Regioselective sulfonylation at O-2 of cyclomaltoheptaose with 1-(p-tolylsulfonyl)-(1H)-1,2,4-triazole

2(I)-O-p-Tolylsulfonylcyclomaltoheptaose was obtained in 42% yield by reaction of 1-(p-tolylsulfonyl)-(1H)-1,2,4-triazole on NaH-deprotonated cyclomaltoheptaose in DMF and further converted into the corresponding mono-2(I),3(I)-manno-epoxide.     

Discovery of a novel sub-class of ROMK channel inhibitors typified by 5-(2-(4-(2-(4-(1H-Tetrazol-1-yl)phenyl)acetyl)piperazin-1-yl)ethyl)isobenzofuran-1(3H)-one

A sub-class of distinct small molecule ROMK inhibitors were developed from the original lead 1. Medicinal chemistry endeavors led to novel ROMK inhibitors with good ROMK functional potency and improved hERG selectivity. Two of the described ROMK inhibitors were characterized for the first in vivo proof-of-concept biology studies, and results from an acute rat diuresis model confirmed the hypothesis that ROMK inhibitors represent new mechanism diuretic and natriuretic agents.     

5-{2-[4-(2-methyl-5-quinolinyl)-1-piperazinyl]ethyl}-2(1H)-quinolinones and 3,4-dihydro-2(1H)-quinolinones: dual-acting 5-HT1 receptor antagonists and serotonin reuptake inhibitors. Part 3

5-{2-[4-(2-Methyl-5-quinolinyl)-1-piperazinyl]ethyl}-2(1H)-quinolinones and 3,4-dihydro-2(1H)-quinolinones have been identified with different combinations of 5-HT(1) autoreceptor antagonist and hSerT potencies and excellent rat PK profiles. The availability of tool compounds with a range of profiles at targets known to play a key role in the control of synaptic 5-HT levels will allow exploration of different pharmacological profiles in a range of animal behavioral and disease models.     

Antioxidant activity and low toxicity of (E)-1-(1-(methylthio)-1-(selenopheny) hept-1-en-2-yl) pyrrolidin-2-one

The aim of the present study was to evaluate the potential pharmacological and toxicological properties of (E)-1-(1-(methylthio)-1-(selenopheny) hept-1-en-2-yl) pyrrolidin-2-one (compound 1), an organoselenium compound. In vitro experiments showed that compound 1 presented a reduction in the lipid peroxidation induced by Fe2? in thiobarbituric acid-reactive species (TBARS) production, and in the generation of reactive species caused by Fe2?/malonate in DCFH-DA oxidation. The high dose (500 mg/kg) induced an increase on ALT but not on AST activity. Hepatic, but not cerebral, δ-ALA-D activity from mice treated with 500 mg/kg presented a significant inhibition. Brain catalase activity was significantly inhibited by 100 mg/kg whereas hepatic catalase activity showed a significant increase at all doses. Hepatic lipid peroxidation was diminished only at lowest dose (100 mg/kg) whereas for brain tissue, all doses induced a significant reduction in TBARS levels. Brain and liver ascorbic acid contents were increased only at highest dose of compound 1. Urea and creatinine levels were not significantly altered by treatments. This is a promising compound with antioxidant activity and low toxicity, suggesting the potential beneficial activity of compound 1 against oxidative damage in many parameters studied in rats and mice.     

[18F](R)-5-chloro-1-(1-cyclopropyl-2-methoxyethyl)-3-(4-(2-fluoroethoxy)-2,5-dimethyl phenylamino)pyrazin-2(1H)-one: Introduction of N3-phenylpyrazinones as potential CRF-R1 PET imaging agents

Based on a favorable balance between CRF-R1 affinity, lipophilicity and metabolic stability, compound 10 was evaluated for potential development as PET radioligand. Compound [¹⁸F]10 was prepared with high radiochemical purity and showed promising binding properties in rat brain imaging experiments.     

