Microbial degradation of papaverine (author's transl)]

A bacterium growing on papaverine as sole carbon and nitrogen source was isolated by incubation of soil with papaverine. The bacterium could be identified as a Nocardia strain by morphological and physiological tests. When growing on papaverine, this strain excretes metabolites into the medium. Based on the structure of the metabolites 1--9 a degradation pathway is proposed. 1 = 1-(3,4-Dimethoxybenzyl)-3,4-dihydro-6,7-dimethoxy-3,4-isoquinolinediol; 2 = 1-(3,4-dimethoxybenzyl)-6,7-dimethoxy-3,4-isoquinolinediol; 3 = 2-(3,4-dimethoxyphenyl)-1-[2-(2-hydroxyethyl)-4,5-dimethoxyphenly]ethanone; 4 = 2-hydroxy-4,5-dimethoxybenzeneethanol; 5 = 3,4-dimethoxybenzeneacetic acid; 6 = 2-hydroxy-4,5-dimethyoxybenzeneacetic acid; 7 = 4-hydroxy-3-methoxybenzeneacetic acid; 8 = 3,4-dimethoxybenzaldehyde; 9 = 2-(hydroxymethyl)-4,5-dimethoxybenzeneethanol.     

Decomposition reaction of sesamin in supercritical water

The methylenedioxyphenyl moiety in the structure of sesamin and episesamin was changed into the catechol moieties, (1R,2S,5R,6S)-6-(3,4-dihydroxyphenyl)-2-(3,4-methylenedioxyphenyl)-3,7-dioxabicyclo[3,3,0]octane, (1R,2R,5R,6S)-2-(3,4-dihydroxyphenyl)-6-(3,4-methylenedioxyphenyl)-3,7-dioxabicyclo[3,3,0]octane, (1R,2R,5R,6S)-6-(3,4-dihydroxyphenyl)-2-(3,4-methylenedioxyphenyl)-3,7-dioxabicyclo[3,3,0]octane, (1R,2S,5R,6S)-2,6-bis(3,4-dihydroxyphenyl)-3,7-dioxabicyclo[3,3,0]octane, and (1R,2R,5R,6S)-2,6-bis(3,4-dihydroxyphenyl)-3,7-dioxabicyclo[3,3,0]octane, in supercritical water. These products had same structures as the sesamin metabolites which act as antioxidants in the liver. These features suggested the direct preparation of antioxidants from sesamin by a one-step reaction using supercritical water.     

Product profiles in enzymic and non-enzymic oxidations of the lignin model compound erythro-1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol

The erythro form of the lignin model compound 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol (1) was oxidized with laccase/ABTS, lead(IV) tetraacetate (LTA), lignin peroxidase/H₂O₂, cerium(IV) ammonium nitrate (CAN) and Fenton's reagent. The product profiles obtained with the different oxidants were compared after separation, identification and quantification of the products using HPLC, UV-diode array detector and electrospray ionization mass spectrometry in positive ionization mode. The oxidants generated different product profiles that reflected their different properties. Oxidation with laccase/ABTS resulted almost exclusively in formation of 1-(3,4-dimethoxyphenyl)-3-hydroxy-2-(2-methoxyphenoxy)-1-propanone (2). Oxidation with LTA resulted in more 3,4-dimethoxybenzaldehyde (3) than ketone 2. Lignin peroxidase and CAN gave similar product profiles and aldehyde 3 was the predominant product (only small amounts of ketone 2 were formed). Oxidation with Fenton's reagent resulted in the formation of more aldehyde 3 than ketone 2 but the yields were very low. CAN served as an excellent model for the lignin peroxidase-catalyzed oxidation, while the laccase-mediator system, LTA and Fenton's reagent provided distinctly different product profiles. Erythro-1-(3,4-dimethoxyphenyl)-1,2,3-propanetriol was present among the products obtained on oxidation with LTA, lignin peroxidase, CAN and Fenton's reagent. The differences in redox potential between the oxidants afford an explanation of the diverse product patterns but other factors may also be of importance. The reactions leading to cleavage of the β-ether bond with formation of 1-(3,4-dimethoxyphenyl)-1,2,3-propanetriol (veratrylglycerol) were found to proceed without affecting the configuration at the β-carbon atom.     

