Crystal structure of 5-benzoyl-2-(2-chlorophenyl)-4-phenyl-2-oxazoline, C22H16ClNO2

Abstract

C 22 H 16 ClNO 2 ,monoclinic, P12 1 /n1(no. 14), a =10.6113(7) Å, b =9.6680(6) Å, c =17.176(1) Å, b =92.910(1)°, V =1759.8 Å 3 , Z =4,Rgt(F) =0.045, wRref(F 2 ) =0.111, T =100 K. Source of materialAs olution of trans-2-bezoyl-N-(2-chlorobenzoyl)-3-phenylaziridine (0.361 g, 1.0 mmol) in CH 3CN (15 ml) and NaI (0.2 mmol) was stirred at 50°C for 6h ours. Then the mixture was rinsed twice with water, the organic layer was separated and dried with anhydrous Na 2 SO 4 .E vaporation of the solvent under reduced pressure and subsequent purification of the residue by column chromatography (silica gel, EtOAc/hexane: 1/4) provided 5-benzoyl-2-(2-chlorophenyl)-4-phenyl-2-oxazoline (0.325 g, 0.9 mmol) in 90 %yield, mp =125 -127°C. Elemental analysis -found: C, 73.12 %; H, 4.40 %; N, 3.77 %; calculated for C 22 H 16 ClNO 2 :C,73.08 %; H, 4.47 %; N, 3.87 %. Melting points were measured on aBuchi melting point B-540 instrument and are uncorrected. Elemental analyses were made by a Carlo-Erba EA1110CNNO-S analyzer. Experimental detailsThe H(C) atom positions were calculated. All hydrogen atoms were refined in isotropic approximatiom in riding model with the U iso(H) parameters equal to 1.2 Ueq(Ci), where Ueq(Ci) are the equivalent thermal parameters of the carbon atoms to which corresponding Hatoms are bonded. DiscussionThe oxazolines group is an important functionality in synthetic organic chemistry [1]. 2-Substituted 2-oxazolines as important heterocyclic intermediates and precursors of great variety of carboxylic acid derivatives and many biologically active compounds and ligands in amultitude of metal-catalyzed reactions, have attracted strong attentions [2-6]. Substituted oxazoline derivatives prepared stereospecifically were used in the synthesis of naturally occurring non-proteinogenic β-hydroxy-a-amino acids [7] and as starting material in the synthesis of the neurotrophic factor Lactacystin [8,9]. Several synthetic methods have been described for the synthesis of oxazolines. One interesting method is the ring expansion of N-ketoaziridines induced by iodide [10]. In the iodide isomerization of trans-2-bezoyl-N-(2-chlorobenzoyl)-3-phenylaziridine, formation of two regio-isomers is possible, namely 5-benzoyl-2-(2-chlorophenyl)-4-phenyl-2-oxazoline (1) and 4-benzoyl-2-(2-chlorophenyl)-5-phenyl-2-oxazoline. In the assignment of the right isomer, spectral data (IR, NMR and MS) were not conclusive therefore, X-ray structure analysis was conducted on the reaction product which established the formation of the title regioisomer. Despite the extensive studies on 2-oxazoline ring, only few metal-free species have been examined by X-ray diffraction methods [11][12][13][14][15][16][17][18]. Single crystals were obtained by slow evaporation of the ethyl acetate solution. In the title compound bond lengths and angles in the oxazoline ring are comparable with those in related structures [11][12][13][14][15][16]

Synthesis and Structure of bis(cyclohexylmethyl) 3,6-bis(4-chlorophenyl)-1,2,4,5-tetrazine-1,2-dicarboxylate

“…Most of them suffer at least from one of the following disadvantages: (1) high costs of preparations, (2) long reaction times, (3) hygroscopicity, (4) no selectivity, (5) photosensitivity, (6) dangerous procedures for their preparation, and (7) tedious work-up procedures. [21][22][23][24][25][26][27][28][29][30][31][32] In continuation of our previous works, on oxidation and synthesis of heterocyclic compounds, [33][34][35][36][37][38][39] we now introduce an efficient, mild and rapid method for the oxidation of urazoles to their corresponding 4-substituted-1,2,4-triazole-3,5-diones (TADs), by using benzyltriphenylphosphonium nitrate (I, BTPPN) as a mild and novel oxidising reagent which is readily prepared by reaction of an aqueous solution of benzyltriphenylphosphonium chloride with NaNO 3 solution at room temperature (Scheme 1).…”

K5[PW11ZnO39].23H2O-catalyzed acylation/ring expansion of ketoaziridines in a single pot: a new regio- and stereo-selective route for the synthesis of oxazolines

“…Here we report synthesis of N-acyl ketoaziridines from the corresponding ketoaziridines with acyl chlorides. Then N-acyl ketoaziridines in the presence of a nucleophilic and Lewis acids afforded oxazolines [40][41][42].Although a few methods have been described for the preparation of N-acyl aziridines none of them described direct synthesis of oxazolines from N-H aziridines with carboxylic acid .In continuation of our recent interest in the reaction of ketoaziridines [48] and success for using Polyoxometalates [49], herein, we report a one-pot regio-and stereo-selective synthesis of trans-4-benzoyloxazolines, catalyzed by the K 5 [PW 11 ZnO 39 ].23H 2 O catalytic system with moderate to good yields under mild conditions. Abstract A new and one-pot synthesis of oxazolines has been accomplished by K 5 [PW 11 ZnO 39 ].23H 2 O-catalyst acylation followed by C-N ring opening/C-O bond formation in NH ketoaziridines.…”

“…Here we report synthesis of N-acyl ketoaziridines from the corresponding ketoaziridines with acyl chlorides. Then N-acyl ketoaziridines in the presence of a nucleophilic and Lewis acids afforded oxazolines [40][41][42].…”

Synthesis of tert-Butyl 1,3-Diaryl-3-oxopropylcarbamates by a Regiocontrolled Reduction of Ketoaziridines

“…[20][21][22][23][24][25][26][27] Previous reports have shown that replacement of the hydrogen of the N-H moiety with an electron-withdrawing substituent increases the susceptibility of N-H aziridines to ring-opening or ring-enlargement reactions. [28][29][30] So, our first aim was to synthesize N-Boc-substituted ketoaziridines as a precursor for preparation of the corresponding nitrogen-containing compounds via ring opening or ring enlargement.…”

“…Based on the well-documented transformation of Nacyl-or N-Boc-substituted aziridines into oxazolines in the literature [31][32][33][34] and our success 20,21 with the ring-expansion reaction of N-acyl-substituted aziridines with sodium iodide, we envisioned that ring expansion of 1a with (Boc) 2 O in the presence of sodium iodide might be similarly achieved to give oxazolidin-2-one 6a in a one-pot reaction. Thus, we examined the reaction of aziridine 1a with (Boc) 2 O in the presence of sodium iodide in acetone for achieving this aim; however, no reaction occurred, even under refluxing conditions (Table 1, entry 5).…”