Patent ID: 8222427

Claim:
A process for purifying the compound of Formula I the process comprising: (a) extracting an organic phase comprising: (i) the compound of Formula I; and (ii) one or more organic solvents, with an aqueous bisulfite solution, thereby forming an aqueous phase comprising a bisulfite adduct of the compound of Formula I; and (b) regenerating the compound of Formula I in a precipitate form by: (i) a process comprising: (1) extracting the aqueous phase containing the bisulfite adduct of the compound of Formula I provided in Step (a) with an organic phase comprising one or more water-miscible organic solvents, thereby forming an organic phase containing the compound of Formula I; and (2) mixing the organic phase provided in extracting Step (b)(i)(1) with water at a temperature suitable to precipitate the compound of Formula I; or (ii) adding the aqueous phase prepared in Step (a) into an organic phase comprising one or more water-miscible organic solvents thereby precipitating the compound of Formula I; or (iii) adding to the aqueous phase provided in Step (a) a carbonyl compound or an oxidant suitable to precipitate the compound of Formula I; or (iv) a process comprising: (1) extracting the aqueous phase provided in Step (a) with an organic phase comprising at least one organic solvent and optionally a carbonyl compound or an oxidant compound; and (2) adding the organic phase obtained in extracting Step (b)(iv)(1) to a solvent or mixture of solvents in which the compound of Formula I is insoluble (an antisolvent) at a temperature suitable to precipitate the compound of Formula I.