Beta(3)-adrenoceptor agonists for the treatment of frequent urination and urinary incontinence: 2-[4-(2-[[(1S,2R)-2-hydroxy-2-(4-hydroxyphenyl)-1-methylethyl]amino]ethyl)phenoxy]-2-methylpropionic acid.

In a search for novel analogues of β₃-adrenoceptor (AR) agonists relaxing the bladder for treatment of urinary dysfunction, 2-[4-(2-{[(1S,2R)-2-hydroxy-2-(4-hydroxyphenyl)-1-methylethyl]amino}ethyl)phenoxy]-2-methylpropionic acids (1a–e), into which a fibrate-like structure had been incorporated, were synthesised. Compound 1a was found to be a selective β₃-AR agonist in functional assays using the ferret detrusor (β₃-AR), rat uterus (β₂-AR), and rat atrium (β₁-AR); β₃: EC₅₀=7.8 nM, β₂: IC₅₀=7,300 nM, β₁: EC₂₀=23,000 nM. The introduction of a chlorine atom or methyl substituent at the ortho-position on the phenyl ring of 1a further improved β₃-AR selectivity. In an in vivo study, 1a lowered intrabladder pressure (ED₅₀=31 μg/kg) in rats, without increasing heart rate, in keeping with the in vitro results. Consequently, it is proposed that 1a and its analogues (1b–e), possess β₃-AR agonistic activity in the absence of undesirable β₁- or β₂-AR mediated actions, and may be useful for clinical treatment and pharmacological studies.     

Molecular pharmacology of the AMPA agonist, (S)-2-amino-3-(3-hydroxy-5-phenyl-4-isoxazolyl)propionic acid [(S)-APPA] and the AMPA antagonist, (R)-APPA

The heterocyclic analogue of (S)-glutamic acid, (S)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid [(S)-AMPA] is a potent and selective AMPA receptor agonist, whereas the enantiomeric compound, (R)-AMPA, is virtually inactive. We have previously characterized (RS)-2-amino-3-(3-hydroxy-5-phenyl-4-isoxazolyl)propionic acid [(RS)-APPA] as a partial AMPA receptor agonist showing about 60% of the efficacy of (RS)-AMPA. This partial agonism produced by (RS)-APPA is, however, only apparent, since resolution of (RS)-APPA has now been shown to provide the full AMPA receptor agonist, (S)-APPA, whereas (R)-APPA is a acid (non-NMDA) receptor antagonist showing preferential AMPA blocking effects. In agreement with classical theories for competitive interaction between agonists and antagonists, the efficacy of depolarizations produced by (S)-APPA in the rat cortical wedge preparation was shown to be progressively reduced with increasing molar ratios of (R)-APPA/(S)-APPA. These compounds and the competitive antagonists (RS)-2-amino-3-(3-carboxymethoxy-5-methyl-4-isoxazolyl)propionic acid [(RS)-AMOA], 6-cyano-7-nitroquinoxalin-2,3-dione (CNQX) and 6-nitro-7-sulfamoylbenzo(f)quinoxalin-2,3-dione (NBQX) were also tested in [³H]AMPA and [³H]CNQX binding systems, the latter ligand being used in the absence or presence of thiocyanate ions. On the basis of these studies it is suggested that (RS)-AMPA and the AMPA agonist (S)-APPA interact with a high-affinity receptor conformation, whereas the competitive antagonists (RS)-AMOA and (R)-APPA, derived from these agonists, preferentially bind to a low-affinity AMPA receptor conformation. The competitive antagonists, CNQX and NBQX which are structurally unrelated to (RS)-AMPA or (RS)-APPA, do not seem to discriminate between these two AMPA receptor conformations. The modified [³H]CNQX binding assay containing thiocyanate ions was shown to provide receptor affinity data for AMPA receptor agonists as well as antagonists, which correlate with the potencies of these compounds in the cortical wedge preparation. Using autoradiographic techniques, (S)- and (R)-APPA were shown to exhibit significantly different absolute potencies as inhibitors of [³H]AMPA binding in a number of regions of the rat brain.     

