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    A chalcone showing positional disorder, two related diarylcyclohexenones showing enantiomeric disorder and a related hydroxyterphenyl, all derived from simple carbonyl precursors
    (Int Union Crystallography, 2015) Salian, Vinutha V.; Narayana, Badiadka; Yathirajan, Hemmige S.; Akkurt, Mehmet; Celik, Omer; Ersanli, Cem Cuneyt; Glidewell, Christopher
    Four compounds are reported, all of which lie along a versatile reaction pathway which leads from simple carbonyl compounds to terphenyls. (2E)-1-(2,4- Dichlorophenyl)-3-[4-(prop-1-en-2-yl)phenyl]prop-2-en-1-one, C18H14Cl2O, (I), prepared from 4-(prop-1-en-2-yl)benzaldehyde and 2,4-dichloroacetophenone, exhibits disorder over two sets of atomic sites having occupancies of 0.664 (6) and 0.336 (6). The related chalcone (2E)-3-(4-chlorophenyl)-1-(4-fluorophenyl)-prop-2-en-1-one reacts with acetone to produce (5RS)-3-(4-chlorophenyl)-5-[4-(propan-2-yl)phenyl]cyclohex-2-en-1-one, C21H21ClO, (II), which exhibits enantiomeric disorder with occupancies at the reference site of 0.662 (4) and 0.338 (4) for the (5R) and (5S) forms; the same chalcone reacts with methyl 3-oxobutanoate to give methyl (1RS, 6SR)-4-(4-chlorophenyl)-6-[4-(propan-2-yl)phenyl]-2-oxocyclohex-3-ene-1-carboxylate, C23H23ClO3, (III), where the reference site contains both (1R,6S) and (1S,6R) forms with occupancies of 0.923 (3) and 0.077 (3), respectively. Oxidation, using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, of ethyl (1RS, 6SR)-6-(4-bromophenyl)-4-(4-fluorophenyl)-2-oxocyclohex-3-ene-1-carboxylate, prepared in a similar manner to (II) and (III), produces ethyl 4 ''-bromo-4-fluoro-5'-hydroxy-1,1':3',1 ''-terphenyl-4'-carboxylate, C21H16BrFO3, (IV), which crystallizes with Z' = 2 in the space group P (1) over bar. There are no significant intermolecular interactions in the structures of compounds (I) and (II), but for the major disorder component of compound (III), the molecules are linked into sheets by a combination of C-H center dot center dot center dot O and C-H center dot center dot center dot pi(arene) hydrogen bonds. The two independent molecules of compound (IV) form two different centrosymmetric dimers, one built from inversion-related pairs of C-H center dot center dot center dot O hydrogen bonds and the other from inversion-related pairs of C-H center dot center dot center dot pi(arene) hydrogen bonds. Comparisons are made with related compounds.
  • [ X ]
    Öğe
    Dihydrooxazolones and dihydroimidazolones derived from acylglycines: syntheses, molecular structures and supramolecular assembly
    (Int Union Crystallography, 2015) Subbulakshmi, Karanth N.; Narayana, Badiadka; Yathirajan, Hemmige S.; Akkurt, Mehmet; Celik, Omer; Ersanli, Cem Cuneyt; Glidewell, Christopher
    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.