Microwave-assisted three-component synthesis of 7-aryl-2-alkylthio-4,7-dihydro-1,2,4-triazolo[1,5-a]-pyrimidine-6-carboxamides and their selective reduction.
Multicomponent reactions (MCRs) and microwave-assisted organic synthesis (MAOS) have been used as key methods for the synthesis of fused dihydropyrimidine derivatives. The three-component condensation of 3-amino-5-alkylthio-1,2,4-triazoles with aromatic aldehydes and acetoacetamides under microwave irradiation was developed as a rapid and efficient solution-phase method for the high-yielding preparation of 7-aryl-2-alkylthio-4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidine-6-carboxamide libraries. In addition, the selective reduction of the formed dihydrotriazolopyrimidines to trans-trans-2-alkylthio-7-aryl-4,5,6,7-tetrahydro-1,2,4-triazolo[1,5-a]pyrimidine-6-carboxamides was established. The described synthetic protocols provide rapid access to novel and diversely substituted dihydroazolopyrimidine libraries.
Chebanov
Valentin A
VA
Department of Chemistry of Heterocyclic Compounds, State Scientific Institution Institute for Single Crystals of National Academy of Sciences of Ukraine, Kharkiv. chebanov@isc.kharkov.com
Muravyova
Elena A
EA
Desenko
Sergey M
SM
Musatov
Vladimir I
VI
Knyazeva
Irina V
IV
Shishkina
Svetlana V
SV
Shishkin
Oleg V
OV
Kappe
C Oliver
CO