Diaminobenzidine an electron donor to photosystem 1 and to photosystem 2 in chloroplasts.

1. 3,3'-Diaminobenzidine was shown to serve as an electron donor to photosystem 1 in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea. In Tris-treated chloroplasts diaminobenzidine serves as an electron donor to photosystem 1 and to photosystem 2; the latter is sensitive to 3-(3,4-dichlorophenyl)-1,1-dimethylurea. 2. Addition of diaminobenzidine to Tris-treated chloroplasts causes an increase in fluorescence yield. 3. Diaminobenzidine-dependent electron transport mediated by photosystem 2 is coupled to synthesis of ATP even in the absence of an electron acceptor. This phosphorylation which is presumably supported by cyclic electron flow, is sensitive to 3-(3,4-dichlorophenyl)-1,1-dimethylurea. 4. Diaminobenzidine-dependent ATP formation, in Tris-treated chloroplasts exhibits the red-drop phenomenon. 5. The diaminobenzidine-induced cyclic photophosphorylation (mediated by photosystem 2) is resistant to a large extent to KCN-treatment which is known to inhibit reactions catalyzed by photosystem 1. On the other hand ATP formation supported by electron transport from diaminobenzidine to methyl viologen [in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea] is largely inhibited by KCN-treatment. This observation suggests that there are two coupling sites of ATP formation, one catalyzed by diaminobenzidine as a donor to photosystem 1 (in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea), and the other supported by diaminobenzidine which acts both as a donor to photosystem 2 (in Tris-treated chloroplasts) and as an acceptor (in its oxidized form) from a carrier located between the two photosystems.     

Anthraquinones from Hedyotis capitellata

Four new furanoanthraquinones, 2-hydroxymethyl-3,4-[2'-(1-hydroxy-1-methylethyl)-dihydrofurano]-8-hydroxyanthraquinone, 2-hydroxymethyl-3,4-[1'-hydroxy-2'-(1-hydroxy-1-methylethyl)-dihydrofurano]-8-hydroxyanthraquinone, 2-hydroxymethyl-3,4-[2'-1-hydroxy-1-methylethyl)-dihydrofurano]anthraquinone and 2-methyl-3,4-[2'-(1-hydroxy-1-methylethyl)-dihydrofurano] anthraquinone or capitellataquinone A-D and four known anthraquinones, rubiadin, anthragallol 2-methyl ether, alizarin 1-methyl ether and digiferruginol, together with scopoletin were isolated from the stems of Hedyotis capitellata Wall (Rubiaceae). Lucidin-3-O-beta-glucoside was isolated from the roots of the plant. Characterization of the new compounds was carried out by extensive NMR studies using FGCOSY, FGHMQC, FGHMBC and DEPT-135 in addition to other spectroscopic methods.     

