The synthesis of 14-(aryl)-14H-naphto[2,1-b]pyrano[3,2-e][1,2,4]triazolo[1,5-c]pyrimidine-2-yl) acetamidoximes 2a-e has been accomplished by reaction of 2-acetonitrile derivatives 1a-e with hydroxylamine. Cyclocondensation reaction of precursors 2a-e with some elctrophilic species such as ethylorthoformate, acetic anhydride, and methyl-acetoacetate provided the new oxadiazole derivatives 3a-e, 4a-e, and 5a-e, respectively. On the other hand, the reaction of precursors 2a-e with 2-chloropropanoyl chloride afforded the new acetimidamides 6a-e which evolve under reflux of toluene to the new oxadiazoles 7a-e. The synthetic compounds were screened for their anti-xanthine oxidase, anti-soybean lipoxygenase, and cytotoxic activities. Moderate to weak xanthine oxidase and soybean lipoxygenase inhibitions were obtained but significant cytotoxic activities were noted. The most cytotoxic activities were recorded mainly (i) 5a was the most active (IC50 = 4.0 μM) and selective against MCF-7 and (ii) 2a was cytotoxic against the four cell lines with selectivity for MCF-7 and OVCAR-3 (IC50 = 17 and 12 μM, respectively) while 2e is highly selective against OVCAR-3 (IC50 = 10 μM).
Please cite this article as: A. Rahmouni, A. Romdhane, A.B. said, V. Guérineau, D. Touboul, H.B. Jannet, Synthesis of novel isoxazolines and isoxazoles of N-substituted pyrazolo[3,4-d]pyrimidin-4(5H)-one derivatives through[3+2] cycloaddition, Arabian Journal of Chemistry (2014), doi: http://dx.Abstract 3,6-Dimethyl-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4(5H)-one 3 was prepared by an intramolecular cyclisation of N-(4-cyano-3-methyl-1-phenyl-1H-pyrazol-5-yl) acetamide 2 in ethanol in the presence of piperidine. N-allylation and N-propargyl alkylation of N-substituted pyrazolo [3, 4-d] pyrimidin-4(5H)-one 3 yielded the corresponding dipolarophiles 4 and 5which afford by condensation with arylnitrile oxides in toluene the expected new isoxazolines 6 and isoxazoles 7, respectively. On the other hand, the aminopyrazole 1 in refluxing with ethanol in the presence of sodium hydroxide afforded the corresponding carboxamide 8, which then, was converted to its ethyl 3-methyl-4-oxo-1-phenyl-4,5-dihydro-1H-pyrazolo [3, 4-d] pyrimidine-6-carboxylate 9 with neat diethyl oxalate. The dipolarophile 10 on regiospecific 1,3-dipolar cycloaddition with arylnitrile oxides affords isoxazoles 11 and the unexpected deethoxycarbonylated isoxazoles 12. The target compounds were completely characterized by 1 H NMR, 13 C NMR, IR and HRMS. 3
3-Substituted-1-phenyl-1 H -pyrazolo[3,4-d ]pyrimidin-4-amines 2a-c were synthesized by treating 5-aminopyrazole-4-carbonitriles 1a-c with formamide. The reactivity of compounds 1a-c towards some cyclic anhydrides was studied. The condensation of 5-aminopyrazole-4-carbonitrile 1b with triethylorthoformate gives imidate 7b, which reacts with a series of primary amines and leads to pyrazolo[3,4-d ]pyrimidine-4-amines 9 and 10. The reaction of imidate 7b with ammonia and hydroxylamine afforded pyrazolopyrimidine 2b and pyrazolo[3,4-d ]pyrimidin-5-(4 H) -ol 11, respectively. The synthesized compounds were completely characterized by 1 H NMR, 13 C NMR, IR, and HRMS.The antibacterial activity of some new synthesized compounds was evaluated and appeared to be significant.
The influence of the presence of trimethylsilyl and triphenylsilyl groups in substituents of anthraquinone on the properties of anthraquinone vat, acid, and dispersion dyes was investigated.
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