Synthesis of l-(4-2H)erythrose,l-)1-13C, 5-2H)arabinose and l-(2-13C, 5-2H)arabinose and identification of the intermediates by 2H and 13C-N.M.R. spectroscopy

l-(1-¹³C, 5-²H)Arabinose (6D) and l-(2-¹³C, 5-²H)arabinose (8D) have been synthesized by degradation of 2,3-O-isopropylidene-α-l-rhamnofuranose (2) to l-(4-²H)erythrose (5β,5αD), with subsequent chain elongation to 6D plus l-(1-¹³C, 5-²H)ribose (7D), the latter being converted into 8D. Intermediates were identified by complete assignment of the ¹³C chemical shifts employing carbon-carbon and carbon-deuterium coupling constants, deuteration shifts, differential isotope-shifts, and deuterium spectra. The anomeric carbon atoms of 2 and 2,3-O-isopropylidene-l-(1-²H) erythrose (4D) gave only single ¹³C resonances, suggesting that these two compounds exists in only one major anomeric configuration, clarifying previously reported work. The synthesis of 2,3-O-isopropylidene-l-(1-²H)rhmanitol (3D) facilitated the assignment of the signals in the ¹³C spectra of the nondeuterated analog. Specific deuterium-enrichment and the observed carbon-deuterium coupling (¹J_C,D ∼22 Hz) not only served to identify the deuterated carbon atom unambiguously in 3 but also permitted assignment of closely spaced resonances. The deuterium spectrum of 2,3-O-isopropylidene-l-(1-²H)erythrofuranose (4D) showed only a single resonance, indicating preponderance of one anomer, in accord with the observation of a single C-1 resonance in the ¹³C spectrum.     

Improved and efficient synthesis of 1alpha-hydroxy-[6-(2)H] and 1alpha-hydroxy-[6,19,19-(2)H]vitamin D3 derivatives.

Improved and efficient procedures for deuterium-labeling at the 6,19,19 positions of 1alpha-hydroxyvitamin D3 derivatives via its sulfur dioxide-adduct by using a base-catalyzed H-D exchange reaction are described. Application of the known procedure using tBuOK/DMF-D2O, which is effective for labeling vitamin D3 derivatives, to 1alpha-hydroxy compounds gave only poor results because of isomerization and decomposition. We found that this procedure is improved by the use of iPrONa/iPrOD. During this study, we also found that the 6-monodeuterated product was selectively obtained when MeONa/CD3OD was employed instead of iPrONa/iPrOD. On the other hand, simple addition of 1,3-dimethyl-2-imidazolidinone as a co-solvent to the above conditions was effective for 1alpha,25-dihydroxy compounds. These improved procedures were successfully applied to the synthesis of 1alpha-hydroxy-[6,19,19-(2)H]vitamin D3 derivatives 4 and 1alpha-hydroxy-[6-(2)H]vitamin D3 derivatives 6 from the corresponding 1alpha-hydroxyvitamin D3 derivatives 1 via its sulfur dioxide-adducts 2, 3 and 5 in good over-all yield with high deuterium incorporation.     

Discovery of (-)-6-[2-[4-(3-fluorophenyl)-4-hydroxy-1-piperidinyl]-1-hydroxyethyl]-3,4-dihydro-2(1H)-quinolinone--a potent NR2B-selective N-methyl D-aspartate (NMDA) antagonist for the treatment of pain

(-)-6-[2-[4-(3-Fluorophenyl)-4-hydroxy-1-piperidinyl]-1-hydroxyethyl]-3,4-dihydro-2(1H)-quinolinone was identified as an orally active NR2B-subunit selective N-methyl-d-aspartate (NMDA) receptor antagonist. It has very high selectivity for NR2B subunits containing NMDA receptors versus the HERG-channel inhibition (therapeutic index=4200 vs NR2B binding IC(50)). This compound has improved pharmacokinetic properties compared to the prototype CP-101,606.     

Prostaglandin H2 (PGH2) accelerates formation of amyloid beta1-42 oligomers

Epidemiologic evidence implicates cyclooxygenase activity in the pathogenesis of Alzheimer's disease, in which amyloid plaques have been found to contain increased levels of dimers and higher multimers of the amyloid beta peptide. The product of the oxygenation of arachidonic acid by the cyclooxygenases, prostaglandin H2 (PGH2), rearranges non-enzymatically to several prostaglandins, including the highly reactive gamma-keto aldehydes, levuglandins E2 and D2. We demonstrate that PGH2 markedly accelerates the formation of dimers and higher oligomers of amyloid beta1-42. This is associated with the formation of levuglandin adducts of the peptide. These findings provide the molecular basis for a hypothesis linking cyclooxygenase activity to the formation of oligomers of amyloid beta.     

