Takuma Yoshida

Climatic adaptations and distributions in the Drosophila takahashii species subgroup (Diptera: Drosophilidae)

Among subtropical species of the Drosophila takahashii species subgroup, temperature adaptations were related to altitudinal distribution; D. trilutea was adapted to lower temperature and occurred at high altitudes in September in Taiwan, D. takahashii was adapted to higher temperature and occurred mainly at low altitudes, and D. prostipennis was adapted to an intermediate range of temperature and occurred at mid to high altitudes. A temperate species, D. lutescens, was adapted to a wider range of temperature than the subtropical species: it was more cold-hardy than all three subtropical species and more heat-tolerant than D. prostipennis and D. trilutea. The temperature ranges encountered in the temperate region far exceed the range in subtropical areas, and this is likely to be reflected in the temperature adaptations of these temperate and subtropical species. D. lutescens has a photoperiodically controlled reproductive diapause. No latitudinal cline was observed on cold-hardiness of D. takahashii. By ...

Alternative One-Pot Synthesis of (Trifluoromethyl)phenyldiazirines from Tosyloxime Derivatives: Application for New Synthesis of Optically Pure Diazirinylphenylalanines for Photoaffinity Labeling

Alternative one-pot synthesis of 3-(trifluoromethyl)-3-phenyldiazirine derivatives from corresponding tosyloximes is developed. The deprotonation of intermediate diaziridine by NH2(-) is a new approach for construction of diazirine. Moreover, a novel synthesis of optically pure (trifluoromethyl)diazirinylphenylalanine derivatives was attempted involving these methods.

Hydrogen/deuterium exchange of cross-linkable α-amino acid derivatives in deuterated triflic acid

In this paper we report here a hydrogen/deuterium exchange (H/D exchange) of cross-linkable α-amino acid derivatives with deuterated trifluoromethanesulfonic acid (TfOD). H/D exchange with TfOD was easily applied to o-catechol containing phenylalanine (DOPA) within an hour. A partial H/D exchange was observed for trifluoromethyldiazirinyl (TFMD) phenylalanine derivatives. N-Acetyl-protected natural aromatic α-amino acids (Tyr and Trp) were more effective in H/D exchange than unprotected ones. The N-acetylated TFMD phenylalanine derivative afforded slightly higher H/D exchange than unprotected derivatives. An effective post-deuteration method for cross-linkable α-amino acid derivatives will be useful for the analysis of biological functions of bioactive peptides and proteins by mass spectrometry. Graphical Abstract Hydrogen-deuterium exchange of cross-linkable α-amino acid derivatives in deuterated triflic acid proceeded smoothly at low temperature.

Synthesis of CPZEN-45: Construction of the 1,4-Diazepin-2-one Core by the Cu-Catalyzed Intramolecular Amidation of a Vinyl Iodide

CPZEN-45 was developed as an antibiotic against Mycobacterium tuberculosis by the chemical modification of caprazamycins. CPZEN-45 has been synthesized in this study by the Cu-catalyzed intramolecular amidation of a complex vinyl iodide precursor bearing uridine and sugar moieties with a secondary amide, allowing for the construction of its 1,4-diazepin-2-one core.

Utilization of Acidic α-Amino Acids as Acyl Donors: An Effective Stereo-Controllable Synthesis of Aryl-Keto α-Amino Acids and Their Derivatives

Aryl-keto-containing α-amino acids are of great importance in organic chemistry and biochemistry. They are valuable intermediates for the construction of hydroxyl α-amino acids, nonproteinogenic α-amino acids, as well as other biofunctional components. Friedel-Crafts acylation is an effective method to prepare aryl-keto derivatives. In this review, we summarize the preparation of aryl-keto containing α-amino acids by Friedel-Crafts acylation using acidic α-amino acids as acyl-donors and Lewis acids or Brönsted acids as catalysts.