(3S,4S,5R)-3,4,5-trihydroxy-1-cyclohexene-carboxylic acid from Sequoiadendron giganteum

From the leafy lateral branchlets of Sequoiadendron giganteum, (3S,4S,5R)-3,4,5-trihydroxy-1-cyclohexenecarboxylic acid has been isolated. Its structure was proved spectroscopically.     

Stereoselective total synthesis of a potent natural antifungal compound (6S)-5,6,dihydro-6-[(2R)-2-hydroxy-6-phenyl hexyl]-2H-pyran-2-one

A practical stereoselective synthesis of (6S)-5,6,dihydro-6-[(2R)-2-hydroxy-6-phenyl hexyl]-2H-pyran-2-one (1), a potent natural antifungal compound, is described. The sequence involves diastereoselective iodine-induced electrophilic cyclization, epoxide ring opening with a vinyl Grignard reagent and ring closing metathesis (RCM) as the key steps.     

Design, synthesis and evaluation of racemic 1-(4-hydroxyphenyl)-2-[3-(substituted phenoxy)-2-hydroxy-1-propyl]amino-1-propanol hydrochlorides as novel uterine relaxants

Novel 1-(4-hydroxyphenyl)-2-[3-(substituted phenoxy)-2-hydroxy-1-propyl]amino-1-propanol hydrochlorides were designed based on the pharmacophore for potent uterine relaxant activity and by utilizing the principles of structural hybridization. The designed molecules were synthesized as racemates by a novel route and were evaluated for uterine relaxant activity in vitro on isolated rat uterus and in vivo in pregnant rats. Their cAMP-releasing potential was studied using rat uterus tissue homogenates by the cAMP [(3)H] assay, and cardiac stimulant potential was evaluated on isolated guinea pig right atrium. All compounds exhibited potent uterine relaxant activity in vitro and produced a significant delay in the onset of labour in pregnant rats; their cAMP-releasing potential was slightly less, while their cardiac stimulant potential was insignificant as compared to isoxsuprine hydrochloride.     

Biotransformation of 3-substituted methyl (R,S)-4-cyanobutanoates with nitrile- and amide-converting biocatalysts

Whole cells of Rhodococcus equi A4 chemoselectively hydrolyzed methyl (R,S)-3-benzoyloxy-4-cyanobutanoate and methyl (R,S)-3-benzyloxy-4-cyanobutanoate into monomethyl (R,S)-3-benzoyloxyglutarate and monomethyl (R,S)-3-benzyloxyglutarate, respectively. The intermediates of the biotransformations were the corresponding amides which were also obtained using the purified nitrile hydratase from the same microorganism.     

Synthesis and evaluation of [(1R)-1-amino-2-(2,5-difluorophenyl)ethyl]cyclohexanes and 4-[(1R)-1-amino-2-(2,5-difluorophenyl)ethyl]piperidines as DPP-4 inhibitors

A series of 4-amino cyclohexanes and 4-substituted piperidines were prepared and evaluated for inhibition of DPP-4. Analog 20q displayed both good DPP-4 potency and selectivity against other proteases, while derivative 20k displayed long half life and modest oral bioavailability in rat. The most potent analog, 3-(5-aminocarbonylpyridyl piperidine 53j, displayed excellent DPP-4 activity with good selectivity versus other proline enzymes.     

Determination of (R)- and (S)-Disophyramide in human plasma using a chiral α1-acid glycoprotein column

The direct resolution and quantitation of (R)- and (S)-disopyramide, isolated from human plasma, was accomplished using a chiral α₁-acid glycoprotein column. A LiChrosorb RP-2 column (50 × 3.0 mm I.D.) was used as a precolumn. Phosphate buffer, pH 6.20, containing 2-propanol and N,N-dimethyloctylamine was used as mobile phase, expressed as the relative standard deviation, was 1.8% and 3.3% for (R)- and (S)-disopyramide, respectively, at a drug level of 0.5 μg/ml. In two subjects who received a single capsule of racemic disopyramide (150 mg), the plasma levels of the (R) isomer were about half those of the (S) isomer. The half-lives of (R)- and (S)-disopyramide were similar.     

