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H K Fun

Publications and source records attributed to H K Fun.

At least 19 recordsLinked to original sources
PubMed2005

1,2,3-Trimethoxy-5,11-dihydroindolo[1,2-b]isoquinoline-5,11-dione.

The title compound, C15H19NO5, crystallizes in the monoclinic space group P2(1)/c with four molecules in the asymmetric unit, which differ from each other in the orientation of their methoxy groups. Of the three methoxy groups in each molecule, one lies close to the plane of the molecule and the other two have an out-of-plane conformation where they point in opposite directions. In the crystal structure, four different types of pi-stacks are observed and the molecules pack in two different types of stacking sheets, with alternating molecules A and B in one ribbon and alternating molecules C and D in the other. The supramolecular structure is supported by C-H...O and pi-pi interactions.

Journal Article↗
PubMed2003

Supramolecular structures of 2-cyano-3-dimethylamino-N-(4-methylphenyl)acrylamide and 2-cyano-3-dimethylamino-N-(2-methoxyphenyl)acrylamide.

In the title compounds, C(13)H(15)N(3)O, (I), and C(13)H(15)N(3)O(2), (II), the dihedral angles between the planes of the phenyl ring and the amide group are 4.1 (1) and 20.7 (1) degrees, respectively. The molecules adopt a fully extended conformation, aided by intramolecular interactions. The molecular structures of (I) and (II) display different crystal packing and hydrogen-bonding networks.

Journal Article↗
PubMed2003

Synthesis of lateral macrobicyclic compartmental ligands: structural, magnetic, electrochemical, and catalytic studies of mono- and binuclear copper(II) complexes.

A series of putative mono- and binuclear copper(II) complexes, of general formulas [CuL](ClO(4)) and [Cu(2)L](ClO(4))(2), respectively, have been synthesized from lateral macrocyclic ligands that have different compartments, originated from their corresponding precursor compounds (PC-1, 3,4:9,10-dibenzo-1,12-[N,N'-bis[(3-formyl-2-hydroxy-5-methyl)benzyl]diaza]-5,8-dioxacyclotetradecane; and PC-2, 3,4:9,10-dibenzo-1,12-[N,N'-bis[(3-formyl-2-hydroxy-5-methyl)benzyl]diaza]-5,8-dioxacyclopentadecane). The precursor compound PC-1 crystallized in the triclinic system with space group P(-)1. The mononuclear copper(II) complex [CuL(1a)](ClO(4)) is crystallized in the monoclinic system with space group P2(1)/c. The binuclear copper(II) complex [Cu(2)L(2c)](ClO(4))(2) is crystallized in the triclinic system with space group P(-)1; the two Cu ions have two different geometries. Electrochemical studies evidenced that one quasi-reversible reduction wave (E(pc) = -0.78 to -0.87 V) for mononuclear complexes and two quasi-reversible one-electron-transfer reduction waves (E(1)(pc) = -0.83 to -0.92 V, E(2)(pc) = -1.07 to -1.38 V) for binuclear complexes are obtained in the cathodic region. Room-temperature magnetic-moment studies convey the presence of antiferromagnetic coupling in binuclear complexes [mu(eff) = (1.45-1.55)mu(B)], which is also suggested from the broad ESR spectra with g = 2.10-2.11, whereas mononuclear complexes show hyperfine splitting in ESR spectra and they have magnetic-moment values that are similar to the spin-only value [mu(eff) = (1.69-1.72)mu(B)]. Variable-temperature magnetic susceptibility study of the complex shows that the observed -2J value for the binuclear complex [Cu(2)L(1b)](ClO(4))(2) is 214 cm(-1). The observed initial rate-constant values of catechol oxidation, using complexes as catalysts, range from 4.89 x 10(-3) to 5.32 x 10(-2) min(-1) and the values are found to be higher for binuclear complexes than for the corresponding mononuclear complexes.

