Triazolylbenzimidazolthiones and derivatives of the new 1,2,3‐triazolo[ 1,5‐a][ 1,3,5]benzotriazepine heterocycle

Four new triazolylbenzimidazolthione derivatives (2a‐d), analogous to triazolylbenzimidazolone derivatives previously tested as activators of the BK_Ca potassium channels, were prepared and assayed without success. Some derivatives of a new tricyclic nitrogen heterocycle, 1,2,3‐triazolo[1,5‐a][1,3,5]benzo‐triazepine, bearing a carboxamido group in the 3 position, other substituents in the 8 position and a carbonyl (5a‐d) or thione (6a‐c) or methylthio (7a‐c) function in the 5 position were synthesised. The nucleophilic displacement of the methylthio substituent with morpholine or cyclopentylamine provided the 5‐amino‐substituted tricyclic derivatives 8a‐d. Starting from the l‐(2‐nitrophenyl)‐4‐cyano‐5‐amino‐1,2,3‐triazole (9), the 3‐cyano‐triazolobenzotriazepin‐5‐one derivative 12 was also obtained. The majority of the new compounds were tested towards the BK_Ca potassium channels, the benzodiazepine and adenosine A₁ and A_2a receptors, but no remarkable activity was detected.     

VISUAL PIGMENTS AND BACTERIORHODOPSINS FORMED FROM AROMATIC RETINAL ANALOGS

Abstract— Rhodopsin (Rh) and bacteriorhodopsin (bR) analogs have been prepared from retinals containing various aromatic and heterocyclic nuclei. In the case of Rh, aromatic methyl substituents facilitate the regeneration and stabilize the pigments formed; in bR, however, methyl substituents seem to have little influence. Rhodopsins derived from unsubstituted aromatic retinals show fine structure in the relatively stable "pre-pigment" intermediate and their maxima are red-shifted compared to pigments derived from methylated aromatic retinals. This implies that in these aromatic rhodopsins the ring moiety adopts a more planar conformation when unsubstituted. In bR derivatives also the aromatic ring adopts a close-to-planar conformation when unsubstituted, but comparison with indene-derived bR suggests that even the unsubstituted phenyl ring may not be coplanar with the side-chain.     

Generalized van der Waals Theory of Interfaces in Simple Fluid Mixtures

An efficient implementation of the generalized van der Waals theory of fluids is presented for the calculation of surface tension in simple fluid mixtures. While detailed correlation analysis is avoided the dominant binding energy contribution and the negative contribution due to the nonlocal entropy are accounted for in the free energy density functional by simple physical approximations of the type originally introduced by van der Waals. Efficient computation is achieved by the use of a single-parameter optimization of a tanh-shaped profile representing the total density as well as the composition variation across the interface. This simple profile nevertheless incorporates the expected adsorption to the interface of the volatile component. Application is made to argon/krypton mixtures represented by Lennard-Jones potentials and Lorentz-Berthelot combining rules. Surface tension predictions compare well with both experimental observations and computer simulation results which also indicated close agreement in particle density profiles, especially if the Berthelot rule is amended with a binary interaction parameter slightly (3%) less than unity. Copyright 2001 Academic Press.     

Heterocyclic compounds from 3,3-dimercapto-1-aryl-2-propen-1-ones. Note 3. Condensation with N-methyl-o-phenylenediamine and N-benzyl-o-phenylenediamine

Two seven-membered ring compounds and three five-membered ring compounds were obtained by reaction in hot xylene of 3,3-dimercapto-l-phenyl-2-propen-1-one (1) with N-alkyl-o-phenylenediamines (2) . Compounds isolated were the 4-phenyl-5-alkyl-1,5-dihydro-2H-1,5-benzodiazepine-2-thiones (3) the 1-alkyl-4-phenyl-1,3-dihydro-2H-1,5-benzodiazepine-2-thiones (4) , the 1-alkyl-2-phenacylbenzimidazoles (5) , the 1-alkyl-2-phenylbenzimidazoles (6) and the 1-alkyl-2-methylbenzimidazoles (7) . The structures of these compounds were elucidated from their chemical reactivity and their nmr and ir spectra.     

Regio- and stereoselectivity of the addition of O-, S-, N-, and C-nucleophiles to the beta vinyl oxirane derived from D-glucal

6-O-Trityl- (1a) and 6-(O-benzyl)-substituted epoxide (1b) derived from D-glucal were examined in their addition reactions with O-, C-, N-, and S-nucleophiles. A 1,4-regio- and beta-stereoselective or an anti 1,2-addition pathway is commonly observed depending on the ability of the nucleophile to coordinate with the oxirane oxygen. When TMSN(3) or LiN(3) are used as azide-based nucleophiles, a 1,2-syn-addition pathway is also observed.     

Novel copolymers of styrene. 4. Halogen ring-substituted propyl 2-cyano-3-phenyl-2-propenoates

Novel trisubstituted ethylenes, halogen ring-substituted propyl 2-cyano-3-phenyl-2-propenoates, RPhCH ? C(CN)CO₂C₃H₇ (where R is 2-Br, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-F, 3-F, 4-F were prepared and copolymerized with styrene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and propyl cyanoacetate, and characterized by CHN analysis, IR, ¹H and ¹³C-NMR. All the ethylenes were copolymerized with styrene (M₁) in solution with radical initiation (ABCN) at 70°C. The compositions of the copolymers were calculated from nitrogen analysis and the structures were analyzed by IR, ¹H and ¹³C-NMR. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–500°C range with residue (0.9–4.7% wt.), which then decomposed in the 500–800°C range.     

N,N′-Linked 1,2-benzisothiazol-3(2H)-one 1,1-dioxides: synthesis, biological activity, and derived radicals

A number of N,N′-linked benzoannelated isothiazol-3(2H)-one 1,1-dioxides, not available via oxidation of isothiazolium salts, were obtained with good yields by reaction of N-amino heterocycles with 2-chlorosulfonylbenzoyl chloride and evaluated for their inhibitory activity toward human leukocyte elastase (HLE) and acetylcholinesterase (AChE). 2-(Phthalimid-1-yl)-1,2-benzisothiazol-3(2H)-one 1,1-dioxide and 2-(2-methyl-4-oxo-3(4H)-quinazolinyl)-1,2-benzisothiazol-3(2H)-one 1,1-dioxide were found to be inhibitors of HLE and tested as potential precursors of nitrogen-centered radicals using 266 nm laser flash photolysis.