Low-molecular-weight components of olive oil mill waste-waters

A new lignan 1-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-6-(3-acetyl-4-hydroxy-5-methoxyphenyl)-3,7-dioxabicyclo[3.3.0]octane, the secoiridoid 2H-pyran-4-acetic acid,3-hydroxymethyl-2,3-dihydro-5-(methoxycarbonyl)-2-methyl-, methyl ester, the phenylglycoside 4-[beta-D-xylopyranosyl-(1-->6)]-beta-D-glucopyranosyl-1,4-dihydroxy-2-methoxybenzene and the lactone 3-[1-(hydroxymethyl)-1-propenyl] delta-glutarolactone were isolated and identified on the basis of spectroscopic data including two-dimensional NMR, as components of olive oil mill waste-waters. The known aromatic compounds catechol, 4-hydroxybenzoic acid, protocatechuic acid, vanillic acid, 4-hydroxy-3,5-dimethoxybenzoic acid, 4-hydroxyphenylacetic acid, 3,4-dihydroxyphenylacetic acid, tyrosol, hydroxytyrosol, 2-(4-hydroxy-3-methoxy)phenylethanol, 2-(3,4-dihydroxy)phenyl-1,2-ethandiol, p-coumaric acid, caffeic acid, ferulic acid, sinapic acid, 1-O-[2-(3,4-dihydroxy)phenylethyl]-(3,4-dihydroxy)phenyl-1,2-ethandiol, 1-O-[2-(4-hydroxy)phenylethyl]-(3,4-dihydroxy)phenyl-1,2-ethandiol, D(+)-erythro-1-(4-hydroxy-3-methoxy)-phenyl-1,2,3-propantriol, p-hydroxyphenethyl-beta-D-glucopyranoside,2(3,4-dihydroxyphenyl)ethanol 3beta-D-glucopyranoside, and 2(3,4-dihydroxyphenyl)ethanol 4beta-D-glucopyranoside were also confirmed as constituents of the waste-waters.     

Structure-activity relationship for a series of 2-substituted 1,2,3,4-tetrahydro-9H-pyrido[3,4-b]indoles: potent subtype-selective inhibitors of N-methyl-D-aspartate (NMDA) receptors.

A series of 2-substituted 1,2,3,4-tetrahydro-9H-pyrido[3,4-b]indoles was synthesized as potential antagonists for the NR1A/2B subtype of N-methyl-D-aspartate (NMDA) receptors. Assayed by electrical recording under steady-state conditions, 7-hydroxy-2-(4-phenylbutyl)- 1,2,3,4-tetrahydropyrido-[3,4-b]indole (30) was the most potent compound in the series having an IC50 value of 50 nM at the NR1A/2B receptors.     

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.     

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.     

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.     

Synthesis of the antistroke drug lubeluzole and its enantiomer. Lipase-catalyzed resolution of chiral building block

1-Chloro-3-(3,4-difluorophenoxy)-2-propanol was kinetically resolved by lipase-catalyzed esterification with vinyl butanoate in organic medium to yield the (S)-butanoate and the (R)-alcohol as the remaining substrate. In an enantioconvergent synthesis the mixture was subject to Mitsunobu esterification in one pot which converted the (R)-alcohol to the (S)-ester. The (S)-butanoate was hydrolyzed by lipase catalysis to give (S)-1-chloro-3-(3,4-difluorophenoxy)-2-propanol. The two enantiopure chiral building blocks were used for synthesis of Lubeluzole and its enantiomer respectively.     

Antagonists of the human CCR5 receptor as anti-HIV-1 agents. Part 2: structure-activity relationships for substituted 2-Aryl-1-[N-(methyl)-N-(phenylsulfonyl)amino]-4-(piperidin-1-yl)butanes

(2S)-2-(3,4-Dichlorophenyl)-1-[N-(methyl)-N-(phenylsulfonyl)amino]-4-[spiro(2,3-dihydrobenzthiophene-3,4'-piperidin-1'-yl)]butane S-oxide (3) has been identified as a potent CCR5 antagonist lead structure having an IC50 = 35 nM. Herein, we describe the structure-activity relationship studies directed toward the requirement for and optimization of the C-2 phenyl fragment. The phenyl was found to be important for CCR5 antagonism and substitution was limited to small moieties at the 3-position (13 and 16: X= H, 3-F, 3-Cl, 3-Me).     

