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SYNTHESIS OF METHYL(ETHYL) PYRAZOLO[4,3-b]PYRIDINE-6-CARBOXYLATES AND THEIR CONVERSION TO tert-BUTYL 4,5,6,7-TETRAHYDROPYRAZOLO-[4,3-b]PYRIDINE-6-CARBOXYLATES

Георгий Г. Яковенко, Леся Н. Салиева, Эдуард Б. Русанов, Илья С. Дончак, Михаил В. Вовк
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Abstract


N-Boc-4-aminopyrazole-5-carbaldehydes react with methyl 3,3-dimethoxypropanoate or β-keto esters in acetic acid under reflux to form methyl(ethyl) pyrazolo[4,3-b]pyridine-6-carboxylates, which were converted to the corresponding tert-butyl carboxylates via intermediate carboxylic acids. Their subsequent hydrogenation on a 10% Pd/C catalyst at 100°C and 25 atm afforded tert-butyl 4,5,6,7-tetrahydropyrazolo[4,3-b]pyridine-6-carboxylates.

 


Keywords


alkyl pyrazolo[4,3-b]pyridine-6-carboxylates; N-Boc-4-aminopyrazole-5-carbaldehydes; 3,3-dimethoxypropionate; β-keto esters; tetrahydropyrazolo[4,3-b]pyridine-6-carboxylates; Pd/C catalytic hydrogenation.

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