Determination of 1-β- -arabinofuranosylcytosine and 1-β- -arabinofuranosyluracil in human plasma by high-performance liquid chromatography

A method is described for the determination of 1-β- -arabinofuranosylcytosine (Ara-C) and its metabolite 1-β- -arabinofuranosyluracil (Ara-U) in human plasma. After deproteinization of the plasma sample, separation is performed by reversed-phase liquid chromatography. For Ara-C concentrations exceeding 0.05 mg/l and for Ara-U concentrations exceeding 1 mg/l, injection volumes of 100 μl are applied. For lower concentrations an injection volume of 500 μl is used. Ara-C is detected at 280 nm with a lowest detection limit of 0.002 mg/l in plasma. Ara-U is detected at 264 nm with a lowest detection limit varying from 0.01 to 0.1 mg/l in plasma. This variation is caused by an unknown substance with the same elution properties as Ara-U and which appears to be present in plasma in variable concentrations. The coefficient of variation of the whole procedure is about 6% for Ara-C concentrations above 0.005 mg/l and for Ara-U concentrations above 0.1 mg/l. For lower concentrations the coefficient of variation is about 14%.     

Preparation of (2S, 3R)-methyl-3-phenylglycidate using whole cells of Pseudomonas putida

Preparation of (2S, 3R)-methyl 3-phenylglycidate via enantioselective hydrolysis of racemic phenylglycidate was carried out using whole cells of Pseudomonas putida. Under optimal conditions (2S, 3R)-methyl-3-phenylglycidate could be got with ee value 99 and 48% chemical yield.     

Metabolic Fate of [3H]1-β-d-Arabinofuranosyl-5-[(E)-2-bromovinyl]uracil in Herpes Simplex Virus Type 1-Infected Cells

The metabolic fate of 1-β-d -arabinofuranosyl-5-[(E)-2-bromovinyl]uracil (BV-araU) in herpes simplex virus type 1-infected cells was studied using tritium-labeled BV-araU. [³H]BV-araU was selectively taken-up by infected cells. Approximately 10% of the total uptake of [³H]BV-araU was recovered from the acid-insoluble fraction at any time post-infection. Both cellular uptake of [³H]BV-araU and its incorporation into the acid-insoluble fraction increased with increasing incubation time through 8 hr post-infection. Uptake of [³H]BV-araU and its incorporation into the acid-insoluble fraction also increased proportionally to the duration of exposure to [³H]BV-araU. An alkaline sucrose gradient sedimentation analysis revealed that the radioactive DNA obtained from cells pulse-labeled with [³H]BV-araU were small DNA fragments which remained at the top following a chasing period in isotope-free medium, whereas that pulse-labeled with [³H]thymidine was chased to a fraction of high molecular weight DNA. Nuclease P₁ digestion reduced 99% of the [³H]BV-araU-labeled DNA extracted from infected cells to a low molecular weight. Following digestion of [³H]BV-araU-labeled DNA with micrococcal nuclease and spleen exonuclease, all of the radioactivity was recovered as [³H]BV-araU 3′-monophosphate. Thus, BV-araU strongly inhibits the elongation of viral DNA strands as demonstrated by the alkaline sucrose gradient sedimentation analysis, whereas at least a portion of the [³H]BV-araU is incorporated inside viral DNA strands in infected cells.     

