Mitsunobu reactions 2/7-1,2,3-triazole

Triazolopyridines and 1,2,4-triazolopyrimidines were synthesized using a modified Mitsunobu reaction starting from acylated 2-hydrazinopyridines and acylated-hydrazinopyrimidines under mild conditions <07ARK132>. A series of 3-alkylthio-4,5-diaryl-4//-1,2,4-triazoles were prepared from benzoic acid hydrazides <07JHC1323>. 

Syntheses of quaternary l-alkyl-3-perfluoroalkyl-4,5-dimethyl-l,2,4-triazolium iodides have led to the disclosure of a variety of new quaternary salts <04JOC1397>. Arylation of 3-alkylthio-5-aryl-l,2,4-triazoles under basic conditions gave 5-alkylthio-l,3-diaryl-l,2,4-triazoles in moderate yields <04JHC201>. Acyl hydrazides 155 reacted with imidates 156 to yield 1,2,4-triazoles 157 followed by Mitsunobu reactions with amino alcohols 158 to give regioisomeric... 

D-Xylose has been converted to (25)-3-(indol-3-yl)propane-l,2-diol 237 by two different routes, one involving direct Fischer indolization of 238. The dibenzyl-dithioacetal 239 was elaborated to the fused triazoline 240 following reaction with MCPBA. Initial oxidation was followed by elimination of acetic acid allowing intramolecular 1,3-dipolar cycloaddition reaction to construct the triazole ring. The bicyclic iV,S -acetals 242 and 241 were prepared by reaction of the 2,3-0-isopropylidene-D-ribofuranose with 2-aminoethane thiol followed by Mitsunobu reaction. These products are considered analogues of castanosper-mine and australine. ... 

Alkylation. Alkylation of the title compound is also a key transformation to gain access to more elaborated triazoles. It has been shown that alkylation of the N-2 position using methyl iodide is possible by a Sn2 process (eq 3). Both N-1 and N-2 positions can be alkylated with no selectivity for either regioisomer. Various alkylating aromatic or aliphatic agents can be used and yields higher than 80% can be obtained. It is also possible to alkylate via a Mitsunobu reaction to afford a similar alkylation at the N-2 position (eq A)P It has also been shown that it is possible to alkylate both the N-1 and N-3 posihons to form nitrenium ions using an intermolecular hydroamination method (eq 5). ... 

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