Practical stereoselective synthesis of (2,3,4, 5-tetrahydro-1H-benzo[b]azepin-5-yl)acetic acid

Highly enantioselective asymmetric hydrogenation of readily accessible olefins, (E)- and (Z)-[1-(toluene-4-sulfonyl)-1,2,3, 4-tetrahydro-1H-benzo[b]azepin-5-ylidene]acetic acid (4a and 4b, respectively) and [1-(toluene-4-sulfonyl)-2, 3-dihydro-1H-benzo[b]azepin-5-yl]acetic acid (4c), is presented as an efficient and straightforward route to (R)-[1-(toluene-4-sulfonyl)-2,3,4, 5-tetrahydro-1H-benzo[b]azepin-5-yl]acetic acid [(R)-1] which is a key intermediate for the synthesis of non-peptide AVP V2-agonist. Hydrogenation of carboxylic acid 4c gave (R)-1 in quantitative yield and 85% ee using Ru(OAc)2[(S)-H8-BINAP], a Ru(II) complex of a partially hydrogenated BINAP (H8-BINAP), as a catalyst. When (R)-1 of 76% ee was transformed into the corresponding isopropylamide 6, pure enantiomer (R)-6 was obtained in 75% yield by recrystallization from MeOH.     

Tsukamurella sp. E105 as a new biocatalyst for highly enantioselective hydrolysis of ethyl 2-(2-oxopyrrolidin-1-yl) butyrate

A new bacterial strain, E105, has been introduced as a biocatalyst for the enantioselective hydrolysis of ethyl (R,S)-2-(2-oxopyrrolidin-1-yl) butyrate, (R,S)-1, to (S)-2-(2-oxopyrrolidin-1-yl) butyric acid, (S)-2. This strain was isolated from 60 soil samples using (R,S)-1 as the sole carbon source. The isolate was identified as Tsukamurella tyrosinosolvens E105, based on its morphological characteristics, physiological tests, and 16S rDNA sequence analysis. The process of cell growth and hydrolase production for this strain was then investigated. The hydrolase activity reached its maximum after cultivation at 200?rpm and 30?°C for 36?h. Furthermore, the performance of the enantioselective hydrolysis of (R,S)-1 was studied. The optimal reaction temperature, initial pH, substrate concentration, and concentration of suspended cells were 30?°C, 6.8, 10 and 30?g/l (DCW), respectively. Under these conditions, a high conversion (>45?%) of the product (S)-2 with an excellent enantiomeric excess (ee) (>99?%), and a satisfied enantiomeric ratio (E) (>600) as well were obtained. This study showed that the bacterial isolate T. tyrosinosolvens E105 displayed a high enantioselectivity towards the hydrolysis of racemic ethyl 2-(2-oxopyrrolidin-1-yl) butyrate.     

Preparation of optically pure 4-(hydroxymethyl)-2-pentadecyl-1,3-dioxolanes and their corresponding phosphodiester ether lipid derivatives.

Semi-preparative HPLC on a chiral stationary phase (Chiracel OD) was utilized in the course of this synthesis to separate the four possible diastereomers [cis-(2R,4S)-2a, trans-(2S,4S)-2b, cis-(2S,4R)-2a', and trans-(2R,4R)-2b'] of a 2,4-disubstituted-1,3-dioxolane into optically pure forms (100% de, 100% ee). The syntheses of phosphodiester head group derivatives from each of these four conformationally constrained diastereomeric dioxolanes gave phospholipids which are monocyclic ether lipid analogs. First, the series of four [[(2-pentadecyl-1,3-dioxolan-4-yl)methyl]oxy]phosphocholines 5 were synthesized to give optically pure conformationally constrained analogues of ET-16-OCH(3). A head group variation was also demonstrated by the syntheses of the four diastereomeric [[(2-pentadecyl-1,3-dioxolan-4-yl)-methyl]oxy]phospho-beta-(N-methylmorpholino)ethanols 6.     

