Tetsutaro Kimachi

SPARTEINE-MEDIATED ENANTIOSELECTIVE 2,3-WITTIG REARRANGEMENT OF ALLYL ORTHO-SUBSTITUTED BENZYL ETHERS AND ORTHO-SUBSTITUTED BENZYL PRENYL ETHERS

Abstract The (−)-sparteine-mediated enantioselective [2,3]-Wittig rearrangement of N , N -dialkyl- o -allyloxymethylbenzamides and o -substituted benzyl prenyl ethers has been investigated. Enantiomeric excess up to 60% was observed as for the reaction with N , N -diethyl- o -allyloxymetylbenzamide. From the mechanistic investigations, it was suggested that the stereoinformation was introduced at the deprotonation step. Substoichiometric amount of (−)-sparteine (0.2 equiv.) did not decrease the enantioselectivity. Introduction of functional groups other than carbamoyl group did not enhance the enantioselectivity in this rearrangement.

The role of the planar chirality of iron tricarbonyl substituted homochiral amino alcohols in the asymmetric alkylation of aldehydes with diethylzinc

Abstract Homochiral amino alcohols bearing an iron tricarbonyl moiety were prepared from 2-amino-1,1-diphenylethanol derivatives 4a–d and [(3S,4S)-η4,7-octa-4,6-dien-3-ol]Fe(CO)3 complex 2. The addition of diethylzinc to aldehydes bearing electron donating substituents in the presence of these chiral ligands gave the alkylated products in good enantiomeric excess (up to 93% e.e.), whereas the addition to aldehydes bearing electron withdrawing substituents resulted in low yields and poor enantiomeric excesses.

SYNTHESIS AND DNA BINDING PROPERTIES OF AMIDE BOND-MODIFIED ANALOGUES RELATED TO DISTAMYCIN

Abstract Novel nitro analogues of distamycin which have trans olefin or α-diketo moiety instead of amide bond were synthesized. Their DNA binding properties studied by ethidium displacement assay and MPE footprinting experiments were also described.

Synthesis and cytotoxicity of 5-deazaflavins containing o- and p-quinone moieties

Abstract A series of 5-deazaflavo-10,11-quinones having o-quinone structure in the molecule were synthesized. The cytotoxicity of 5-deazaflavo-6,9-quinones (p-quinone derivatives) and 5-deazaflavo-10,11-quinones (o-quinones) was evaluated in vitro against L1210 and KB cells. Some of the synthesized compounds exhibited cytotoxic activity comparable to that of mytomycin C.

Synthesis of a new type of 5-deazaflavoquinone. (hybrid model compound of 5-deazaflavin and coenzyme PQQ)

Abstract A novel chemical hybrid model compound of 5-deazaflavin and PQQ was designed and synthesized via the suitably substituted 5-deazaflavin (5-deazaisoalloxazine) intermediate, followed by the oxidation to introduce orthoquinone group; the obtained model compound showed higher autorecycling oxidizing ability for benzylamine than usual 5-deazaflavins.

One-pot transformation of p-toluenesulfonates of 2,3-epoxy alcohols into allyic alcohols

Abstract A convenient and efficient method for the synthesis of synthetically useful non-racemic allylic alcohols from 4-methylbenzenesulfonates of non-racemic 2,3-epoxy alcohols is described. Satisfactory yields are obtained by treatment of 4-methylbenzenesulfonates of non-racemic 2,3-epoxy alcohols with potassium iodide followed by zinc powder and ammonium chloride in a one-pot manner. The method has been successfully applied to the synthesis of a key building block of C 30 C 37 botryococcenes.

Effects of 10-n-Butyl-3-methyl-5-deazaflavo-6,9-quinone (5-dFlQ) on Mitochondrial Respiration

10-n-Butyl-3-methyl-5-deazaflavo-6,9-quinone (5-dFlQ) significantly stimulated the state 4 respiration in mitochondria in a concentration-dependent manner. The respiration inhibited by rotenone and antimycin A was recovered by the addition of 5-dFlQ. These facts suggest that 5-dFlQ acts as electron carriers such as flavins or ubiquinone in the mitochondrial respiratory chain and forms a new pathway for electron transfer.

Synthetic study on CP-263,114 (phomoidride B) by SET-mediated fragmentation

Assembly of the highly functionalized carbocyclic core of CP-263,114 has been accomplished by using radical-mediated fragmentation with lithium naphthalenide as a key step.

Synthesis and catalytic properties of 5-deazaflavo-6,9-quinones

Novel 5-deazaflavo-6,9-quinones, which can be regarded as chemical hybrids of 5-deazaflavin and coenzyme Q, were designed and synthesized in a search for more powerful autorecycling redox catalysts for amine oxidation. 9-Methoxy-5-deazaflavins, which were synthesized from 6-aminouracils and 2,3-dimethoxybenzaldehydes, were exposed to oxidation with cerium ammonium nitrate in aqueous acetonitrile to give 5-deazaflavo-6,9-quinones. While 8-unsubstituted 5-deazaflavo-6,9-quinones thus obtained were unstable in the amine oxidation, 8-methoxy-5-deazaflavo-6,9-quinones were rather stable under the same conditions and showed an autorecycling amine-oxidizing ability.