Treatment of 5-amino-1,3-dialkyl-2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-ones with sodium nitrite in aqueous HCl gave 1,3-dialkyl-1H-imidazo[4,5-b]pyridine-2,5(3H,4H)-diones which were nitrated with potassium nitrate in sulfuric acid to 6-nitro derivatives, and the latter underwent recyclization into 4-amino-1,3-dialkyl-5-(1H-pyrazol-5-yl)-2,3-dihydro-1H-imidazol-2-ones by the action of hydrazine hydrate.

中文翻译：

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1,3-二烷基-6-硝基-1 H-咪唑并[4,5-b]吡啶-2,5（3 H，4 H）-二酮的环化成咪唑衍生物

的处理5-氨基1,3-二烷基-2,3-二氢-1- ħ -咪唑并[4,5- b ]吡啶-2-酮与HCl水溶液亚硝酸钠，得到1,3-二烷基-1- ħ -咪唑并[4,5 - b ]吡啶-2,5（3 H，4 H）-二酮用硝酸钾在硫酸中硝化成6-硝基衍生物，然后再环化成4-氨基-1,3 -二烷基-5-（1 H-吡唑-5-基）-2,3-二氢-1 H-咪唑-2-酮在水合肼的作用下。