Yohmei Okuno

Photochemical synthesis of 1,2,3,4-tetrahydroisoquinolin-3-ones from N-chloroacetylbenzylamines

When N-chloroacetyl-3-hydroxybenzylamine (37) in aqueous acetonitrile was irradiated, both ortho and para photocyclizations with reference to the OH group occurred to give 7- and 5-hydroxy-3-oxo-1,2,3,4-tetrahydroisoquinolines (52,53). Similarly, 1-methylisoquinoline derivatives (54,55) were synthesized. N-Chloroacetyl-3,5-dihydroxybenzylamine (39) gave a single photoproduct, 5,7-dihydroxy-3-oxo-1,2,3,4-tetrahydroisoquinoline (56). These photocyclizations were smoothly extended to the synthesis of 1-benzyl, 1-(4′-methoxybenzyl)- and 1-(3′,4′,5′-trimethoxybenzyl)-isoquinoline derivatives (58∼64).

Stabilising effects on the 4Fe−4S core analogues for high-potential iron−sulphur proteins with a hydrophobic environment provided by macrocycles

Studies of redox potentials and reactions with molecular oxygen of a series of 4Fe–4S complexes attached to a 36-membered macrocycle show that all three electron transfer processes, 1–/2–, 2–/3–, and 3–/4–, are reversible for the cyclic aryl-substituted clusters, and that half-wave potentials for alkyl derivatives with hydrophobic macrocycles showed largely positive shifts of the 1–/2– couples as given in high-potential iron–sulphur proteins as well as a stabilising effect of the cores towards molecular oxygen.

Electron spin resonance of Pt(III) in anticancer platinum pyrimidine green

Abstract The electron spin resonance (ESR) of Pt(III) in platinum pyrimidine green is investigated. The spectrum shows a typical powder pattern of uniaxial symmetry and g ∥ and g ⊥ are determined to be 1.991 and 2.413, respectively. It is concluded that the spectrum derives essentially from the 5d z 2 -like hole state of Pt(III) (5d 7 ). The hyperfine structure of the spectrum suggests that the unpaired spin is not localized on one platinum center but has a wide orbital extended over four platinum atoms. The molecular structure is expected to resemble that of α-pyridone blue.

New entry to tetranuclear clusters with tetrathiol ligands anchored to hydrophobic macrocycles in iron–sulphur protein analogues; Fe4S4{cyclo-(XN[CH2]8)4}2– and Fe4S4{cyclo-(XN[CH2]8NX–p-C6H4–p-CH2C6H4)2}2–(X =p-SC6H4CO)

Efficient synthetic routes to novel tetrathiol compounds attached to a 36- or a 38-membered ring consisting of a methylene backbone or a cyclophane type macrocycle have been developed which involve a double condensation as the key reaction; a new class of synthetic 4Fe–4S analogues of iron–sulphur proteins could be introduced using these hydrophobic SH ligands.

A convenient method for the synthesis of macrocyclic tetra-amides by double condensation reaction

A facile condensation reaction between bifunctional amines and carboxylic acid derivatives has been found to be very efficient for the formation of macrocyclic tetra-amide rings, and tetralactams with 33- to 37-membered rings were readily synthesized in good yields (60–90%).

Use of inclusion complexes of hydrophibic viologens with cyclodextrin to protect the pyridinium moiety from hydrogenation in photochemical hydrogen formation

Cyclodextrin inclusion complexes of viologens with hydrophobic tails increaded the stability of the pyridium moiety of the viologen to hydrogenation, which resulted in up to five times higher efficiency in terms of hydrogen produced per viologen consumed.

Transannular formation of 1,10-dimethoxy-4-azatricyclo[6,2,2,04,8]dodeca-9,11-dien-3-one

Photolysis of N-chloroacetyl-3,4-dimethoxy-phenylpropylamine (1) gave the eight-membered lactam (2) and the novel aza-azulene derivatives (4 and 5); the nine-membered lactam (9) was synthesized similarly from N-chloroacetyl-3,4-dimethoxyphenylbutylamine (8).