Patent ID: 8519168

Claim:
A process for making the compounds of Formula A, the process comprising: (a) forming the dialkyl-squarate of Formula A1 in situ by reacting (R 3 —O—) 3 —CH with squaric acid, wherein R 3 is selected from linear, branched, and cyclic alkyls of up to 10 carbon atoms; (b) reacting the amino-hydroxy-benzamide compound of Formula B wherein [Anion − ] is a monovalent anionic moiety, with the dialkylsquarate from step “a” to form the compound of Formula C, wherein R 3 is as defined above; (c) reacting the compound of formula C formed in step “b” with a free base amino-furan compound of formula D1 formed in situ, wherein R 2 is H or a substituent comprising from 1 carbon atom to about 10 carbon atoms selected from linear, branched, or cyclic alkyl moieties and substituted linear, branched and cyclic alkyl moieties, to provide the compound of formula A; and (d) optionally precipitating the compound of Formula A by: (i) successive cycles of concentrating the reaction mixture formed in step “c” by distillation followed by the addition of an aliquot of an alcohol; (ii) adding an aliquot of the alcohol used in Step “d(i)” and acetic acid to the concentrate formed in step “i”; (iii) heating the solution formed in step “ii”; (iv) adding an aliquot of water and seed crystals to the hot solution from step “iii”; (v) cycling the temperature of the seeded solution prepared in step “iv” until crystals of the compound of Formula A having a desired size are formed; and (vi) optionally isolating the crystals from the mixture prepared in step “v”.