Bimanes (1,5-diazabicyclo[3.3.0]octadienediones): Laser activity in syn-bimanes

The conversion of 3-methyl-4-benzyl-4-chloro-2-pyrazolin-5-one 10b was catalyzed by a mixture of potassium fluoride and alumina to give syn-(methyl, benzyl)bimane 6 (62%) without detectable formation of the anti isomer, A6 [a 1 : 1 mixture (87%) of the isomers 6 and A6 was obtained when the catalyst was potassium carbonate]. In a similar reaction syn-(methyl,carboethoxymethyl)bimane 7 (15%) with the anti isomer A7 (36%) was obtained from 3-methyl-4-carboethoxymethyl-4-chloro-2-pyrazolin-5-one 10c . syn-(Methyl, β-acetoxyethyl)bimane 8 (70%) was obtained from 3-methyl-4-β-acetoxyethyl-4-chloro-2-pyrazolin-5-one 10d (potassium carbonate catalysis) and was converted by hydrolysis to syn-(methyl, β-hydroxyethyl)bimane 9 (40%). Acetyl nitrate (nitric acid in acetic anhydride) converted anti-(amino,hydrogen)bimane 11 to anti-(amino,nitro)bimane 15 (91%), anti-(methyl,hydrogen)bimane 13 to anti-(methyl,nitro)(methyl,hydrogen)bimane 16 (57%), and degraded syn-(methyl,hydrogen)bimane 12 to an intractable mixture. Treatment with trimethyl phosphite converted syn-(bromomethyl,methyl)bimane 17 to syn-(dimethoxyphosphinylmethyl,methyl)bimane 18 (78%) that was further converted to syn-(styryl,methyl)bimane 19 (29%) in a condensation reaction with benzaldehyde. Treatment with acryloyl chloride converted syn-(hydroxymethyl,methyl)bimane 20 to its acrylate ester 21 (22%). Stoichiometric bromination of syn-(methyl,methyl)bimane 1 gave a monobromo derivative that was converted in situ by treatment with potassium acetate to syn-(acetoxymethyl,methyl)(methyl,methyl)bimane 47 . N-Amino-μ-amino-syn-(methylene,methyl)bimane 24 (68%) was obtained from a reaction between the dibromide 17 and hydrazine. Derivatives of the hydrazine 24 included a perchlorate salt and a hydrazone 25 derived from acetone. Dehydrogenation of syn-(tetramethylene)bimane 26 by treatment with dichlorodicyanobenzoquinone (DDQ) gave syn-(benzo,tetramethylene)bimane 27 (58%) and syn-(benzo)bimane 28 (29%). Bromination of the bimane 26 gave a dibromide 29 (92%) that was also converted by treatment with DDQ to syn-(benzo)bimane 28 . Treatment with palladium (10%) on charcoal dehydrogenated 5, 6, 10, 11-tetrahydro-7H,9H-benz [6, 7] indazol [1, 2a]benz[g]indazol-7,9-dione 35 to syn-(α-naphtho)bimane 36 (71%). The bimane 35 was prepared from 1,2,3,4-tetrahydro-1-oxo-2-naphthoate 37 by stepwise treatment with hydrazine to give 1,2,4,5-tetrahydro-3H-benz[g]indazol-3-one 38 , followed by chlorine to give 3a-chloro-2,3a,4,5-tetrahydro-3H-benz[g]indazol-3-one 39 , and base. Dehydrogenation over palladium converted the indazolone 34 to 1H-benz[g] indazol-3-ol 36 . Helicity for the hexacyclic syn-(α-naphtho)bimane 36 was confirmed by an analysis based on molecular modeling. The relative efficiencies (RE) for laser activity in the spectral region 500–530 nm were obtained for 37 syn-bimanes by reference to coumarin 30 (RE 100): RE > 80 for syn-bimanes 3, 5, 18 , and μ-(dicarbomethoxy)methylene-syn-(methylene,methyl)bimane 22 : RE 20–80: for syn-bimanes 1,2,4,20,24,26 , and μ-thia-syn-(methylene,methyl)bimane 50 : and RE 0-20 for 26 syn-bimanes. The bimane dyes tended to be more photostable and more water-soluble than coumarin 30. The diphosphonate 18 in dioxane showed laser activity at 438 nm and in water at 514 nm. Presumably helicity, that was demonstrated by molecular modeling, brought about a low fluorescence intensity for syn-(α-naphtho)bimane 36 , Φ0.1, considerably lower than obtained for syn-(benzo)bimane 28 , Φ0.9.     