Journal Article↗
PubMed2002

Trimethyl[3-methyl-1-(o-tolenesulfonyl)indol-2-ylmethyl]ammonium iodide and benzyl[3-bromo-1-(phenylsulfonyl)indol-2-ylmethyl]tolylamine.

The title compounds, C(20)H(25)N(2)O(2)S(+).I(-), (I), and C(29)H(25)BrN(2)O(2)S, (II), respectively, both crystallize in space group P-1. The pyrrole ring subtends an angle with the sulfonyl group of 33.6 degrees in (I) and 21.5 degrees in (II). The phenyl ring of the sulfonyl substituent makes a dihedral angle with the best plane of the indole moiety of 81.6 degrees in (I) and 67.2 degrees in (II). The lengthening or shortening of the C-N bond distances in both compounds is due to the electron-withdrawing character of the phenylsulfonyl group. The S atoms are in distorted tetrahedral configurations. The molecular structures are stabilized by C-H.O and C-H.I interactions in (I), and by C-H.O and C-H.N interactions in (II).

Journal Article↗
PubMed2002

Photochemistry of arylidene-beta-ionones: a highly efficient route to novel tricyclic ketones through intramolecular, exoselective photochemical (4 + 2) cycloadditions, occurring only in an aqueous-organic solvent.

(E,E)-Arylidene-beta-ionones (1a-f) are converted to 1,7,7-trimethyl-3-(E-2'-arylethenyl)-2-oxabicyclo[4.4.0]deca-3,5-dienes (3a-f, approximately 90%) by irradiating in anhydrous solvents. Irradiation of (3a-f) in aqueous methanol results in Z,E-arylidene-beta-ionones (2), through retro-electrocyclization, which undergoes an intramolecular, exo-selective [4 + 2] photocycloaddition leading to 11-(exo)-aryl-1,7,7-trimethyl-tricyclo[4.4.0.1(2,4)]undec-5-ene-3-ones (8a-f, 60-80%). The latter rearrange over silica gel to afford, quantitatively, 5-aryl-7,11,11-trimethyl-tricyclo[5.4.0.0(3,6)]undec-1-ene-4-ones (5a-f). Irradiation of 1a-f in aqueous methanol leads to 8a-f, except in case of 1c,f wherein formation, respectively, of tricyclic ketones 9c (55%) and 9f (80%), derived from photodeconjugation in 2, followed by intramolecular [4 + 2] cycloaddition, is observed.

Journal Article↗
PubMed2002

Peptide design using omega-amino acids: unusual turn structures nucleated by an N-terminal single gamma-aminobutyric acid residue in short model peptides.

Incorporation of omega-amino acids into peptide sequences plays an important role in designing peptides with modified backbone conformation and enhanced stability against proteolysis. The present study establishes the presence of unusual turns involving 12-membered hydrogen bonded rings in terminally blocked tri- and tetrapeptides. X-ray diffraction analysis of single crystals and NMR studies have been used to probe the three-dimensional structures of two terminally protected short peptides, Boc-gamma-Abu(1)-Aib(2)-Ala(3)-OMe 1 and Boc-gamma-Abu(1)-Aib(2)-Ala(3)-Aib(4)-OMe 2 (gamma-Abu = gamma-aminobutyric acid), in which conformationally flexible omega-amino acids (gamma-Abu) and conformationally restricted alpha-aminoisobutyric acid (Aib) residues are positioned contiguously. The crystal structures of both peptides 1 and 2 exhibit unusual turns composed of 12-membered hydrogen bonded rings involving C [double bond] O from the Boc-group and Ala(3) NH. A type I' beta-turn was observed in the structure of peptide 2 adjacent to the unusual turn with a hydrogen bond between gamma-Abu(1) C [double bond] O and Aib(4) NH. The crystals of peptide 1 are in the space group P2(1), a = 9.3020(10) A, b = 23.785(2) A, c = 10.022(3) A, beta = 101.35 degrees(4), Z = 4, R = 5.7%, and R(w) = 14.5%. Similarly, the crystals of peptide 2 are in the space group C2, a = 19.0772(6) A, b = 8.7883(2) A, c = 16.7758(3) A, beta = 110.7910 degrees(10), Z = 4, R = 6.71%, and R(w) = 15.11%. The unusual turn in both peptides 1 and 2 are retained in solution as is evident from NMR studies in CDCl(3). The role of the adjacently located Aib residue to nucleate the 12-membered hydrogen bonded ring is also addressed.

