Zenei Taira

Terpenoids of the liverwort Frullanoides densifolia and Trocholejeunea sandvicensis

Abstract Two new rearranged pinguisane-type sesquiterpenoids, spirodensifolin A and B, a pinguisane-type sesquiterpene, isonaviculol, and two new ent-kaurane-type diterpenoids, ent-kauran-16β-ol-3-one, ent-kaurane-3β,16β-diol, have been isolated from the Bolivian liverwort Frullanoides densifolia, and a pinguisane-type sesquiterpene, furanopinguisanol and lepidozane-type sesquiterpene alcohol have been isolated from the Japanese Trocholejeunea sandvicensis. Their stereostructures have been elucidated by the extensive analysis of the spectral data as well as the X-ray crystallographic analysis.

New highly oxidized fusicoccane diterpenoids from the liverwort Plagiochila acanthophylla subsp. japonica

Abstract Four novel fusicoccane diterpenoids, fusicoplagins A, B, C, and D, have been isolated from the liverwort Plagiochila acanthophylla subsp. japonica and the structures determined by spectroscopic methods, chemical transformations, and X-ray crystallographic analysis.

Synthesis and activity of brefeldin A analogs as inducers of cancer cell differentiation and apoptosis

Abstract We designed and synthesized several brefeldin A (BFA) analogs. These compounds were evaluated for the ability to induce differentiation and apoptosis in human colonic carcinoma cell line HCT116. Diacetyl BFA (2a), 4-acetyl BFA (2b), 7-acetyl BFA (2c), and 10,11-epoxy BFA (3b) were active but tetrahydro BFA (3a) and other analogs could not induce the malignant cells to differentiate. The results suggested that the moiety from 1- to 4-position in BFA as well as its conformational rigidity is essential for its biological activity.

Synthesis of uracil-5- and adenine-8-phosphonic acids

Abstract Successive treatments of 5-bromo-2,4-dimethyoxypyrimidine (I) with n-butyllithium and diethyl chlorophosphonate followed by dealkylation afforded uracil-5-phosphonic acid (V). Adenine-8-phosphonic acid (IX) was also prepared by a similar method, starting from 6-chloro-9-(tetrahdyro-2-pyranyl)purine (VI).

Coupling of alkynes promoted by Ru(CO)3(PPh3)2 and carbon dioxide: syntheses and structures of (η4-C4R2R′2CO)Ru(CO)2(PPh3) (R=R′=Ph; R=Ph, R′=CCPh) and {Ph2C4(CCPh)2}Ru(CO)(PPh3)2

Abstract Dimerization of alkyne by Ru(CO) 3 (PPh 3 ) 2 proceeded under carbon dioxide in refluxing toluene or C 6 H 6 to afford a cyclopentadienone Ru(0) complex (R 2 C 4 R′ 2 CO)Ru(CO) 2 (PPh 3 ) (R=R′=Ph; R=Ph, R′=–CCPh) and cyclobutadiene Ru(0) complex (R 2 C 4 R′ 2 )Ru(CO) 2 (PPh 3 ) (R=Ph, R′=–CCPh) in moderate yields, each compound being formed as mixtures of isomers, 2,4-and 3,4-diethynylated cyclobutadiene-1-one and 1,2-and 1,3-diethynylated cyclobutadiene, from MS, IR, 13 C-, 31 P-NMR and X-ray analyses. At higher temperatures, a carbonate Ru(II) complex Ru(CO 3 )(CO) 2 (PPh 3 ) 2 was also obtained in 85% yield from the reaction in presence of diphenylacetylene. A cationic Ru(II) species supplied by (CO+CO 3 2− ) formed via a reductive disproportionation of CO 2 is proposed as an intermediate in an earlier stage of the coupling reactions of the alkyne molecules.

Gymnocolin, a new cis-clerodane diterpenoid from the liverwort Gymnocolea inflata. Crystal structure analysis.

