No abstract

The identity of the 2-(4-Methyl-2-phenyl-4,5-dihydrooxazol-4-ylmethyl)-isoindole-1,3-dione, previously synthesized in our laboratory, was proven without doubt by means of 1D and 2D NMR spectroscopy. Two-dimensional NMR spectroscopy played a major role. The analysis of the 2D-COSY spectrum of isoindoline-1,3-dione derivative shows a perfect correlation between neighboring protons. Thus, a correlation was noted between the protons of the phthalimide, H(8) and H(9) on the one hand and H(8') and H(9') on the other hand. The analysis of the 2D-HSQC spectrum of the studied compound indicates a faultless correlation between protons and adjacent carbons, and no correlation in the case of all quaternary carbons.

The organo-amino compound of title 2-(4-methyl-2-phenyl-4,5-dihydro-oxazol-4-ylmethyl)-isoindole-1,3-dione was synthesized by the mixture of (4-methyl-2-phenyl-4,5-dihydrooxazol-4-yl)methyl-4-methylbenzenesulfonate and isoindoline-1,3-dione in N,N-dimethylformamide with a yield of around 65%. The structural study of the compound, C19H16N2O3, is realized using single crystal X-Ray diffraction which shows that this compound crystallizes in the monoclinic system (P21/c, Z = 4) with the unit cell parameters: a = 14.3728 (13) Ã…, b = 9.6829 (10) Ã…, c = 11.8964 (12) Ã… and β = 107.384 (3). The refinement of the structure by the least-squares method with complete matrix leads to the following reliability factors R/Rw are 0.044/0.130.In the crystal, the molecules are linked together by hydrogen bonds and π…π interactions.The Infrared spectroscopic studies show the bands confirming the presence of the groups C=O, C-O, C-N, -CH3, -CH2 and =CH. 

In this paper, we describe the regioselective synthesis of a novel tri-heterocyclic compound, a biheterocyclic amino acid precursor, derived from both triazole and tetrazole. The key step of our synthesis approach was the Huigsen 1,3-dipolar cycloaddition reaction, catalyzed by the copper (I) formed in situ by reduction of Cu(II) salts (CuSO4), 5H2O) by sodium ascorbate, and using as dipole the oxazoline azide derivative 4-(azidomethyl)-4-ethyl-2-phenyl-4,5-dihydrooxazole (4) and as dipolarophile 5-(4-methoxyphenyl)-2-(prop-2-yn-1-yl)-2H-tetrazole (3).  The Cu(I) catalysis allowed us to carry out the cycloaddition at room temperature during a reaction time of only 8 hours and also to selectively obtain the 1,4-regioisomer; one of the two possible isomers, with a yield of 90% after chromatography on a silica gel column (ether/hexane: 1/2), and recrystallization in an ether/acetone mixture. The desired compound, 4-ethyl-4-((4-((5-(4-methoxyphenyl)-2H-tetrazol-2-yl)methyl)-1H-1,2,3-triazol-1-yl)methyl)-2-phenyl-4,5-dihydrooxazole (5) was analyzed by 1D magnetic resonance spectroscopy (1H, 13C), and characterized physico-chemically by mass spectrometry and elemental analysis.

Considering the richness of heterocyclic chemistry, and the diversity of applications it possesses, in the present work we were interested in preparing new polyfunctional α,α-diaminodiesters derived from glycine, via the N-alkylation reaction of methyl 2-azido-2-benzamidoacetate with a series of heterocyclic and non-heterocyclic carboxylic aminoesters, using different bases. The structures of the synthesized molecules were characterized by 1D and 2D NMR spectroscopy, mass spectrometry (MS-ESI) and elemental analysis. Two compounds from this series were isolated as single crystals and their chemical structures were determined by X-ray diffraction. The antioxidant effect of the synthesized compounds was tested in vitro using the free radical scavenging power (DPPH) and reducing power (FRAP) tests. The results show that the different extracts tested have a relatively high antioxidant power compared to the positive control considered, especially for the compound methyl 2-benzamido-2-(2-methoxy-2-oxo-1-phenylethyl)amino)acetate, which showed a very strong antiradical power and reducing power.