Isotropic transition behaviour of an amphiphilic di-block copolymer under pressure

The present work deals with the interactions between carbon dioxide, used as pressure medium, either in the gas state (GCO₂) or in the supercritical state (SCCO₂) and amphiphilic di-block copolymers PEO_m-b-PMA(Az)_n. The effect of pressure on the isotropic transition of the PEO_m-b-PMA(Az)_n copolymer was investigated using scanning transitiometry (ST). The experimental results were compared with those measured when using ‘relatively inert’ mercury (Hg) as pressure medium. Morphological observation of a PEO_m-b-PMA(Az)_n thin film submitted to SCCO₂ was performed by atomic force microscopy (AFM) to investigate the nano-structure organization. These results indicate the possibility of modifying the nano-structure in a specific way depending on the CO₂ physical state.     

Impurity profiling of seized MDMA tablets by capillary gas chromatography

Impurity profiles of 3,4-methylenedioxymethylamphetamine (MDMA) tablets seized in France have been examined. The samples were extracted with methylene chloride under basic conditions and then analyzed by capillary gas chromatography. Almost 30 compounds were identified as precursors, intermediates and by-products. Palmitic and stearic acid were also found as tableting materials. The comparison of the different profiles obtained by the reported procedure provided very useful information about the synthetic processes used by clandestine laboratories and enabled a classification into several groups of profiles. According to these results, the reductive amination route appears to be the most common synthetic pathway in Western Europe. Furthermore, 3,4-methylenedioxyphenyl-2-propanone seems to be the most used precursor in clandestine laboratories.     

A preconditioned conjugate gradient Uzawa-type method for the solution of the stokes problem by mixed Q1–P0 stabilized finite elements

We study the behaviour of a conjugate gradient Uzawa-type method for a stabilized finite element approximation of the Stokes problem. Many variants of the Uzawa algorithm have been described for different finite elements satisfying the well-known Inf-Sup condition of Babu?ka and Brezzi, but it is surprising that developments for unstable ‘low-order’ discretizations with stabilization procedures are still missing. Our paper is presented in this context for the popular (so-called) Q1–P0 element. First we show that a simple stabilization technique for this element permits us to retain the property of a convergence factor bounded independently of the discretization mesh size. The second contribution of this work deals with the construction of a less costly preconditioner taking full advantages of the block diagonal structure of the stabilization matrix. Its efficiency is supported by 2D and. 3D numerical results.     

Etude dans la serie des organogallylazoles I. Synthese et structure

A series of N-dimethylgallylazoles have been prepared by treatment of azoles (imidazoles, benzimidazoles, pyrazoles, s-triazole and benzotriazole) with trimethylgallium.The structure (monomeric, dimeric, polymeric) of the resulting compounds depends on the position of the nitrogen atoms in the azole moiety. In the case of pyrazolyl derivatives, the NMR study in acetone or acetonitrile shows the existence of an equilibrium between the monomeric and dimeric forms.     

Preparation,Chemical and structural studies of a new (η-allyl)dihalocarbonyltungsten(II) compound

The complex (C₂H₅)₄N(ν₃H₅)Cl₂(CO)₂WP(C₆H₅)₃] (I) prepared from the anion W(CO)₅Cl, crystallizes in the triclinic system, P1, a 11.264(5), b 14.697(6), c 10.318(4) Å; α 99.37(3), β 111.87(5), γ 90.21°; V 1559ų; Z  2. The structure was refined to R  0.057 for 4509 independent reflections. The crystal is made up of discrete monomeric ions. In the anion the tungsten atom is at the center of an ocahedron, with two chlorine atoms and two CO groups in the equatorial plane, and the two remaining apices occupied by a (ν-allyl) ligand and a triphenylphosphine group.     

Separation of variables in Einstein spaces. II. No ignorable coordinates

We prove that the only Einstein spaces which admit a coordinate system with no ignorable coordinates which separates the Hamilton-Jacobi equation are certain symmetric spaces of Petrov typeD due to Kasner and the constant-curvature de Sitter spaces. We also show that a space admitting a coordinate system with no ignorable coordinates which separates the Helmholtz (Schrödinger) equation must be of Petrov type