Decreased l-tryptophan concentration in distinctive brain regions of mice treated repeatedly with phencyclidine

It has been reported that repeated phencyclidine (PCP) treatment induces schizophrenia-like behavior in mice. l-Tryptophan (Trp) concentrations in brain tissues of control (n?=?8) and PCP-treated mice (10 mg/kg/day, s.c., 14 days, n?=?10) were determined using high-performance liquid chromatography (HPLC) with fluorescence detection. The HPLC method involved pre-column fluorescence derivatization with (R)-(?)-4-(N,N-dimethylaminosulfonyl)-7-(3-isothiocyanatopyrrolidin-1-yl)-2,1,3-benzoxadiazole (DBD-PyNCS). Eight different parts of the brain, namely, the frontal cortex, nucleus accumbens, striatum, hippocampus, amygdala, thalamus, hypothalamus, and cerebellum, of both groups were investigated. A significant decrease in the l-Trp concentration in the nucleus accumbens (p?=?0.024) and hippocampus (p?=?0.027) was observed in PCP-treated mice, suggesting that alteration of the l-Trp metabolism might occur in these brain parts.     

Microwave-Accelerated Selective Acylation of (Hydroxyalkyl)phenols Using Acid Chlorides

Highly selective acylation of the alcoholic hydroxy group can be achieved with (hydroxyalkyl)phenols carrying both alcoholic and phenolic hydroxyls by the use of the most common acylating agents, acid chlorides, under microwave irradiation.     

Time Courses and Time‐Resolved Spectra of Firefly Bioluminescence Initiated by Two Methods of ATP Injection and Photolysis of Caged ATP

The time‐dependent characteristics of firefly bioluminescence initiated by manual injection of adenosine triphosphate (ATP) into buffer solution containing luciferin (Ln), luciferase (Luc) and Mg²⁺ were measured with a resolution of 10 ms, and compared with those obtained by photolysis of caged ATP. The time course depends on pH; both rise and decay rates decrease when pH is lowered from 7.8 to 6.8. In contrast, the parameter λ in the kinetic formula related to diffusion of ATP is almost independent of pH. The pH dependence of the time course of bioluminescence can be explained by the same pH tendency as the rate of ATP binding at the active site of Luc. The time‐resolved spectra can be decomposed into two Gaussian components with maxima at 2.2 and 2.0 eV. At pH 7.8, the band at 2.2 eV is more intense than that at 2.0 eV for all three concentration conditions. At lower pH, the band at 2.2 eV becomes weaker than that at 2.0 eV. The intensity ratio of the 2.0 and 2.2 eV bands is constant for duration time of 600 s for both injection and photolysis experiments, and the above conclusions are unaffected by the concentration ratio [Ln]/[Luc].     

Mechanistic study of asymmetric Michael addition of malonates to enones catalyzed by a primary amino acid lithium salt

A mechanistic study was carried out for the asymmetric Michael addition reaction of malonates to enones catalyzed by a primary amino acid lithium salt to elucidate the origin of the asymmetric induction. A primary β-amino acid salt catalyst, O-TBDPS β-homoserine lithium salt, exhibited much higher enantioselectivity than that achieved with the corresponding catalysts derived from α- and γ-amino acids for this reaction. Detailed studies of the transition states with DFT calculations revealed that the lithium cation and carboxylate group of the β-amino acid salt catalyst have important roles in achieving high enantioselectivity in the Michael addition reaction of malonates to enones.     

Synthesis of 2,3-dihydro-1H-isoindole-1-thiones via the bromine–lithium exchange between 1-bromo-2-(1-isothiocyanatoalkyl)benzenes and butyllithium

The reaction of 1-bromo-2-(1-isothiocyanatoalkyl)benzenes, which are easily derived from 2-bromophenyl ketones or (2-bromophenyl)methanamine, with butyllithium generates 1-(1-isothiocyanatoalkyl)-2-lithiobenzenes, which immediately underwent intramolecular cyclization to give rise to the corresponding 3-substituted and 3,3-disubstituted 2,3-dihydro-1H-isoindole-1-thiones in good yields.     

Improved synthesis of (R)-7-hydroxycarvone from (S)-α-pinene

A three-step synthesis of (R)-7-hydroxycarvone (1), which is anticipated to be a valuable building block for the versatile preparation of natural products, is described. Optimization of the reaction conditions for photooxygenation and migration of (S)-α-pinene 2, tetrapropylammonium perruthenate (TPAP) oxidation of the generated alcohol, and a subsequent ring-opening reaction in the presence of Cu(OTf)₂ led to the synthesis of 1 with good reproducibility. The desired product 1 was thus obtained in 46% yield over three steps.     

Hydrogen-bonded liquid crystals built from hydrogen-bonding donors and acceptors. Infrared study on the stability of the hydrogen bond between carboxylic acid and pyridyl moieties

Abstract

The stability of a hydrogen-bonded complex built through inter-molecular hydrogen bonding between carboxylic acid and pyridine fragments has been examined using infrared spectroscopy. Infrared spectra as a function of temperature have been recorded for the 1:1 complex of 4-hexyloxybenzoic acid and trans-4-propoxy-4′-stilbazole from the crystalline state to the isotropic state. A dependence of the stability of the hydrogen bond on molecular orientation is observed clearly in the infrared spectra. The spectra also suggest that the hydrogen bond is an unionized type with a double minimum potential energy.     

Spectroscopic and thermodynamic studies of binary mixtures composed of nematogenic and non-nematogenic components

The effect of a non-nematic guest, tetracyanoethylene (TCNE), on the liquid-crystaline state of the host, 4-n-pentyl-4′-cyanobiphenyl (5CB), has been investigated. It was shown by absorption spectroscopy that TCNE forms a 1 : 1 charge transfer complex with 5CB in the nematic phase, similar to that in the isotropic solution. The effect of TCNE on the transition temperature was investigated by comparison with a normal guest, 2,3-dimethylbutane (DMB), which has a molecular volume comparable with that of TCNE but has no specific interaction with the host. TCNE was found to lower the transition temperature much more strikingly than DMB, suggesting the peculiar effect of complex formation. The theoretical background is given based on molecular field theory.     

A new memory effect: smectic liquid crystalline memory having both conductive and optical memory

In order to compensate for light leakage in the oblique viewing directions of the dark state of the horizontal-switching mode such as the in-plane switching and fringe field switching modes. The viewing angle performance of the horizontal-switching mode with an compensation film has been evaluated on a case by case basis according to the retardation values of the films. Consequently, we found that a much better dark state can be achieved by using an optimised compensation film.