Synthesis and in vitro antitubercular activity of some 1-[(4-sub)phenyl]-3-(4-{1-[(pyridine-4-carbonyl)hydrazono]ethyl}phenyl)thiourea

Various isonicotinyl hydrazones were prepared by reacting isonicotinyl hydrazide [INH] with 1-(4-acetylphenyl)-3-[(4-sub)phenyl]thiourea and were tested for their antimycobacterial activity in vitro against Mycobacterium tuberculosis H37Rv and INH-resistant M. tuberculosis using the BACTEC 460 radiometric system. Among the synthesized compounds, 1-(4-fluorophenyl)-3-(4-{1-[(pyridine-4-carbonyl)-hydrazono]ethyl}phenyl)thiourea (4d) was found to be the most potent compound with a minimum inhibitory concentration of 0.49 microM against M. tuberculosis H37Rv and INH-resistant M. tuberculosis. When compared to INH, 4d was found to be 3 and 185 times more active against M. tuberculosis H37Rv and INH-resistant M. tuberculosis, respectively, with a selectivity index of >300.     

Assessing the absolute configuration of (7S,8R)-(−)-epoxyjasmone

The absolute configuration of cis-epoxyjasmone (−)-2, isolated from Trichosporum cutaneum CCT 1903 whole cells, has been unambiguously established as (7S,8R), [α]_D²⁰ −29.0° (c 1.3, CHCl₃), by a new two step method, using a regioselective epoxide opening as the key step followed by Mosher acid derivatization.     

Synthesis of 17 beta-[(1S)-1-hydroxy-2-propynyl]- and 17 beta-[(1R)-1-hydroxy-2-propynyl]androst-4-en-3-one. Potential suicide substrates of 20 alpha- and 20 beta-hydroxysteroid dehydrogenases.

The title compounds have been synthesized for evaluation as potential suicide substrates of 20 alpha- and 20 beta-hydroxysteroid dehydrogenases. Synthesis was achieved by the following route. Acetylenedimagnesium bromide was reacted with 3 beta-hydroxyandrost-4-ene-17 beta-carboxaldehyde to give 17 beta-[(1R,S)-1-hydroxy-2-propynyl] androst-4-en-3 beta-ol. Separation of the R and S diols was achieved by HPLC (high pressure liquid chromatography). Selective oxidation of the 3 beta-hydroxyl group with Jones reagent at 0 degrees gave the title compounds. Further oxidation with Jones reagent converted each acetylenic alcohol to the conjugated acetylenic ketone, 17 beta-(1-oxo-2-propynyl)androst-4-en-3-one.     

Novel antioxidant agents deriving from molecular combinations of vitamins C and E analogues: 3,4-dihydroxy-5(R)-[2(R,S)-(6-hydroxy-2,5,7,8-tetramethyl-chroman-2(R,S)-yl-methyl)-[1,3]dioxolan-4(S)-yl]-5H-furan-2-one and 3-O-octadecyl derivatives

Molecular combinations of two antioxidants (i.e., ascorbic acid and the pharmacophore of α-tocopherol), namely the 2,3-dihydroxy-2,3-enono-1,4-lactone and the chromane residues, have been designed and tested for their radical scavenging activities. When evaluated for their capability to inhibit malondialdehyde (MDA) production in rat liver microsomal membranes, the 3,4-dihydroxy-5R-2(R,S)-(6-hydroxy-2,5,7,8-tetramethylchroman-2(R,S)yl-methyl)-1,3]dioxolan-4S-yl]-5H-furan-2-one (11a–d), exhibited an interesting activity. In particular the 5R,2R,2R,4S and 5R,2R,2S,4S isomers (11c,d) displayed a potent antioxidant effect compared to the respective synthetic α-tocopherol analogue (5) and natural α-tocopherol or ascorbic acid, used alone or in combination. Moreover, the mixture of stereoisomers 11a–d also proved to be effective in preventing damage induced by reperfusion on isolated rabbit heart, in particular at the higher concentration of 300 μM. In view of these results our study represents a new approach to potential therapeutic agents for applications in pathological events in which a free radical damage is involved. Design, synthesis and preliminary biological activity are discussed.     

