Synthesis of affinity ligands and radioactive probes for isolation and study of myo-inositol 1,4,5-trisphosphate binding proteins

To synthesize an affinity matrix for isolation of D-myo-inositol 1,4,5-trisphosphate binding proteins, racemic 3-cyclohexene-1-carboxaldehyde was oxidized and converted to a mixture of trans-3,4-di-hydroxycyclohexane-1-carboxylic acid methyl ester isomers, which was phosphorylated and separated into (+-)-(1R,3R,4R)- and (+-)-(1R,3S,4S)-trans-3,4-bis[(diphenoxyphosphoryl)oxy]cyclohex an e-1- carboxylic acid methyl esters. Each of these racemic compounds was hydrogenolyzed and reacted with ethylenediamine to give a monoamide, N-(2-aminoethyl)-bis(phosphonyloxy)cyclohexane-1-carboxamide, that was coupled to cyanogen bromide activated Sepharose 4B to provide the desired affinity matrices. The intermediate trans-3,4-bis[(diphenoxyphosphoryl)oxy]cyclohexane-1-carboxylic acid methyl ester was also reduced with lithium borotritide to give the (hydroxy[3H]methyl)cyclohexane derivative, which was phosphorylated and hydrogenolyzed to yield trans-3,4-bis(phosphonyloxy)-1-[(phosphonyloxy)[3H]methyl]cy clohexane, a radiolabeled analogue of inositol 1,4,5-trisphosphate. The carboxamide was also coupled to 4-azidosalicylic acid, and the product was iodinated to provide a 125I-radiolabeled photoactivatable cross-linking derivative of cyclohexanediol bisphosphate.     

Xanthones from a microfungus of the genus Xylaria

Chemical investigations of a microfungus Xylaria sp. isolated from the Australian rainforest tree Glochidion ferdinandi have afforded two new natural products, 2-hydroxy-6-methyl-8-methoxy-9-oxo-9H-xanthene-1-carboxylic acid (1) and 2-hydroxy-6-hydroxymethyl-8-methoxy-9-oxo-9H-xanthene-1-carboxylic acid (2). Compound 1 has previously been synthesised but only partially characterised. Methylation of 1 using diazomethane afforded the crystalline compound 2,8-dimethoxy-6-methyl-9-oxo-9H-xanthene-1-carboxylic acid methyl ester (3), whose structure was determined by single crystal X-ray analysis. This paper reports the full spectroscopic characterisation of compounds 1-3 by NMR, UV, IR and MS data. All compounds were inactive in a brine shrimp lethality assay and several antimicrobial screens.     

棕色扁海绵中的吡咯生物碱

从中国南海棕色扁海绵Phakellia fusca Schimidt的乙醇浸提物中,分离得到3个吡咯生物碱,结合理化性质,波谱分析,文献检索,确定其结构分别为4,5-二溴-1H-吡咯-2-甲酸甲酯(1)、4,5-二溴-3-氰-1H-吡咯-2-甲酸甲酯(2)、4,5-二溴-1H-吡咯-2-甲酰氨(3)。其中化合物(2)未见文献报道。     

Alkaloids from Portulaca oleracea L

Five alkaloids (oleraceins A, B, C, D and E) were isolated from Portulaca oleracea L., and their structures determined by spectroscopic methods as 5-hydroxy-1-p-coumaric acyl-2,3-dihydro-1H-indole-2-carboxylic acid-6-O-beta-D-glucopyranoside, 5-hydroxy-1-ferulic acyl-2,3-dihydro-1H-indole-2-carboxylic acid-6-O-beta-D-glucopyranoside, 5-hydroxy-1-(p-coumaric acyl-7'-O-beta-D-glucopyranose)-2,3-dihydro-1H-indole-2-carboxylic acid-6-O-beta-D-glucopyranoside, 5-hydroxy-1-(ferulic acyl-7'-O-beta-D-glucopyranose)-2,3-dihydro-1H-indole-2-carboxylic acid-6-O-beta-D-glucopyranoside and 8,9-dihydroxy-1,5,6,10b-tetrahydro-2H-pyrrolo[2,1-a]isoquinolin-3-one, respectively.     

