4,6-Diamino-1H-pyrimidine-2-thione (1) was used for the preparation of pyrimidine derivatives 2-5. Compound 5 was cyclized to produce pyrimido[2,1-b][1,3]thiazine derivative 6 which was condensed with p-chlorobenzaldehyde to give compound 7. The latter compound was reacted with hydroxylamine to give isoxazolo[4,5-d]thiazino[2,3-a]pyrimidine 8. Compound 8b was treated with 2-chloroethyl methyl e...

C-5 alkynylated and N-1 alkylated pyrimidine derivatives were synthesized by N-alkylation reaction of 5-iodouracil in the presence of NaH, as a base, followed by Pd-catalyzed Sonogashira cross-coupling reaction of N-alkyl-5-iodouracil derivatives (1 and 2) with corresponding terminal alkynes. Intramolecular in situ O-heteroannulation ring closure of N-1-alkyl-C-5-alkynylpyrimidine derivatives (...

The novel hydrazone-containing thieno[2,3-d]pyrimidine, namely, N′-(1,3-dioxo-1,3-dihydro-2H-inden-2-ylidene)-2-(4-oxo-5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidin-3(4H)-yl)acetohydrazide 4 was synthesized in a very good yield from the reaction of triketoester 1 or ninhydrin 2 with exocyclic acetohydrazide 3 methanol. Good-quality crystals were obtained by recrystallization compound DMF/M...

H etero-Diels-Alder Reaction, a,/?-Unsaturated Ketones, Styrenes Cycloadditions of 3-aryl-2-benzoyl-2-propenenitriles la,b to styrene (2a) and its methylor methoxy-substituted derivatives 2b-d proceed regioand diastereoselectively yielding cis and trans diastereoisomers of 2,4,6-triaryl-3,4-dihydro-2//-pyran-5-carbonitriles 3 and 4 in 59-72% yield. Cycloadducts cis-3 were the major products. Re...

Novel, diverse pyrido [2,3-d] pyrimidine and pyrimido [4,5-d] pyrimidine analogs were synthesized by the reaction of 1,3-substituted-5-cyano uracil derivatives with appropriate nucleophile under mild conditions. Utilising 5-cyano uracil with various substitutions as a substrate leads to rapid synthesis of annulated uracils with diverse biological properties.

The reaction between barbituric acid or 2-thiobarbituric acid and different benzaldehydes, dependent upon the applied reaction conditions, selectively yields three different product types, i.e. 5-benzylidene(thio)barbituric acids II, symetric Michael adducts III or 5-phenyl-1H-pyrano[2,3-d]pyrimidine-2,4(3H,5H)-diones and 5-phenyl-2-thioxo-2,3-dihydro-1H-pyrano[2,3-d]pyrimidin-4(5H)-ones IV. Th...