Chemoenzymatic synthesis of (1S,2R)-1-amino-2-indanol, a key intermediate of HIV protease inhibitor, indinavir

The synthesis of (1S,2R)-1-amino-2-indanol, a key component of HIV protease inhibitor is accomplished in four steps starting from indanone efficiently and with high levels of diastereo- and enantioselectivity. The starting material is converted into 2-acetoxy-1-indanone involving Manganese (III) acetate oxidation . The 2-acetoxyketone is hydrolyzed to 2-hydroxy-1-indanone enantioselectively using Rhizopus oryzae. Selective reduction of 2-hydroxyoxime derivative, derived from the 2-hydroxyketone, gives the amino alcohol up to 98% diastereo- and enantioselectivity.     

Evidence that enzymatic conversion of N-[1(R,S)-carboxy-3-phenylpropyl]-Ala-Ala-Phe-p-aminobenzoate, a specific inhibitor of endopeptidase 24.15, to N-[1 (R,S)-carboxy-3-phenylpropyl]-Ala-Ala is necessary for inhibition of angiotensin converting enzyme

N-[1 (R,S)-Carboxy-3-phenylpropyl]-Ala-Ala-Phe-p-aminobenzoate (cFP-AAF-pAB) is a potent, substrate-related, specific inhibitor of endopeptidase 24.15, an enzyme involved in the metabolism of bioactive peptides including bradykinin, neurotensin, and proenkephalin, and prodynorphin-derived enkephalin precursors. The observation that this inhibitor causes a pronounced decrease in blood pressure after intravenous infusion into normotensive rats posed the question of the mechanism of this hypotensive response. It was suggested previously that cFP-AAF-pAB is an inhibitor of angiotensin converting enzyme (ACE) and that this function can account for the hypotensive response to the inhibitor. We present here evidence that cFP-AAF-pAB has no intrinsic ACE-inhibitory activity. The previously observed inhibition is shown to be dependent on cleavage of the Ala-Phe bond in the inhibitor by endopeptidase 24.11 (enkephalinase, EC 3.4.24.11), a contaminant of some ACE preparations.     

X-ray crystal, and molecular, structure of 1,2,3-tri-O-acetyl-4,5-dideoxy-4-C-[(R)-phenylphosphinyl]-α- -lyxofuranose: The first x-ray analysis of a pentofuranose having phosphorus in the hemiacetal ring

X-Ray crystallographic analysis was performed on the compound to which had been assigned the structure of 1,2,3-tri-O-acetyl-4,5-dideoxy-4-C-[(R)-phenylphosphinyl]-α- -lyxofuranose. The results showed that the compound has the proposed configuration, the five-membered ring is in the E₃ conformation, with a tendency towards the ³T₂ form, the substituents at P-5 and C-5 are linked bisectionally, the acetoxyl group at C-2 and the methyl group at C-4 are linked quasiequatorially, and the acetoxyl group at C-3 is linked axially.     

Optimization of (R,S)-1-phenylethanol kinetic resolution over Candida antarctica lipase B in ionic liquids

The kinetic resolution of racemates constitutes one major route to manufacture optically pure compounds. The enzymatic kinetic resolution of (R,S)-1-phenylethanol over Candida antarctica lipase B (CALB) by using vinyl acetate as the acyl donor in the acylation reaction was chosen as model reaction. A systematic screening and optimization of the reaction parameters, such as enzyme, ionic liquid and substrates concentrations with respect to the final product concentration, were performed. The enantioselectivity of immobilized CALB commercial preparation, Novozym 435, was assayed in several ionic liquids as reaction media. In particular, three different ionic liquids: (i) 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF₆], (ii) 1-butyl-3-methylimidazolium tetrafluoroborate [bmim][BF₄] and (iii) 1-ethyl-3-methylimidazolium triflimide [emim][NTf₂] were tested. At 6.6% (w/w) of Novozym 435, dispersed in 9.520 M of [bmim][PF₆] at 313.15 K, using an equimolar ratio of vinyl acetate/(R,S)-1-phenylethanol after 3 h of bioconversion, the highest possible conversion (50%) was reached with enantiomeric excess for substrate higher than 99%.