Cyclin-dependent kinase (CDK) inhibitors: development of a general strategy for the construction of 2,6,9-trisubstituted purine libraries. Part 3
作者:Virginie Brun、Michel Legraverend、David S Grierson
DOI:10.1016/s0040-4039(01)01753-1
日期:2001.11
Experiments to effect Sonogashira (Ph3P)(2)Cl2Pd-CuI-based coupling of 3-methylpentyn-3-ol at C-2 of a 2-iodo-6-thiopurine derivative, bound via the sulfur atom to a Merrifield resin failed. In contrast, the analogous reaction with Pd(dppe)CI, and trans-di(mu -acetato)bis[o-(di-o-tolylphosphino)benzyl]dipalladium catalysts were successful (20 25%), indicating that (Ph3P)(2)Pd(0) loses its ligands irreversibly on contact with the resin bound purine. The coupling yield was improved considerably (58%) using a Merrifield resin in which a valeric acid linker is interposed between the purine and the resin. (C) 2001 Elsevier Science Ltd. All rights reserved.