Combinatorial synthesis of small-molecule libraries using 3-amino-5-hydroxybenzoic acid

Summary A non-peptide library of 2001 compounds has been prepared utilizing solid-phase techniques. The split/combine method was demonstrated to work well to form mixtures of compounds based on 3-amino-5-hydroxybenzoic acid as a core structure. The benzoic acid of the core structure served as the attachment point for the resin and the amino and hydroxy positions were variably substituted.     

Metallabis(phosphonate) als Chelatliganden. II. Synthese und Reaktivität ein- und zweikerniger Palladiumbis(phosphonat)-Komplexe mit OHO- und OBF2O-Brückenbindungen

Metallabisphosphonates as Chelating Ligands. II. Synthesis and Reactivity of Mono- and Binuclear Palladiumbisphosphonate Complexes Containing OHO and OBF₂O Bridges The complexes C₅H₅Pd[{P(OR)₂O}₂H] ( 1 : R = Me; 2 : R = Et) are formed either by reaction of C₅H₅Pd(2-MeC₃H₄) with dimethyl- and diethylphosphite or by reaction of [ClPd{P(OR)₂O}₂H]₂ ( 3 : R = Me; 4 : R = Et) with TlC₅H₅. With excess HP(O)(OMe)₂, the π-allyl complex (2-MeC₃H₄)Pd[{P(OMe)₂O}₂H] ( 5 ) is also formed (besides 1 ) from C₅H₅Pd(2-MeC₃H₄). The ¹H and ³¹P n.m.r. spectra indicate that in 1 – 5 the PdP₂O₂H chelate ring presumably contains a symmetrical OHO-hydrogen bond. The reaction of 3 with BF₃ etherate leads to the binuclear complex [ClPd{P(OMe)₂O}₂BF₂]₂ ( 6 ) which reacts with TlC₅H₅ to yield C₅H₅Pd[{P(OMe)₂O}₂BF₂] ( 7 ). From C₅H₅Pd[{P(OR)₂O}₂H] ( 1 , 2 ) and NH₃ the bisamminepalladium bisphosphonates(NH₃)₂Pd[P(OR)₂O]₂ ( 8 , 9 ) are formed which probably possess a trans-configuration. The reaction of 8 , 9 with CF₃COOH does not lead to a corresponding Pd[{P(OR)₂O}₂H] chelate complex but instead gives by elimination of NH₃ polymeric palladium bisphosphonates [Pd{P(OR)₂O}₂]_n ( 10 , 11 ). 1 reacts with thallium acetylacetonate to give C₅H₅Pd[P(OMe)₂O]₂Tl ( 12 ).     

Nouveau precurseur de prostaglandines

We describe the stereospecific synthesis of a potential precursor of prostaglandins, starting from bicyclo(4.3.0)nonene-7,9-dione.     

On convection in a fluid filling the cavity of a moving solid body

The problem of simultaneous motion about a fixed point O of a solid body and unevenly heated viscous incompressible fluid completely filling a finite cavity of the body is considered in linear formulation. The center of mass of the system body plus fluid in the state of mechanical equilibrium is assumed to coincide with point O. The theorem on solvability of the Cauchy problem for small unsteady equilibrium perturbations is proved, and normal perturbations and the spectrum of the problem arising in the analysis of such perturbations are investigated. It is shown that the whole spectrum consists of normal eigenvalues and lies in some half-band containing the real axis. It is shown that the respective system of root vectors is complete. Properties of the spectrum and the dependence on Rayleigh numbers are investigated. Rayleigh numbers for which the real parts of eigenvalues are positive,i.e. when the generated oscillating normal perturbations are damped in time, are evaluated in the case of the fluid being heated from below and above.     

Contribution a la synthese de prostaglandines

A new general method for grafting the β chain of natural Prostaglandins and homologs is proposed.     

Thermally switchable and discretely tunable comb filter with a linearly chirped fiber Bragg grating

We propose and experimentally demonstrate a novel switchable and discretely tunable comb filter based on a thermally induced linearly chirped fiber Bragg grating. Experimentally we achieved a thermally induced optical bandpass filter that has eight switchable passband peaks with peak separations of 1.6 and 3.2 nm, a very narrow bandwidth (as small as 10 pm) of each peak, a tunable range of 16.5 nm, and a greater than 25 dB rejection ratio. Two spectral peaks separated by only 0.8 nm were also obtained with this comb filter. This filter provides the unique advantages of an all-fiber structure, switchable spectral peaks, independent tuning of the center wavelength and wavelength spacing of the spectral peaks, low polarization sensitivity, simple structure, ease of fabrication, and low cost.     

Functionalized macrocycles from functionalized tetra-amines: pendent-arm macrocycles derived from dichloropivalic acid

Reaction between ethane-1,2-diamine and 3,3'-dichloropivalic acid results in different, isomeric tetra-amine derivatives, one a tetraamino carboxylic acid and the other a carboxamidotriamino alcohol, depending upon reaction conditions. Intended conversion of the Cu(II) complex of the former to a cyclam-like macrocycle through reaction with nitroethane and formaldehyde results in isolation of derivatives of both the former and the latter. This can be rationalized by assuming the intermediacy of an azetidinone, a species similar to that seen in simpler reactions of dichloropivalates. A single reaction thereby provides pendent-arm macrocycles where one has an electrophilic and the other a nucleophilic substituent. Parallel chemistry is not seen in the reaction between propane-1,3-diamine and 3,3'-dichloropivalate.     

Room-temperature multiwavelength erbium-doped fiber ring laser employing sinusoidal phase-modulation feedback

An effective method for achieving a room-temperature multiwavelength erbium-doped fiber ring laser is presented. Simultaneous multiwavelength lasing with 0.5-nm intervals is achieved both experimentally and theoretically by addition of sinusoidal phase modulation in the ring cavity to prevent single-wavelength oscillation.     

Study on the isomeric ratios of (γ,p) photonuclear reactions with isotopes 40 92 Zr and 74 183 W in the giant dipole resonance region

We have carried out the study on the isomeric ratios in (γ,p) photonuclear reactions with isotopes ₄₀ ⁹² Zr and ₇₄ ¹⁸³ W in the giant dipole resonance (GDR) region. The targets were irradiated with bremsstrahlungs produced by electron accelerator Microtron MT-25 of the Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Dubna, Russia. Spectra of the irradiated samples were measured with a spectroscopic system consisting of 8192-channel analyzer CANBERRA and high-energy resolution semiconductor detector CANBERRA. The results were discussed and compared with those of other authors. The text was submitted by the authors in English.