Design and synthesis of novel inhibitors of human kynurenine aminotransferase-I

Herein we report 6-ethoxy-6-oxo-5-(2-phenylhydrazono) hexanoic acid and 3-(2-carboxyethyl)-1H-indole-2-carboxylic acid derivatives as synthetically accessible leads for human kynurenine aminotransferase-I (KAT-I) inhibitors. In total, 12 compounds were synthesized and their biological activities were determined using the HPLC-UV based KAT-I inhibition assay. Of the 12 compounds synthesized, 10 were found to inhibit human KAT-I and the most active compound was found to be 5-(2-(4-chlorophenyl) hydrazono)-6-ethoxy-6-oxohexanoic acid (9a) with an IC(50) of 19.8 μM.     

Inhibition of wound ethylene in Lycopersicum esculentum fruit discs by 1-amino cyclopropane-1-carboxylic acid oxidase inhibitors

Inhibition of wound-ethylene by eight structural analogues of 1-aminocyclopropane-1-carboxylic acid (ACC) studied seperately was investigated in unripe tomato fruit discs (Lycopersicum esculentum). The compounds tested were: trans-2-phenylcyclopropane-1-carboxylic acid (PCCA), cyclopropane-1,1-dicarboxylic acid (CDA), cyclopropylamine (CPA), cyclopropyl methyl ketone (CMK), chrysanthemyl alcohol (CHRA), 2-methyl cyclopropanecarboxylic acid (MCA), cyclopropanecarboxylic acid (CCA), 2-methyl-cyclopropane-methanol (2-MCM). The level of inhibition was a function of treatment concentration and time. Differential inhibition induced by the tested compounds was related to their structure.     

Biocatalytic ammonolysis of (5S)-4,5-dihydro-1H-pyrrole-1,5-dicarboxylic acid, 1-(1,1-dimethylethyl)-5-ethyl ester: preparation of an intermediate to the dipeptidyl peptidase IV inhibitor Saxagliptin

An efficient biocatalytic method has been developed for the conversion of (5S)-4,5-dihydro-1H-pyrrole-1,5-dicarboxylic acid, 1-(1,1-dimethylethyl)-5-ethyl ester (1) into the corresponding amide (5S)-5-aminocarbonyl-4,5-dihydro-1H-pyrrole-1-carboxylic acid, 1-(1,1-dimethylethyl)ester (2), which is a critical intermediate in the synthesis of the dipeptidyl peptidase IV (DPP4) inhibitor Saxagliptin (3). Candida antartica lipase B mediates ammonolysis of the ester with ammonium carbamate as ammonia donor to yield up to 71% of the amide. The inclusion of Ascarite and calcium chloride as adsorbents for carbon dioxide and ethanol byproducts, respectively, increases the yield to 98%, thereby offering an efficient and practical alternative to chemical routes which yield 57-64%.     

小金梅草化学成分研究(英文)

从小金梅草乙醇提取物中分离得到了12个化合物,分别为3-O-β-D-槲皮素葡萄糖苷(1)、3-O-β-D-山柰酚葡萄糖苷(2)、5-O-β-D-芹菜素葡萄糖苷(3)、α-菠甾醇(4)、2,6-二甲氧基苯甲酸(5)、3-吲哚甲酸(6)、(2S,3R,4E,8E)-1-(β-D-吡喃葡萄糖苷)-N-[(R)-2’-羟基-二十碳酰基]-9-甲基-4,8-二烯-1,3-二醇-2-氨基-十八烷(7)、正三十二烷醇(8)、14,15-二十碳烯酸(9)、木腊酸(10)、β-谷甾醇(11)、胡萝卜苷(12)。以上化合物均为首次从该植物中得到。     

Substituted furans as potent lipoxygenase inhibitors: Synthesis,in vitro and molecular docking studies

A number of 2-methyl-4-(2-oxo-2-phenyl-ethyl)-5-phenyl-furan-3-carboxylic acid alkyl ester derivatives (3a–j) were synthesized and evaluated for their in vitro inhibitory activity on soybean lipoxygenase enzyme. Among the screened compounds, 5-(4-bromo-phenyl)-4-[2-(4-bromo-phenyl)-2-oxo-ethyl]-2-methyl-furan-3-carboxylic acid methyl ester (3g) has been found to exhibit potent inhibitory activity with IC₅₀12.8 μM using nordihydroguaiaretic acid (NDGA) as standard. Molecular modeling was employed for better understanding of the binding between compounds and soybean lipoxygenase enzyme. The predicted binding energy values correlated well with the observed in vitro data.     