Abstract Gymnocolin, a new diterpenoid from the liverwort Gymnocolea inflata (HUds) Dum., has been shown to have the cis -clerodane structure (1) by X-ray crystallographic analysis.

Bridge-splitting reaction of a dinuclear platinum(II) complex cross-linked by tetra-acetylethane dianion [Pt2(L2)2(dahd-O2O′2)][BF4]2 (dahd = tetra-acetylethane; L = SEt2, PMe2Ph; L2 = 1,5-cyclooctadiene); metal-carbon bonded platinum(II) complex of tetra-acetylethane with (C3,O′)-chelate

Abstract A Pt(II) complex of tetra-acetylethane (dahd = 3,4-diacetyl-2,4-hexadiene-2,5-diol) dianion bonding with (C3,O′)-chelate, Pt(L)(L′)(dahd-C3,O′){L = L′= SEt2; L = L′= PMe2Ph; L = SEt2, L′ = PPh3; L = L′ = 2,9-R2-1,10-phen(R = H, Me) where L′ is trans to C3} has been prepared. cis-PtCl2L2(L = SEt2, PMe2Ph) reacts with K2-dahd in CH3OH to produce a dinuclear cationic complex [Pt2L4(dahd-O2,O′2)]2+ in which dahd is cross-linked with symmetrical bifunctional chelation. An analogous COD (1,5-cyclo-octadiene) complex [Pt2(COD)2(dahd-O2,O′2)][BF4]2 has been prepared by treating PtCl2(COD) with AgBF4 and H2-dahd. [Pt2L4(dahd-O2O′2)][BF4]2, by treating with K2-dahd, readily transforms into PtL2(dahd-C3,O′) (L = SEt2, PMe2Ph). This PtL2(dahd-C3,O′)(L = SEt2, PMe2Ph) in HBF4/acetone solution converts to the dinuclear complex [Pt2L4(dahd-O2,O′2)][BF4]2, liberating H2-dahd in a stoichiometric yield. These anomalous Pt(II) complexes linked by the dahd dianion are characterized using IR, 1H, 13C-NMR and fast atom bombardment mass spectroscopy, conductance and molecular weight measurements.

Spirodensifolins A and B, new rearranged pinguisane sesquiterpenoids, from the liverworth frullanoides densifolia

Abstract New rearranged pinguisane type sesquiterpenoids A (1) and B, have been isolated and their relative stereostructures elucidated by means of extensive spectroscopic and X-ray crystallographic analyses of 1.

X-Ray crystal structure of (+)-crispatanolide, a novel eudesmane-type sesquiterpene δ-lactone from Makinoa crispata(liverwort)

From the liverwort, Makinoa crispata(Dilaenaceae), a novel eudesmane-type sesquiterpene δ-lactone, crispatanolide, was isolated and its structure was established to be 2,4-cycloeudesman-14,7-olide (1) by X-ray analysis.

A new technique for assaying cytochrome P450 enzyme activity in a single cell.

A new microspectrofluorometric technique for measuring the ethoxyresorufin-O-deethylase (EROD) activity of cytochrome P450 (CYP)1A1 in single living cells is described. The system, which uses a perfusion chamber and an HPLC pump, allowed cells to be stained, fixed, blocked, and washed by injecting each treatment solution into the on-line carrier stream of buffer from the sampling block of the HPLC pump. After addition of the substrate 7-ethoxyresorufin, the fluorescence intensity of the metabolite resorufin was measured in individual cells. Fluorescence intensity steeply increased to a unique peak for each cell and then decreased to the basal level. Furthermore, CYP1A1 in each cell was stained with its antibody and quantified using the fluorescence intensity of an FITC-conjugated secondary antibody. EROD activity was normalized using the FITC fluorescence. The results show that the initial slopes and peak values of resorufin production by the cells were dependent on the CYP1A1 level. Treatment of hepatocytes with two nonspecific P450 inhibitors, cimetidine and SKF-525A, suppressed EROD activity.