Synthesis and structure of norbornane/ene-fused thiouracils and thiazino[3,2-a]pyrimidinones

Géza Stájer, Angela E. Szabó, Pál Sohár

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Ethyl diexo- 3-aminobicyclo[ 2.2.1]heptane- and -hept-5-ene-2- carboxylares (1a,b) and the diendo derivatives were transformed with thiophosgene to the isothiocyanates (2a,b and 3a, b) and then cyclized to the norbornane/enecondensed 2-thioxopyrimidin-4-ones (4a, b and 5a, b). On heating, the norbornene compounds (4b and 5b) furnished thiouracil (6) via cyelopentadiene elimination. With dimethyl acetylenedicarboxylate, the thioxopyrimidinones (4a,b) and (5a,b) form angularly-fused [1,3]thiazino[3,2- a]pyrimidinones (7a,b and 8a,b). On heating, 7b decomposes to give 3-methyl- 2,3-dihydro-2-thioxo-4(1H)-pyrimidinone (9) in a retro Diels-Alder process by methyl migration and splitting-off of cyclopentadiene. The structures were elucidated by IR and NMR spectroscopies, with DNOE, DEPT and 2D-HSC techniques.

Original languageEnglish
Pages (from-to)1849-1854
Number of pages6
JournalHeterocycles
Volume51
Issue number8
DOIs
Publication statusPublished - Aug 1 1999

ASJC Scopus subject areas

  • Analytical Chemistry
  • Pharmacology
  • Organic Chemistry

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