Reaction of 3-Amino-4,6-diarylthieno[2,3-b]pyridine-2-carboxamides with Ninhydrin

The reaction of N-substituted amides of 3-amino-4,6-diarylthieno[2,3-b]pyridine-2-carboxylic acids with ninhydrin in the presence of catalytic amounts of sulfuric acid gave 1′-spiro[indene-2,2′-pyrido[3′,2′:4,5]thieno[3,2-d]pyrimidine]-1,3,4′(3′H)-triones. Structure of a number of key compounds was studied using 2D NMR spectroscopy; the bioavailability parameters of the obtained compounds in silico were calculated. In a laboratory experiment, a moderate antidote effect was revealed with respect to the 2,4-D herbicide for one compound.