Partial resolution of racemic trans-4-[5-(4-alkoxyphenyl)-2,5-dimethylpyrrolidine-1-oxyl-2-yl]benzoic acids by the diastereomer method with (R)- or (S)-1-phenylethylamine

The partial resolution is described of a series of racemic trans-4-[5-(4-alkoxyphenyl)-2,5-dimethylpyrrolidine-1-oxyl-2-yl]benzoic acids (1), which are the key intermediates for the synthesis of chiral organic radical liquid crystalline compounds and are crystallized to give racemic compounds. Racemic acid 1 [(+/-)-1] with a long alkyl chain (C7 to C13) could be resolved by the conventional diastereomeric salt formation using (R)- or (S)-1-phenylethylamine (2) as the resolving agent, whereas resolution of (+/-)-1 with a short alkyl chain (C4 to C6) was unsuccessful. Use of six equiv of (R)- or (S)-2 for the initial diastereomeric salt formation of (+/-)-1 with a C7-C13 alkyl chain, followed by recrystallization of the resulting salts once or twice, gave 2S,5S- or 2R,5R-enriched 1, respectively, in an ee range of 75-92% and with an overall recovery of 11-27%, based on the original quantity of (+/-)-1.     

Ligand based design of novel histamine H₄ receptor antagonists; fragment optimization and analysis of binding kinetics

The histamine H(4) receptor is a G protein-coupled receptor that has attracted much interest for its role in inflammatory and immunomodulatory functions. In our search for new H(4)R ligands, a low affinity isoquinoline fragment was optimized to 7-(furan-2-yl)-4-(piperazin-1-yl)quinazolin-2-amine (VUF11489), as a new H(4)R antagonist. Analysis of its binding kinetics at the human H(4)R showed this compound to have a very different dissociative half-life in comparison with reference antagonist JNJ7777120.     

Molecular docking based screening of neem-derived compounds with the NS1 protein of Influenza virus

AbbreviationsNS1 protein - Non Structural 1 proteinNA - Neuraminidase, HA - Hemagglutinin, M - Matrix, 127-40-2 - 4-[(1E, 3E, 5E,7Z, 9E, 11E, 13E, 15E, 17E)-18-(4-hydroxy-2,6,6-trimethylcyclohex-2-en-1-yl)-3,7,12,16-tetramethyloctadeca-1,3,5,7,9,11,13,15,17- nonaenyl]-3, 5, 5-trimethylcyclohex-3-en-1-ol, Quercitrin 2 - (3,4-dihydroxyphenyl)-5,7-dihydroxy-3- [(2S,3R,4R,5R,6S)-3,4,5-trihydroxy-6-methyloxan-2-yl]oxychromen-4-one, Tiplasinin 2 - [1-benzyl-5-[4-(trifluoromethoxy) phenyl] indol-3-yl]-2-oxoacetic acid, Hyperoside 2 - (3,4-dihydroxyphenyl)-5,7-dihydroxy-3- [(2S,3R,4S,5R,6R)-3, 4, 5-trihydroxy-6- (hydroxymethyl)oxan-2- yl]oxychromen-4-one LGH 4-(2-chloro-4-nitrophenyl)piperazin-1-yl][3-(2-methoxyphenyl)-5-methyl-1,2-oxazol-4-yl]methanone, nRUTIN 2 - (3, 4-dihydroxyphenyl) -5, 7-dihydroxy-3-[(2S, 3R, 4S, 5S, 6R)-3, 4, 5-trihydroxy-6-[[(2R, 3R, 4R, 5R, 6S)-3,4,5-trihydroxy- 6-methyloxan-2-yl]oxymethyl]oxan-2-yl]oxychromen-4-one.     

