115315-94-1

Several bacteria rely on the reductive sulphur assimilation pathway, absent in mammals, to synthesise cysteine. Reduction of virulence and decrease in antibiotic resistance have already been associated with mutations on the genes that codify cysteine biosynthetic enzymes. Therefore, inhibition of cysteine biosynthesis has emerged as a promising strategy to find new potential agents for the treatment of bacterial infection. Following our previous efforts to explore OASS inhibition and to expand and diversify our library, a scaffold hopping approach was carried out, with the aim of identifying a novel fragment for further development. This novel chemical tool, endowed with favourable pharmacological characteristics, was successfully developed, and a preliminary Structure–Activity Relationship investigation was carried out.

Disclosed herein are small molecule calpain modulator compositions, pharmaceutical compositions, the use and preparation thereof.

Reactions of ethyl 3-[(E)-(dimethylamino)methylidene]pyruvate (3) and 3-[(dimethylamino)methylidene]-2-oxosuccinate (4) with hydrazine monohydrochloride (5a) and (hetero)arylhydrazines (5b-i) afforded, regioselectively, 1-substituted ethyl 1H-pyrazole-5-carboxylates 9a-f and diethyl 1H-pyrazole-3,4-dicarboxylates, 11a-i, respectively. Upon treatment of 3 with pyridazinylhydrazines 5d-f, the stable intermediates, 1-substituted ethyl 4,5-dihydro-5-hydroxy-1H-pyrazole-5-carboxylates 8d-f, were isolated. Treatment of compounds 8d-f in acetic acid under reflux furnished the pyrazoles 9d-f. On the other hand, reaction of 3 with N,N′-dimethylhydrazine (5I) gave ethyl 1-methyl-1H-pyrazole-3-carboxylate (14). The structures of compounds 3, 4, 14 were determined by nmr (noesy and hmbc techniques), while the structures of compounds 8f, 9f, and 11e,f were determined by X-ray diffraction.

A one-pot synthesis of 1-methyl- and 1-phenylpyrazole-3(5)-ethyl esters 2,3a-e by the cyclocondensation of β-alkoxyvinyl trichloromethyl ketones 1a- e with methyl and phenyl hydrazine hydrochloride under mild conditions, is reported. A study using compounds la-e with different substituents proved that these are versatile building blocks for the synthesis of pyrazole derivatives, having a 3(5)-ethoxycarbonyl substituent in good yields (60- 89%). The hydrazine and β-alkoxyvinyl trichloromethyl ketone substituent effects on the reaction regiochemistry on the formation of the 1,3- and 1,5- isomer were observed.