DNA-protein cross-linking: model systems for pyrimidine-aromatic amino acid cross-linking.

[reaction: see text] We have synthesized simple model systems to explore the possibility of photo-cross-linking between the pyrimidine bases and the side chains of the aromatic amino acids. Thymine/phenylalanine and thymine/tyrosine models gave cross-links, and thymine/tryptophan models gave complex mixtures; the cytosine/phenylalanine model was unreactive. The quantum yields for the model cross-linking reactions were 18-46 times smaller than those for thymine dimer formation. Biphotonic excitation contributes little to the yield of these reactions.

Synthesis of a novel, recyclable, solid-phase acylating reagent.

In this paper, we describe the synthesis of N-(6-cyano-1,3-dimethyl-2,4-dioxo-5-substituted-1,3-dihydropyridino[2,3-d] pyrimidin-7-yl)imides 1. We will show the synthesis of 1 using both conventional heating and microwave techniques. In addition, the imide was attached to polystyrene and this immobilized imide was equally as effective at acylating various primary and secondary amines as its solution-phase counterpart.