N1C2=NC=CC=C2C=N1.[C:10](Cl)(=[O:17])[C:11]1[CH:16]=[CH:15][CH:14]=[N:13][CH:12]=1.ClC1N=CC=CC=1C(Cl)=O.NN.[C:31]1([NH:37][NH2:38])[CH:36]=[CH:35][CH:34]=[CH:33][CH:32]=1>C(Cl)Cl.C(N(CC)CC)C>[C:31]1([N:37]2[C:12]3=[N:13][CH:14]=[CH:15][CH:16]=[C:11]3[C:10]([OH:17])=[N:38]2)[CH:36]=[CH:35][CH:34]=[CH:33][CH:32]=1Scheme 4 depicts the synthesis of the 1H-pyrazolo[3,4-b]pyridine q. A nicotinoylchloride k (e.g., 2-chloronicotinoyl chloride) is reacted with a hydrazine m (e.g., phenylhydrazine) and a base such as triethylamine in a solvent such as anhydrous methylene chloride to give o (e.g., 1-phenyl-1H-pyrazolo[3,4-b]pyridin-3-ol). The compound o is then cyclized by heating at 175° C. to provide p. p is reacted as in the transformation of d to g in Scheme 1 to provide q.
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