Inhibition by prostacyclin and carbacyclins of endothelin-induced DNA synthesis in cultured vascular smooth muscle cells

Effects of prostacyclin and carbacyclins on endothelin-induced DNA synthesis were investigated in vascular smooth muscle cells. DNA synthesis was estimated by [3H]thymidine incorporation. Five carbacyclins used in this report were 5-[(1S, 5S, 6R, 7R)-7-hydroxy-6-[(E)-(S)-3-hydroxy-1-octenyl]bicyclo [3.3.0]oct-2-en-3-yl) pentanoic acid (TEI-7165), methyl 5-[(1S, 5S, 6R, 7R)-7-hydroxy-6-[(E)-(S)-3-hydroxy-1-octenyl]bicyclo[3.3.0]oct-2-en-3- yl]pentanoate (TEI-9090), 5-[(1S, 5S, 6R, 7R)-7-hydroxy-6-[(E)-(3S, 5S)-3-hydroxy-5-methyl-1-nonenyl]bicyclo[3.3.0]oct-2-en-3-yl)penta noic acid (TEI-9063), methyl 5-[(1S, 5S, 6R, 7R)-7-hydroxy-6-[(E)-(3S, 5S)-3-hydroxy-5-methyl-1- nonenyl]bicyclo[3.3.0]oct-2-en-3-yl)pentanoate (TEI-1324), 5-[(1S, 5S, 6R, 7R)-7-hydroxy-6-[(E)-(S)-4-hydroxy-4-methyl-1- octenyl]bicyclo[3.3.0]oct-2-en-3-yl] pentanoic acid (TEI-3356). Prostacyclin and the carbacyclins inhibited the endothelin-induced DNA synthesis within the nanomolar range. These results suggest that prostacyclin and carbacyclins are possibly effective in inhibiting the proliferation of vascular smooth muscle cells under some situations in vivo.     

Design and synthesis of a novel series of 4-heteroarylamino-1′-azaspiro[oxazole-5,3′-bicyclo[2.2.2]octanes as α7 nicotinic receptor agonists 2. Development of 4-heteroaryl SAR

Quinuclidine-containing spirooxazolines, as described in the previous report in this series, were demonstrated to have utility as α7 nicotinic acetylcholine receptor (α7 nAChR) partial agonists. In this work, the SAR of this chemotype was expanded to include an array of diazine heterocyclic substitutions. Many of the heterocyclic analogs were potent partial agonists of the α7 receptor, selective against other nicotinic receptors and the serotinergic 5HT_3A receptor. (1′S,3′R,4′S)-N-(6-phenylpyrimidin-4-yl)-4H-1′-azaspiro[oxazole-5,3′-bicyclo[2.2.2]octan]-2-amine, a potent and selective α7 nAChR partial agonist, was demonstrated to improve cognition in the mouse novel object recognition (NOR) model of episodic memory.     

Synthesis and evaluation of [¹⁸F]fluororasagiline, a novel positron emission tomography (PET) radioligand for monoamine oxidase B (MAO-B)

