Dihydrooxazolones and dihydroimidazolones derived from acylglycines: syntheses, molecular structures and supramolecular assembly

Abstract

Syntheses and structures are described for some alkylidene-substituted dihydrooxazolones and dihydroimidazoles derived from simple acylglycines. A second, triclinic, polymorph of 4-benzylidene-2-(4-methylphenyl)-1,3-oxazol-5(4H)-one, C17H13NO2, (I), has been identified and the structure of 2-methyl-4-[(thiophen-2-yl)methylidene]-1,3-oxazol-5(4H)-one, C9H7NO2S, (II), has been rerefined taking into account the orientational disorder of the thienyl group in each of the two independent molecules. The reactions of phenylhydrazine with 2-phenyl-4-[(thiophen-2-yl)methylidene]-1,3-oxazol-5(4H)-one or 2-(4-methylphenyl)-4-[(thiophen-2-yl)methylidene]-1,3-oxazol-5(4H)-one yield, respectively, 3-anilino-2-phenyl-5-[(thiophen-2-yl)methylidene]-3,5-dihydro-4H-imidazol-4-one, C10H15N3OS, (III), and 3-anilino-2-(4-methylphenyl)-5-[(thiophen-2-yl)methylidene]-3,5-dihydro-4H-imidazol-4-one, C21H17N3OS, (IV), which both exhibit orientational disorder in their thienyl groups. The reactions of 2-phenyl-4-[(thiophen-2-yl)methylidene]-1,3-oxazol-5(4H)-one with hydrazine hydrate or with water yield, respectively, N-[3-hydrazinyl-3-oxo-1-(thiophen-2-yl)prop-1-en-2-yl]benzamide and 2-(benzoylamino)-3-(thiophen-2-yl)prop-2-enoic acid, which in turn react, respectively, with thiophene-2-carbaldehyde to form 2-phenyl-5-[(thiophen-2-yl)methylidene]-3-{[(E)-(thiophen-2-yl)methylidene]amino}-3,5-dihydro-4H-imidazol-4-one, C19H13N3OS2, (V), which exhibits orientational disorder in only one of its thienyl groups, and with methanol to give methyl (2Z)-2-(benzoylamino)-3-(thiophen-2-yl)prop-2-enoate, C15H13NO3S, (VI). There are no direction-specific intermolecular interactions in the crystal structure of the triclinic polymorph of (I), but the molecules of (II) are linked by two independent C-H···O hydrogen bonds to form C2(2)(14) chains. Compounds (III) and (IV) both form centrosymmetric R2(2)(10) dimers built from N-H···O hydrogen bonds, while compound (V) forms a centrosymmetric R2(2)(10) dimer built from C-H···O hydrogen bonds. In the structure of compound (VI), a combination of N-H···O and C-H···π(arene) hydrogen bonds links the molecules into sheets. Comparisons are made with some similar compounds.

Crystal structure of 2-benzoylamino-N′-(4-hydroxybenzylidene)-3-(thiophen-2-yl)prop-2-enohydrazide

“…We report here the crystal structure of the title compound, (I) ( Fig. 1), which we compare with the closely related compound methyl 2-benzoylamino-3-(thiophen-2-yl)prop-2enoate, (II) (Subbulakshmi et al, 2015). The constitutions of compounds (I) and (II) differ simply in the notional replacement of the COOMe unit in (II) by the CONHN CHC 6 H 4 OH group in (I).…”

“…In the crystal structure of compound (II) (Subbulakshmi et al, 2015), a combination of N-HÁ Á ÁO and C-HÁ Á Á(arene) hydrogen bonds links the molecules into sheets; in the struc-research communications ture of (E)-N 0 -[1-(2-hydroxyphenyl)ethylidene]-3-methoxybenzohydrazide the molecules are linked by a single N-HÁ Á ÁO hydrogen bond to form simple C(4) chains (Li & Ban, 2009); and the molecules of (E)-N 0 -(4-hydroxybenzylidene)-3nitrobenzohydrazide are linked into sheets by a combination of N-HÁ Á ÁO, O-HÁ Á ÁÁ(N,O) and C-HÁ Á ÁO hydrogen bonds (Meng et al, 2012).…”

Spectroscopic, Structural and Density Functional Theory (DFT) Studies of Two Oxazol-5-one Derivatives

“…Except the torsion angles, the bond parameters are comparable with the other oxazol-5-one derivatives. [28][29][30][31][32] N1/C3/C4/C5 torsion angles [-7.78(1) Å for 1 and 8.39(1) Å for 2] are slightly different. Also, as can be seen from the results, there is a good correlation between the experimental and theoretical data.…”