Masato Tazaki

Template-directed formation of luminescent lanthanide complexes: versatile tools for colorimetric identification of single nucleotide polymorphism.

We present the facile technique of colorimetric SNP (single nucleotide polymorphism) analysis through DNA-templated cooperative complexation between a luminescent lanthanide ion (Ln(III): Tb(III) or Eu(III)) and two ODN (oligodeoxyribonucleotide) conjugates carrying a metal chelator. Families of complexane-type chelators and heterocyclic aromatic ligands were covalently attached to ODNs to form conjugates for application as capture and sensitizer probes. The sequences of the conjugates were designed so as to form a ternary tandem duplex with the target, where their auxiliary units face each other, providing a microenvironment to accommodate Ln(III). Only the combination of EDTA (ethylenediaminetetraacetic acid) conjugates and phen (1,10-phenanthroline) conjugates provided significant emissions with quantum yields of 3.3% and 1.5% for Tb(III) and Eu(III), respectively, in the presence of the target. Biallelic polymorphism in the TPMT (thiopurine S-methyltransferase) gene, wt/wt (G/G), mut/mut (C/C), and wt/mut (G/C), were distinguished as emissions in green, red, and yellow, respectively; the colors were identified even by the naked eye.

Sesquiterpene alcohols from Cryptomeria japonica and C. fortunei leaf oil

Abstract 4β-Hydroxygermacra-1(10),5-diene, thujopsan-2α,-ol and hedycaryol were found in the leaf oil of Cryptomeria japonica obtained by hexane extraction. Both the first and last were present in all races of C. japonica native in Kyushu main island, but thujopsan-2α-ol was found in about one-third and not found in C. fortunei so far examined. Moreover, some C. fortunei lacked 4β-hydroxygermacra-1(10),5-diene. On the other hand some contained only this as sesquiterpene alcohol. When the leaves were steam-distilled, 4β-hydroxygermacra-1(10),5-diene isomerized to α-cadinol and hedycaryol isomerized to elemol and eudesmols. Thujopsan-2α-ol was synthesized from mayurone.

Sesquiterpene alcohols from Chamaecyparis obtusa leaf oil

Abstract Three new sesquiterpene alcohols were found in the hexane extract of Chamaecyparis obtusa leaf oil and the structures were elucidated as 10-epi-cubebol, β-hinokienol and α-hinokienol. The absolute configuration of the last two alcohols was established by synthesis from (−)menthone.

SOLVENT EXTRACTION OF PLATINUM (lV) WITH A NOVEL SULFUR-CONTAINING EXTRACTING REAGENT

Abstract A novel sulfur-containing solvent extraction reagent, 3,3-diethylthietane (DETE) was synthesized and its extraction mechanism of platinum (IV) from aqueous hydrochloric acid solution was investigated at 30 °C in terms of the equilibrium distribution and extraction kinetics as well as its aqueous distribution and inter-facial adsorption equilibrium. Toluene was used as a diluent. It was elucidated that platinum(IV) is extracted as a solvated complex of the type, PtCl4-4DETE. DETE was found to have no inter-facial activity and the aqueous partition coefficient as high as 8.17xl0-4. Extraction rate was measured by using a vigorously stirred cell. It was of the first order with respect to DETE while it is 0th and inversely first order with respect to chloride ion in its low and high concentration region; this result was interpreted in terms of the classical hetero-phase homogeneous reaction model.

Facile, Convenient Synthesis of Highly Pure ω-Ferrocenylalkanethiols as Probes for Self-Assembled Monolayer (SAM) on Gold Surface

Abstract High purity synthesis of ω-ferrocenylalkanethiols (Fc(CH2)n−SH, n=6, 8, 11) was developed for their use in self-assembled monolayers on gold surface. The method employs a separation and purification of isothiuronium salt 6 to improve the purity of final products 7. The use of hazardous mercury in the Clemmensen reduction of acylferrocene 4 to alkylferrocenes 5 is avoided by an alternative LAH/AlCl3 reduction.

S–S Bond cleavage of polymerization resistant 1,2-dithiolanes by acetylides: intrinsic reactivity of enzyme-bound lipoic acid toward stable, localized carbanions

The S–S bond of polymerization-resistant 1,2-dithiolanes 2 was cleaved cleanly by acetylides 4, giving the corresponding ring-opened products 5 in aprotic THF (quenched as silylsulfide 6) and their re-cyclized products 6,7-dihydro-1,4-dithiepins 3 in protic ButOH in excellent yields. The reactivity of 2 is discussed in relation to the reductive acylation of the enzyme-bound lipoic acid (Lip-E2).

REACTION OF POLYMERIZATION-RESISTANT 1,2-DITHIOLANES WITH SULFONIUM YLIDES

Abstract Reaction of the polymerization resistant 1,2-dithiolane 1 with sulfonium ylides 2 was examined in relation to coenzyme lipoic acid. The strained cyclic disulfide 1 was highly reactive towards stabilized carbanions 2 to give the corresponding ring-opened products, which further reacted to give the 1,3-dithiane 4 and the 1,3-dithianyl sulfide 5. The 1,3-dithiane formation was nearly quantitative when the ylide from benzyldimethylsulfonium was used.

REACTION OF POLYMERIZATION-RESISTANT 1,2-DITHIOLANES WITH SULFOXONIUM YLIDES. NEW METHOD FOR 1,3-DITHIANE SYNTHESIS

Abstract Reaction of polymerization-resistant 1,2-dithiolanes 1 with dimethylsulfoxonium methylide 3 was developed for the synthesis of the corresponding 1,3-dithianes 4 by a high-dilution method. Oxygen did not prevent the formation of 4, but facilitated the product separation leading to a good yield and the excellent purity of 4.

REACTION OF POLYMERIZATION-RESISTANT 1,2-DITHIOLANES WITH LITHIATED PICOLINES: SIMPLE RING OPENING AND 1,3-DITHIANE FORMATION

Abstract Reaction of polymerization resistant 1,2-dithiolanes 1 with excess pyridylmethyllithiums 3 in THF gave the corresponding ring-opened products 2 in good yields, but the by-products 2-pyridyl-1,3-dithianes 5 and 1,3-propanedithiols 6 could not be excluded. Addition of hexamethylphosphoric triamide (HMPT) to the reaction mixture resulted in the selective formation of 5.

REACTION OF 1,2-DITHIOLANE WITH α-LITHIATED THIOPHENES: SELECTIVE SYNTHESES OF MONO-S-THIENYL-1,3-PROPANEDITHIOLS

Abstract Lithiated thiophenes 3 cleaved S[sbnd]S bond of 4,4-disubstituted 1,2-dithiolane 1 and naphthalene-1,8-disulfide 5 to give the ring opened products 2 and 6, respectively, in excellent yields.