US 7,511,139 B2
Process for the preparation of entecavir and novel intermediates thereof via carbon-silicon oxidation
Maotang X. Zhou, Jamesville, N.Y. (US); Emily A. Reiff, Milltown, N.J. (US); Purushotham Vemishetti, Monmouth Junction, N.J. (US); Yadagiri R. Pendri, South Glastonbury, Conn. (US); Ambarish K. Singh, Bordentown, N.J. (US); Siva Josyula Prasad, Kendall Park, N.J. (US); Ulhas P. Dhokte, Kendall Park, N.J. (US); Xinhua Qian, Flemington, N.J. (US); Pia Mountford, Barceloneta, Puerto Rico (US); Kerry B. Hartung, Minoa, N.Y. (US); and Helen Sailes, Dublin (Ireland)
Assigned to Bristol-Myers Squibb Company, Princeton, N.J. (US)
Filed on Jun. 02, 2005, as Appl. No. 11/143,268.
Claims priority of provisional application 60/576899, filed on Jun. 04, 2004.
Prior Publication US 2005/0272932 A1, Dec. 08, 2005
Int. Cl. C07D 473/00 (2006.01)
U.S. Cl. 544—264 3 Claims
 
1. A process for the preparation of a compound of formula I,

OG Complex Work Unit Drawing
comprising:
(a) converting the compound of formula 3a to a compound of formula 3b via protodesilylation, wherein Ra is allyl, phenyl, or phenyl substituted with one, two or three C1-C4 alkyl or C1-C4 alkoxy; each Rb is independently C1-C4 alkyl; and Rc is H or Bn,

OG Complex Work Unit Drawing
(b) further converting the compound of formula 3b to a compound of formula 3f,

OG Complex Work Unit Drawing
wherein each Rb and Rc are defined as hereinabove;
(c) oxidizing the compound of formula 3f to give the compound of formula I when Rc is H; or a compound of formula 3 g when Rc is Bn,

OG Complex Work Unit Drawing
(d) deprotecting the benzyl group in the compound of formula 3g wherein Rc is Bn to give a compound of I.