Original scientific paper

Hydropyrimidines. V. Isomeric Dihydro 2- and 4-0xopyrimidines

V. Škarić ; Institute »Ruder Boskovic«, Zagreb, Croatia, Yugoslavia
B. Gašpert ; Institute »Ruder Boskovic«, Zagreb, Croatia, Yugoslavia
I. Jerkunica ; Institute »Ruder Boskovic«, Zagreb, Croatia, Yugoslavia

Abstract

Desulfurization of, thio analogs of 5,f.-dihydrouracil and partial
hydrogenation of oxopyrimidines* were investigated as synthetic
routes for the preparation of isomeric dihydropyrimidines.
The synthesis of unstable 1-methyl-5,6-dihydro-4-oxopyrimidine
(IX) from 1-methyl-5,6-dihydro-2-thiouracil (X) is described.
Desulfurization of 5,6-dihydro-2-thiouracil (XV) and its 3-methyl
derivative (XI) afforded the corresponding dihydro-4-oxo-pyrimidines
XVI and XII having the double bond at 1V.2 position. The
structures of XII and XVI were confirmed by hydrogenation to the
tetrahydro compounds XVII and XIII.
The more stable dihydro-2-oxopyrimidines III, IV and XIX were
prepared from the corresponding 4-thiouracils XX, XXI and
XVIII. The NMR spectra of 2- and 4-oxopyrimidines, their dihydro
and tetrahydro derivatives as well as of 5,6-dihydrouracil and its
thio analogs are discussed.

Keywords

Hrčak ID:

208178

URI

https://hrcak.srce.hr/208178

Publication date:

25.7.1966.

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