Kaoru Hanaya

Reduction of aromatic nitro-compounds to amines with sodium borohydride–copper(II) acetylacetonate

The reduction of aromatic nitro-compounds by NaBH4 in ethanol in the presence of various transition metal cetylacetonates has been investigated. Copper(II) acetylacetonate was found to be the most effective catalyst for reduction to the corresponding amines. This reaction appears to proceed through a hydride metal complex.

Synthesis of azacyclic compounds by an aminium radical route: orbital overlap requirements

Model compounds of Δ4,5-, Δ5,6-, and Δ6,7-alkenylnitrosamines were synthesized and photolyzed to generate the corresponding alkenylaminium radicals. The Δ5,6-alkenylaminium radicals underwent efficient intramolecular addition leading to the exclusive formation of pyrrolidine derivatives, the yield of which was lower if the steric strain and hindrance were severe in the cyclization transition state. The Δ6,7-alkenylaminium radical cyclized inefficiently to piperidine derivatives and the Δ4,5-alkenylaminium radicals did not appear to cyclize; in both cases other pathways having lower activation energies, such as elimination and hydrogen abstraction, predominated. Evidence that the direction of cyclization is controlled by the degree of p-orbital overlap, but not by stability of the developing products, in the transition state is presented. The stereochemical factors associated with the overlap determined the yields of the cyclization products. This is in excellent agreement with the fact that the transition...

The hydrogen-stretching absorptions and conformations of tetralin-1-ol, chroman-4-ol, thiochroman-4-ol, and indan-1-ol derivatives

The conformations of 1-alkyl (or phenyl)tetralin-1-ols, 4-alkylchroman-4-ols, 4-alkylthiochroman-4-ols, and some secondary and tertiary indan-1-ols have been examined by measurement of the OH stretching absorptions in carbon tetrachloride. For these alcohols, the conformations can be characterized by the following frequencies; quasiequatorial 3 614–3 628 (free OH) and 3 597–3 610 (OH ⋯π hydrogen bonded); quasi-axial, 3 610–3 620 cm–1(OH ⋯π hydrogen bonded).

The Rearrangement of .ALPHA.-(Phenoxy)phenylacetic Acids and Benzyl phenyl Ethers with Polyphosphoric Acid.

α-フェノキシフェニル酢酸(1a)のポリリン酸による環化反応では予想生成物の2-フェニル-3(2H)-ベンゾフラノン(2a)ではなく3-フェニル-2(3H)-ベンゾフラノン(3a)が生成した。1aとα-(P-メチルフェノキシ)-P-トリル酢酸(1d) を用いた交差実験の結果から,1から3への環化反応においては分子内的転位反応の後に脱水縮合が起こっていることがわかった。1の基本骨格と考えられるベンジルフェニルエーテル誘導体はポリリン酸を作用させることによりo-ベンジル-およびP-ベンジルフェノール誘導体に変換された。この場合も交差実験により分子内的転位生成物が優先的に得られる。なお,ベンジル基のp-置換基が電子供与基ほどo-転位体に対するP-転位体の生成比が大きくなることが確認された。