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19th March 2018 @ 15:14

2-chloro-6-(2-hydrazinyl(4-(dimethylamino)benzylidene))pyrazine) (51 mg, 0.18 mmol, 1.00 equiv.) was dissolved in DCM (20 mL) forming a yellow solution. PIDA (62 mg, 0.19 mmol, 1.1 equiv.) was then added. The yellow solution became progressively orange within two hours. The reaction was stirred for 2.5 hours at room temperature before heating to 30 °C for a further two hours. The reaction was monitored by TLC (3:7 Ethyl acetate : PET ether) however starting material remained so it was left stirring at room temperature overnight. After 22.5 hours the solution was a darker orange and TLC showed that only a small amount of starting material remained. The reaction was quenched with saturated sodium hydrogen carbonate solution. The organic layer was isolated by separation with brine before drying over MgSO4. The dried filtrate was concentrated in vacuo to a dark brown crude oil. The crude product was characterised by IR and 1HNMR before purification by silica column (5 g silica) with a 1:1 Ethyl acetate : PET ether solvent system. A dark brown powder (13.2 mg, 26 %) was obtained and the pure product, 5-chloro-3-(4-(dimethylamino)phenyl)-[1,2,4]triazolo[4,3-a]pyrazine, was then characterised by IR, 1HNMR, and 13CNMR, DEPT and MS.

 *Combined fractions 10-23 as pure product, fractions 3-9 were combined and retained in case of later analysis.

Attached Files
1HNMR Spectrum of 5-chloro-3-(4-(dimethylamino)phenyl)-[1,2,4]triazolo[4,3-a]pyrazine.pdf