Midori Goto

The habenula is crucial for experience-dependent modification of fear responses in zebrafish

The zebrafish dorsal habenula (dHb) shows conspicuous asymmetry in its connection with the interpeduncular nucleus (IPN) and is equivalent to the mammalian medial habenula. Genetic inactivation of the lateral subnucleus of dHb (dHbL) biased fish towards freezing rather than the normal flight response to a conditioned fear stimulus, suggesting that the dHbL-IPN pathway is important for controlling experience-dependent modification of fear responses.

Facile regio- and stereoselective hydrometalation of alkynes with a combination of carboxylic acids and group 10 transition metal complexes: selective hydrogenation of alkynes with formic acid.

A facile, highly stereo- and regioselective hydrometalation of alkynes generating alkenylmetal complex is disclosed for the first time from a reaction of alkyne, carboxylic acid, and a zerovalent group 10 transition metal complex M(PEt(3))(4) (M = Ni, Pd, Pt). A mechanistic study showed that the hydrometalation does not proceed via the reaction of alkyne with a hydridometal generated by the protonation of a carboxylic acid with Pt(PEt(3))(4), but proceeds via a reaction of an alkyne coordinate metal complex with the acid. This finding clarifies the long proposed reaction mechanism that operates via the generation of an alkenylpalladium intermediate and subsequent transformation of this complex in a variety of reactions catalyzed by a combination of Brϕnsted acid and Pd(0) complex. This finding also leads to the disclosure of an unprecedented reduction of alkynes with formic acid that can selectively produce cis-, trans-alkenes and alkanes by slightly tuning the conditions.

Stereospecific Coupling of H-Phosphinates and Secondary Phosphine Oxides with Amines and Alcohols: A General Method for the Preparation of Optically Active Organophosphorus Acid Derivatives†

The reaction of H-phosphinates and secondary phosphine oxides with amines and alcohols proceeds highly stereospecifically to give the corresponding coupling products with inversion of configuration at the phosphorus center under the Atherton-Todd reaction conditions. This finding leads to the establishment of a general and efficient method for the synthesis of a variety of optically active organophosphorus acid derivatives from the easily available chiral H-phosphinates and secondary phosphine oxides.

Anisotropic Refractive Indices of Organic Crystals of Thiophene/Phenylene Co-Oligomers Determined by Microspectroscopic Measurements

We have measured and determined the anisotropic refractive indices of thiophene/phenylene co-oligomer (TPCO) crystals. The refractive indices were calculated from the crystal thicknesses and optical path lengths on the basis of the interference of the reflectance spectra measured along the crystal axes by a polarizing microscope with a white light source. The higher refractive indices were observed along the crystal short axis and this was attributed to a denser molecular packing along that axis.

Peralkylcyclotrisilane: crystal and molecular structure of [(t-BuCH2)2Si[3

Abstract The crystal and molecular structure of the first peralkylcyclotrisilane, [(t-BuCH 2 Si] 3 , have been determined by X-ray diffraction. Crystal data: orthorhombic, space group Pnna , a 35.668(3), b 16.963(1), c 12.251(1) A, d calcd 0.9183 g cm −3 for Z = 8 and V 7392.8 A 3 . Final R factor, based on 851 reflections (| F o | > 3σ|( F o )|), 0.069. The SiSi bond length in the Si 3 ring is the longest among those of various peralkylcyclopolysilanes, [R 1 R 2 Si] n ( n = 3−6), and is comparable with that in the perarylcyclotrisilane [2,6-Me 2 C 6 H 3 ) 2 Si] 3 .

Stereospecific Halogenation of P(O)-H Bonds with Copper(II) Chloride Affording Optically Active Z1Z2P(O)Cl

A general and efficient method for the preparation of optically active Z1Z2P(O)Cl from the easily prepared optically active H-phosphinates and H-phosphine oxides was reported. H-Phosphinates and H-phosphine oxides react stereospecifically with CuCl2 to produce the corresponding optically active Z1Z2P(O)Cl with retention of configuration at the phosphorus center. Optically active Z1Z2P(O)Cl reacts easily with a variety of nucleophiles to produce other chiral organophosphorus acid derivatives with inversion of configuration at phosphorus.

Fluorescence Spectroscopic Properties of Nitro-Substituted Diphenylpolyenes: Effects of Intramolecular Planarization and Intermolecular Interactions in Crystals

The steady-state absorption and fluorescence properties of (E,E,E)-1,6-diaryl-1,3,5-hexatrienes (2, aryl = 2-nitrophenyl; 3, aryl = 3-nitrophenyl; 4, aryl = 4-nitrophenyl) have been investigated in solution and in the crystalline state. The solid-state absorption spectra of 2-4 shifted to longer wavelengths than those in solution. A combination of theoretical calculations and single-crystal X-ray structure analyses shows considerable planarization of molecules in the solid state, which is mainly responsible for the spectral red shifts. The effects of intermolecular interactions on the absorption spectra appeared to be relatively small in these crystals. This is consistent with the monomeric origin of the solid-state emission. Molecule 2 was nonfluorescent in all solvents studied, probably due to the efficient nonradiative deactivation from ionic species produced by excited-state intramolecular proton transfer (ESIPT) along the C-H...O-type hydrogen bonds. The fluorescence of 3, observed only in medium polar solvents, originated from an intramolecular charge transfer (ICT*) state, while that of 4 derived from locally excited (LE*) and/or ICT* states depending on the solvent polarity. All three molecules exhibited LE* fluorescence in the solid state. No observation of ICT* emission in crystals strongly suggests the twisted geometries for ICT* (TICT) of 3 and 4 in solution. The measurable fluorescence from crystal 2 can be attributed to the restricted torsional motions in the solid excited state.

Novel reactions of 1,1,4,4-tetraaryl-1,2,3-butatrienes with elemental sulfur and selenium

Abstract Sulfurization and selenation reactions of 1,1,4,4-tetraaryl-1,2,3-butatrienes were examined to give novel 1,2,3,4,5-pentathiepane and 1,2,5-triselenepane ring systems. Further degradation of these new heterocycles using DBU/DMF was also described.

Novel photorearrangements of (2′,2′-diaryl-vinylidene)cyclopropanes

Abstract Irradiation of 7-(2′,2′-diarylvinylidene)bicyclo[4.1.0] hept-2-enes in benzene gave 8-(diarylmethylene)tricyclo-[2.2.2.11,5]oct-2-enes via their excited singlet states, but exo-7-(diarylvinylidene)tricyclo[4.1.12,5.0]hept-3-enes afforded 4-(diarylvinylidene)bicyclo[3.2.1]octa-2,6-dienes via their excited triplet states.

Singlet oxygen and triazolinedione additions to α,β-unsaturated sulfoxides

Abstract The reaction of singlet oxygen with 2-methyl-3-phenylsulfinyl-2-butene ( 1a ) and E 2-phenylsulfinyl-2-butene ( 1b ) gives the corresponding allyl alcohols ( 2a and 2b ) after reduction with dimethyl sulfide. α,β-Unsaturated sulfoxides with s- trans conformation failed to proceed the ene-type oxidation but afforded S-oxidation products. On the other hand, 4-methyl-1,2,4-triazoline-3,5-dione (MeTAD) reacted with α,β-unsaturated sulfoxides ( 1a and 1b ) and E -2-ethylidenethiolan-1-oxide ( 1g ) to give the corresponding allyl triazolidines as ene-type products.