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SYNTHESIS OF METHYL 2-[2-(4-PHENYL[1,2,4]TRIAZOLO[4,3-a]QUINOXALIN-1-YLSULFANYL)ACETAMIDO]ALKANOATES AND THEIR N-REGIOISOMERIC ANALOGS

Walid Fathalla
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Abstract


Methyl 2-[2-(4-phenyl[1,2,4]triazolo[4,3-a]quinoxalin-1-ylsulfanyl)acetamido]alkanoates were formed by the reaction of 2-(4-phenyl-1,2-dihydro[1,2,4]triazolo[4,3-a]quinoxalin-1-ylsulfanyl)acetic acid with a variety of amino acid esters via DCC coupling method in the presence of N-hydroxybenzotriazole in good yields. These amino acid derivatives linked to triazoloquinoxaline moiety were also obtained by the reaction of 2-(4-phenyl[1,2,4]triazolo[4,3-a]quinoxalin-1-ylsulfanyl)acetohydrazide with amino acid ester derivatives via azide coupling method in poor yields due to the competing decomposition of the corresponding azide resulting in the starting 4-phenyl[1,2,4]triazolo[4,3-a]quinoxaline-1(2H)-thione. The N-regioisomeric methyl 2-[3-(4-phenyl-1-thioxo[1,2,4]triazolo[4,3-a]quinoxalin-2(1H)-yl)propanamido]alkanoates were efficiently produced from the 3-(4-phenyl-1-thioxo[1,2,4]triazolo[4,3-a]quinoxalin-2(1H)-yl)propanohydrazide and amino acid esters via azide coupling method in good to moderate yields.

How to Cite
Fathalla, W. Chem. Heterocycl. Compd. 2015, 51, 73. [Khim. Geterotsikl. Soedin. 2015, 51, 73.]

For this article in the English edition see DOI 10.1007/s10593-015-1662-0


Keywords


amino acids; N,N'-dicyclohexylcarbodiimide; azide coupling; chemoselective alkylation; Michael addition; tautomerism

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