Synthesis of 4-alkoxy-2-phenylquinoline derivatives as potent antiplatelet agents

In our continuing search for novel antiplatelet agents, 4-alkoxy derivatives of 2-phenylquinoline as well as related compounds were prepared. Through biological screening, a preliminary structure antiplatelet activity relationship was established. Compounds 5-ethyl-4-methoxy-2-phenylquinoline (8), 4-ethoxy-5-ethyl-2-phenylquinoline (9), 4-ethoxycarbonylmethoxy-5-ethyl-2-phenylquinoline (10), 4-ethoxycarbonylbutoxy-5-ethyl-2-phenylquinoline (12) and 5-ethyl-4-(N-ethylcarboxido)methoxy-2-phenylquinoline (17) all demonstrated potent antiplatelet activity. Among them, compound 8 was the most potent with an IC50 value of 0.08 microM and was about 3-fold more active than indomethacin. The mechanism of antiplatelet action of 8 is possibly through its inhibition on cyclooxygenase or thromboxane synthetase.     

Antidiabetogenic oligostilbenoids and 3-ethyl-4-phenyl-3,4-dihydroisocoumarins from the bark of Shorea roxburghii

A methanol extract of the bark of Shorea roxburghii (Dipterocarpaceae) was found to inhibit plasma glucose elevation in sucrose-loaded mice. From the extract, three new 3-ethyl-4-phenyl-3,4-dihydroisocoumarins, 1'S-dihydrophayomphenol A(2) (1) and phayomphenols B(1) (2) and B(2) (3), were isolated together with 24 known compounds including 20 stilbenoids and oligostilbenoids. The structures of 1-3 were determined on the basis of their spectroscopic properties as well as of chemical evidences. Among the isolates, (-)-hopeaphenol (6), hemsleyanol D (8), (+)-α-viniferin (15), and (-)-balanocarpol (18) showed inhibitory activity against plasma glucose elevation in sucrose-loaded rats at doses of 100-200mg/kg, p.o. To clarify the mode of action of the antihyperglycemic property, effects of these oligostilbenoids on gastric emptying in mice, those on glucose uptake in isolated intestinal tissues as well as inhibitory activities against rat intestinal α-glucosidase and rat lens aldose reductase were examined.     

The formation mechanism by yeast of 4-hydroxy-2(or 5)-ethyl-5(or 2)-methyl-3(2H)-furanone in Miso

The mechanism of the formation of 4-hydroxy-2(or 5)-ethyl-5-(or 2)-methyl-3(2H)-furanone (HEMF) with yeast under caltivation in a medium containing amino-carbonyl reactants of ribose and glycine was investigated using stable isotopes of the corresponding compounds. It was confirmed that the skeleton of the five-membered ring and the methyl group of the side chain of HEMF was formed from ribose, and that the ethyl group was derived from the glucose metabolite by yeast. The formation of HEMF was confirmed when acetaldehyde as the glucose metabolite and a cell-free extract from yeast were added to the medium containing amino-carbonyl reactants. These results suggest that the role of yeast in HEMF formation is not only to provide the glucose metabolite, but also in combining the amino-carbonyl reactants with the glucose metabolite.     

Essential carboxyl residues in yeast enolase.

Yeast enolase (EC 4.2.1.11) is rapidly inactivated at pH 6.1 by three different water-soluble carbodiimides — 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride, 1-cyclohexyl-3-(2-morpholinoethyl)-carbodiimide metho-p-toluenesulfonate, and 1-ethyl-3-(4-azonia-4,4-dimethylpentyl)-carbodiimide iodide. Inactivation is most likely due to the modification of essential carboxyl residues at the enzyme active site.     

Steroidal constituents of Solanum xanthocarpum

From the extract of the fruits of Solanum xanthocarpum (Solanaceae), five new steroidal compounds were isolated and characterized: 4α-methyl-24ξ-ethyl-5α-cholest-7-en-3β,22ξ-diol (1), 3β,22ξ-dihydroxy-4α-methyl-24ξ-ethyl-5α-cholest-7-en-6-one (2), 3β-benzoxy-14β,22ξ-dihydroxy-4α-methyl-24ξ-ethyl-5α-cholest-7-en-6-one (3), 3β-benzoxy-14α,22ξ-dihydroxy-4α-methyl-24ξ-ethyl-5α-cholest-7-en-6-one (4) and 3β-(p-hydroxy)-benzoxy-22ξ-hydroxy-4α-methyl-24ξ-ethyl-5α-cholest-7-en-6-one (5).     

Chemical synthesis, spectral properties, and chromatography of 4alpha-methyl and 4beta-methyl isomers of (24R)-24-ethyl-5alpha-cholestan-3beta-ol and (24S)-24-ethyl-cholesta-5,22-dien-3beta-ol.

Described herein are chemical syntheses of the following compounds: 4-methyl-(24S)-24-ethyl-cholesta-4,22-dien-3-one, 4,4-dimethyl-(24S)-24-ethyl-cholesta-5,22-dien-3-one, 4beta-methyl-(24R)-24-ethyl-5alpha-cholestan-3beta-ol, 4alpha-methyl-(24R)-24-ethyl-5alpha-cholestan-3beta-ol, 4alpha-methyl-(24S)-24-ethyl-5alpha-cholest-22-en-3beta-ol, 4-methyl-6beta-bromo-(24S)-24-ethyl-cholesta-4,22-dien-3-one, 4alpha-methyl-(24S)-24-ethyl-cholesta-5,22-dien-3beta-ol, 4alpha,5alpha-epoxy-(24S)-24-ethyl-cholesta-4,22-dien-3beta-yl acetate, 4beta-methyl-(24S)-24-ethyl-cholest-22-en-3beta,5alpha-diol, 4beta-methyl-5alpha-hydroxy-(24S)-24-ethyl-cholest-22-en-3beta-yl acetate, 4beta-methyl-(24S)-24-ethyl-cholesta-5,22-dien-3beta-yl acetate and 4beta-methyl-(24S)-24-ethyl-cholesta-5,22-dien-3beta-ol. Chromatographic, nuclear magnetic resonance, and mass spectral data are presented for the compounds under consideration.     

Effects of the amino-carbonyl reaction of ribose and glycine on the formation of the 2(or 5)-ethyl-5(or 2)-methyl-4-hydroxy-3(2H)-furanone aroma component specific to miso by halo-tolerant yeast

The formation of HEMF[2(or 5)-ethyl-5(or 2)-methyl-4-hydroxy-3(2H)-furanone], the aroma component specific to miso and soy sauce, was promoted by cultivating the halo-tolerant yeast, Zygosaccharomyces rouxii, in a medium including the amino-carbonyl reaction products based on ribose and glycine. The glucose concentration in the medium influenced the HEMF formation by Z. rouxii.     

Two new resorcinol derivatives with strong cytotoxicity from the roots of Ardisia brevicaulis Diels

Two new resorcinol derivatives, 4-hydroxy-2-methoxy-6-[(8Z)-pentadec-8-en-1-yl]phenyl acetate (1) and 4-hydroxy-2-methoxy-6-pentadecylphenyl acetate (2), together with known compounds ardisiphenol D (3), 5-tridecylresorcinol (4), 5-pentadecylresorcinol (5), 5-[(8Z)-pentadec-8-en-1-yl]resorcinol (6), belamcandaquinones C and D (7 and 8, resp.), ardisicrenoside A, ardisiacrispin B, (22E)-24-ethyl-5α-cholesta-7,22-dien-3-one, and (22E)-24-ethyl-5α-cholesta-7,22-dien-3β-ol were isolated from the MeOH extract of the roots of Ardisia brevicaulis Diels. Their structures were determined by spectroscopic analysis including ESI- and EI-MS, and NMR data. Cytotoxicities of 1-4 against cell lines A549, MCF-7, and PANC-1 were tested in vitro by the MTT (=3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) method. Compounds 1-4 showed cytotoxic activity against all cell lines stronger than that of cisplatin against A549.     

Synthesis and anticonvulsant evaluation of 4-(4-alkoxylphenyl)-3-ethyl-4H-1,2,4-triazoles as open-chain analogues of 7-alkoxyl-4,5-dihydro[1,2,4]triazolo[4,3-a]quinolines

A series of 4-(4-alkoxylphenyl)-3-ethyl-4H-1,2,4-triazole derivatives was synthesized as open-chain analogues of 7-alkoxyl-4,5-dihydro[1,2,4]triazolo[4,3-a]quinolines. Their anticonvulsant activities were evaluated by the maximal electroshock test (MES test) and their neurotoxicity was evaluated by the rotarod neurotoxicity test (Tox). MES test showed that 3-ethyl-4-(4-octyloxyphenyl)-4H-1,2,4-triazole 3q was found to be the most potent with ED(50) value of 8.3mg/kg and protective index (PI=TD(50)/ED(50)) value of 5.5, but compound 3r, 3-ethyl-4-(4-octyloxyphenyl)-4H-1,2,4-triazole, exhibited better PI value of 9.3, which was much greater than PI value of the prototype drug phenytoin. For explanation of the possible mechanism of action, the compound 3r was tested in pentylenetetrazole test, isoniazid test, thiosemicarbazide test, 3-mercaptopropionic acid and strychnine test.     

A facile synthesis of (3α-3H]β-sitosterol

Direct oxidation of the parent sterol using CrO₂ provided (24R)-24-ethyl-5-cholesten-3-one which on treatment with NaBT₄ gave [3α-³H] (24R)-24-ethyl-5-cholesten-3β-ol. Purification at each stage afforded samples which were compared spectrally with the corresponding cholesterol series compounds.     

Retinoic acid metabolism inhibition by 3-azolylmethyl-1H-indoles and 2, 3 or 5-(alpha-azolylbenzyl)-1H-indoles

Among a library of 70 azoles, 8 indole derivatives substituted in the 2-, 3- or 5- position with an azolylmethyl or alpha-azolylbenzyl chain were evaluated for retinoic acid (RA) metabolism inhibitory activity. The most active inhibitors identified in this study were 5-bromo-1-ethyl-3-methyl-2-[(phenyl)(1H-1,2,4-triazol-1-yl)methyl]-1H-indole (3) (68.9% inhibition) and 5-bromo-1-ethyl-2-[(4-fluorophenyl) (1H-1,2,4-triazol-1-yl)methyl]-3-methyl-1H-indole (6) (60.4% inhibition). At the same concentration (100 microM) ketoconazole exerted similar inhibitory effect (70% inhibition).     

Responses of individual antennal olfactory cells of tsetse flies (Glossina m. morsitans) to phenols from cattle urine

Abstract. Action potentials from olfactory cells in antennae (funiculi) of living tsetse flies, Glossina morsitans morsitans Westwood, were recorded using a surface-contact technique. Stimuli were the vapours of the seven alkylphenols identified in cattle urine: phenol, 3-methyl-, 3-ethyl-, 3- n -propyl-, 4-methyl-, 4-ethyl-, and 4- n -propylphenol. In addition, responses to the vapours of 1-octen-3-ol, acetone and dichloromethane were recorded. The phenol-sensitive cells could be grouped into four subclasses. Subclass, 1, 2 and 3 cells responded to the phenols only, cells of subclass 1 and 2 being activated by these substances, those of subclass 3 inhibited. Cells of subclass 4 were activated to a similar degree by all phenols and by one or more of the other chemicals tested. Subclass 1 cells were strongly activated by the 3-alkylphenols, whereas subclass 2 cells were most sensitive to 4-methylphenol. Subclass 3 cells were most strongly inhibited by phenol, and 3- and 4-methylphenol. The results suggest that though individual phenols may be attractive to G. m. morsitans , preference for certain blends of phenols may exist; for example, blends composed of moderate doses of 4-methylphenol and 3-methyl-, 3-ethyl- or 3- n -propylphenol.     

Effect of media constituents on the formation by halophilic yeast of the 2 (or 5)-ethyl-5 (or 2)-methyl-4-hydroxy-3 (2H)-furanone aroma component specific to miso.

The formation of HEMF [2 (or 5)-ethyl-5 (or 2)-methyl-4-hydroxy-3 (2H)-furanone] by yeast was examined in an attempt to investigate its mechanism and involved factors. HEMF formation was promoted by yeast cultivation in a heat-sterilized medium which included glucose, ribose, and a nitrogenous compound such as an extract of shoyu koji, poly-peptone, casamino acid, or an amino acid (glutamic acid, threonine, serine, or alanine).     