4-(1H-indazol-5-yl)-6-phenylpyrimidin-2(1H)-one analogs as potent CDC7 inhibitors

A series of 4-(4-hydroxyphenyl)-6-phenylpyrimidin-2(1H)-ones were identified by HTS as inhibitors of CDC7. Molecular modeling and medicinal chemistry techniques were employed to explore the SAR for this series with a focus on removing potential metabolic liabilities and improving cellular potency.     

A comparative 1H NMR study of mouse alpha(1-53) and beta(2-53) epidermal growth factors

The three-dimensional structure of the mouse epidermal growth factor (EGF) in solution was studied by comparison of the 1H NMR spectra of alpha EGF (1-53) and beta EGF (2-53, des-asparaginyl 1 form). Using pH dependence of chemical shifts and a two-dimensional difference spectrum, the effect of the N-terminal deletion was investigated based on the complete assignment of the proton resonances. The affected residues were all found to be located exactly in the triple-stranded, beta-sheet core in the N-terminal domain of the EGF molecule.     

Stereoselective synthesis of chirally deuterated (S)-D-(6-(2)H(1))glucose

Chirally deuterated (S)-D-(6-(2)H(1))glucose has been prepared in good overall yield from d-(6,6'-(2)H(2))glucose by a short, five-step synthesis from D-(6,6-(2)H(2))glucose utilizing (R)-(+)-Alpine-Borane [(R)-9-[(6,6-dimethylbicyclo[3.1.1]hept-2-yl)methyl]-9-borabicyclo[3.3.1]nonane]. Suitably protected methyl 2,3,4-tri-O-benzyl-D-(6,6-(2)H(2))glucopyranoside was prepared and the deuterated O-6 primary alcohol was oxidized to an aldehyde by Swern oxidation. Stereoselective reduction with nondeuterated (R)-(+)-Alpine-Borane gave methyl 2,3,4-tri-O-benzyl-(6S)-D-(6-(2)H(1))glucopyranoside, which was deprotected under standard conditions to afford the title compound. The key stereoselective reduction step was achieved in 90% yield. The preparation uses economical, commercially available starting materials and will be useful for elucidating biosynthetic mechanisms.     

Substituted 3-(2-benzoxazyl)-benzimidazol-2-(1H)-ones: a new class of GABA(A) brain receptor ligands

A novel class of potent benzodiazepine receptor (BZR) ligands has been designed and synthesized aided by molecular modeling of known benzodiazepine ligands such as CGS-8216 and the use of known pharmacophore models.     

Enzymatic and chemical preparation of 5-amino-4-chloro-2-(2,3-dihydroxyphen-1-yl)-3(2H)-pyridazinone

A hypothetical intermediate of the microbial degradation of pyrazon, 5-amino-4-chloro-2(2,3-dihydroxyphen-1-yl)-3(2H)-pyridazinone, was prepared by enzymatic and chemical treatment of 5-amino-4-chloro-2(2,3-dihydroxy-cyclohexa-4,6-dien-1-yl)-pyridazinone. The properties of the metabolite are described.     

2(S)-(Cycloalk-1-enecarbonyl)-1-(4-phenyl-butanoyl)pyrrolidines and 2(S)-(aroyl)-1-(4-phenylbutanoyl)pyrrolidines as prolyl oligopeptidase inhibitors

In order to replace the P2-P1 amide group, different 1-cycloalkenyls and 2-aryls were studied in the place of the P1 pyrrolidine group of a 4-phenylbutanoyl-L-Pro-pyrrolidine structure, which is a well-known prolyl oligopeptidase inhibitor SUAM-1221. The 1-cyclopentenyl and the 2-thienyl groups gave novel compounds, which were equipotent with the corresponding pyrrolidine-analog SUAM-1221. It was shown that the P2-P1 amide group of POP inhibitors can be replaced by an alpha,beta-unsaturated carbonyl group or the aryl conjugated carbonyl group.     

