2-Pyrazinecarboxylic acid, hydrazide

Pyrazine-2-carboxylic acid hydrazide. To a stirred solution of pyrazine-2-carboxylic acid methyl ester (11.1 g, 80 mmol) in 140 mL OF ETOH was added hydrazine hydrate (15.6 ML, 320 mmol). The resultant solution was heated to reflux for 2h. The solvent was removed under reduced pressure and dried under high vacuum to yield the title amide (11.1 g, 100percent) as a white solid. The product was used in subsequent steps without purification.Example 261; 5-Phenyl-2-(3-pyrazin-2-yl-ureido)-thiophene-3-carboxylic acid (S)-azepan-3-ylamide pyrazine-2-carbohydrazide. ; To a stirred solution of methyl pyrazine-2-carboxylate (11.1 g, 80 mmol) in 140 mL of EtOH was added hydrazine hydrate (15.6 mL, 320 mmol). The resultant solution was heated to reflux for 2h. The solvent was removed under reduced pressure and dried under high vacuum to yield the title amide (11.1 g, 100percent) as a white solid. The product was used in subsequent steps without purification.'H NMR (d6-DMSO 8 10.1, br s, 1H; 8 9.12, d, 1H ; 8 8. 83, d, 1H ; 8 8.70, dd, 1H; 8 4.64, br s, 2H), LC/MS (APCI, ES, M+H=139).General procedure: To a solution of an appropriate methyl esters17(a–j) (1.0 mmol) in 50 mL of methanol was added 99 percenthydrazine hydrate (4.0 mmol) and the mixture was refluxedfor 5 h up to reaction completed (TLC). After completionof reaction, it was allowed to cool and the obtained solidwas washed with methanol. The crude products wererecrystallized from ethanol.Example 21.1Pyrazine-2-carbohydrazide To the title compound of Example 19.1 (1.28 mg, 9.3 mmol) in ethanol (10 mL) was added hydrazine hydrate (0.54 mL, 11.1 mmol) and then heated at 78° C. overnight. The reaction mixture was cooled and concentrated in vacuo. The residue was triturated with ethyl acetate, filtered and dried to give the title product as a yellow solid (870 mg, 68percent).Methyl pyrazine-2-carboxylate (0.5g; 3.6mmol) was dissolved in THF (5mL), and 98percent hydrazine (0.53mL; 11mmol) was added. The mixture was refluxed for 3h and cooled to rt. The resulting solid was filtered off, washed with THF and dried over PGeneral procedure: A mixture of the ester derivative 8a or 8b (5.5 mmol) and hydrazine hydrate (11 mmol) in 50 mL of ethanol was heated under reflux for 6 h. The reaction mixture was left overnight at room temperature, and the solid which separated was collected by filtration. The solid was then washed with ethanol, dried, and recrystallized from ethanol (Yoshino et al., 2006; Vlaovic et al., 1990).A mixture of pyrazine-2-carboxamide (1) 50 g (0.406 mol) in ethanol (500 mL) and hydrazine hydrate (98percent) 34.76 g (0.695 mol) was refluxed for 12 h. The completion of reaction was monitored by TLC (Hexane 6: Ethyl acetate 4). The reaction mass cooled to 10-15°C and filtered off under vacuum. Pyrazin-2-carboxamide is highly soluble in iso-octane at 25-30°C. Iso-octane (50 mL) washing given and suck dried to give pure white to off white solid compound (2) 41.50 g (80.00percent) mp-168-170°C. IR (KBr, cm

Molecular Weight:138.13
XLogP3:-0.9
Hydrogen Bond Donor Count:2
Hydrogen Bond Acceptor Count:4
Rotatable Bond Count:1
Exact Mass:138.05416083
Monoisotopic Mass:138.05416083
Topological Polar Surface Area:80.9
Heavy Atom Count:10
Complexity:127
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes