Reacción #1340630

Ecuación de reacción

methyl (5-hydroxy-1-methyl-1H-pyrazol-3-yl)acetate

methyl[1-(2-chlorophenyl)-5-hydroxy-1H-pyrazol-3-yl]acetate

acetic acid

BuC(OEt)3

→

methyl[(4Z)-4-(1-ethoxypentylidene)-1-methyl-5-oxo-4,5-dihydro-1H-pyrazol-3-yl]acetate

Disolventes

acetonitrile

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONThe mixture of the
2. 2
   ConcentraciónThe resulting red solution was concentrated in vacuo
3. 3
   Otroto afford a red syrup that
4. 4
   Lavadowas washed with cyclohexane
5. 5
   Otrodried in vacuo
6. 6
   OtroDue to its relative instability, no further purification of methyl[(4Z)-4-(1-ethoxypentylidene)-1-methyl-5-oxo-4,5-dihydro-1H-pyrazol-3-yl]acetate

Procedimiento

The mixture of the above obtained methyl (5-hydroxy-1-methyl-1H-pyrazol-3-yl)acetate (Compound of Formula (IV), 0.80 g) in acetonitrile (5 mL), glacial acetic acid (21 μl 0.1 equiv.) and BuC(OEt)3 (3 eq.) was heated at 70° C. for 1 h 15. The resulting red solution was concentrated in vacuo to afford a red syrup that was washed with cyclohexane and then dried in vacuo. Due to its relative instability, no further purification of methyl[(4Z)-4-(1-ethoxypentylidene)-1-methyl-5-oxo-4,5-dihydro-1H-pyrazol-3-yl]acetate was conducted (1.0 g, quantitative yield). MS (ESI+): 283.4; MS (ESI−): 281.3.

Fuente