Patent ID: 6756512
Filing Date: 2004-06-29
Classification: C07C

Abstract:
A process for preparing a compound of the formula (I) where R is C1-C6-aIkyI, comprising(a) reacting a compound of the formula (II) â€ƒwhere R has the above meanings, with (a1) a base in a high-boiling organic diluent of the formula (III) R1â€”OHâ€ƒâ€ƒ(III), where R1 is R2â€”Oâ€”(CH2)2â€”Oâ€”(CH2)2â€”, R2â€”Oâ€”(CH2)2â€”O (â€”CH2)2â€”Oâ€”(CH2)2â€”, R2â€”Oâ€”(CH2)2â€”O(â€”CH2)2â€”Oâ€”(CH2)2â€”Oâ€”(CH2) 2â€”, or C6 to C10-alkyl, where R2 is hydrogen, methyl, or ethyl, optionally in the presence of a catalyst, wherein the water released by the reaction is continuously removed, to form a reaction mixture that is acidified with a dilute acid, or (a2) a base in a high-boiling organic diluant of the formula (III) R1â€”OHâ€ƒâ€ƒ(III), where R1 has the above meanings, optionally in the presence of a catalyst, wherein any water released during the reaction is continuously removed, to form a compound of the formula (IV) where R and R1 have the above meanings, that is then treated with a relatively highly concentrated acid, or (b) reacting a compound of the formula (II) â€ƒwhere R has the above meanings, with (b1) a base in a primary alcohol having 1 to 3 carbon atoms used as a diluent under pressure, to form a reaction mixture that is acidified with a dilute acid, or (b2) a base in a primary alcohol having 1 to 3 carbon atoms used as a diluent under pressure, to form a compound or the formula (IV) â€ƒwhere R has the above meanings, and R1 is the residue of a primary alcohol having 1 to 3 carbon atoms, that is then treated with a relatively highly concentrated acid.