A novel approach to the synthesis of oligodeoxyribonucleotide boranophosphates

Deoxyribonucleoside 3′-boranophosphate derivatives including adenine, cytosine, guanine, and thymine bases were synthesized in good yields by the use of a new boranophosphorylation reaction. The reaction was found to be effective for the formation of internucleotidic boranophosphate linkages

Bicyclization Involving Pseudo-Intramolecular Imination with Diamines

α-Nitro-δ-keto nitriles and α-nitro-δ-keto ester were readily converted to diazabicyclo compounds having vicinal functionality upon treatment with diamines. The keto nitrile attracts the diamine nearby to an acidic hydrogen to cause the pseudo-intramolecular imination which proceeds efficiently without any catalyst at room temperature

金属塩を活用する有機合成反応および2-ハロピリジニウム塩を用いる縮合反応の研究

四塩化チタンは典型的なハードな酸であり、しかも他のルイス酸と比較して酸素原子に対する親和性がとくに強く、分子内に酸素原子をもつアルコール、エーテル、カルボニル化合物と反応して配位化合物あるいはチタン－酸素結合をもつ有機化合物を生成することが知られている。さらに、強力な脱水能力も併せもっていることも知られており、これらの性質を巧みに利用すれば、酸素原子をもつ有機化合物を酸性条件下で活性化し種々の求核試剤と反応させることにより新しい有機化合反応の開拓が可能になるものと考え、種々の検討を行った。東京工業大

One-step synthesis of differently bis-functionalized isoxazoles by cycloaddition of carbamoylnitrile oxide with β-keto esters

A new protocol for synthesizing different functionalized isoxazoles is provided. Carbamoylnitrile oxide generated from nitroisoxazolone underwent inverse electron-demand 1,3-dipolar cycloaddition with 1,3-dicarbonyl compounds in the presence of magnesium acetate that formed magnesium enolatein situ. Although electron-deficient trifluoroacetoacetate did not undergo this cycloaddition under the same conditions, conversion to sodium enolate furnish the corresponding bis-functionalized trifluoromethylisoxazole. The DFT calculations using B3LYP 6-31G+(d,p) also supported the aforementioned reactivity

Reactive 2-Quinolones Dearomatized by Steric Repulsion between 1-Methyl and 8-Substited Groups

Usual 1-methyl-2-quinolone (MeQone) derivatives are not reactive because of aromatic property in the heterocyclic ring. On the other hand, 8-substituted MeQones have been proved to be highly reactive, which is caused by steric repulsion between the 1-methyl and the 8-substituted groups. When 1-methyl-3,6,8-trinitro-2-quinolone was treated with potassium (or trimethylsilyl) cyanide, cyanation proceeded at the 4-position regioselectively as a result of cine-substitution. This reaction is initiated with addition of cyanide species, and the cyanoquinolone is formed by the protonation of the resultant anionic intermediate followed by elimination of nitrous acid. The high reactivity was maintained even when one of the nitro groups on the benzene moiety was replaced by a methyl group, which afforded corresponding cine-substituted products upon treatment with potassium cyanide

Chemical synthesis of novel taurine-containing uridine derivatives

Recently, novel taurine-containing uridine derivatives were discovered in mammalian mitochondrial tRNAs, and these modified ribonucleosides existed at the first position of the anti-codon. This paper describes the chemical synthesis of these novel uridine derivatives, 5-taurinomethyluridine (τm5U) and 5-taurinomethyl-2-thiouridine (τm5s2U). These taurine-containing uridine derivatives were synthesized in the good yields by the reaction of the corresponding S-hydroxymethyluridine derivatives with taurine under basic conditions

Regio- and diastereo-controlled synthesis of bis(formylmethano)[60]fullerenes and their application to the formation of [60]fullerene pearl-necklace polyimines

The tether-directed method was firstly applied to the biscyclopropanation of [60]fullerene via the addition?elimination reaction of bis(sulfonium ylide)s to give bis(formylmethano)[60]fullerenes with satisfactory regio- and stereoselectivity. The equatorial-bisadduct thus obtained was used for the polycondensation with an aromatic diamine to afford the corresponding pearl-necklace polyimine with satisfactorily high degree of polymerization