A base-promoted ring expansion of 3-amino-4-hydroxyhexahydropyrimidine-2-thiones into 2,4,5,6-tetrahydro-3H-1,2,4-triazepine-3-thiones has been developed. Experimental data and DFT calculations showed that the reaction proceeded through fast formation of intermediate acyclic isomers of pyrimidines followed by their slow cyclization into triazepines. The starting hydroxypyrimidines were prepared by reaction of α,β-unsaturated ketones or β-alkoxy ketones with HNCS followed by treatment of the obtained β-isothiocyanato ketones with hydrazine.
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LINEAR REGRESSION MODELS OF MOULTING ACCELERATING COMPOUNDS WITH INSECTICIDE ACTIVITY AGAINST THE SILKWORM BOMBYX MORI L.Next Article in session
A Novel Ring Expansion of Pyrimidines to 1,2,4-Triazepines
Published: 01 November 2016 by MDPI in The 20th International Electronic Conference on Synthetic Organic Chemistry session General Organic Synthesis
Keywords: Isothiocyanato ketones; Thiosemicarbazides; Pyrimidines; Ring expansion; 1,2,4-Triazepines