US 7,414,114 B2
Process for preparation of anhydrous azithromycin
Shiva P. Singh, Gujarat (India); Siddiqui M. Jaweed Mukarram, Maharashtra (India); Manish Purohit, Mahatashtra (India); and Anjum R. Khan, Aurangabad (India)
Assigned to Wockhardt Limited, Mumbai (India)
Filed on Feb. 24, 2003, as Appl. No. 10/373,349.
Application 10/373349 is a continuation of application No. PCT/IB01/01523, filed on Aug. 23, 2001.
Claims priority of provisional application 60/227341, filed on Aug. 23, 2000.
Prior Publication US 2003/0139583 A1, Jul. 24, 2003
Int. Cl. C07H 17/08 (2006.01)
U.S. Cl. 536—7.4 11 Claims
 
1. A process for preparing an anhydrous compound having formula I:

OG Complex Work Unit Drawing
wherein R1 represents hydrogen, (C1-C6)-alkyl, (C6-C10)-aryl or (C7-C16)-aralkyl; and each R2, R3, R4, R5 and R6 individually represents hydrogen or (C1-C4)alkyl; consisting essentially of removing, by distillation, a halo(C1-C6)alkane solvent from a solution prepared by dissolving a hydrated compound of Formula I and water in the halo(C1-C6)alkane solvent so as to provide the anhydrous compound through removal of the water from the solution by co-distillation or azeotropic distillation of the water with the solvent.