Koki Yamaguchi

Cyclic sulfoxides-garlicnins K1, K2, and H1-extracted from allium sativum

Newly identified cyclic sulfoxides-garlicnins K1 (1), K2 (2), and H1 (3)-were isolated from the acetone extracts of the bulbs of garlic, Allium sativum. Garlicnin H1 (3) demonstrated potential to suppress tumor cell proliferation by regulating macrophage activation. The structures of garlicnins K1 and K2, 3,4-dimethyl-5-allyl-tetrahydrothiophen-2-one-S-oxides, and the structure of garlicnin H1, 3-carboxy-3-hydroxy-4-methyl-5-allylsulfoxide-tetrahydrothiophen-2-(ethane-1,2-diol)-S-oxide were characterized by spectroscopic analysis.

Acyclic sulfides, garlicnins L-1-L-4, E, and F, from Allium sativum.

Six novel acyclic sulfides, named garlicnins L-1-L-4 (1-4), E (5), and F (6), were isolated from the acetone extracts, with the ability to suppress M2 macrophage activation, of the bulbs of garlic (Allium sativum L.), and their chemical structures were characterized.

A new diterpenoid from the leaves of Clerodendron trichotomum

A new diterpenoid was isolated from the leaves of Clerodendron trichotomumThunb. (Verbenaceae) along with one each of a known diterpenoid, phenylethanoid glycoside, and sterol and two known flavonoids. Their chemical structures were characterized on the basis of spectroscopic data and X-ray analysis. In addition, their antioxidant activities were evaluated using four different analyses.

Reaction of 1-Acyl- and Aroyl-2-hydroxy-3,3-dimethylindolines with Arylamines Catalyzed by BF3・Etherate. Formation of Dihydroindolo[1,2-c]quinazoline

The reaction of (4-chlorophenyl)(2-hydroxy-3,3-dimethyl-2,3-dihydroindol-1-yl)methanone or 1 -(2-hydroxy-3,3-dimethyl-2,3-dihydroindol-1-yl)ethanone with 2-aminonaphthalene in the presence of excess amounts of BF 3 ·Et 2 O gave the 14,14-dimethyl-14,14a-dihydrobenzo[f]indolo[1,2-c]-quinazoline derivatives which are derived from the dehydrative cyclization of the coupling reaction product [2-(2-aminonaphthalen-1-yl)-3,3-dimethyl-2,3-dihydroindol-1-yl] (4-chlorophenyl)methanone or 1- [2-(2-aminonaphthalen-1 -yl)-3,3-dimethyl-2,3-dihydroindol-l-yl]ethanone. The reactions of several (2-hydroxy-3,3-dimethyl-2,3-dihydroindol- -yl)(substituted-phenyl)methanones or 1-(2-hydroxy-3,3-dimethyl-2,3-dihydroindol-1-yl)ethanone with m-anisidine gave the cyclization products together with the coupling reaction products. The structure of the cyclization product and the reaction mechanism are discussed based on the crystallographic and molecular orbital (MO) calculation data.

ROLE OF 2-NAPHTHYL ETHER INTERMEDIATE IN FORMATION OF ISOLABLE ATROPISOMERS DERIVED FROM THE COUPLING REACTION OF (2-HYDROXY-3,3-DIMETHYLINDOLIN-1-YL)-(SUBSTITUTED PHENYL)METHANONES WITH 2-NAPHTHOL

The formation pathway of the atropisomers derived from the reaction of (2-hydroxy-3,3-dimethylindolin-1-yl)(4-substituted phenyl)methanones with 2-naphthol in the presence of BF 3• Et 2 O was discussed on the basis of the isolation of the 2-naphthyl ether intermediate whose structure was determined by single crystal X-ray analysis. The results indicate that the coupling reaction proceeds through stepwise mechanism, i.e., the ether intermediate formation followed by Fries-type rearrangement.

Formation pathway of novel cycloadduct obtained by reaction of 3,5-disubstituted 4-oxo-4H-pyrazole 1,2-dioxide with dimethyl acetylenedicarboxylate

A new formation pathway via [3,3]-sigmatropic rearrangement of the 1,3-dipolar reaction product was proposed for the novel nitrogen-free compound formed from the reaction of 3,5-disubstituted 4-oxo-4H-pyrazole 1,2-dioxide with dimethyl acetylenedicarboxylate.