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16th April 2019 @ 21:52

5-chloro-3-(2-hydroxyphenyl)-[1,2,4]triazolo[4,3-a]pyrazine was synthesised using previously synthesised intermediate 2-chloro-6-(2-hydrazinyl)(2-hydroxybenzylidene)pyrazine.

Reagent Mass/g Moles/mmol Equivalents
2-chloro-6-(2-hydrazinyl)(2-hydroxybenzylidene)pyrazine 0.020 0.080 1.00
diacetoxyiodobenzene 0.0290 0.090 1.13

Yield: 54.3%


2-chloro-6-(2-hydrazinyl(2-hydroxybenzylidene)pyrazine (20 mg, 0.080 mmol, 1 eq.) and diacetoxyiodobenzene (29 mg, 0.090 mmol, 1.13 eq.) was dissolved in DCM (10 mL) and left overnight stirring under an atmosphere of nitrogen. The reaction was monitored by TLC using a variety of solvent systems (1:1 PET ether: EtOAc, 1:3 PET ether: EtOAc, 100% EtOAc, 20% MeOH in EtOAc and 1% acetic acid in EtOAc) however the spots did not move off the baseline and so the product was not suitable for purification by column chromatography. The solvent was removed in vacuoto give a dark orange powder which was analysed by mass spec and 1H NMR. Both NMR and mass spec showed that the intended product was not formed.

Analytical Data 

mp 261-264 °C.

InChI Key:

2-chloro-6-(2-hydrazinyl(2-hydroxybenzylidene)pyrazine: BTVQPPGRWZUSCA-LHHJGKSTSA-N


5-chloro-3-(2-hydroxyyphenyl)-[1,2,4]triazolo[4,3-a]pyrazine: GLKVTIUQXSULMV-UHFFFAOYSA-N


Attached Files
2-hydroxybenzaldehyde reaction 2.pdf
ESI MS 5-chloro-3-(2-hydroxyphenyl)-[1,2,4]triazolo[4,3-a].png
1H NMR 5-chloro-3-(2-hydroxyphenyl)-[1,2,4]triazolo[4,3-a].png