Regio- and stereoselective cyclizations of dianhydro sugar alcohols catalyzed by a chiral (salen)Co(III) complex

The (salen)Co(III)OAc ((R,R)-1 and (S,S)-1) catalyzed cyclizations of the chiral dianhydro sugars, 1,2:5,6-dianhydro-3,4-di-O-methyl-D-glucitol (2), 1,2:5,6-dianhydro-3,4-di-O-methyl-D-mannitol (3), 1,2:5,6-dianhydro-3,4-di-O-methyl-L-iditol (4), and 1,2:4,5-dianhydro-3-O-methyl-L-arabinitol (5), is a facile method for the synthesis of anhydroalditol alcohols. Cyclization of 2 using (R,R)-1 and (S,S)-1 proceeded diastereoselectively to form 2,5-anhydro-3,4-di-O-methyl-D-mannitol (6) and 2,5-anhydro-3,4-di-O-methyl-L-iditol (7), respectively. The cyclization of 3 and 5 is a novel method for obtaining 1,6-anhydro-3,4-di-O-methyl-D-mannitol (11) and a stereoselective route to 1,5-anhydro-3-O-methyl-L-arabinitol (13). It is proposed that the reaction occurs via endo-selective cyclization of an epoxy alcohol produced by the endo-selective ring-opening of one of the two epoxide moieties in the starting material.     

Laccase-catalyzed oxidation of 1-(3,4-dimethoxyphenyl)-1-propene using ABTS as mediator

The fungal laccases catalyzed oxidation of 1-(3,4-dimethoxyphenyl)-1-propene (2) with dioxygen in acetate buffer (pH 4.5) producing 1-(3,4-dimethoxyphenyl)propane-1,2-diol (4) and its 1-O-acetyl and 2-O-acetyl derivatives 5 and 6, and 3,4-dimethoxybenzaldehyde (7). However, in phosphate buffer (pH 5.9), the same reaction produced only 4 and 7. When 4 was treated in the same fashion in the phosphate buffer, it was converted into 7 with more than 95 mol% yield. This, together with the formation of 5 and 6 in the acetate buffer, showed that 2 is converted into 3–5 via 1-(3,4-dimethoxyphenyl)propane-1,2-epoxide (3) in the acetate buffer in the presence of ABTS. The major reaction of fungal laccase-catalyzed oxidation of 2 with dioxygen in the presence of ABTS is epoxidation of the double bond conjugated to the aromatic ring.     

Cleavage of nonphenolic beta-1 diarylpropane lignin model dimers by manganese peroxidase from Phanerochaete chrysosporium.

Purified manganese peroxidase (MnP) from Phanerochaete chrysosporium oxidizes nonphenolic beta-1 diarylpropane lignin model compounds in the presence of Tween 80, and in three- to fourfold lower yield in its absence. In the presence of Tween 80, 1-(3',4'-diethoxyphenyl)-1-hydroxy-2-(4'-methoxyphenyl)propane (I) was oxidized to 3,4-diethoxybenzaldehyde (II), 4-methoxyacetophenone (III) and 1-(3',4'-diethoxyphenyl)-1-oxo-2-(4'-methoxyphenyl)propane (IV), while only 3,4-diethoxybenzaldehyde (II) and 4-methoxyacetophenone (III) were detected when the reaction was conducted in the absence of Tween 80. In contrast to the oxidation of this substrate by lignin peroxidase (LiP), oxidation of substrates by MnP did not proceed under anaerobic conditions. When the dimer (I) was deuterated at the alpha position and subsequently oxidized by MnP in the presence of Tween 80, yields of 3,4-diethoxybenzaldehyde, 4-methoxyacetophenone remained constant, while the yield of the alpha-keto dimeric product (IV) decreased by approximately sixfold, suggesting the involvement of a hydrogen abstraction mechanism. MnP also oxidized the alpha-keto dimeric product (IV) to yield 3,4-diethoxybenzoic acid (V) and 4-methoxyacetophenone (III), in the presence and, in lower yield, in the absence of Tween 80. When the reaction was performed in the presence of 18O2, both products, 3,4-diethoxybenzoic acid and 4-methoxyacetophenone, contained one atom of 18O. Finally, MnP oxidized the substrate 1-(3',5'-dimethoxyphenyl)-1-hydroxy-2-(4'-methoxyphenyl)propane (IX) to yield 3,5-dimethoxybenzaldehyde (XI), 4-methoxyacetophenone (III) and 1-(3',5'-dimethoxyphenyl)-1-oxo-2-(4'-methoxyphenyl)propane (X). In sharp contrast, LiP was not able to oxidize IX. Based on these results, we propose a mechanism for the MnP-catalyzed oxidation of these dimers, involving hydrogen abstraction at a benzylic carbon, rather than electron abstraction from an aromatic ring.     