6-Substituted 3,4-Dihydro-naphthalene-2-carboxylic Acids: Synthesis and Structure-Activity Studies in a Novel Class of Human 5α Reductase Inhibitors

Novel 3,4-dihydro-naphthalene-2-carboxylic acids were synthesized and evaluated for 5 α reductase inhibitory activity. This enzyme exists in two isoforms and is a pharmacological target for the treatment of benign prostatic hyperplasia, male pattern baldness and acne. In the present study non-steroidal compounds capable of mimicking the transition state of the steroidal substrates were prepared. The synthetic strategy for the preparation of compounds 1 - 6 consisted of triflation followed by subsequent Heck-type carboxylation or methoxy carbonylation for 6-phenyl-3,4-dihydro-naphthalen-2(1H)-one 1c. A Negishi-type coupling reaction between 6-(trifluoro-methanesulfonyloxy)-3,4-dihydro-naphthalene-2-carboxylic acid methyl ester 7b and various aryl bromides led, after further transformations, to 6-substituted 3,4-dihydro-naphthalene-2-carboxylic acids 7 - 15. In a similar way the corresponding naphthalene-2-carboxylic acids 16 and 17 were obtained. The DU 145 cell line and prostate homogenates served as enzyme sources for the human type 1 and type 2 isozymes, whereas ventral prostate was employed to evaluate rat isozyme inhibitory potency. The most active inhibitors identified in this study were 6-[4- (N, N -dicyclohexylaminocarbonyl)phenyl]-3,4-dihydro-naphthalene-2-carboxylic acid (3) (IC 50 =0.09 μM, rat type 1), 6-[3- (N, N -dicyclohexylaminocarbonyl)phenyl]-3,4-dihydro-naphthalene-2-carboxylic acid (13) (IC 50 =0.75 μM, human type 2; IC 50 =0.81 μM, human type 1) and 6-[4- (N, N -diisopropylamino-carbonyl)phenyl]naphthalene-2-carboxylic acid (16) (IC 50 =0.2 μM, human type 2). The latter compound was shown to deactivate the enzyme in an uncompetitive manner (Ki=90 nM; Km, Testosterone=0.8-1.0 μM) similar to the steroidal inhibitor Epristeride. Select inhibitors (13 and 16) were tested in vivo using testosterone propionate-treated, juvenile, orchiectomized SD-rats. None of the compounds was active at a dose of 25 mg/kg. This result might in part be ascribed to the relatively poor in vitro rat isozyme inhibitory potency.     

6-Substituted 3,4-dihydro-naphthalene-2-carboxylic acids: synthesis and structure-activity studies in a novel class of human 5alpha reductase inhibitors

Novel 3,4-dihydro-naphthalene-2-carboxylic acids were synthesized and evaluated for 5alpha reductase inhibitory activity. This enzyme exists in two isoforms and is a pharmacological target for the treatment of benign prostatic hyperplasia, male pattern baldness and acne. In the present study non-steroidal compounds capable of mimicking the transition state of the steroidal substrates were prepared. The synthetic strategy for the preparation of compounds 1-6 consisted of triflation followed by subsequent Heck-type carboxylation or methoxy carbonylation for 6-phenyl-3,4-dihydronaphthalen-2(1H)-one 1c. A Negishi-type coupling reaction between 6-(trifluoro-methanesulfonyloxy)-3,4-dihydro-naphthalene-2-carboxylic acid methyl ester 7b and various aryl bromides led, after further transformations, to 6-substituted 3,4-dihydro-naphthalene-2-carboxylic acids 7-15. In a similar way the corresponding naphthalene-2-carboxylic acids 16 and 17 were obtained. The DU 145 cell line and prostate homogenates served as enzyme sources for the human type 1 and type 2 isozymes, whereas ventral prostate was employed to evaluate rat isozyme inhibitory potency. The most active inhibitors identified in this study were 6-[4-(N,N-dicyclohexylaminocarbonyl)phenyl]-3,4-dihydro-naphthalene-2-carboxylic acid (3) (IC50 = 0.09 microM, rat type 1), 6-[3-(N,N-dicyclohexylaminocarbonyl)phenyl]-3,4-dihydro-naphthalene-2-carboxylic acid (13) (IC50 = 0.75 microM, human type 2; IC50 = 0.81 microM, human type 1) and 6-[4-(N,N-diisopropylamino-carbonyl)phenyl]naphthalene-2-carboxylic acid (16) (IC50 = 0.2 microM, human type 2). The latter compound was shown to deactivate the enzyme in an uncompetitive manner (Ki = 90 nM; Km, Testosterone = 0.8-1.0 microM) similar to the steroidal inhibitor Epristeride. Select inhibitors (13 and 16) were tested in vivo using testosterone propionate-treated, juvenile, orchiectomized SD-rats. None of the compounds was active at a dose of 25 mg/kg. This result might in part be ascribed to the relatively poor in vitro rat isozyme inhibitory potency.     