The aim of this study was to synthesize and evaluate a novel fluorine-18 labeled analogue of rasagiline (6) as a PET radioligand for monoamine oxidase B (MAO-B). The corresponding non-radioactive fluorine-19 ligand, (1S,2S)-2-fluoro-N-(prop-2-yn-1-yl)indan-1-amine (4), was characterized in in vitro assays. The precursor compound (3aS,8aR)-3-(prop-2-yn-1-yl)-3,3a,8,8a-tetrahydroindeno[1,2-d][1,2,3]oxathiazole 2,2-dioxide (3) and reference standard 4 were synthesized in multi-step syntheses. Recombinant human MAO-B and MAO-A enzyme preparations were used in order to determine IC(50) values for compound 4 by use of an enzymatic assay employing kynuramine as substrate. Radiolabeling was accomplished by a two-step synthesis, compromising a nucleophilic substitution followed by hydrolysis of the sulphamidate group. Human whole hemisphere autoradiography (ARG) was performed with [(18)F]fluororasagiline. Blocking experiments with pirlindole (MAO-A), L-deprenyl and rasagiline (MAO-B) were conducted to demonstrate the specificity of the binding. A positron emission tomography (PET) study was carried out in a cynomolgus monkey where time activity curves for whole brain and regions with high and low MAO-B activity were recorded. Radiometabolites were measured in monkey plasma using gradient HPLC. Compound 4 inhibited MAO-B with an IC(50) of 27 nM and MAO-A with an IC(50) of 2.3 μM. Radiolabeling of precursor 3 and subsequent hydrolysis of the protecting group towards (1S,2S)-2-[(18)F]fluoro-N-(prop-2-yn-1-yl)indan-1-amine (6) was successfully accomplished with an radiochemical yield of 40-70%, a radiochemical purity higher than 99% and a specific radioactivity higher than 200GBq/μmol. ARG demonstrated selective binding for [(18)F]fluororasagiline (6) to MAO-B containing brain regions, for example, striatum. The initial uptake in the monkey brain was 250% SUV at 4 min post injection. The highest amounts of radioactivity were observed in the striatum and thalamus as expected whereas in the cortex and cerebellum lower levels were observed. Metabolite studies demonstrated 30% unchanged radioligand at 90 min post injection. Our investigations demonstrated that the new ligand [(18)F]fluororasagiline (6) binds specifically to MAO-B in vitro and has a MAO-B specific binding pattern in vivo. Thus, it could serve as a novel potential candidate for human PET studies.     

Facile, alternative route to lubeluzole, its enantiomer, and the racemate

Lubeluzole [(S)-9] has been synthesized by a convergent synthesis, alkylation of N-methyl-N-piperidin-4-yl-1,3-benzothiazol-2-amine (4) with (+)-(R)-1-chloro-3-(3,4-difluorophenoxy)propan-2-ol [(+)-(R)-8] being the key step. Alcohol (+)-(R)-8 was obtained from commercially available (R)-epichlorohydrin [(R)-6], while the thiazole derivative 4 was easily obtained starting from N-protected piperidin-4-one (1) in a three-step procedure. The same method was used in order to obtain both the (R)-stereoisomer of lubeluzole [(R)-9] and its racemate [(RS)-9]. Overall yields ranged from 20% to 35%. The enantiomeric excess values for (S)-9 and (R)-9 were 97% and 94% respectively, as analyzed by chiral HPLC.     

4-(Benzimidazol-2-yl)-1,2,5-oxadiazol-3-ylamine derivatives: Potent and selective p70S6 kinase inhibitors

We report herein the design and synthesis of 4-(benzimidazol-2-yl)-1,2,5-oxadiazol-3-amine derivatives as inhibitors of p70S6 kinase. Screening hits containing the 4-(benzimidazol-2-yl)-1,2,5-oxadiazol-3-ylamine scaffold were optimized for p70S6K potency and selectivity against related kinases. Structure-based design employing an active site homology model derived from PKA led to the preparation of benzimidazole 5-substituted compounds 26 and 27 as highly potent inhibitors (K_i <1 nM) of p70S6K, with >100-fold selectivity against PKA, ROCK and GSK3.     

Discovery of INCB10820/PF-4178903, a potent, selective, and orally bioavailable dual CCR2 and CCR5 antagonist

We report the discovery of a potent, selective, and orally bioavailable dual CCR2 and CCR5 antagonist (3S,4S)-N-[(1R,3S)-3-isopropyl-3-({4-[4-(trifluoromethyl)pyridin-2-yl]piperazin-1-yl}carbonyl)cyclopentyl]-3-methoxytetrahydro-2H-pyran-4-amine (19). After evaluation in 28-day toxicology studies, compound 19 (INCB10820/PF-4178903) was selected as a clinical candidate.     

