778570-09-5Relevant articles and documents
An efficient and large-scale enantioselective synthesis of PNP405: A purine nucleoside phosphorylase inhibitor
Prashad, Mahavir,Har, Denis,Chen, Lijian,Kim, Hong-Yong,Repic, Oljan,Blacklock, Thomas J.
, p. 6612 - 6617 (2007/10/03)
An efficient and large-scale enantioselective synthesis of PNP405 (1), a purine nucleoside phosphorylase inhibitor, is described. This synthesis of 1 involved eight steps starting from o-fluorophenylacetic acid with a 21.6% overall yield and >99.5% enantiopurity. The key stereogenic center with (R)-configuration was created using Evans' asymmetric alkylation methodology. This synthesis also features the racemization-free reductive removal of the chiral auxiliary in 5 using sodium borohydride, protection of the γ-cyano alcohol 6 as the trityl ether by a new water-assisted tritylation with trityl chloride and triethylamine or with trityl alcohol and catalytic trifluoroacetic acid, and an efficient one-pot cyclo-guanidinylation of 10 using cyanamide as the guanidinylating agent.