A challenging synthetic approach to phosphonium ylide-betaines of the pyrimidine series

• Published in: Tetrahedron Vol. 52; no. 26; pp. 8835 - 8852
• Main Authors: Meervelt, Luc Van, Smolii, Oleg B., Mishchenko, Nikolai I., Shakhnin, Dmitrii B., Romanenko, Evgenii A., Drach, Boris S.
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier Ltd 1996; Elsevier
• Subjects: Chemistry; Chemistry, Organic; Physical Sciences; Science & Technology; (2,2-DICHLORO-1-ACYLAMINOVINYL)TRIPHENYLPHOSPHONIUM CHLORIDES; SALTS; DERIVATIVES
• ISSN: 0040-4020; 1464-5416
• DOI: 10.1016/0040-4020(96)00425-5

Adducts of the available ylide Ph 3 P + -C̄HCN with acylisocyanates and their thio analogues undergo facile cyclization, promoted by hydrogen chloride in methanol, to give high yields of 2-alkyl(aryl)-4-hydroxy(mercapto)-6-oxo-1,6-dihydropyrimidin-5-yl-triphenyl-phosphonium chlorides suitable to prepare several types of phosphonium ylide-betaines of the pyrimidine series, the structure of which was established by chemical transformations and X-ray diffraction analysis. Despite the mesomeric character of these heterocyclic nucleophilic agents, they are alkylated in a regioselective manner, which proves this approach to be important for the synthesis of non-phosphorylated pyrimidine derivatives, which are otherwise difficult to obtain. The obtained reagents (A) have been applied in regioselective synthesis of many new phosphorylated and non-phosphorylated pyrimidine derivatives.