trans-Di-bromido-tetra-kis-(5-methyl-1H-pyrazole-κN2)manganese(II).

The title compound, trans-di-bromido-tetra-kis-(5-methyl-1H-pyrazole-κN 2)manganese(II), [MnBr2(C4H6N2)4] or [Mn(3-MePzH)4Br2] (1) crystallizes in the triclinic P space group with the cell parameters a = 7.6288 (3), b = 8.7530 (4), c = 9.3794 (4) Šand α = 90.707 (4), ß = 106.138 (4), γ = 114.285 (5)°, V = 542.62 (5) Å3, T = 120 K. The asymmetric unit contains only half the mol-ecule with the manganese atom is situated on a crystallographic inversion center. The 3-MePzH ligands are present in an AABB type manner with two methyl groups pointing up and the other two down. The supra-molecular architecture is characterized by several inter-molecular C-H⋯N, N-H⋯Br, and C-H⋯π inter-actions. Earlier, a polymorphic structure of [Mn(3-MePzH)4Br2] (2) with a similar geometry and also an AABB arrangement for the pyrazole ligands was described [Reedijk et al. (1971 ▸). Inorg. Chem. 10, 2594-2599; a = 8.802 (6), b = 9.695 (5), c = 7.613 (8) Šand α = 105.12 (4), ß = 114.98 (4), γ = 92.90 (3)°, V = 558.826 (5) Å3, T = 295 K]. A varying supra-molecular pattern was reported, with the structure of 1 featuring a herringbone type pattern while that of structure 2 shows a pillared network type of arrangement along the a axis. A nickel complex [Ni(3-MePzH)4Br2] isomorphic to 1 and the analogous chloro derivatives of FeII, CoII and CuII are also known.

Modulation of bone turnover by Cissus quadrangularis after ovariectomy in rats.

In women, age-related bone loss is associated with increased risk of bone fracture. Existing therapies are associated with severe side effects; thus, there is a need to find alternative medicines with less or optimal side effects. Cissus quadrangularis (CQ), an Ayurvedic medicine used to enhance fracture healing, was tested for its bone protective properties and studied to discern the mechanism by which it is beneficial to bone. Female Sprague Dawley rats were either sham operated or ovariectomized and were fed CQ for 3 months. Several biochemical markers, cytokines and hormones were assayed. Femur, tibia and lumbar vertebrae were subjected to pQCT and µCT densitometry. MC3T3 cells were cultured, treated with CQ and used to analyze miRNA content and subjected to qPCR for gene expression analysis related to bone metabolism. CQO rats showed protected bone mass and microarchitecture of trabecular bone in the distal femoral metaphysis and the proximal tibial metaphysis. The lumbar vertebrae, however, showed no significant changes. Serum protein expression levels of P1NP increased and Trap5b and CTX levels decreased with in vivo CQ treatment. Some influence on the anti- and pro-inflammatory markers was also observed. Significantly high level of estradiol in the CQO rats was observed. In vitro expression of a few genes related to bone metabolism showed that osteocalcin increased significantly. The other genes-collagen I expression, SPP1, BMP2, DCAT1-decreased significantly. Certain miRNA that regulate bone turnover using the BMP pathway and Wnt signaling pathways were upregulated by CQ. qPCR after acute treatment with CQ showed significantly increased levels of osteocalcin and decreased levels of Wnt/ß catenin antagonist DCAT1. Overall, CQ protected the microarchitecture of the long bones from ovariectomy-induced bone loss. This may be because of decreased inflammation and modulation through the BMP and Wnt signaling pathways. We conclude that CQ is a potential therapeutic agent to treat postmenopausal osteoporosis with no side effects.

A Protocol for the exo-Mono and exo,exo-Bis Functionalization of the Diazocine Ring of Tröger's Base.

An efficient protocol has been developed for the exo-mono and exo,exo-bis functionalization of Tröger's base in the benzylic 6 and 12 positions of the diazocine ring. The lithiation of Tröger's base using s-BuLi/TMEDA followed by electrophilic quench affords exo-mono- and exo,exo-bis-substituted derivatives of Tröger's base in good to excellent yields. The variation of the number of equivalents of s-BuLi/TMEDA and the order of addition of the electrophile strongly govern the outcome of the reaction for each electrophile.

Synthesis, molecular structure, and chiroptical properties of dibenzylidene derivatives of bicyclo[3.3.1]nonane and brexane.