Catalase enrichment using recombinant adenovirus protects alphaTN4-1 cells from H(2)O(2)

Since oxidative stress has been implicated in the development of numerous diseases including cataract, this laboratory has created and investigated the stress response of murine immortal lens epithelial cell lines (alphaTN4-1) conditioned to withstand lethal peroxide concentrations. Two of a group of antioxidative defense (AOD) enzymes found in such cells to have markedly enhanced activity are catalase (CAT) and GSH S-transferase alpha2 (GST). In order to determine if enrichment of one or both of these AODs is sufficient to protect alphaTN4-1 cells from lethal H(2)O(2) levels, these cells were infected with adenovirus vectors capable of expressing these AODs at a high level. With this system, gene enrichment and increased enzyme activity were observed with both CAT and GST vectors. The percentage of cells infected ranged from about 50 to 90% depending on the multiplicity of infection (MOI). CAT but not GST protected the cells from H(2)O(2) stress. The CAT activity was increased from 15- to 150-fold and even at the lower levels protected the cells from H(2)O(2) concentrations as high as 200 microM or more (H(2)O(2) levels which rapidly kill non-enriched cells). Even when only about 50% of the cell population is infected as judged by GFP infection, the entire population appeared to be protected based on cell viability. The CAT enrichment appears to protect other intracellular defense systems such as GSH from being depleted in contrast to non-enriched cell populations where GSH is rapidly exhausted. The overall results suggest that enriching the cellular CAT gene level with an appropriate recombinant viral vector may be sufficient to protect in vivo systems from peroxide stress.     

Solution conformation of asparagine-linked oligosaccharides: alpha(1-2)-, alpha(1-3)-, beta(1-2)-, and beta(1-4)-linked units

The solution conformation is presented for representatives of each of the major classes of asparaginyl oligosaccharides. In this report the conformation of alpha(1-3)-, alpha(1-2)-, beta(1-2)-, and beta(1-4)-linked units is described. The conformational properties of these glycopeptides were determined by high-resolution 1H nuclear magnetic resonance in conjunction with potential energy calculations. The NMR parameters that were used in this analysis were chemical shifts and nuclear Overhauser enhancements. Potential energy calculations were used to evaluate the preferred conformers available for the different linkages in glycopeptides and to draw conclusions about the behavior in solution of these molecules. It was found that the linkage conformation of the Man alpha 1-3 residues was not affected by substitution either at the 2-position by alpha Man or beta GlcNAc or at the 4-position by beta GlcNAc or by the presence of a bisecting GlcNAc on the adjacent beta Man residue.     

Synthesis and biological evaluation of 1-(benzenesulfonamido)-2-[5-(N-hydroxypyridin-2(1H)-one)]acetylene regioisomers: a novel class of 5-lipoxygenase inhibitors

A hitherto unknown class of linear acetylene regioisomers were designed such that a SO₂NH₂ group was located at the ortho-, meta-, or para-position of the acetylene C-1 phenyl ring, and a N-hydroxypyridin-2(1H)-one moiety was attached via its C-5 position to the C-2 position on an acetylene template (scaffold). All three regioisomers inhibited 5-lipoxygenase (5-LOX), where the relative potency order was 2-SO₂NH₂ (IC₅₀ = 10 μM) >3-SO₂NH₂ (IC₅₀ = 15 μM) >4-SO₂NH₂ (IC₅₀ = 68 μM) relative to the reference drug nordihydroguaiaretic acid (NDGA; IC₅₀ = 35 μM). The 2-SO₂NH₂ regioisomer (ED₅₀ = 86.0 mg/kg po) exhibited excellent oral anti-inflammatory (AI) activity that was more potent than aspirin (ED₅₀ = 128.9 mg/kg) and marginally less potent than ibuprofen (ED₅₀ = 67.4 mg/kg). The N-hydroxypyridin-2(1H)one moiety provides a novel pharmacophore for the design of cyclic hydroxamic mimetics capable of chelating 5-LOX iron for exploitation in the design of 5-LOX inhibitory AI drugs.