Hydrazine, propyl- → 2,4,6,7-Tetrahydro-3-phenyl-7-(phenylmethylene)-2-propylpyrano[4,3-c]pyrazole
Reaction equation
[C:1]1([CH:7]=[C:8]2[C:13](=O)[C:12](=[CH:15][C:16]3[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=3)[CH2:11][O:10][CH2:9]2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[CH2:22]([NH:25][NH2:26])[CH2:23][CH3:24]>CO>[C:1]1([C:7]2[N:25]([CH2:22][CH2:23][CH3:24])[N:26]=[C:13]3[C:12](=[CH:15][C:16]4[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=4)[CH2:11][O:10][CH2:9][C:8]=23)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
A mixture of tetrahydro-3,5-bis-(phenylmethylene)-4H-pyran-4-one (3.6 g, 13 mmole) and propylhydrazine (1.1 g, 14 mmole) in methanol (250 ml) is heated at reflux temperature for 3-4 hours. MeOH is then removed in vacuo. The residue is dissolved in CHCl3 and washed with dilute HCl and water, then dried (anhydrous MgSO4) and concentrated in vacuo to give a yellow oil. When this crude oil is triturated with a small amount of acetonitrile the major product of this reaction precipitates out. The filtrate is concentrated and the residue is applied to a dry-packed Al2O3 (Activity I, neutral) column. The fractions eluted with ether are combined and recrystallized first from ether/hexane, then from cyclohexane until a constant m.p. (126.5°-128.5° C.) is reached, giving the product in crystalline form (99% pure).