SYNTHESIS OF PHOTOREACTIVE DIAZIRINYL SALICIN DERIVATIVE TO ELUCIDATE FUNCTIONAL ANALYSIS OF THE BITTER TASTE RECEPTOR

Salicin (salicyl alcohol glucoside) is a substance well known for its bitter taste. A photoreactive diazirinyl derivative of salicin will be utilized for the functional analysis of interactions between the bitter taste receptor and salicin. Glucosides of salicyl derivatives are more difficult than phenol derivatives that are unsubstituted at the ortho-position. A diazirinyl salicin derivative was synthesized at moderate yields by glucosidation of 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide and 2-hydroxy-4-[3-(trifluoromethyl)-3H-diazirin-3-yl]-benzaldehyde in the presence of a phase-transfer catalyst, nBuEt3NBr, followed by reduction and deprotection. Salicin is long known as one of the major components of phenyl glycosides in the family Salicaceae and is a bitter anti-inflammatory compound. Elucidation of the functions of its gustatory receptor on the basis of structure–activity relationships may reveal the mechanism of homeostatic functions, which is of great interest to scientists. Photoaffinity labeling is one of the most common techniques used in the analysis of chemical biology. To the best of our knowledge, there are no reports on the preparation of photoreactive salicin derivatives for the analysis of bitter taste receptors. Two modifications of phenyl glucoside derivatives using diazirine have been reported. The derivatives are not substituted at the o-position of phenol. One modification is glucosidation of p-diazirinyl phenol to synthesize α-glucoside and the other This paper is dedicated to Prof. Dr. Isao Kuwajima on the occasion of his 77th birthday. is construction of the diazirine moiety in the precursor of the phenyl glucoside derivative. However, glucosides of salicyl alcohol derivatives are more complicated than glucosides of the o-position unsubstituted phenol derivatives. Optimization of glucosidation of salicyl alcohol or salicyl aldehyde derivatives is essential to the synthesis of target diazirinyl derivatives of salicin. In this study, we report the synthesis of diazirinyl derivative and preliminary screening of glucosidations for salicyl alcohol and salicyl aldehyde derivatives. O OH HO HO OH O F3C N N OH O OAc AcO AcO AcO OAc F3C N N

Synthesis of Cross-linkable 2,5-Diketopiperazine Derivatives

Synthesis of cross-linkable diketopiperadine derivatives is described. Cross-linkable a-amino acid methyl esters were subjected to peptide synthesis with Boc-protected glycine or L-tyrosine. No protections of cross-linkable functional groups (catechol and phenylazide) are necessary for constructions of diketopiperazine skeleton.

2,3-Bis(4-(3-(trifluoromethyl)-3H-diazirin-3-yl)phenyl)oxirane

The title compound, which has two photoreactive groups in a molecule, was synthesized by the coupling reaction of 3-(4-(bromomethyl)phenyl)-3-(trifluoromethyl)- 3H-diazirine in the presence of silver oxide in DMSO.

The life history and host-searching behaviour of the aquatic parasitoid wasp Apsilops japonicus (Hymenoptera: Ichneumonidae), a parasitoid of the aquatic moth Neoshoenobia testacealis (Lepidoptera: Crambidae)

The life history and host-searching behaviour of Apsilops japonicus parasitizing the aquatic moth Neoshoenobia testacealis were studied in the field and in the laboratory in Japan. Moth larvae initially mine the floating leaves of the yellow water lily, later boring into the petiole and pupating in the petiole underwater. While the wasps did not attack leaf-mining larvae, they were idiobiont ectoparasitoids of the pupae or mature larvae of N. testacealis in the petioles. The wasps did not swim with their wings or legs when searching for hosts underwater, they walked down leaf petioles into the water. It is presumed that the wasps overwinter as adults. The laboratory observations suggested that the female wasps could not detect the host presence in the petiole from the floating leaves and they randomly searched for hosts by probing with their ovipositors underwater.

Taxonomic study of the genus Dichrogaster Doumerc (Hymenoptera: Ichneumonidae: Cryptinae) in Japan

Japanese species of the genus Dichrogaster are revised. Four species are recognized. Two species, D. imperialis n. sp. and D. parva n. sp., are described. Dichrogaster liostylus (Thomson) and D. kichijoi (Uchida) are redescribed. A key to the Japanese species is provided.