Glycosidation of 2,5-anhydro-3,4-di-O-benzyl-D-mannitol with different glucopyranosyl donors: a comparative study

2,5-Anhydro-3,4-di-O-benzyl-D-mannitol was glycosylated using different donors such as tetra-O-acetyl-alpha-D-glucopyranosyl bromide in the presence of Hg(CN)(2), the corresponding beta-thiophenylglycoside in the presence of NIS and TfOH as well as the alpha- and beta-trichloroimidate with TMSOTf as promoter. The resulting mixtures were analyzed by HPLC and the following main components were isolated and characterized: 2,5-anhydro-3,4-di-O-benzyl-1-O-(2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl)-d-mannitol; 6-O-acetyl-2,5-anhydro-3,4-di-O-benzyl-1-O-(2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl)-D-mannitol; 2,5-anhydro-3,4-di-O-benzyl-1,6-bis-O-(2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl)-D-mannitol; 2,5-anhydro-3,4-di-O-benzyl-1-O-[-2-O-(2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl)-3,4,6-tri-O-acetyl-beta-D-glucopyranosyl]-6-O-(2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl)-D-mannitol and 2,5-anhydro-3,4-di-O-benzyl-1,6-bis-O-(3,4,6-tri-O-acetyl-1,2-O-ethylidene-2'-yl-alpha-D-glucopyranosyl)-D-mannitol. The latter compound representing a bis-orthoester might be a common intermediate in all the investigated reactions, as its rearrangement and/or decomposition can yield all of the isolated compounds.     

Synthesis and anti-inflammatory activities of N4,N5-disubstituted-3-methyl- H-pyrazolo[3,4-c]pyridazines

The synthesis and anti-inflammatory activity of 4,5-dihydroxy-3-methyl-1H-pyrazolo[3,4-c]pyridazine (4), 4,5-dichloro-3-methyl-1H-pyrazolo[3,4-c]pyridazine (5), 4,-benzoyloxy-3-methyl-1-benzoyl-1H-pyrazolo[3,4-c]pyridazin-5yl benzoate (6), 3-methyl-N4,N5-bis(4-methylphenyl)-1H-pyrazolo[3,4-c]pyridazine-4,5-diamine (7), 4[[5-(4-carboxyanilino)-3-methyl-1H-pyrazolo[3,4-c]pyridazin-4yl]amino]benzoic acid (8), N-[5-(benzoylamino)-3-methyl-1H-pyrazolo[3,4-c]pyridazin-4-yl]benzamide (9) and 3-methyl-N4,N5-bis[4-(1H-benzimidazol-2yl)phenyl]-1H-pyrazolo[3,4-c]pyridazine-4,5-diamine (10) are being reported.     

Synthesis and biological evaluation of 3,4-diphenyl-1,2,5-oxadiazole-2-oxides and 3,4-diphenyl-1,2,5-oxadiazoles as potential hybrid COX-2 inhibitor/nitric oxide donor agents

