), carry out one or more of the following operations, if necessary: (i) converting a Δ 2 isomer to the desired Δ 3 isomer, (ii) separating any silyl group by alcoholysis or hydrolysis, (iii) reducing a sulfoxide compound to form the desired sulfide compound, (iv) separating any group of blocking in the acyl side chain R, (v) converting an ester compound into a free acidic compound or a free acidic compound into a salt thereof. (Machine-translation by Google Translate, not legally binding)