合成路线1

Synthesis of the aminopyrazole intermediate (XIII): The reaction of butanal (I) with methylhydrazine (II) in dichloromethane in the presence of MgSO4 gives the corresponding hydrazide (III), which is alkylated with ethyl bromoacetate (IV) by means of the polymer-supported base 2-(tert-butylimino)-2-(diethylamino)-1,3-dimethylperhydro-1,3,2-diazaphosphorine (PS-BEMP) (V) and polymer-supported methylamine (VI) to yield the hydrazino ester (VII). Treatment of compound (VII) with an ion exchange tetramethylammonium cyanide resin (VIII) in refluxing ethanol containing a catalytic amount of HOAc affords the adduct (IX), which is dehydrogenated with Pd/C/cyclopentene or MnO2 and treated with a polymer-supported ethyl isocyanate resin (X) in order to eliminate the unreacted product, providing the hydrazone (XI). Cyclization of (XI) by means of PS-BEMP (V) in ethanol gives 4-amino-1-methyl-3-propyl-1H-pyrazole-5-carboxylic acid ethyl ester (XII), which is finally treated with ammonia in methanol to afford the desired pyrazolecarboxamide intermediate (XIII).