Development of 2-substituted-N-(naphth-1-ylmethyl) and N-benzhydrylpyrimidin-4-amines as dual cholinesterase and Aβ-aggregation inhibitors: Synthesis and biological evaluation

A group of 2-substituted N-(naphth-1-ylmethyl)pyrimidin-4-amines (6a-k) and N-benzhydrylpyrimidin-4-amines (7a-k) in conjunction with varying steric and electronic properties at the C-2 position were designed, synthesized and evaluated as dual cholinesterase and amyloid-β (Aβ)-aggregation inhibitors. The naphth-1-ylmethyl compound 6f (2-(4-cyclohexylpiperazin-1-yl)-N-(naphth-1-ylmethyl)pyrimidin-4-amine) exhibited optimum dual ChE (AChE IC(50)=8.0 μM, BuChE IC(50)=3.9 μM) and hAChE-promoted Aβ-aggregation inhibition (30.8% at 100 μM), whereas in the N-benzhydryl series, compound 7f (N-benzhydryl-2-(4-cyclohexylpiperazin-1-yl)pyrimidin-4-amine) exhibited optimum combination of dual ChE (AChE IC(50)=10.0 μM, BuChE IC(50)=7.6μM) and hAChE-promoted Aβ-aggregation inhibition (32% at 100 μM). These results demonstrate that a 2,4-disubstituted pyrimidine ring serves as a suitable template to target multiple pathological routes in AD, with a C-2 cyclohexylpiperazine substituent providing dual ChE inhibition and potency whereas a C-4 diphenylmethane substituent provides Aβ-aggregation inhibition.     

Cytotoxic steroidal saponins from Polygonatum punctatum

Four new steroidal saponins, polypunctosides A-D (1-4, resp.), were isolated from the rhizomes of Polygonatum punctatum, together with five known steroidal saponins. On the basis of chemical and spectral evidence, the structures of the new saponins were established as (3beta,23S,25R)-23-(alpha-L-arabinopyranosyloxy)spirost-5-en-3-yl 4-O-(6-deoxy-alpha-L-mannopyranosyl)-D-glucopyranoside (1), (3beta,23S,25R)-23-[(2-O-acetyl-alpha-L-arabinopyranosyl)oxy]spirost-5-en-3-yl 4-O-(6-deoxy-alpha-L-mannopyranosyl)-D-glucopyranoside (2), (3beta,23S,25R)-23-[(3-O-acetyl-alpha-L-arabinopyranosyl)oxy]spirost-5-en-3-yl 4-O-(6-deoxy-alpha-L-mannopyranosyl)-D-glucopyranoside (3), and (3beta,23S,25R)-23-[(4-O-acetyl-alpha-L-arabinopyranosyl)oxy]spirost-5-en-3-yl 4-O-(6-deoxy-alpha-L-mannopyranosyl)-D-glucopyranoside (4). The cytotoxic activity of the isolated saponins was evaluated towards HeLa cells.     

Design, synthesis and biological activity of novel dimethyl-[2-[6-substituted-indol-1-yl]-ethyl]-amine as potent, selective, and orally-bioavailable 5-HT(1D) agonists

A novel series of highly potent human 5-HT_1D agonists, dimethyl-{2-[6-substituted-indol-1-yl]-ethyl}-amine, was synthesized. Structure–activity relationship (SAR) investigation revealed 4-[1-(2-dimethylamino-ethyl)-1H-indol-6-yl]-tetrahydro-thiopyran-4-ol, 11b (ALX-2732), as a potent (K_i=2.4 nM) agonist at the human 5-HT_1D receptor with good selectivity over the other serotonin receptor subtypes. This compound demonstrated favorable in vitro metabolic stability in human and rat liver microsomes and was found to be orally bioavailable in rats (F_po=51%).     

