Yoshifumi Maki

Reductive cleavage of the ribose moiety in purine nucleosides using diisobutylaluminum hydride: A new method for the preparation of acyclonucleosides

Abstract Reaction of purine nucleosides, such as 2′,3′- O - isopropylideneinosine 1a and 2′,3′- O -isopropylideneadenosine 1c , with diisobutylaluminum hydride in dry tetrahydrofuran resulted in the reductive cleavage of the ribose moiety at the anomeric position to give the corresponding 9-(2′,3′- O -isopropylideneribityl)purines 2a , c in good yields.

Efficient oxygen-atom transfer agent: photochemical hydroxylation of benzene derivatives by pyrimido[5,4-g]pteridine n-oxide

Abstract Pyrimido[5,4- g ]pteridine N -oxide (1) oxidizes efficiently benzene, toluene, and anisole under UV irradiation to give the corresponding phenol derivatives 4, though the easiness of the reaction significantly depends upon the nature of the substituents on the benzene ring.

A Newly Devised Method for the Debenzylation of N 6-Benzyladenosines. A Convenient Synthesis of [6-15 N]-Labeled Adenosines

Abstract [6-15-N]-Labeled adenosine was conveniently prepared from inosine (la) by the silylation-benzylamination of la and subsequent oxidative debenzylation with ammonium peroxydisulfate in a pH 7.2 buffer solution.

Synthesis of a ring-scission analogue of neplanocin A as a potential inhibitor of S-adenosylhomocysteine hydrolase

The ring scission analogue of neplanocin A (1), acycloneplanocin A (2), as a potential S-adenosylhomocysteine hydrolase inhibitor was synthesized via the reductive cleavage of 2′,3′-O-isopropylideneadenosine (3) by DIBALH.

Vibrational spectra of β-lactams—III. potassium 2-azetidinone-1-sulfonate and its isotopic compounds

Abstract The IR and Raman spectra of potassium 2-azetidinone-1-sulfonate and its three deuterated and two 15N-substituted compounds have been recorded, and the observed bands have been assigned on the basis of the isotope effects and the normal coordinate analysis. Comparison of the force constants for the amide group among 2-azetidinone, 1-methyl-2-azetidinone and potassium 2-azetidinone-1-sulfonate indicates that there is a correlation between these constants and the ease of hydrolysis which was determined by NMR spectroscopy, depending on the amide resonance.

Novel Intramolecular Rearrangement of 5-Carbamoyluracils into Barbituric Acids.

Abstract Heating of 5-carbamoyl- (1) and 5-thiocarbamoyl-3-methyl-1-phenyluracil (5) derivatives in ethanolic sodium ethoxide causes a novel intramolecular rearrangement to give 5-anilinomethylenebarbituric acids(2) and 5-anilinomethylene-4-thiobarbituric and(6), respectively.

Novel reactiom of 5-nitro(or carbamoyl)uracil derivatives with amines. Thermal exchange reaction of N1-portion of the uracils for amines via ring-opening and ring-closure processes☆

Abstract The reaction of 1,3-disubstituted uracils possessing an electron withdrawing group at the 5-position with amines induced exchange of N 1 -portion of the uracil ring for amines. This reaction was accelerated by substitution of phenyl groups at the N 1 -position.

Photochemical oxidative CαCβ bond cleavage of tryptophan side-chain by pyrimido[5,4-g]pteridine N-oxide

Abstract Tryptophan derivatives 1 undergo with ease the oxidative C α C β bond cleavage by pyrimido[5,4- g ]pteridine N -oxide 2 under irradiation with UV-visible light in the presence of acid-catalyst to give 3-indolecarboxaldehydes 3 and the corresponding glycine derivatives 4 .

Synthesis of phidolopin, 7-(4-hydroxy-3-nitrobenzyl)-1,3-dimethylxanthine from the bryozoan Phidolopora pacifica

Abstract A total synthesis of a biologically active compound, phidolopin, was accomplished and its regioisomer was also synthesized.

Oxidative photocyclization of N6-benzoyladenosine derivatives. Facile formation of the quinazolinopurine ring system

Irradiation of 2′,3′,5′-tri-O-acetyl-N6-benzoyl adenosine derivatives 1 in the presence of an oxidant resulted in a novel type of the oxidative photocyclization leading to 8-(2′,3′,5′-tri-O-acetyl-β-D-ribofuranosyl)quinazolino[2,1-i]purin-12-one derivatives 2.