5-Phenyl-1,3,4-oxadiazole-2-thiol

slightly yellow crystalline powder

A mixture of benzohydrazine (0.41 g, 3 mmol), potassium phosphate (1.02 g, 3 mmol), and carbon disulfide (0.23 g, 3 mmol) in water (15 mL) was stirred at rt for 10 min. After refluxing for an additional 2 h, 1 N HCl was added to pH=7, the solid formed was filtered and dried in vacuum to afford 5-phenyl-1, 3, 4-oxadiazole-2-thiol 13 (0.51 g, 96percent) as a white solid. Mp: 197-199 °C (lit.Take benzoic hydrazide 4.08g (30.00mmol) dissolved in absolute ethanol 50mL, 1.85 g (33.00 mmol) of potassium hydroxide was added, and 5.71 g (75.00 mmol) of carbon disulfide was slowly added dropwise with stirring. The mixture was heated to reflux for 2h after the addition was completed. After the reaction was completed, the solvent was distilled off under reduced pressure, The residue dissolved in water, filtered, the filtrate was acidified with dilute hydrochloric acid 5percent to pH 3 ~ 4 precipitated solid, Filtered, washed, dried to give a white solid 4.82g, yield 90percent.In 100 ml round-bottom flask by adding 1.5 g (11.02mmol) [...] and 0.93 g (16.53 mmol) potassium hydroxide, and add 50 ml methanol, dropping 1.00 ml (16.53 mmol) carbon bisulfide, stirring under the room temperature condition to 12h, TLC detection 5 - (4-chlorophenyl) - 1, 3, 4-oxadiazol-2-thiols are all changed into 5 - (4-chlorophenyl) - 1, 3, 4-oxadiazol-2-sulfate potassium salt, then adding 0.62 g (11.02 mmol) potassium hydroxide, the oil bath temperature is 80General procedure: Hydrazide 3 (0.01 mol) was dissolved in absolute ethanol (10 mL) in a 250 mL round bottom flask. Carbon disulfide (0.03 mol) was then added to the solution followed by the addition of excess potassium hydroxide (0.02 mol) in water (5 mL).This reaction mixture was properly stirred and reflux for 6 h. the mixture was diluted with distilled water (50 mL) and acidified with dilute hydrochloric acid to pH 1–2. It was then filtered, washed with ethanol and distilled water, dried under vacuum, and recrystallized from ethanol to give pure products 4a–4h.250mL round bottom flask was added 19. 00g (139. 6mmol) benzoic hydrazide and 100mL of absolute ethanol under ice-cooling (square ° C) with stirring, then added 42. 43g (558. 2mmol) CSjP 7 · 81g (139. 6mmol) K0H, the addition was complete retreatThe ice bath was heated to reflux for 7h. Cooled to room temperature spin off the solvent, the residue after adding an appropriate amount of water dissolved in hydrochloric acid to adjust pH 2~3, stirred 2h, filtration, recrystallized from ethanol to give 18. 16g of white solid, yield 73percent.250mL round bottom flask was added 19.00g (139.6mmol) of benzoyl hydrazine, and 100mL of absolute ethanol under ice (0oC) with stirring, was added 42.43g (558.2mmol) CS2 and 7.81g (139.6mmol) KOH, feeding finished ice bath was removed, it was heated under reflux for 7 hours. Cooled to room temperature spin off the solvent, the residue was dissolved in water by adding an appropriate amount of hydrochloric acid to adjust the pH to 2-3, stirred for 2 hours, filtration, recrystallized from ethanol to give 18.16g of white solid, yield 73percent.General procedure: Benzoyl hydrazine (6.81 g, 50 mmol) was added to a solution of KOH (2.8 g, 50 mmol) in 150 mL ethanol, and them carbon disulfide (4.19 g, 55 mmol) was added dropwise. The reaction mixture was refluxed for 10 h before the solvent was evaporated. The residue was neutralized with 10percent aquous HCl. The solid product was collected by filtration and recrystallized from ethanol to give pure white 5-phenyl-[1, 3, 4]oxadiazole-2-thiol (6.07 g, 68.2percent yield).General procedure: To a solution of acid hydrazide in anhydrous 5–15mL of DMF, carbon disulfide (2.5mL/mmol) was added at room temperature and under a nitrogen atmosphere. The reaction mixture was then heated to 40°C for 15min and then to 70°C for 4–8h until the reaction was completed. After completion, the reaction mixture was cooled to room temperature and poured dropwise into ice cold water. The solids formed were separated by filtration, washed with water and dried in vacuo.

Molecular Weight:178.21
XLogP3:2
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:3
Rotatable Bond Count:1
Exact Mass:178.02008399
Monoisotopic Mass:178.02008399
Topological Polar Surface Area:65.7
Heavy Atom Count:12
Complexity:221
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes