2,3-Dichloro-1,4-hydroquinone 2,3-dichloro-1,4-benzoquinone monohydrate: a quinhydrone-type 1:1 donor-acceptor [D-A] charge-transfer complex

In the crystal structure of the title compound (systematic name: 2,3-dichlorobenzene-1,4-diol 2,3-dichlorocyclohexa-2,5-diene-1,4-dione monohydrate), C(6)H(4)Cl(2)O(2)center dot C(6)H(2)Cl(2)O(2)center dot H(2)O, the 2,3-dichloro-1,4-hydroquinone donor (D) and the 2,3-dichloro-1,4-benzoquinone acceptor (A) molecules form alternating stacks along [100]. Their molecular planes [maximum deviations for non-H atoms: 0.0133 (14) (D) and 0.0763 (14) angstrom (A)] are inclined to one another by 1.45 (3)degrees and are thus almost parallel. There are pi-pi interactions involving the D and A molecules, with centroid-centroid distances of 3.5043 (9) and 3.9548 (9) angstrom. Intermolecular O-H center dot center dot center dot O hydrogen bonds involving the water molecule and the hydroxy and ketone groups lead to the formation of two-dimensional networks lying parallel to (001). These networks are linked by C-H center dot center dot center dot O interactions, forming a three-dimensional structure.

Bicyclo[3.2.1]amide-DNA: a chiral, non-chiroselective base-pairing system

The design, synthesis and base-pairing properties of bicyclo[3.2.1]amide-(bca)DNA, a novel phosphodiester based DNA analogue, is reported. This analogue consists of a conformationally constrained backbone entity which emulates a B-DNA geometry, to which the nucleobases were attached via an extended, acyclic amide linker. Homobasic adenine-containing bca-decamers form duplexes with complementary oligonucleotides containing the bca-, the DNA the RNA and, surprisingly, also the L-RNA backbone. UV- and CD-spectroscopic investigations revealed the duplexes with D- or L-complement to be of similar stability and enantiomorphic in structure. Bca-oligonucleotides containing all four bases form strictly antiparallel, left-handed complementary duplexes with itself and complementary DNA but not with RNA. Base-mismatch discrimination is comparable to that of DNA while the overall thermal stabilities of bca-oligonucleotide duplexes are inferior relative to that of DNA or RNA. A detailed molecular modeling study of left- and right-handed bca-DNA containing duplexes showed only minor changes in the backbone structure and revealed a structural switch around the base-linker unit to be responsible for the generation of enantiomorphic duplex structures. The obtained data are discussed with respect to the structural and energetic role of the ribofuranose entities in DNA and RNA association

Reactions of CF3-enones with arenes under superelectrophilic activation: a pathway to trans-1,3-diaryl-1-CF3-indanes, new cannabinoid receptor ligands

4-Aryl-1,1,1-trifluorobut-3-en-2-ones ArCH[double bond, length as m-dash]CHCOCF3 (CF3-enones) react with arenes in excess of Brønsted superacids (TfOH, FSO3H) to give, stereoselectively, trans-1,3-diaryl-1-trifluoromethyl indanes in 35-85% yields. The reaction intermediates, the O-protonated ArCH[double bond, length as m-dash]CHC(OH(+))CF3 and the O,C-diprotonated ArHC(+)CH2C(OH(+))CF3 species, have been studied by means of (1)H, (13)C, (19)F NMR, and DFT calculations. Both types of the cations may participate in the reaction, depending on their electrophilicity and electron-donating properties of the arenes. The formation of CF3-indanes is a result of cascade reaction of protonated CF3-enones to form chemo-, regio- and stereoselectively three new C-C bonds. The obtained trans-1,3-diaryl-1-trifluoromethyl indanes were investigated as potential ligands for cannabinoid receptors CB1 and CB2 types. The most potent compound showed sub-micromolar affinity for both receptor subtypes with a 6-fold selectivity toward the CB2 receptor with no appreciable cytotoxicity toward SHSY5Y cells.

