Benzaldehyde, hydrazone

To a solution of hydrazine hydrate (2.5 mL, 30 mmol) in EtOH (10 mL) benzaldehyde (1.04 mL, 10 mmol) was added dropwise under nitrogen over 10 min. The resulting solution was stirred at RT for 1.5 h. After this time, water was added and ethanol was evaporated under vacuum. The aqueous phase was extracted with DCM (x 4). Combined organics were dried and concentrated to obtain (phenylmethylidene)hydrazine (p2, 1.2 g, y= quant.) as yellow oil MS (/T7/z): 121.1 [MH]General procedure: Amixture ofDHPMs a–h(0.01mol) and excess hydrazine hydrate (5 mL) was heatedunder reflux for 6 h. The reaction mixture was allowed tocool and poured on crushed ice.The obtained solid producta–d was filtered, crystallized from ethanol, and finallydried.The evaporation of the filtrate gave solid residue whichupon fractional crystallization from water gave the pyrazole and urea (a)/thiourea (b), respectively. 2.4.1. 3-Methyl-1H-pyrazol-5-ol (13). Yield: 42–55percent (for a–h); m.p. 221–223 °C (Lit. [49] m.p. 220–222 °C); 1H-NMR(DMSO-6) δ (ppm): 2.47 (s, 3H, -CH3), 6.83 (s, 1H, Ar-H), 10.07 (s, 1H, OH), 12.10 (s, 1H, NH).General procedure: Amixture ofDHPMs a–h(0.01mol) and excess hydrazine hydrate (5 mL) was heatedunder reflux for 6 h. The reaction mixture was allowed tocool and poured on crushed ice.The obtained solid producta–d was filtered, crystallized from ethanol, and finallydried.The evaporation of the filtrate gave solid residue whichupon fractional crystallization from water gave the pyrazole and urea (a)/thiourea (b), respectively. 2.4.1. 3-Methyl-1H-pyrazol-5-ol (13). Yield: 42–55percent (for a–h); m.p. 221–223 °C (Lit. [49] m.p. 220–222 °C); 1H-NMR(DMSO-6) δ (ppm): 2.47 (s, 3H, -CH3), 6.83 (s, 1H, Ar-H), 10.07 (s, 1H, OH), 12.10 (s, 1H, NH).

Molecular Weight:120.15
XLogP3:1.4
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:2
Rotatable Bond Count:1
Exact Mass:120.068748264
Monoisotopic Mass:120.068748264
Topological Polar Surface Area:38.4
Heavy Atom Count:9
Complexity:93.1
Undefined Bond Stereocenter Count:1
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes