Ethyl 5-Oxo-4,5-dihydro-1H-pyrazole-3-carboxylate synthesis
- Product Name:Ethyl 5-Oxo-4,5-dihydro-1H-pyrazole-3-carboxylate
- CAS Number:85230-37-1
- Molecular formula:C6H8N2O3
- Molecular Weight:156.14
Yield: 92%
Reaction Conditions:
Stage #1:diethyl oxalacetate sodium salt in benzene for 0.333333 h;
Stage #2: with acetic acid for 0.5 h;
Stage #3:hydrazine hydrochloride at 100; for 24.5 h;Heating / reflux;
Steps:
1 Example 1; 5-HYDROXY-LH-PYRAZOLE-3-CARBOXYLIC acid ethyl ester
Diethyloxalacetate, sodium salt (14. 53 g, 69. 15 mmol) was dissolved in 100 mL of benzene and stirred for 20 min. To the solution was added 100 ML of acetic acid and the reaction mixture was stirred for a further 30 min. Hydrazine monohydrochloride (9. 47 g, 138 mmol) was added and the reaction mixture was stirred for an additional 30 min. The reaction was brought to reflux at 100 C for 24 h. The reaction was then removed from heat and cooled to room temperature and extracted with ethyl acetate and washed with 10% hydrochloric acid, saturated sodium bicarbonate solution, water and then brine. The solvent was removed IN VACUO TO yield an oily solid which was then triturated with a 2 : 1 mixture of diethyl ether : hexanes to yield 3 (10. 00 g, 92%) as an off-white solid : LRMS (electrospray) ; m/z [M+H1+ = 157.
References:
F. HOFFMANN-LA ROCHE AG WO2004/74257, 2004, A1 Location in patent:Page 26; 37; 38
64-17-5
700 suppliers
$10.00/50g
3702-98-5
54 suppliers
$17.67/250mgs:
85230-37-1
91 suppliers
$58.00/1g