Synthesis and reactions of binuclear diolefin rhodium(I) compounds bridged by nitrogen heterocycles. Crystal structure of dichloro-di-1,5-cyclooctadiene(μ-pyrazine)-dirhodium(I) [{Rh(1,5-C8H12)Cl}2(μ-C4H4N2)]

Binuclear complexes of rhodium(I) of the type [(dien)(X)Rh(μ-N-N)Rh(X)(dien)] (dien = 1,5-cyclooctadiene or norbornadiene; N-N = pyrazine, 4,4′-bipyridine or Phenazine and X = Cl or Br) with bridging heterocycles have been isolated and their reactions with carbon monoxide, 2,2′-bipyridine and 1,10-phenanthroline investigated. The crystal structure of [(COD)(Cl)Rh(μ-pyrazine)Rh(Cl)(COD)] has been determined.     

Inclusive γ-production in\bar pp interactions at 0.76 and 2.0 GeV/c

The inclusive production of photons in \(\bar pp\) interactions has been studied at incident momenta of 0.76 and 2.0 GeV/c. The inclusive cross sections for γ-production and the average multiplicities of γ, «n _γ», are presented as a function of the charged prong topology. Results on the two particle correlation parametersf ⁰⁰ andf ^?0 are presented. The inclusive distributions of the Feynman variablex and of the transverse momentump _T of the photons are compared with the expectations from charged pion distributions on the basis of charge independence. A search has been made for direct γ-production in \(\bar pp\) interactions at 0.76 GeV/c by looking for events which fit uniquely the hypothesis \(\bar pp \to m\pi ^ + + m\pi ^ - + \gamma \) . An estimate of the ratio $$R = \frac{{\sigma (\bar pp \to m\pi ^ + + m\pi ^ - + \gamma )}}{{\sigma (\bar pp \to m\pi ^ + + m\pi ^ - + \pi ^0 )}}$$ is given.     

General characteristics of\bar pp interactions at low energies in terms of principal axis and impact parameter variables

The reaction configuration in momentum and position space has been investigated in detail from exclusive final states in \(\bar pp\) interactions at centre of mass energies 2.01 and 2.96 GeV. In momentum space one finds a tendency towards a planar configuration at low multiplicities. In position space, one sees the average impact parameter decreasing with increasing multiplicity. At large multiplicities, events become more phase-space like i.e., more central whereas at lower multiplicities the effect ofp _t damping can be seen.     

Facile synthesis of novel (1-Aryl/alkyl-1<Emphasis Type="Italic">H</Emphasis>-1,2,3-triazol- 4-yl)methyl-2-bromo-4-methylthiazole-5-carboxylates by Cu(I) catalyzed click reaction

A number of novel thiazole-triazole heterocycles bearing (1-aryl/alkyl-1H-1,2,3-triazol-4-yl)methyl- 2-bromo-4-methylthiazole-5-carboxylates was synthesized through the click reaction. The structure of all new synthesized compounds was established by ¹H and ¹³C NMR spectroscopy and mass spectrometry methods.     

β-Strand mimetics: formation of bend-strands in oligomers of enantiomeric β-amino acids

Oligomers comprising of enantiomeric cis-oxo-β-norbornene amino acid [2R,3S] and [2S,3R] residues at alternate positions were synthesized and characterized by extensive NMR and MD studies, which showed robust bend-strand secondary structures.     

1‐Arylsulfonyl‐2‐styrylsulfonylthenes — source for a new class of bis heterocycles

New and novel sulfone linked bis heterocycles_ bis pyrroles and pyrrolyl pyrazolines are prepared from 1‐arylsulfonyl‐2‐styrylsulfonylethenes by 1,3‐dipolar cycloaddition methodology.     

Michael adducts--source for biologically potent heterocycles

A new class of pyrimidinetriones, thioxopyrimidinediones, pyrazolidinediones and isoxazolidinediones were prepared from (E)-1,4-diarylbut-2-ene-1,4-diones. All the new compounds synthesized were screened for antimicrobial activity.     

Stereoselective total synthesis of paecilomycin E and F and its two congeners Cochliomycin C and 6-epi-Cochliomycin C

An efficient and concise approach to the total synthesis of Paecilomycins E (1) and F (2), Cochliomycin C (4) and 6-epi-Cochliomycin C (3) is described. The synthesis involves novel route to the synthesis of Paecilomycin E and F and further conversion to Cochliomycin C and 6-epi-Cochliomycin C. Olefin metathesis and base promoted macro lactonization being the key reactions followed by chlorination to achieve target Cochliomycin C and 6-epi-Cochliomycin C.