Haruko Takechi

Photoreaction of N-(ω-indol-3-ylalkyl)phthalmides: intramolecular oxetane formation of the aromatic imide system.

Abstract Photoreaction of N-(ω-indol-3-ylalkyl)phthalimides ( 1a and 1c ) gave oxeto[2,3-b]indoles ( 3a and 3c ), the first example of oxetane formation of the aromatic imide carbonyl in the Paterno-Buchi reaction.

Analysis of stereoisomeric C27-bile acids by high performance liquid chromatography with fluorescence detection.

A method for differentially measuring the 24-hydroxylated stereoisomeric intermediates (3 alpha,7 alpha,12 alpha,24-tetrahydroxy- and 3 alpha,7 alpha,24-trihydroxy-5 beta-cholestan-26-oic acids) and related C27-bile acids in beta-oxidation of bile acid biosynthesis has been developed by high performance liquid chromatography with fluorescence detection. The method involved the derivatization of the above intermediable C27-bile acids into fluorescent esters with 3-(4-bromomethylphenyl)-7-diethylaminocoumarin, a newly synthesized labeling reagent for carboxylic acids. The fluorescent derivatives were subjected to a short silica gel column to eliminate interfering products prior to analysis by high performance liquid chromatography. The separation of the 16 kinds of bile acids containing stereoisomers was carried out using a reversed-phase Inertsil C8-column by gradient elution and detected with a fluorometer (Ex. 400 nm, Em. 475 nm). The linearity of calibration curve for each bile acid was from 0.5 to 250 pmol (r = 0.999) and the detection limits were about 15 fmol at a signal-to-noise ratio of 3. The method was applied to the determination of intermediates in beta-oxidation of bile acid biosynthesis using rat liver homogenate. The results showed that two stereoisomers of 24-hydroxylated C27-bile acids were predominantly produced, indicating the formation of the isomers by the cis-hydration with water.

Direct C-C bond formation between thymine derivatives and naphthalene through [2+2]-photocycloaddition

In contrast to our previous findings that UV-irradiation of 1,3-dimethylthymine (la) with naphthalene (2) underwent 1,4-cycloaddition to give an ethenobenzoquinazoline derivative, UV-irradiation of a mixture of la and 2 in the presence of piperylene preferentially underwent 1,2-cycloaddition to give cis-tetrahydronaphthocyclobutapyrimidine in high stereoselectivity. Similar irradiation of 1,3-dimethyluracil and its derivatives (1) with substituents at C-5 gave the corresponding cis-1,2-adducts (3) in fair yields.

Crystal structures of coumarin-3-carbamate derivatives with herbicidal activities

Coumarin-3-carbamate derivatives were prepared by the reaction of alcohols with coumarin-3-carbonyl azide. The testosterone derivative has herbicidal activities, but the benzene derivative does not have the activities. The crystal structures of two coumarin-3-carbamate derivatives were analyzed by X-ray crystallography. The crystals of the testosterone derivative had intermolecular N-H···O, C-H···O, and C-H···π interactions.

SYNTHESIS AND PROPERTIES OF PET FLUOROIONOPHORE HAVING 1-PYRIDIN-2-YLPIPERAZINE GROUP

9-[4-(2-pyridinyl)-1-piperazinyl]methyl]anthracene (1) and 9,10-bis[[4-(2-pyridinyl)-l-piperazinyl]methyl]anthracene (2) were synthesized as a fluorescent PET sensor. The sensor functions as an off-on-off fluorescence switch for proton.

5-Benzyl-1,3,5-trimethylpyrimidine-2,4,6(1H,3H,5H)-trithione

Barbiturates act as central nervous system depressants and produce a wide spectrum of effects, from mild sedation to anesthesia (Bideau et al., 1976; Gotthardt et al., 1980). Some are also used as anticonvulsants. Although a number of barbiturates have been studied, there have been only a few studies of their sulfur analogs (trithiobarbiturate) (Greenberg et al., 2000) and while most crystals of barbiturates are colorless those of thiobarbiturates, such as (I), are usually colored.

Synthesis and complexation behavior of 4,10-bis(1-pyrenylmethyl)-1,7-dioxa-4,10-diazacyclododecane

Fluorescent photoinduced electron transfer (PET) fluoroionophore (2c) that consists of diaza-12-crown-4 and two 1-pyrenylmethyl pendants shows fluorescent enhancement with various metal cations. The sensor (2c) exhibited Zn 2+ selectivity and in the presence of this cation the host fluorescence was increased by a factor of 38.