Electric Literature of 768-05-8, A common heterocyclic compound, 768-05-8, name is Pyrazinoic acid hydrazide, molecular formula is C5H6N4O, its traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route.
Potassium hydroxide 11.5 g (0.20 mol) was dissolved in absolute ethanol (400 mL) at ambient temperature. Then pyrazine-2-carbohydrazide (2) 40g (0.299 mole) added and reaction mass was cooled. Carbon disulfide 25.08 g (0.33 mol) added in small portions and the mixture was stirred at reflux temperature for 12 h. The reaction mixture changed to green colour with the evolution of hydrogen sulfide. The completion of reaction was monitored by TLC (Chloroform 9.5: Methanol 0.5). Ethanol completely distilled under vacuum below 50C. The reaction mass cooled to 25-30C. Water (100 mL) added to dissolve salts and pH 6.0-7.0 adjusted by conc. HCl (20 mL). Solid precipitated out. Stir at 25-30C for 1h, solid filtered, water (50 mL) washing given and dried to give white to off white solid compound (3) 36.32 g (70.00%). Thus yield obtained was used in the next step without further purification. mp- 208-210C. IR (KBr, cm-1): 3352.4 (-NH2 stretch), 3230.3 (>NH stretch), 2845 (-OCH3), 1640.65 (>C=O stretch), 764 (>C-Br); 1H NMR (400 MHz, DMSO-d6 ppm): delta 8.76 (s, 1H), 8.80 (s, 1H), 9.19 (s, 1H), 14.82 (s, 1H). 13C NMR (400MHz, DMSO-d6 ppm): 138.58 (pyrazine C-N), 143.45 (pyrazine C=N), 145.28 (pyrazine C=N), 147.29 (pyrazine C=N), 158.32 (-C=O), 178.48 (-C-SH). MS: 178.9; m/z: 179.9 (M+H).
The basis of chemical reaction formula synthesis, the synthesis route is composed of some specific reactions and combined according to certain logical thinking. We look forward to the emergence of more reaction modes in the future.
Reference:
Article; Patil, Sanjeev R.; Asrondkar, Ashish; Patil, Vrushali; Sangshetti, Jaiprakash N.; Kalam Khan, Firoz A.; Damale, Manoj G.; Patil, Rajendra H.; Bobade, Anil S.; Shinde, Devanand B.; Bioorganic and Medicinal Chemistry Letters; vol. 27; 16; (2017); p. 3845 – 3850;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem