Synthesis, absolute configuration and biological activities of both enantiomers of 2-(5,7-Dichloro-3-indolyl)propionic acid: a novel dichloroindole auxin and antiauxin

Racemic 2-(5,7-dichloro-3-indolyl)propionic acid (5,7-Cl(2)-2-IPA) was synthesized from 5,7-dichloroindole-3-acetic acid by successive esterification, methoxycarbonylation, methylation, and double hydrolysis. The racemate was converted to diastereomeric esters of l-menthol; these were separated by recycling HPLC into two optically active diastereomers that were then hydrolyzed with p-TsOH to two optically active enantiomers of 5,7-Cl(2)-2-IPA. The absolute configurations of both these enantiomers were determined by comparing the (1)H-NMR spectra of their diastereomeric l-menthyl esters with those of the diastereomeric l-menthyl esters of 2-(3-indolyl)propionic acid (2-IPA) of known absolute configurations.An assay by the coleoptile elongation of Avena sativa showed the (S)-(+)-enantiomer of 5,7-Cl(2)-2-IPA to have weak auxin activity, whereas the (R)-(-)-antipode had no auxin activity at any concentration tested. Interestingly, the (R)-(-)-enantiomer had antiauxin activity very close to that of 2-(5,7-dichloro-3-indolyl)isobutyric acid (5,7-Cl(2)-IIBA), a strong antiauxin. These data indicate that, of the two methyl groups in its molecule, the antiauxin activity of 5,7-Cl(2)-IIBA was due only to the (R)-methyl group.     

Enzymatic resolution of 3-(3-indolyl)butyric acid: a key intermediate for indolmycin synthesis

Both enantiomers of 3-(3-indolyl)butyric acid, a key intermediate of indolmycin, were successfully prepared by lipase-catalysed enantioselective hydrolysis. Of the enzymes examined, Pseudomonas fluorescens lipase (lipase AK) showed the best enantioselectivity and highest reactivity for the hydrolysis of (±)-trifluoroethyl 3-(3-indolyl)butyrate. Under optimal conditions, optical resolution was completed in one enzyme-catalysed step, the S-acid and unreacted R-ester being obtained in high optical purity.     

Cyclization of N[2-(3-indolyl)acetyl]-5-aminovaleraldehydes and N[2-(3-indolyl)ethyl]-5-aminovaleraldehydes

Various model cyclizations related to the organic or biological synthesis of diverse indole alkaloids, are described and discussed, including: 18 → 20, 23 → 25, 28 → 31 and 29 → 35, 37, 38 and 39 (as aldehydes).     

Synthesis, absolute configuration and biological activity of both enantiomers of 2-(5,6-dichloro-3-indolyl)propionic acid: new dichloroindole auxins

Racemic 2-(5,6-dichloro-3-indolyl)propionic acid (5,6-Cl2-2-IPA) was synthesized from 5,6-dichloroindole-3-acetic acid (5,6-Cl2-IAA) by successive esterification, methoxycarbonylation, methylation, and double hydrolysis. The racemate was converted to the diastereomeric esters of (S)-(-)-1-phenylethyl alcohol. These were separated by HPLC into two optically active diastereomers and then hydrolyzed with p-TsOH to the optically active enantiomers of 5,6-Cl2-2-IPA. The absolute configurations of both the 5,6-Cl2-2-IPA enantiomers were determined by comparing the 1H-NMR spectra of their diastereomeric (S)-(-)-1-phenylethyl esters with those of the diastereomeric (S)-(-)-1-phenylethyl esters of 2-(3-indolyl)propionic acid (2-IPA) whose absolute configurations are already known. There was no essential difference between (S)-(+)- and (R)-(-)-5,6-Cl2-2-IPA in hypocotyl growth-inhibiting activity toward Chinese cabbage, but their inhibitory activities were stronger than that of the potent mother auxin, 5,6-Cl2-IAA. No essential difference in the coleoptile elongating activity of Avena sativa was apparent for the enantiomers, this activity being about one-third that of 5,6-Cl2-IAA.     

Synthesis of 3,5-bis(2-indolyl)pyridine and 3-[(2-indolyl)-5-phenyl]pyridine derivatives as CDK inhibitors and cytotoxic agents

We here report the synthesis and biological evaluation of new 3,5-bis(2-indolyl)pyridine and 3-[(2-indolyl)-5-phenyl]pyridine designed as potential CDK inhibitors. Indole, 5-hydroxyindole, and phenol derivatives were used to generate three substitutions of the pyridine. The resulting skeletons were successively exploited to introduce various dimethylaminoalkyl side chains by Williamson type reactions. The synthesis includes Stille or Suzuki type reactions, which were realized on the 3,5-dibromopyridine. The preparation and the use of stannylindoles in mono or bis cross-coupling reactions were also described and each step was optimized and detailed. Kinase assays were realized and shown that nude compounds 7, 18, and 25 inhibited CDK1 in the 0.3–0.7 micromolar range with a good selectivity over GSK-3. Cytotoxicity against CEM human leukemia cells was evaluated with IC₅₀ values in the 5–15 micromolar range. Precise structure–activity relationships were delineated. Molecular modeling and docking solutions were proposed to complete the studies and to explain the observed SAR in the CDK assays.     

Synthesis and anti-inflammatory activity of 3-(4'-geranyloxy-3'-methoxyphenyl)-2-trans propenoic acid and its ester derivatives

Different esters of 3-(4'-geranyloxy-3'-methoxyphenyl)-2-trans propenoic acid (1), an anti-inflammatory principle of Acronychia baueri Schott (Rutaceae), were synthesized. Their topical anti-inflammatory activity was evaluated using the Croton oil ear test in mice as a model of acute inflammation. The activity of the paracetamol, guaiacol and hydroquinone esters of (1) was higher than that of the parent compound, being similar to that exerted by indomethacin, used as reference drug.     

The presence of N-acetyllactosamine and lactose: beta (1-3)N-acetylglucosaminyltransferase activity in human urine

Normal human urine was found to contain beta (1-3)N-acetylglucosaminyltransferase catalyzing the transfer of N-acetylglucosamine from UDP-GlcNAc to N-acetyllactosamine and lactose. Lacto-N-tetraose which carries the terminal Gal beta (1-3)GlcNAc structure was a poor acceptor. The product of the transferase reaction with N-acetyllactosamine as acceptor was identified by methylation analysis as GlcNAc beta (1-3)Gal beta (1-4)GlcNAc. The beta-linkage of the GlcNAc in the synthesized trisaccharide was confirmed by the action of the specific beta-N-acetylhexosaminidase. The enzyme requires Mn2+ ions for its activity, shows a broad pH optimum from 7 to 9, and appears to have a molecular weight of about 200,000 as estimated by Sephadex gel filtration.     

Inhibitors of HCV NS5B polymerase. Part 2: Evaluation of the northern region of (2Z)-2-benzoylamino-3-(4-phenoxy-phenyl)-acrylic acid

A novel series of non-nucleoside HCV NS5B polymerase inhibitors was prepared from a (2Z)-2-benzoylamino-3-(4-phenoxy-phenyl)-acrylic acid template. Solution and solid phase analog synthesis focused on the northern region of the template combined with structure based design led to the discovery of several potent and orally bioavailable lead compounds.     

Quantitative relationships between lipophilicity and mutagenic effects of N-substituted amides of 3-(5-nitro-2-furyl)-acrylic acid on Salmonella typhimurium

Mutagenic effects of 10 N-alkylamides of 3-(5-nitro-2-furyl)-acrylic acid were assessed in two strains of Salmonella typhimurium TA100 (rfa+ and rfa-). Experimental data were confronted with physiologically based compartment model comprising passive membrane transport, metabolical inactivation in cytoplasm and formation of a reactive intermediate which is responsible for receptor modification. The quantitative dependences observed between mutagenicity and lipophilicity indicate that, in both cases, the drug-receptor interaction takes place in a hydrophobic compartment localized in the cytoplasm. The mutagenic potency of some derivatives was influenced also by stericity.     

Synthesis and biological evaluation of 2,5-di(7-indolyl)-1,3,4-oxadiazoles,and 2- and 7-indolyl 2-(1,3,4-thiadiazolyl)ketones as antimicrobials

A range of novel hydrazine bridged bis-indoles was prepared from readily available indole-7-glyoxyloylchlorides and 7-trichloroacetylindoles and underwent cyclodehydration to produce 2,5-di(7-indolyl)-1,3,4-oxadiazoles and a 2,2′-bi-1,3,4-oxadiazolyl with phosphoryl chloride in ethyl acetate. This efficient protocol was subsequently used for the synthesis of 2- and 7-indolyl 2-(1,3,4-thiadiazolyl)ketones from related indolyl-hydrazine carbothioamides. The synthesised bis-indoles were evaluated for their antimicrobial properties, particularly the inhibition of protein–protein complex formation between RNA polymerase and σ factor and their bactericidal effect on Gram positive Bacillus subtilis and Gram negative Escherichia coli.     

Growth rates and auxin effects in graviresponding gynophores of the peanut, Arachis hypogaea (Fabaceae)

The gynophore of the peanut plant (Arachis hypogaea) is a specialized organ that carries and buries the fertilized ovules into the soil in order for seed and fruit development to occur underground. The rates of growth of vertically and horizontally oriented gynophores were measured using a time-lapse video imaging system. We found that the region of maximum extension growth due to elongation (termed the Central Elongation Zone) is located on average at 2-5 mm from the tip. In the first 0-4 h after horizontal reorientation (gravistimulation), new zones of growth emerge on the upper surface, while the elongation zone of the lower side decreases in size and magnitude. Four to six hours after reorientation the zones of maximum growth are almost equal in size and location on the upper and lower sides. The growth rate and the gravitropic response decreased dramatically, upon the excision of the ovule region (terminal 1.5 mm), but a gravitropic growth response could be restored by applying the auxin indole-3-acetic acid exogenously to the excised tip. The addition of napthylphthalamic acid (an auxin transport inhibitor) at the ovule region allowed some growth to occur, but the gynophores do not respond normally to gravity, upon horizontal reorientation. We discuss the role of auxin in the gravitropic response of the gynophore.     

Production of (R)-3-amino-3-phenylpropionic acid and (S)-3-amino-3-phenylpropionic acid from (R,S)-N-acetyl-3-amino-3-phenylpropionic acid using microorganisms having enantiomer-specific amidohydrolyzing activity

(R)-3-Amino-3-phenylpropionic acid ((R)-beta-Phe) and (S)-3-amino-3-phenylpropionic acid ((S)-beta-Phe) are key compounds on account of their use as intermediates in synthesizing pharmaceuticals. Enantiomerically pure non-natural amino acids are generally prepared by enzymatic resolution of the racemic N-acetyl form, but despite the intense efforts this method could not be used for preparing enantiomerically pure beta-Phe, because the effective enzyme had not been found. Therefore, screening for microorganisms capable of amidohydrolyzing (R,S)-N-acetyl-3-amino-3-phenylpropionic acid ((R,S)-N-Ac-beta-Phe) in an enantiomer-specific manner was performed. A microorganism having (R)-enantiomer-specific amidohydrolyzing activity and another having both (R)-enantiomer- and (S)-enantiomer-specific amidohydrolyzing activities were obtained from soil samples. Using 16S rDNA analysis, the former organism was identified as Variovorax sp., and the latter as Burkholderia sp. Using these organisms, enantiomerically pure (R)-beta-Phe (>99.5% ee) and (S)-beta-Phe (>99.5% ee) with a high molar conversion yield (67%-96%) were obtained from the racemic substrate.     

Synthesis and anti-inflammatory activity of some 3-(4,6-disubtituted-2-thioxo-1,2,3,4-tetrahydropyrimidin-5-yl) propanoic acid derivatives

A series of 3-(4,6-disubtituted-2-thioxo-1,2,3,4-tetrahydropyrimidin-5-yl) propanoic acid derivatives has been synthesized by condensation of thiourea, 5-(4-subtituted phenyl)-5-oxopentanoic acid and substituted aldehyde. The synthesized compounds were screened for their anti-inflammatory activity using rat paw edema method. Most of the compounds from the series showed significant (p <0.05) anti-inflammatory activity.     