New metabolites from the alga-derived fungi Penicillium thomii Maire and Penicillium lividum Westling

A new meroterpenoid, austalide H acid ethyl ester (1), 5-(2′,4′-dihydroxy-6′-methylphenyl)-3-methylfuran-2-carboxylic acid (2), 5-(2′-hydroxy-6′-methylphenyl)-3-methylfuran-2-carboxylic acid (3) and 5-((6′-methyl-4′-oxo-3′,4′-dihydro-2H-pyran-2′-yl)methyl)-3-methylfuran-2-carboxylic acid (4), along with six known compounds, austalides H, J, K, and P (5–8), questin (9) and sulochrin (10) were isolated from the lipophilic extract of the alga-derived fungi Penicillium thomii KMM 4645 and Penicillium lividum KMM 4663. The structures of the isolated compounds were determined based on spectroscopic methods. The austalides showed significant inhibitory activity against endo-1,3-β-d-Glucanase from a crystalline stalk of the marine mollusk Pseudocardium sachalinensis.     

Methyl trisporate E. A sex pheromone in Phycomyces blakesleeanus

Combined mating type cultures of Phycomyces blakesleeanus accumulate 41 mg of trisporic acids/l of medium, of which 30% is trisporic acid E. The methyl ester of trisporic acid E exhibits the same zygophore -inducing activity in bioassays with P. blakesleeanus and Mucor mucedo as does the pheromone methyl trisporate C. The structure of methyl trisporate E is 1,5-dimethyl-2-hydroxyl-4-oxo-6-(2'-hydroxyl-6'- methylocta -5',7'-d ien-8'-yl) -5-cyclohexene-1-carboxylic acid methyl ester.     

Syntheses and evaluation of antioxidant activity of sydnonyl substituted thiazolidinone and thiazoline derivatives

3-Aryl-4-formylsydnone 4'-phenylthiosemicarbazones (3a-d) and 3-aryl-4-formylsydnone thiosemicarbazones (3e-h), which are precursors of 3-aryl-4-heterocyclic sydnones, are prepared by the condensation of 3-aryl-4-formylsydnones (1a-d) with 4'-phenylthiosemicarbazide (2a) and thiosemicarbazide (2b), respectively. The thiosemicarbazones 3 reacted with cyclic reagents such as ethyl chloroacetate (4a), ethyl 2-chloroacetoacetate (4b) and 2-bromoacetophenone (4c) to produce heterocyclic substituted sydnone derivatives 5-7 that possess 4-oxo-thiazolidine and thiazoline groups. The antioxidant activity of synthesized compounds 5a-7h was evaluated. Among these compounds, 4-methyl-2-[(3-arylsydnon-4-yl-methylene)hydrazono]-2,3-dihydro-thiazole-5-carboxylic acid ethyl ester (6e-h) and 4-phenyl-2-[(3-arylsydnon-4-yl-methylene)hydrazono]-2,3-dihydro-thiazoles (7e-h) exhibit the potent DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity, comparable to that of vitamin E.     

Partial isotope fractionation during high-performance liquid chromatography of deuterium-labelled internal standards in plant hormone analysis: A cautionary note

Deuterium-labelled indole-3-acetic acid, abscisic acid and phthalimido-1-aminocyclopropane-1-carboxylic acid were found to separate from the unlabelled compounds on reverse-phase high-performance liquid chromatography (HPLC). A similar separation was found for the methyl esters of these compounds on normal-phase HPLC. Such separations may lead to substantial errors when these compounds are used as internal standards for quantitation by gas chromatography-mass spectrometry/selective ion detection, unless the complete chromatographic peaks are collected.Abbreviations ABA abscisic acid - ACC 1-aminocyclopropane-1-carboxylic acid - IAA indole-3-acetic acid - GC-MS gas chromatography-mass spectrometry - HPLC high-performance liquid chromatography - Pht-ACC phthalimido-ACC - SIM selected ion monitoring     

Studies on Chrysanthemic Acid

Synthesis of (±)-trans-chrysanthemic acid from (±)-1′-hydroxydihydro-trans-chrysanthemic acid by the dehydration with p-toluene-sulfonic acid was attempted. However, the attempt was found to be unsuccessful giving a compound believed to be methyl methyl 2,6 dimethylhepta-3.6-diene-5-carboxylate upon dehydration.