Isoprenoid enzyme systems of silkworm. II. Formation of the juvenile hormone skeletons by farnesyl pyrophosphate synthetase II

Comparative substrate specificities of farnesyl pyrophosphate synthetases I and II purified from larvae of silkworm, Bombyx mori, were studied by use of the possible biosynthetic intermediates of juvenile hormones in the insect. In the presence of Mn2+ ions farnesyl pyrophosphate synthetase II showed higher activity than synthetase I and the corresponding enzyme from pig liver with the following substrate homologues: (Z)-3-methyl-2-pentenyl-, 3-ethyl-3-butenyl-, (2E,6Z)-3,7-dimethyl-2,6-nonadienyl-, and (2E,6Z)-3-ethyl-7-methyl-2,6-nonadienyl pyrophosphate. When (Z)-3-methyl-2-pentenyl-, 3-ethyl-3-butenyl-, and isopentenyl pyrophosphate were mixed and incubated with farnesyl pyrophosphate synthetase II, (2E,6E,10Z)-3,11-dimethyl-7-ethyl-2,6,10-tridecatrienyl-, (2E,6E,10Z)-3,7,11-trimethyl-2,6,10-tridecatrienyl, and a trace amount of (2E,6E,10Z)-3,7-diethyl-11-methyl-2,6,10-tridecatrienyl pyrophosphate, whose carbon skeletons were the same as those of juvenile hormone I, II, and O, respectively, were formed. (Z)-3-Methyl-2-pentenyl pyrophosphate was produced from 3-ethyl-3-butenyl pyrophosphate as a single product by the action of silkworm isopentenyl pyrophosphate isomerase, though the enzyme activity was much lower with this substrate than with the usual substrate, isopentenyl pyrophosphate.     

Transformation of a monoterpene ketone, piperitenone, and related terpenoids using Mucor piriformis

Biotransformation of piperitenone (I), 5,5-dimethyl-2-(1-methylethylidene)-cyclohexanone (II), and 2-(1-ethyl-1-propylidene)-5-methylcyclohexanone (III) was studied using a versatile fungal strain, Mucor piriformis. The organism initiates transformation of these compounds by hydroxylation at the allylic positions or at the tertiary carbon. Transformation of piperitenone (I) by this strain yielded 5-hydroxypiperitenone (Ic), 7-hydroxypiperitenone (Id), 7-hydroxypulegone (Ie), 10-hydroxypiperitenone (If), and 4-hydroxypiperitenone (Ig) as metabolites. It was possible to block some of the metabolic activities of the organism through structural modification of piperitenone (I). This was evidenced by the fact that biotransformation of 5,5-dimethyl-2-(1-methylethylidene)-cyclohexanone (II) yielded 5,5-dimethyl-2-(1-hydroxy-1-methylethyl)-2-cyclohexen-1-one (IIb) and 5,5-dimethyl-3-hydroxy-2-(1-methylethylidene)-cyclohexanone (IIa), whereas 2-(1-ethyl-1-propylidene)-5-methylcyclohexanone (III) yielded 6-(1-ethyl-1-propylidene)-5-methyl-2-cyclohexen-1-one (IIIb) and 6-(1-ethyl-1-propylidene)-5-hydroxy-5-methylcyclohexanone (IIIa) as metabolites. Based on the identification of the metabolites, pathways for the biotransformation of I, II, and III have been proposed. The mode of biotransformation of these compounds by M. piriformis also compared to their modes of metabolism in the rat system.     

Synthesis and pharmacological evaluation of 1-alkyl-N-[2-ethyl-2-(4-fluorophenyl)butyl]piperidine-4-carboxamide derivatives as novel antihypertensive agents

We synthesized and evaluated inhibitory activity against T-type Ca(2+) channels for a series of 1-alkyl-N-[2-ethyl-2-(4-fluorophenyl)butyl]piperidine-4-carboxamide derivatives. Structure-activity relationship studies have revealed that dialkyl substituents at the benzylic position play an important role in increasing inhibitory activity. Oral administration of N-[2-ethyl-2-(4-fluorophenyl)butyl]-1-(2-phenylethyl)piperidine-4-carboxamide (20d) lowered blood pressure in spontaneously hypertensive rats without inducing reflex tachycardia, which is often caused by traditional L-type Ca(2+) channel blockers.     