Nasolabial esthetics in children with complete unilateral cleft lip and palate after 1- versus 3-stage treatment protocols

PURPOSE: Facial esthetics play an important role in social interactions. However, children with a repaired complete unilateral cleft lip and palate usually show some disfigurement of the nasolabial area. To date, few studies have assessed the nasolabial appearance after different treatment protocols. The aim of the present study was to compare the nasolabial esthetics after 1- and 3-stage treatment protocols. MATERIALS AND METHODS: Four components of the nasolabial appearance (nasal form, nasal deviation, mucocutaneous junction, and profile view) were assessed by 4 raters in 108 consecutively treated children who had undergone either 1-stage closure (Warsaw group, 41 boys and 19 girls, mean age 10.8 years, SD 2.0) or 3-stage (Nijmegen group, 30 boys and 18 girls, mean age 8.9 years, SD 0.7). A 5-grade esthetic index of Asher-McDade was used, in which grade 1 indicates the most esthetic and grade 5 the least esthetic outcome. RESULTS: The nasal form was judged the least esthetic in both groups and graded 3.1 (SD 1.1) and 3.2 (SD 1.1). The nasal deviation, mucocutaneous junction, and profile view were scored from 2.1 (SD 0.8) to 2.3 (SD 1.0) in both groups. The treatment outcome after the Warsaw and Nijmegen protocols was comparable. Neither overall nor any of the 4 components of the nasolabial appearance showed intercenter differences (P > .1). CONCLUSIONS: The nasolabial appearance after the Warsaw (1-stage) and Nijmegen (3-stage) protocols was comparable. The technique of lip repair (triangular flap in Warsaw and Millard rotation advancement in Nijmegen) gave comparable results for the esthetics of the nasolabial area.

Chiral Templating Activity of Tris(bipyridine)ruthenium(II) Cation in the Design of Three-Dimensional (3D) Optically Active Oxalate-Bridged {[Ru(bpy) 3 ][Cu 2 x Ni 2(1 - x ) (C 2 O 4 ) 3 ]} n (0 ≤ x ≤ 1; bpy = 2,2‘-bipyridine): Structural, Optical, and Magnetic Studies

Three-dimensional oxalate-based {[Ru(bpy)3][Cu2xNi2(1-x)(ox)3]}n (0≤ x ≤ 1, ox = C2O42-, bpy = 2,2‘bipyridine) were synthesized. The structure was determined for x = 1 by X-ray diffraction on single crystal. The compound crystallizes in the cubic space group P4132. It shows a three-dimensional 10-gon 3-connected (10,3) anionic network where copper(II) has an unusual tris(bischelated) environment. X-ray powder diffraction patterns and their Rietveld refinement show that all the compounds along the series are isostructural and single-phased. According to X-ray absorption spectroscopy, copper(II) and nickel(II) have an octahedral environment, respectively elongated and trigonally distorted. As shown by natural circular dichroism, the optically active forms of {[Ru(bpy)3][CuxNi2(1-x)(ox)3]}n are obtained starting from resolved Δ- or Λ-[Ru(bpy)3]2+. The Curie−Weiss temperatures range between −55 (x = 1) and −150 K (x = 0). The antiferromagnetic exchange interaction thus decreases when the copper contents increases in agreement with the crystallographic structure of the compounds and the electronic structure of the metal ions. At low temperature, the compounds exhibit complex long-range ordered magnetic behavior.

Effects of pH, light and temperature on (1→3,1→4)-β-glucanase stability in wheat leaves

Changes in (1→3,1→4)-β-D-glucan endohydrolase (EC 3.2.1.73) protein levels were investigated in segments from second leaves of wheat (Triticum aestivum L.). The abundance of the enzyme protein markedly increased when leaf segments were incubated in the dark whereas the enzyme rapidly disappeared when dark-incubated segments were illuminated or fed with sucrose. Addition of cycloheximide (CHI) to the incubation medium led to the disappearance of previously synthesized (1→3,1→4)-β-glucanase and suppressed the dark-induced accumulation indicating that the enzyme was rather unstable. The degradation of (1→3,1→4)-β-glucanase was analyzed without the interference of de-novo synthesis in intercellular washing fluid (IWF). The loss of the enzyme protein during incubation of IWF (containing naturally present peptide hydrolases) indicated that the stability increased from pH 4 to pH 7 and that an increase in the temperature from 25 to 35 °C considerably decreased the stability. Chelating divalent cations in the IWF with o-phenanthroline also resulted in a lowered stability of the enzyme. A strong temperature effect in the range from 25 to 35 °C was also observed in wheat leaf segments. Diurnal changes in (1→3,1→4)-β-glucanase activity were followed in intact second leaves from young wheat plants. At the end of the dark period, the activity was high but constantly decreased during the light phase and remained low if the light period was extended. Activity returned to the initial level during a 10-h dark phase. During a diurnal cycle, changes in (1→3,1→4)-β-glucanase activity were associated with reciprocal changes in soluble carbohydrates. The results suggest that the synthesis and the proteolytic degradation of an apoplastic enzyme may rapidly respond to changing environmental conditions.