Reaction of trifluoroacetylchromenes with 6-aminouracils. Synthesis of pyrido[2,3- d]pyrimidines.

The condensation of trifluoroacetyl-substituted 4 H-chromenes and 1 H-benzo[ f]chromenes with 6-amino-1,3-dimethyluracil and 6-aminothiouracil afforded a number of pyrido[2,3-d]pyrimidine derivatives containing a 2-hydroxybenzyl or 2-hydroxynaphthalen-1-ylmethyl group in the 6-position as a result of cascade transformation initiated by Michael addition. [ABSTRACT FROM AUTHOR]