Tomohisa Takita

DNA-bleomycin interaction: Nucleotide sequence-specific binding and cleavage of DNA by bleomycin

Biosynthetic intermediates and synthetic analogues of bleomycin (BLM) have been investigated for their metal binding, dioxygen activation, and DNA cleavage. Molecular O2 was activated by the Fe(II) complex of a synthetic model ligand. Nucleotide sequence specificities in DNA cleavage by the BLM-Fe(II) and deglyco-BLM-Fe(II) complexes were almost identical. It has been shown that (1) the β-aminoalanine-pyrimidine-β-hydroxyhistidine portion of BLM is essential for the metal binding and dioxygen activation and (2) the bithiazole moiety contributes to the specific binding to guanine base of DNA.

Total synthesis of deglyco-bleomycin A2

Abstract Deglyco-bleomycin A2, the aglycon of bleomycin A2, has been synthesized for the first time.

Studies on the total synthesis of oxetanocin; II. Total synthesis if oxetanocin☆

Abstract The first total synthesis of a novel nucleoside oxetanocin 1 is described.

Studies on the total synthesis of oxetanocin; I. The first synthesis of a nucleoside having oxetanosyl-N-glycoside

Abstract The first synthesis of 9-(2-oxetanyl)adenine 12 , a key intermediate for the synthesis of a novel nucleoside oxetanocin 1 , has been achieved via cyclization between allyloxycarbanion and epoxy group.

Stereoselective synthesis of (2s,3s,4r)-4-amino-3-hydroxy-2-methyl-pentanoic acid, an amino acid constituent of bleomycin, by aldold condensation)☆

Abstract (2S,3S,4R)-4-Amino-3-hydroxy-2-methylpentanoic acid, a novel amino acid constituent of bleomycin, has been synthesized stereoselectively through aldol condensation of (R)-2-aminopropionaldehyde derivatives and E-vinyloxyboranes.

Synthesis and antiviral activity of oxetanocin derivatives

Abstract The sugar part of natural oxetanocin A was chemically modified. Some of the derivatives demonstrated strong antiviral activity against human immunodeficiency virus (HIV).

Vanoxonin, a new inhibitor of thymidylate synthetase.

Vanoxonin, a new inhibitor of thymidylate synthetase, was found in cultured broths of the strain MG245-CF2 classified as Saccharopolyspora hirsuta. Vanoxonin, C18H25N3O9, was obtained as colorless powder. Vanoxonin forms a vanadium complex which exhibits a strong inhibition against thymidylate synthetase. The concentration for 50% inhibition of the enzyme (IC50) was 0.7 micrograms/ml.

Synthesis of cleonine, amino(1-hydroxycyclopropyl)acetic acid, a novel amino acid contained in cleomycin

Abstract The synthesis of cleonine, amino(1-hydroxycyclopropyl)acetic acid, a novel amino acid contained in cleomycin, a new bleomycin-phleomycin group antibiotic, is described.

A facile total synthesis of oxanosine, a novel nucleoside antibiotic

Abstract The total synthesis of oxanosine, a novel nucleoside antibiotic, has been achieved for the first time.

A new synthesis of deglyco-bleomycin A2 aiming at the total synthesis of bleomycin

Abstract An improved route to synthesize deglyco-bleomycin A2, the aglycon of bleomycin A2, aiming at the total synthesis of bleomycin is described. The new route is characterized by the stepwise elongation of the amino acid constituents and the use of a thiol ester obtained by aldol condensation.