One-Pot Regioselective Synthesis of 5-Amino-3-Benzyl-7<i>H</i>-[1,3]Thiazolo[3,2-<i>A</i>]Pyrimidin-7-Ones via Sonogashira Coupling Reaction

Keivanloo, Ali; Bakherad, Mohammad; Rajaei, M

doi:10.1080/10426507.2014.885972

Cited by 1 publication

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“…Literature data mainly report the formation of 5-oxopyrimidines by cyclization through the N 3 atom of the starting 2-thiouracil [14][15][16][17][18][19][20][21][22][23][24]. The formation of 7-oxopyrimidines by cyclization through the N 1 atom has been noted only in a few reports [29][30][31][32]. However, reliable data for the identification of the 5-and 7-oxo isomers are not available to date and the determination of the structures of 5-and 7-oxo isomers were mainly based on 1 H NMR spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of 3(2)-phosphonylated thiazolo[3,2-a]oxopyrimidines

Kaskevich¹,

Babushkina²,

Gurzhiy³

et al. 2020

Beilstein J. Org. Chem.

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A series of 3(2)-phosphonylated thiazolo[3,2-a]oxopyrimidines was synthesized for the first time by the reactions of chloroethynylphosphonates with unsubstituted and 5(6)-substituted 2-thiouracils. The reaction of chloroethynylphosphonates with 6-substituted 2-thiouracils bearing electron-donor groups (CH3, Ph) proceeded with high regioselectivity involving the cyclization through the N3-nitrogen atom to form new 3-phosphonylated thiazolo[3,2-a]-5-oxopyrimidines with good yield. In the case of unsubstituted and 5-methyl-2-thiouracils, cyclization occurred predominantly through the N1 atom and partially via the N3-nitrogen atom to form a mixture of the corresponding thiazolo[3,2-a]-7- and 5-oxopyrimidines. A dramatic change in the reaction regioselectivity was observed in the case of 6-trifluoromethyl-2-thiouracil that afforded 2- and 3-phosphonylated 5-oxothiazolopyrimidines in a 1:1 ratio.

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