Patent ID: 8664386

Claim:
A method for the selective crystallization of 9-{(R)-2-[((S)-{[(S)-1-(isopropoxycarbonyl)ethyl]amino}phenoxyphosphinyl)methoxy]propyl}adenine, comprising the steps of: subjecting at 0-50° C. a solution comprising: a) a suitable solvent; b) a suitable base; and c) 9-{(R)-2-[((R,S)-{[(S)-1-(isopropoxycarbonyl)ethyl]amino}phenoxyphosphinyl)methoxy]propyl}adenine, to crystallization-induced dynamic resolution using a seed crystal of 9-{(R)-2-[((R,S)-{[(S)-1-(isopropoxycarbonyl)ethyl]amino}phenoxyphosphinyl)methoxy]propyl}adenine under conditions that provide for the epimerization of the phosphorous center.