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

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Subbulakshmi K. N., NARAYANA B., Yathirajan H. S., AKKURT M., ÇELİK Ö., ERSANLI C. C., ...More

ACTA CRYSTALLOGRAPHICA SECTION C-STRUCTURAL CHEMISTRY, vol.71, pp.742-779, 2015 (SCI-Expanded) identifier identifier identifier


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-1en-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 center dot center dot center dot O hydrogen bonds to form C-2(2)(14) chains. Compounds (III) and (IV) both form centrosymmetric R-2(2)(10) dimers built from N-H center dot center dot center dot O hydrogen bonds, while compound (V) forms a centrosymmetric R-2(2)(10) dimer built from C-H center dot center dot center dot O hydrogen bonds. In the structure of compound (VI), a combination of N-H center dot center dot center dot O and C-H center dot center dot center dot pi (arene) hydrogen bonds links the molecules into sheets. Comparisons are made with some similar compounds.