Patent ID: 6348592
Filing Date: 2002-02-19
Classification: C07D,C09B

Abstract:
A method of making a compound represented by the Structure identified as Compound V below, said method comprising:A) reacting the following Compound I with the following Compound II to form the following Compound III in a first reaction mixture comprising one or more organic solvents, wherein the molar ratio of said Compound I to Compound II initially in said first reaction mixture is from about 1.5:1 to about 2:1, B) reacting the resulting Compound III with an organic acylating agent to form the following Compound IV in the presence of one or more organic solvents, wherein the initial molar ratio of Compound III to said organic acylating agent is from about 0.4:1 to about 0.6:1, wherein R in Compounds IV and V below is a monovalent organic radical derived from said organic acylating agent, â€ƒand C) reacting the resulting Compound IV with squaric acid to form the following Compound V in a separate reaction mixture under conditions that provide for at least partial removal of water from said separate reaction mixture, said separate reaction mixture comprising at least one hydroxylic organic solvent and at least one nonpolar organic solvent, such that squaric acid is at least partially soluble in said hydroxylic organic solvent, and the weight ratio of said hydroxylic organic solvent to said nonpolar solvent is sufficient to provide a ternary azeotrope with water, wherein the molar ratio of Compound IV to squaric acid initially in said separate reaction mixture is at least 1.8:1.