Amino Acids↗
PubMed2001

1-acetyl-3-[benzoyl(4-methoxyphenyl)methylene]-2,3-dihydro-1H-indol-2-one.

In the title compound, C25H19NO4, the indole moiety is not completely planar, the heterocyclic ring being distorted very slightly towards a half-chair conformation. The benzoyl and 4-methoxyphenyl substituents are individually almost planar and are in a bisecting and nearly perpendicular configuration, respectively, with respect to the plane of the indole moiety. The molecular and packing structures in the crystal are stabilized by intramolecular and intermolecular C-H...O interactions.

Journal Article↗
PubMed2001

The 143 and 300 K polymorphs of hexamethylenetetraminium 2,4-dinitrophenolate monohydrate.

The title compound, 3,5,7-triaza-1-azoniatricyclo[3.3.1.1(3,7)]decane 2,4-dinitrophenolate monohydrate, C6H13N4+*C6H3N2O5-*H2O, the 1:1 hydrate adduct of hexamethylenetetramine (HMT) and 2,4-dinitrophenol, undergoes a temperature phase transition. In the room-temperature phase, the adduct crystallizes in the monoclinic P2(1)/m space group, whereas in the low-temperature phase, the adduct crystallizes in the triclinic P1 space group. This phase transition is reversible, with the transition temperature at 273 K, and the phase transition is governed by hydrogen bonds and weak interactions. In both these temperature-dependent polymorphs, the crystal structure is alternately layered with sheets of hexamethylenetetramine and sheets of dinitrophenol stacked along the c axis. The hexamethylenetetramine and dinitrophenol moieties are linked by intermolecular hydrogen bonds. The water molecule in the adduct plays an important role, forming O-H...O hydrogen bonds which, together with C-H...O hydrogen bonds, bridge the adducts into molecular ribbons. Extra hydrogen bonds and weak interactions exist for the low-temperature polymorph and these interconnect the molecular ribbons into a three-dimensional packing structure. Also in these two temperature-dependent polymorphs, dinitrophenol acts as a hydrogen-bond acceptor and HMT acts as a hydrogen-bond donor.

Journal Article↗
PubMed2001

Atomic charges of cerbinal.

The molecule of the title compound, methyl 1-formyl-6-oxa-6H-indene-4-carboxylate, C(11)H(8)O(4), is planar. There are weak C--H...O intramolecular interactions and an intermolecular hydrogen bond in the structure, and these influence the crystal packing.

Crystallography, X-Ray↗
PubMed2001

On the short carbonyl bond in bis[mu-1,2-benzisothiazol-3(2H)-one 1,1-dioxido-kappa2N:O]bis[[1,2-benzisothiazol-3(2H)-one 1,1-dioxido-kappaN]bis(imidazole)copper(II)].

The short carbonyl bond in the title compound, [Cu(2)(C(7)H(4)NO(3)S)(4)(C(3)H(4)N(2))(4)] [Liu, Huang, Li & Lin (1991). Acta Cryst. C47, 41-43], is an artifact of disorder in the isothiazol-3(2H)-one 1,1-dioxide part of the 1,2-benzisothiazol-3(2H)-one entity. In the present redetermination, all bond dimensions in the centrosymmetric dinuclear molecule are normal. The five-coordinate Cu atom shows trigonal-bipyramidal coordination. Hydrogen bonds from the imidazole donor ligand link adjacent molecules into a two-dimensional layer structure.

Copper↗
PubMed2001

1,4-Methano-11a-methyl-4,4a,11,11a-tetrahydro-1H-benzo[b]fluoren-11-one.