A group of 3,4-diphenyl-1,2,5-oxadiazole-2-oxides (3,4-diphenylfuroxans) and the corresponding N-desoxy 3,4-diphenyl-1,2,5-oxadiazoles (3,4-diphenylfurazans) analogs, were synthesized for in vitro evaluation as hybrid cyclooxygenase (COX) inhibitor/nitric oxide donor agents. Reaction of 1-[4-(methylsulfonyl)phenyl]-2-phenylethene with an aqueous sodium nitrite solution in acetic acid afforded a mixture (3:1 ratio) of the inseparable 4-[4-(methylsulfonyl)phenyl]-3-phenyl-1,2,5-oxadiazole-2-oxide (13a) and 3-[4-(methylsulfonyl)phenyl]-4-phenyl-1,2,5-oxadiazole-2-oxide (13b) regioisomers. A group of related regioisomers possessing either a p-aminosulfonylphenyl (16) or a p-azidosulfonylphenyl (17), moiety were obtained by chlorosulfonation of the unsubstituted 3,4-diphenylfuroxan (10) and subsequent reaction with either ammonium hydroxide or sodium azide, respectively. The methanesulfonyl regioisomers 13a,b [COX-1 IC50=11.6 microM; COX-2 IC50=0.12 microM; COX-2 selectivity index (SI)=97] and aminosulfonyl regioisomers 16 (COX-1 IC50=9.8 microM; COX-2 IC50=0.78 microM; COX-2 SI=12), like the reference drug celecoxib (COX-1 IC50=33.1 microM; COX-2 IC50=0.07 microM; COX-2 SI=472), were potent in vitro COX-2 inhibitors with a good COX-2 selectivity index. Release of nitric oxide (NO) from the 3,4-diphenylfuroxan compounds (10, 13a,b, 16, 17) was thiol-dependent since the % NO released was higher upon incubation in the presence of l-cysteine (0.57-3.18%) compared to that in phosphate buffer solution at pH7.4 (0.06-0.15%). Molecular modeling (docking) studies show that the methanesulfonyl (MeSO2) COX-2 pharmacophore present in regioisomers 13a,b is positioned in the vicinity of the COX-2 secondary pocket. The in vitro NO release data, COX-1/COX-2 inhibition and COX-2 SI structure-activity relationships acquired, and molecular modeling docking studies suggest that the 1,2,5-oxadiazole-2-oxide (furoxan) ring possesses beneficial features that should be present in a suitable central ring template (bioisostere) pertinent to the design novel hybrid COX-2 inhibitor/nitric oxide donor agents with a low ulcerogenicity profile that may be free from adverse cardiovascular effects.     

Antagonists of the human CCR5 receptor as anti-HIV-1 agents. part 1: discovery and initial structure-activity relationships for 1 -amino-2-phenyl-4-(piperidin-1-yl)butanes

Screening of the Merck sample collection for compounds with CCR5 receptor binding afforded (2S)-2-(3,4-dichlorophenyl)-1-[N-(methyl)-N-(phenylsulfonyl)amino]-4-[spiro(2,3-dihydrobenzthiophene-3,4'-piperidin-1'-yl)]butane S-oxide (4) as a potent lead structure having an IC50 binding affinity of 35 nM. Herein, we describe the discovery of this lead structure and our initial structure activity relationship studies directed toward the requirement for and optimization of the 1-amino fragment.     

Synthetic studies towards a new scaffold, spirobicycloimidazoline

A new scaffold consisting of a carbocycle and a substituted imidazoline in an orthogonal arrangement was synthesized as a potential specific inhibitor of glycosidases. The spirobicycloimidazoline, (5R,6R,7R,8R)-8-(hydroxymethyl)-2-phenyl-1,3-diazaspiro[4.4]non-1-ene-6,7-diol, was synthesized from methyl 2-O-p-methoxybenzyl-3,4-di-O-benzyl-alpha/beta-D-gluco-6-enopyranoside via (1R,2S,3S,4R,5S)-3,4-bis(benzyloxy)-2-(4-methoxybenzyloxy)-5-vinyl-cyclopentanol. The ring contraction of the 6-enopyranoside in the presence of zirconocene equivalent ('Cp(2)Zr') reagent gave exclusively the corresponding cyclopentanol without cleavage of the PMB protecting group. In the course of the study, a new alpha-mannosidase inhibitor, (1R,2R,3R,5R)-5-amino-3-hydroxymethyl-cyclopentane-1,2-diol, was also discovered.