Takashi Harayama

Combined effect of the extracts from Croton tiglium, Euphorbia lathyris or Euphorbia tirucalli and n-butyrate on Epstein-Barr virus expression in human lymphoblastoid P3HR-1 and Raji cells

The combined usage of n-butyrate and 12-O-tetradecanoylphorbol-13-acetate (TPA) or the oily extracts from Croton tiglium, Euphorbia lathyris or Euphorbia tirucalli exerted a marked effect on induction of Epstein-Barr virus (EBV)-associated early (EA) and viral capsid (VCA) antigens in EBV genome-carrying human lymphoblastoid cell lines. In producer P3HR-1 cells, the enhancing effect of the 2 components was additive both for EA and VCA, while in non-producer Raji cells, a synergistic increase of EA was observed. The possible implication of these findings relating to the cause of EBV-associated diseases is discussed.

Stereoselective syntheses of lycopodium alkaloids, (±)-fawcettimine and (±)-8-deoxyserratinine

Abstract Lycopodium alkaloids, (±)-fawcettimine (1) and (±)-8-deoxyserratinine (3) were stereoselectively synthesized through the stereoselective Diels-Alder reaction and the regioselective aldol condensation reaction of the dialdehyde (8).

Stereochemistry of reaction products of 1,3-dimethylthymine epoxide with amines

Abstract Reaction of 1,3-dimethylthymine epoxide with amines afforded cis and trans adducts, stereostructures of which were elucidated and treatment of trans adduct with boron trifluoride etherate afforded cis adduct; mechanism for the isomerization is presented.

Hydrolysis products of flavins (isoalloxazines)

Abstract Hydrolysis of flavin (I) with Triton B gave the 4a-spirohydantoin (II) as the main product along with III, showing that a main nucleophilic attack of hydroxide ion was initiated on the 10a position of I.

Synthesis of d1-aspterric acid, a carotane type sesquiterpene

Abstract A carotane type sesquiterpene, aspterric acid (1) was stereoselectively synthesized through Robinson annulation of 2 with MVK, dimethylation of 15, introduction of cyano group to 19 and ring contraction of 25.

Mass spectra of serratinine and its derivatives

Abstract The mass spectra of serratinine and its derivatives have been determined. Interpretation of the mechanism for the resulting ions are shown and the diagnostic value of this technique for the serratinine skeleton is also indicated.

Stereostructures of reaction products of thymidine epoxides with amines and L-amino acid ethyl esters

Reaction of thymidine epoxides, (3) and (4), with amines and L-amino acid ethyl esters was investigated and the stereostructures of products were determined.

A novel one-electron reduction system consisting of 1,5-dihydro-5-deazaflavin and flavinium. Application to the reductive repair of 1,3-dimethylthylmine bromohydrin as a model of a damaged nucleic acid

A novel one-electron transfer system consisting of 1,5-dihydro-5-deazaflavin (2) and flavinium (3) at room temperature has repaired efficiently 1,3-dimethylthymine bromohydrin (1), a model of a damaged nucleic acid, to give the original 1,3-dimethylthymine (6).

On the repair of thymidine bromohydrins, damaged nucleosides: A possible new model for the damage and repair of nucleic acids

Bromohydrins, which were damaged products of thymidines (2, 3, and 4), were repaired with sunlight or heat via a radical mechanism to regenerate the thymidines. A hypothesis for the biological significance of thymidine in DNA is presented.