The title compound, C(19)H(16)O, crystallizes with two molecules of opposite chirality in the asymmetric unit. In both molecules, the naphthalene and cyclopentanone moieties are individually planar. The two cyclopentane rings adopt envelope conformations, while the cyclohexane ring adopts a boat conformation.

Coumarins↗
PubMed2001

A mixed-valence manganese(III)-manganese(IV) di-mu-oxo complex, [(cyclam)MnO]2(ClO4)2(NO3).

The title dinuclear di-mu-oxo-bis[(1,4,8,11-tetraazacyclotetradecane-kappa(4)N)manganese(III,IV)] diperchlorate nitrate complex, [Mn(2)O(2)(C(10)H(24)N(4))(2)](ClO(4))(2)(NO(3)) or [(cyclam)MnO](2)(ClO(4))(2)(NO(3)), was self-assembled by the reaction of Mn(2+) with 1,4,8,11-tetraazacyclotetradecane in aqueous media. The structure of this compound consists of a centrosymmetric binuclear [(cyclam)MnO](3+) unit, two perchlorate anions and one nitrate anion. While the low-temperature electron paramagnetic resonance spectra show a typical 16-line signal for a di-mu-oxo Mn(III)/Mn(IV) dimer, the magnetic susceptibility studies also confirm a characteristic antiferromagnetic coupling between the electronic spins of the Mn(IV) and Mn(III) ions.

Journal Article↗
PubMed2001

3-(p-chlorophenyl)-4-phenyl-4,5-dihydroisoxazole-5-spiro-2'-1',2',3',4'-tetrahydronaphthalen-1'-one.

In the title compound, C24H18ClNO2, the phenyl ring and the tetralone moiety are approximately orthogonal to the isoxazoline ring. The isoxazoline ring adopts an envelope conformation, while the cyclohexenone ring of the tetralone moiety has an intermediate sofa/half-chair conformation. In this structure, one C--H...N intermolecular and two C--H...O intramolecular hydrogen bonds occur; the H.A distances are 2.60, and 2.35 and 2.57 A, respectively. The molecules are held together by an intermolecular C--H...N hydrogen bond, forming a one-dimensional chain along the [100] direction.

Antineoplastic Agents↗
PubMed2001

10-(4-fluorophenyl)-3,3,6,6,9-pentamethyl-3,4,6,7,9,10-hexahydroacridine-1,8(2h,5h)-dione and 10-(4-fluorophenyl)-3,3,6,6-tetramethyl-9-propyl-3,4,6,7,9,10-hexahydroacridine-1,8(2h,5h)-dione.

10-(4-fluorophenyl)-3,3,6,6,9-pentamethyl-3,4,6,7,9,10-hexahydroacridine-1,8(2H,5H)-dione, C24H28FNO2, (I), crystallizes with two crystallographically independent molecules (which differ slightly in conformation), while 10-(4-fluorophenyl)-9-propyl-3,3,6,6-tetramethyl-3,4,6,7,9,10-hexahydroacridine-1,8(2H,5H)-dione, C26H32FNO2, (II), crystallizes with one molecule per asymmetric unit. In both structures, the central ring in the acridine moiety is in a sofa conformation, while the outer rings adopt intermediate half-chair/sofa conformations. The central pyridine ring is orthogonal to the substituted phenyl ring. In both structures, the packing of the crystal is stabilized by C--H...O intermolecular hydrogen bonds.

Acridines↗
PubMed2001

3-amino-4'-methyl-5-ethylbiphenyl-2,4-dicarbonitrile and 3-amino-4'-(n,n-diethylamino)-5-ethylbiphenyl-2,4-dicarbonitrile.

In the title compounds, C17H15N3 and C20H22N4, the methyl derivative crystallizes with two molecules in the asymmetric unit, while the N,N-diethylamino derivative crystallizes with one molecule per asymmetric unit. The biphenyl twist angle for both molecular structures is approximately 45 degrees. The molecular packing is stabilized by N-H...N hydrogen bonds.

Journal Article↗