Additive-Free Construction of Tetrahydropyrimidine Skeleton by using 1,3,5-Triazinane as Four-Atom Synthon.

Herein, an unprecedented [4 + 2] cycloaddition of enaminone with 1,3,5-triazinane has been developed. The representative semihydrogenated aromatic heterocycle 1,2,3,4-tetrahydropyrimidines have been synthesized with a broad substrate scope, demonstrating potential antitumor activity. This approach has been smoothly conducted under additive-free and environmentally friendly conditions that are compatible with various functional groups.

Mn(OAc)-promoted [3+2] cyclization of enaminone with isocyanoacetate: Rapid access to pyrrole-2-carboxylic ester derivatives with potent anticancer activity.

The practical and facile Mn(OAc)-promoted [3+2] cycloaddition reaction of enaminones with isocyanoacetate was developed, that delivered a diversity of 3-aroyl pyrrole-2-carboxylic esters with broad substrates scope. The most of the newly synthesized compounds exhibit moderate antiproliferative activity against four cancer cells. Notably, compound 2n demonstrate the most potent activity with average IC values of 5.