ChemicalBook CAS DataBase List 5-BROMO-2-(3-CHLORO-PYRIDIN-2-YL)-3,4-DIHYDRO-2H-PYRAZOLE-3-CARBOXYLIC ACID ETHYL ESTER

5-BROMO-2-(3-CHLORO-PYRIDIN-2-YL)-3,4-DIHYDRO-2H-PYRAZOLE-3-CARBOXYLIC ACID ETHYL ESTER synthesis

8synthesis methods

Product Name:5-BROMO-2-(3-CHLORO-PYRIDIN-2-YL)-3,4-DIHYDRO-2H-PYRAZOLE-3-CARBOXYLIC ACID ETHYL ESTER
CAS Number:500011-91-6
Molecular formula:C11H11BrClN3O2
Molecular Weight:332.58

1H-Pyrazole-5-carboxylic acid, 3-chloro-1-(3-chloro-2-pyridinyl)-4,5-dihydro-, ethyl ester

500011-89-2
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5-BROMO-2-(3-CHLORO-PYRIDIN-2-YL)-3,4-DIHYDRO-2H-PYRAZOLE-3-CARBOXYLIC ACID ETHYL ESTER

500011-91-6
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Yield:500011-91-6 99%

Reaction Conditions:

with hydrogen bromide in 1,1-dibromomethane; for 1.5 h;

Steps:

1.C Step C: Preparation of ethyl 3-bromo-1-(3-chloro-2-pyridinyl)-4,5-dihydro-1H-pyrazole-5-carboxylate

Hydrogen bromide was passed through a solution of ethyl 3-chloro-1-(3-chloro-2-]pyridinyl)-4,5-dihydro-1H-pyrazole-5-carboxylate (i.e. product of step B) (8.45 g, 29.3 mmol) in dibromomethane (85 mL). After 90 minutes the gas flow was terminated, and the reaction mixture was washed with aqueous sodium bicarbonate solution (100 mL). The organic phase was dried and evaporated under reduced pressure to give the title product as an oil (9.7 g, 99% yield), which crystallized on standing. 1H NMR (CDCl3) δ 1.19 (t, 3H), 3.24 (1/2 of AB in ABX pattern, J = 9.3, 17.3 Hz, 1H), 3.44 (1/2 of AB in ABX pattern, J = 11.7, 17.3 Hz, 1H), 4.18 (q, 2H), 5.25 (X of ABX, 1H, J = 9.3, 11.9 Hz), 6.85 (dd, J = 4.7, 7.7 Hz, 1H), 7.65 (dd, J = 1.6, 7.8 Hz, 1H), 8.07 (dd, J = 1.6, 4.8 Hz, 1H).

References:

WO2004/11453,2004,A2 Location in patent:Page 19-20

500011-88-1 Synthesis