Synthesis of several enantiomerically pure unsaturated bicyclo[3.3.1]nonane and related brexane (tricyclo[4.3.0.0(3,7) ]nonane) derivatives bearing exocyclic benzylidene substituents from readily available (+)-(1S,5S)-bicyclo[3.3.1]nonane-2,6-dione was accomplished. Molecular geometry and chiroptical properties of compounds with enone and styrene chromophores were studied by X-ray diffraction analysis, molecular modeling, and circular dichroism (CD) spectroscopy. Difunctional 3,7-dibenzylidenebicyclo[3.3.1]nonanes, such as and , exhibited intense CD couplets, arising from the exciton coupling between the two unsaturated chromophores. The observed negative sign of the exciton couplets is congruent with the negative twist (negative chirality) defined by the two interacting transition dipoles. The sign of the Cotton effect corresponding to the π→π* transitions in the CD spectra of monoenone and tricyclic brexane acetate was correlated with the intrinsic dissymmetry (helicity) of the styrene chromophore.

Cyclometallated gold(III) aryl-pyridine complexes as efficient catalysts for three-component synthesis of substituted oxazoles.

Cyclometallated aryl-pyridine gold(iii) complexes are shown to be efficient catalysts for the multicomponent reaction between N-benzyl imines, alkynes, and acyl chlorides to form trisubstituted oxazoles. The reaction typically proceeds in good yields (up to over 80%) and short reaction times (∼15 minutes). The high stability of the investigated cyclometallated catalysts enables a retained efficiency for this reaction in terms of rate and yield using as little as 0.5 mol% catalyst, a reduction by an order of magnitude compared to previously used Au(iii)-salen complexes. An attractive feature of the present catalytic system is that active catalysts can be formed from simple pre-catalysts under the reaction conditions. Both cyclometallated and non-cyclometallated complexes were characterized in the solid state by single crystal X-ray diffraction.

Synthesis and kinetics of sterically altered photochromic dithizonatomercury complexes.

Following a previous study where 12 electronically altered dithizones were synthesized, here we report on attempts to synthesize 26 dithizones. The purpose was to explore the boundaries within which dithizones may be synthesized, explore spectral tuning possibilities, and investigate steric effects on the photochromic reaction of its mercury complexes. Contrary to expectation, large substituents like phenoxy groups increased the rate of the photochromic back-reaction. In the series H-, 2-CH3-, 4-CH3-, 3,4-(CH3)2-, 2-OC6H5-, and 4-OC6H5-dithizonatophenylmercury(II), the lowest rate of 0.0004 s(-1) was measured for the 2-CH3 complex, while the rate for the 2-OC6H5 derivative was 20 times higher. A solvent study revealed a direct relationship between dipole moment and the rate of the back-reaction, while the relationship between temperature and rate is exponential, with t1/2 = 2 min 8 s for the 4-phenoxy complex. The crystal structures of two dithizone precursors, 2-phenoxy- and 4-phenoxynitroformazan, are reported.

Catalytic three-component domino reaction for the preparation of trisubstituted oxazoles.

Multicomponent reactions are attractive for assembling functionalized heterocyclic compounds. To this end, an efficient gold-catalyzed three-component domino reaction to form oxazoles directly from imines, alkynes, and acid chlorides is presented. The reaction proceeds in a single synthetic step by using a gold(III)-N,N'-ethylenebis(salicylimine) (salen) catalyst to give trisubstituted oxazoles in up to 96 % yield. The substrate scope, a mechanistic study exploring the role of the gold catalyst, and the synthetic applications of the oxazole products are discussed.

4-(2-Bromo-phen-yl)-2-phenyl-pyrano[3,2-c]chromen-5(4H)-one.

In the title compound, C24H15BrO3, the pyran-ochromenone ring is essentially planar, while the 2-bromo-phenyl group is almost perpendicular to it [85.58 (6)°]. In the crystal, inversion dimers linked by pairs of weak C-H⋯π bonds occur; there is also a short inter-atomic contact found between the Br and carbonyl O atoms [3.016 (1) Å].

2,5-Dihexyl-thio-phene 1,1-dioxide.

In the title mol-ecule, C16H28O2S, the two n-hexyl groups are in all-trans conformations. Their C atoms are situated close to the plane of the thio-phene ring with a maximum deviation of 0.718 (6) Šfor one of the terminal methyl groups. In the crystal, a short C-H⋯O contact is observed between thio-phene 1,1-dioxide groups.