4-CHLORO-1-ETHYL-6-METHYL-1H-PYRAZOLO[3,4-B]PYRIDINE-5-CARBOXYLIC ACID ETHYL ESTER synthesis

5synthesis methods

Product Name:4-CHLORO-1-ETHYL-6-METHYL-1H-PYRAZOLO[3,4-B]PYRIDINE-5-CARBOXYLIC ACID ETHYL ESTER
CAS Number:41095-07-2
Molecular formula:C12H14ClN3O2
Molecular Weight:267.71

3528-58-3
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(1-Ethoxyethylidene)propanedioic acid diethyl ester

3044-06-2
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4-CHLORO-1-ETHYL-6-METHYL-1H-PYRAZOLO[3,4-B]PYRIDINE-5-CARBOXYLIC ACID ETHYL ESTER

41095-07-2
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Yield:41095-07-2 57.17%

Reaction Conditions:

Stage #1: 5-Amino-1-ethylpyrazole;diethyl 2-(1-ethoxyethylidene)malonate at 120; for 2 h;
Stage #2: with trichlorophosphate at 115;

Steps:

4

A mixture of l-ethyl-lH-pyrazol-5-amine (16 gm, 0.144 moles) (example 2) and 2-(l-ethoxy-ethylidene)-malonic acid diethyl ester (29 gm, 0.12 moles) (example 3) was stirred at 120⁰C for about 2 hrs. When the reaction was complete on TLC, crude reaction mixture was concentrated in vacuo to remove ethanol, which was formed as byproduct. Crude residue was taken in phosphorous oxychloride (50 ml) and heated at 115 C for about 12-13 hrs. The reaction mixture was poured into ice-cooled water with continuous stirring. Solid which precipitated out was filtered and dried under vacuum to afford title compound as creamy white solid.Yield: 12 gm (57.17%) m/z: (M⁺+l) 268.28

References:

WO2010/46791,2010,A1 Location in patent:Page/Page column 31