Synthesis of New Derivatives of 5-Acetyl-4-hydroxy-2H-1,3-thiazine-2,6(3H)-dione

Abstract

5-Acetyl-4-hydroxy-2H-1,3-thiazine-2,6(3H)-dione reacted with cyclohexyl and benzyl (4-aminophenyl)carbamates in boiling ethanol in the presence of a catalytic amount of glacial acetic acid to give the corresponding Schiff bases, cyclohexyl and benzyl (4-{[(E)-1-(4-hydroxy-2,6-dioxo-3,6-dihydro-2H-1,3-thiazin-5-yl)ethylidene]amino}phenyl)carbamates. Heating of the latter in dimethylformamide for 2 h was accompanied by evolution of COS with the formation of cyclohexyl and benzyl {4-[6-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-yl]phenyl}carbamates. The condensation of the title compound with benzene-1,2-diamine in propan-2-ol, followed by addition of 5-arylfuran-2-carbaldehyde and trifluoroacetic acid afforded 5-(2-{5-[4-bromo(nitro)phenyl]furan-2-yl}-2,3-dihydro-1H-1,5-benzodiazepin-4-yl)-4-hydroxy-2H-1,3-thiazine-2,6(3H)-diones. 5-((E)-3-{5-[4-Bromo(nitro)phenyl]furan-2-yl}prop-2-enoyl)-4-hydroxy-2H-1,3-thiazine-2,6(3H)-diones were synthesized by condensation of 5-acetyl-4-hydroxy-2H-1,3-thiazine-2,6(3H)-dione with 5-[4-bromo(nitro)phenyl]furan-2-carbaldehydes in chloroform in the presence of catalytic amounts of pyridine and piperidine.