Beta-oxidation of 2-ethyl-5-carboxypentyl phthalate in rodent liver

[7-14C]-2-Ethyl-5-carboxypentyl phthalate was isolated and purified from urine of rats given [7-14C]-di-(2-ethylhexyl) phthalate. This metabolite was shown to serve as a precursor for 2-ethyl-3-carboxypropyl phthalate in vivo. 2-Ethyl-5-carboxypentyl phthalate was oxidized to 2-ethyl-3-carboxypropyl phthalate in liver slices from control or, much more rapidly, from clofibrate-pretreated rats. Inhibition by KCN in liver slices from untreated rats, and strong inhibition by acrylate, suggested that formation of 2-ethyl-3-carboxypropyl phthalate involved mitochondrial beta-oxidation. The strong enhancement of the production of this compound by clofibrate (a very weak inducer for mitochondrial dehydrogenases), and strong inhibition by chlorpromazine suggested that peroxisomes may also be able to oxidize 2-ethyl-5-carboxypentyl phthalate. We were able to detect beta-oxidation of 2-ethyl-5-carboxypentyl phthalate to 2-ethyl-3-carboxypropyl phthalate using purified mitochondria, but strong phthalate monoester hydrolase activity observed during incubation of the former compound with purified peroxisomes made it impossible to determine whether 2-ethyl-3-carboxypropyl phthalate could be produced in the latter organelle or not. 2-Ethyl-5-carboxypentyl phthalate was such an inefficient substrate for beta-oxidation compared to palmitic acid that it is unlikely that it contributes significantly to the production of H2O2 in rats chronically exposed to di-(2-ethylhexyl) phthalate. Normal fatty acids are most likely to serve as the dominant substrates for peroxisomal beta-oxidase.     

Chemical studies on yeast hexokinase. Specific modification of a single tyrosyl residue with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide.

1. Of the 15 tyrosyl residues/subunit of yeast hexokinase A (ATP:D-hexose 6-phosphotransferase) only one residue is specifically modified at pH 8.0 with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride. 2. The acylation of this single tyrosyl residue leads to the loss of the enzyme activities (hexokinase and ATPase) by a first-order process, which can be fully reversed by treatment with hydroxylamine. 3. ATP does not protect the enzyme against chemical modification and inactivation; however, glucose exerts a noticeable though indirect protection effect against chemical modification and inactivation. 4. The chemically modified enzyme, purified by column chromatography, has 14% of the activity of the native enzyme, but the Km for ATP-Mg or glucose remains unchanged as does the pH optimum of activity. Results of conformational studies (ultracentrifugation, fluorescence, thermostability and chemical reactivity of the sulfhydryl groups) indicate that the decrease of enzyme activity due to the modification of the tyrosyl residue is related to a localized perturbation of the enzyme active-center region.     

Retinoic Acid Metabolism Inhibition by 3-Azolylmethyl-1H-indoles and 2, 3 or 5-(α-Azolylbenzyl)-1H-indoles

Among a library of 70 azoles, 8 indole derivatives substituted in the 2-, 3- or 5- position with an azolylmethyl or α-azolylbenzyl chain were evaluated for retinoic acid (RA) metabolism inhibitory activity. The most active inhibitors identified in this study were 5-bromo-1-ethyl-3-methyl-2-[(phenyl)(1H-1,2,4-triazol-1-yl)methyl]-1H-indole (3) (68.9% inhibition) and 5-bromo-1-ethyl-2-[(4-fluorophenyl)(1H-1,2,4-triazol-1-yl)methyl]-3-methyl-1H-indole (6) (60.4% inhibition). At the same concentration (100 μM) ketoconazole exerted similar inhibitory effect (70% inhibition).     

A new synthesis of the ORL-1 antagonist 1-[(3R,4R)-1-cyclooctylmethyl-3-hydroxymethyl-4-piperidinyl]-3-ethyl-1,3-dihydro-2H-benzimidazol-2-one (J-113397) and activity in a calcium mobilization assay

A new chiral synthesis of the ORL-1 antagonist 1-[(3R,4R)-1-cyclooctylmethyl-3-hydroxymethyl-4-piperidinyl]-3-ethyl-1,3-dihydro-2H-benzimidazol-2-one (2, J-113397) was developed. J-113397 has a K(e)=0.85nM in an ORL-1 calcium mobilization assay and is 89-, 887-, and 227-fold selective for the ORL-1 receptor relative to the mu, delta, and kappa opioid receptors.