Increases in jasmonic acid caused by indole-3-acetic acid and auxin herbicides in cleavers (Galium aparine)

The effects of indole-3-acetic acid and auxin herbicides on endogenous jasmonic acid (JA) concentrations were studied in relation to changes in ethylene and abscisic acid (ABA) levels in cleavers (Galium aparine). When plants were root-treated with increasing concentrations of indole-3-acetic acid (IAA), ethylene biosynthesis was stimulated in response to the accumulation of endogenous IAA in the shoot tissue. Within 25h of treatment, stimulated ethylene formation was accompanied by increases in immunoreactive concentrations of JA and ABA, which reached maxima of 4.5-fold and 26-fold of the control, respectively, at 100 microM of applied IAA. Corresponding effects were obtained using synthetic auxins and when the ethylene-releasing compound ethephon was applied exogenously. This represents the first report, to our knowledge, of an auxin-mediated increase in JA levels. The increase in JA may be triggered by ethylene.     

Diuretic actions of 1-((tert-butylimino)methyl)-2-(3-indolyl) indoline HCl (MJ 8592-1) in adrenalectomized or ADH-primed rats

MJ 8592-1, an orally active diuretic indolylindoline derivative, effectively reversed the relative oliguria induced by ADH (Pitressin®) in ethanol-saline primed intact rats. It was 5.5, .96 and >18 times as potent, respectively, as furosemide, HCTZ and triamterene in producing a 100% increase in Na excretion in the presence of ADH. Since MJ 8592-1 also elicited a diuretic-saluretic response in ethanolsaline primed rats in the absence of ADH, the antagonism to exogenous vasopressin may be classified as non-specific. In adrenalectomized rats, MJ 8592-1, like triamterene, produced dose-related electrolyte excretion responses in both the presence and absence of exogenous DOCA. Thus, while MJ 8592-1 was effective in counteracting mineralocorticoid-induced Na retention in the distal tubule, it was also capable of increasing Na excretion by a mechanism independent of any direct interactions with adrenal cortical steroids or tubular sites influenced by these hormones.     

Synthesis and biological evaluation of N-(7-indolyl)-3-pyridinesulfonamide derivatives as potent antitumor agents

We herein report the synthesis and antitumor activity of E7070 analogues containing a 3-pyridinesulfonamide moiety. E7070 was selected from our sulfonamide-based compound collections, currently undergoing Phase II clinical trials because of its tolerable toxicity profile and some antitumor responses in the Phase I setting. Of the analogues examined, ER-35745, a 6-amino-3-pyridinesulfonamide derivative, demonstrated significant oral efficacy against the HCT116 human colon carcinoma xenograft in nude mice.     

Excitation of indole-3-acetic acid (an auxin) in a linoleate-lipoxygenase system.

The weak luminescence that accompanies the linoleate-lipoxygenase reaction was greatly enhanced by the addition of indole analogues, and especially indole acetic acid. The main emitting species in the indole acetic acid-linoleate-lipoxygenase system was analysed spectrophotometrically in the visible region and ascribed to the transition of excited indole acetate in triplet state to its ground state. Such an excited indole acetate could be generated by transfer of energy from the excited CO2 and excited carbonyl (generated by the linoleate-lipoxygenase reaction) to indole acetate in the ground state, but not by cleavage of the dioxetane analog (positions 2 and 3 on the indole ring).     

Antioxidative activity of (-)-epigallocatechin-3-(3''-O-methyl)gallate isolated from fresh tea leaf and preliminary results on its biological activity

Antioxidative activity of (-)-epigallocatechin-3-(3'-O-methyl)gallate (catechin e) was examined. Catechin e showed a strong antioxidative activity. A preliminary test using rat cancer cells suggests that catechin e also has a strong cytotoxic activity. Among tested catechins, only catechin e has strong activity for both.