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16th April 2019 @ 15:39

2-chloro-6-(2-hydrazinyl)(4-carboxybenzylidene)pyrazine was synthesised as an intermediate compound in the overall synthesis of 5-chloro-3-(4-carboxyphenyl)-[1,2,4]triazolo[4,3-a]pyrazine.

Reagent Mass/g Moles/mmol Equivalents
2-chloro-6-hydrazinopyrazine  0.0512 0.354 1.00
4-carboxybenzaldehyde 0.052 0.346 0.98

Yield: 70% 

Procedure

2-chloro-6-hydrazinopyrazine (0.0512 g, 0.354 mmol, 1 eq.) was added to a stirred solution of 4-carboxybenzaldehyde (0.052 g, 0.346 mmol, 0.98 eq.) in EtOH (10 mL) at rt in air. The resulting mixture was stirred and heated at reflux for 75 min. Then, the reaction mixture was allowed to cool to rt. The solution was then dried (MgSO4) and evaporated under reduced pressure to give the crude product. Purification by flash column chromatography on silica with 70:30 PET ether-EtOAc as eluent gave I1 (0.0672 g, 70%) as a yellow crystalline solid.

Analytical Data 

mp 229 – 231 °C; RF (70:30 PET ether-EtOAc) 0.28; 1H NMR (300 MHz, DMSO-d6) 𝛿# 11.72 (s, 1H), 8.60 (s, 1H), 8.11-8.08 (d, J = 9.0 Hz, 2H) 7.98-7.95 (d, J = 9.0 Hz, 2H), 7.85-7.82 (d, J = 9.0 Hz, 2H); 13C NMR (75.5 MHz, DMSO-d6) 𝛿( 167.4, 152.6, 146.0, 141.9, 139.0, 133.3, 131.5, 130.2, 129.4, 127.0; MS (ESI) m/z 277.0486

1H NMR spectrum (300 MHz) of 2-chloro-6-(2-hydrazinyl) (4-carboxybenzylidene) pyrazine I1 in DMSO-d6

1C NMR spectrum (75 MHz) of 2-chloro-6-(2-hydrazinyl) (4-carboxybenzylidene) pyrazine I1 in DMSO-d6

ESI Mass spectrum of 2-chloro-6-(2-hydrazinyl) (4-carboxybenzylidene) pyrazine I1.


Risk Assessment

Risk Assessment


Reaction Scheme
Attached Files
Risk Assessment
1H NMR spectrum (300 MHz) of 2-chloro-6-(2-hydrazinyl) (4-carboxybenzylidene) pyrazine I1 in DMSO-d6
1C NMR spectrum (75 MHz) of 2-chloro-6-(2-hydrazinyl) (4-carboxybenzylidene) pyrazine I1 in DMSO-d6
ESI Mass spectrum of 2-chloro-6-(2-hydrazinyl) (4-carboxybenzylidene) pyrazine I1.
Reaction Scheme