How could we prevent dimerization of thienopyrimidinone in basic conditions?

I'm working on nucleophilic substitutions on 2-(chloromethyl)thieno[2,3-d]pyrimidin-4(3H)-one with phenol/thiophenol/aniline derivatives (such as di phenylureas or diphenylacetamide). I have tried...

11 October 2013 568 14 View