Bromination of 4-(2-thienyl)thiazoles and 2-(2-thienyl)quinoline

Depending on the substituent, the bromination of 4-(2-thienyl)thiazoles and 2-(2-thienyl)quinoline takes place in the 5 position of the thiophene or thiazole ring. When an amino group is present in the 2 position of the thiazole ring, bromination takes place in the 5 position of the thiazole ring. When excess brominating agent is present, a second bromine atom enters the 5 position of the free ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 35–38, January, 1982.     

How to search for pentaquarks in high energy hadronic interactions

The strange-anticharmed Pentaquark is a uudc?s or uddc?s five-quark baryon that is expected to be either a narrow resonance, or possibly even stable against strong and electromagnetic decay. We describe this hyperon here, its structure, binding energy and lifetime, resonance width, production mechanisms, production cross sections, and decay modes. We describe techniques to reduce backgrounds in search experiments and to optimize the conditions for Pentaquark observation. Possibilities for enhancing the signal over background in Pentaquark searches are investgated by examining predictions for detailed momentum and angular distributions in multiparticle final states. We consider a loosely bound molecule and also a strongly-bound five-quark system. Fermilab E791 data, currently being analyzed, may have marginal statistics for showing definitive signals. Future experiments in the spirit of the recent CHARM2000 workshop, such as FNAL E781 and CERN COMPASS with 10⁶?10⁷ reconstructed charmed baryon events, should have sensitivity to determine whether or not the Pentaquark exists.     

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Ohne Zusammenfassung     

Peculiarities of the manifestation of the K absorption bands in the UV absorption spectra of azomethine bases

The structure of the UV spectra of azomethine bases of the thiophene and dithienyl series was examined on the basis of the concept of the nonplanar structure of azomethine bases. A peculiarity of the manifestation of the K absorption bands associated with stabilization of the wavelengths of the K bands, which is determined by an increase in the angle of acoplanarity of the azomethine system above 30°, was revealed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1043–1046, August, 1977.     

Glueballs versus quarkonium-flavor symmetry signatures

Flavor symmetry selection rules provide unambiguous signatures for glueball decays at masses above 1500 MeV where many channels are open. For example, a 2⁺⁺ glueball should decay into ππ, K$\text{K}$, ηη, η'η', ωω, ?? and ψψ, but not into K¹$\text{K}$ nor ηη'. A quarkonium or a four-quark state cannot go into all channels allowed for a glueball; at least one is OZI-forbidden for any choice of flavors. But any quarkonium state that goes to K$\text{K}$ should also go to K¹$\text{K}$ and ηη'. These selection rules are shown to be stable against SU(3) symmetry breaking.     

Researches on condensation products of some 2, 2′-dithieniyl compounds. I

Crotonaldehyde-type condensation of 5-acetyl-2, 2-dithienyl with some aromatic and heterotyclic aldehydes and nitroaldehydes in the presence of alkali is used to synthesize a number of hitherto undescribed unsaturated 2, 2-dithienyl ketones. The visible and UV absorption spectra of these compounds of the ketones synthesized are measured in ethanol and 96% sulfuric acid solutions. In sulfuric acid all the compounds investigated form intensely colored halochromic solutions. Comparison of the spectral characteristics of the compounds prepared shows that replacement of the benzene ring by furan and thiophene rings gives rise to a bathochromic effect which is significantly greater in acid solution than in neutral solution. For the neutral solution, introduction of a single nitro group into the benzene or thiophene ring gives rise to a K-band bathchromic shift, while in acid solution there is a hypsochromic effect.