A cleavage upon cyclopropane ring was confirmed by deriving the acid obtained by the hydrolysis of the above ester to already known 2,6-dimethyl-heptane-5-carboxylic acid.

Analogous mode of dehydration and cleavage upon the ester of (±)-2,2-dimethyl-3-trans-hydroxylbenzyl-cyclopropane-l-carboxylic acid was also observed to give 1-phenyl-4-methyl-penta-1,3-diene-3-carboxylic acid. On the other hand, (±)-trans-caronic acid being derived to (±)-1′-oxo-2′-hydroxy-dihydro-trans-chrysanthemic acid, the synthesis of (±)-trans-chrysanthemic acid from (±)-trans-caronic acid became possible using (±)-1′-oxo-2′-hydroxy-dihydro-trans-chrysanthemic acid as a relay substance.     

Chemiluminescent 10-methyl-acridinium-9-(N-sulphonylcarboxamide) salts. Synthesis and kinetics of light emission

10-Methyl-acridinium-9-(N-sulphonylcarboxamide) salts are prepared via acylation of sulphonamides with acridine-9-carboxylic acid chloride and subsequent N-alkylation with methyl triflate. Substituents on the sulphonamide component were varied to show the effect of steric and electronic factors on the kinetics of light output. The lifetime of the chemiluminescence light output ranged from 1 to 50 seconds for the 15 compounds reported. The long-term stability of the new compounds was superior to the phenyl ester counterparts.     

The discovery and structure-activity relationships of indole-based inhibitors of glutamate carboxypeptidase II

A series of N-substituted 3-(2-mercaptoethyl)-1H-indole-2-carboxylic acids were synthesized as inhibitors of glutamate carboxypeptidase II (GCPII). Those containing carboxybenzyl or carboxyphenyl groups at the N-position exhibited potent inhibitory activity against GCPII. These indole-based compounds represent the first example of achiral GCPII inhibitors and demonstrate greater tolerance of the GCPII active site for ligands with significant structural difference from the endogenous substrate, N-acetyl-aspartylglutamate.     

Anaerobic degradation of hydroaromatic compounds by newly isolated fermenting bacteria

Aerobic organisms degrade hydroaromatic compounds via the hydroaromatic pathway yielding protocatechuic acid which is further metabolized by oxygenase-mediated ring fission in the 3-oxoadipate pathway. No information exists on anaerobic degradation of hydroaromatics so far. We enriched and isolated from various sources of anoxic sediments several strains of rapidly growing gram-negative bacteria fermenting quinic (1,3,4,5-tetrahydroxy-cyclohexane-1-carboxylic acid) and shikimic acid (3,4,5-trihydroxy-1-cyclohexene-1-carboxylic acid) in the absence of external electron acceptors. Quinic and shikimic acid were the only ones utilized of more than 30 substrates tested. The marine isolates formed acetate, butyrate, and H₂, whereas all freshwater strains formed acetate and propionate as typical fermentation products. Aromatic intermediates were not involved in this degradation. Characterization of the isolates, fermentation balances for both hydroaromatic compounds, and enzyme activities involved in one degradation pathway are presented.Abbreviations BV benzyl viologen (1,1-dibenzyl-4,4-bipyridinium dichloride) - CoA coenzyme A - CTAB cetyltrimethylammonium bronide - DCPIP 2,4-dichlorophenolindophenol - DTT 1,4-dithiotheriol - MV methyl viologen (1,1-dimethyl-4,4-bipyridinium dichloride) - Tricine N-[tris-(hydroxymethyl)-methyl]-glycine - Tris tris-(hydroxymethyl)-aminomethane     

New Withanolides from Nicandra physaloides (Solanaceae)

Two new withanolides, named nicandrenone methyl ether (1), 26S nicandrenone methyl ether (2), together with ten known compounds were isolated from the whole plants of Nicandra physaloides (Solanaceae). Their chemical structures were deduced on the basis of spectroscopic analysis. Ten known compounds were identified as nicandrenone (3), Nic-7 (4), nicaphysalin E (5), pinosylvin monomethyl ether (6), 2S-pinocembrin (7), (1S, 2R)-1, 2-bis (4-hydroxy-3-methoxyphenyl)-1, 3-propanediol (8), vanillin (9), indole-3-carboxylic acid (10), vanillic acid (11) and drummondol (12).