Substrate specificity and enantioselectivity of 4-hydroxyacetophenone monooxygenase

The 4-hydroxyacetophenone monooxygenase (HAPMO) from Pseudomonas fluorescens ACB catalyzes NADPH- and oxygen-dependent Baeyer-Villiger oxidation of 4-hydroxyacetophenone to the corresponding acetate ester. Using the purified enzyme from recombinant Escherichia coli, we found that a broad range of carbonylic compounds that are structurally more or less similar to 4-hydroxyacetophenone are also substrates for this flavin-containing monooxygenase. On the other hand, several carbonyl compounds that are substrates for other Baeyer-Villiger monooxygenases (BVMOs) are not converted by HAPMO. In addition to performing Baeyer-Villiger reactions with aromatic ketones and aldehydes, the enzyme was also able to catalyze sulfoxidation reactions by using aromatic sulfides. Furthermore, several heterocyclic and aliphatic carbonyl compounds were also readily converted by this BVMO. To probe the enantioselectivity of HAPMO, the conversion of bicyclohept-2-en-6-one and two aryl alkyl sulfides was studied. The monooxygenase preferably converted (1R,5S)-bicyclohept-2-en-6-one, with an enantiomeric ratio (E) of 20, thus enabling kinetic resolution to obtain the (1S,5R) enantiomer. Complete conversion of both enantiomers resulted in the accumulation of two regioisomeric lactones with moderate enantiomeric excess (ee) for the two lactones obtained [77% ee for (1S,5R)-2 and 34% ee for (1R,5S)-3]. Using methyl 4-tolyl sulfide and methylphenyl sulfide, we found that HAPMO is efficient and highly selective in the asymmetric formation of the corresponding (S)-sulfoxides (ee > 99%). The biocatalytic properties of HAPMO described here show the potential of this enzyme for biotechnological applications.     

Lipase-catalyzed enantioselective esterification of mono-aza-benzo-15-crown-5-ether derivatives in organic media

For the purpose of developing a new chiral crown ether unit as a chiral synthon, three racemic mono azabenzo-15-crown-5-ethers, i.e. (R,S)-1-(6,7,9,10,12,13,15,16-octahydro-5,8,14,17-tetraoxa-11-aza-benzocyclopentadecen-11-yl)-propan-2-ol, (R,S)-2-(6,7,9,10,12,13,15,16-octahydro-5,8,14,17-tetraoxa-11-aza-benzocyclopentadecen-11-yl)-1-phenyl-ethanol and (R , S)-1-[2-(6,7,9,10,12,13,15,16-octahydro-5,8,14,17-tetraoxa-11-aza-benzocyclopentadecen-11-ylmethyl)-phenyl]-ethanol were esterified with vinyl acetate using a lipase from Candida antarctica. The enzymatic acylation of alcohols produced monoacylated products. Two optically active azacrown ethers, (R)-propionic acid 1-methyl-2-(6,7,9,10,12,13,15,16-octahydro-5,8,14,17-tetraoxa-11-aza-benzocyclopentadecen-11-yl)-ethyl ester and (R)-acetic acid 1-[2-(6,7,9,10,12,13,15,16-octahydro-5,8,14,17-tetraoxa-11-aza-benzocyclopentadecen-11-ylmethyl)-phenyl]-ethyl ester were obtained within 48% and 36% yields, respectively and, at an enantiometric excess of over 99% in each case.     

Hydrolytic kinetic resolution of the enantiomers of the structural isomers trans-1-phenylpropene oxide and (2,3-epoxypropyl)benzene by yeast epoxide hydrolase

Kinetic resolution of the enantiomers of trans -1-phenylpropene oxide and (2,3-epoxypropyl)benzene was achieved by yeasts from the genus Rhodotorula. The resolution of trans -1-phenylpropene oxide by Rhodotorula glutinis UOFS Y-0123 yielded (1R,2R)-epoxide (ee >98%, yield 30%) and (1R,2S)-diol (ee 95%, yield 40%). The highest enantio- and regioselectivity toward (2,3-epoxypropyl)benzene resided in Rhodotorula sp. UOFS Y-0448 (E = 6.16), yielding (S)-epoxide (ee 64%, yield 33%) and (R)-diol (ee 67%, yield 28%). This confirms the superiority of yeasts from the Basidiomycetes genera in the enantioselective hydrolysis of epoxides from different structural classes.     

Synthesis and computer-aided analysis of the role of linker for novel ligands of the 5-HT6 serotonin receptor among substituted 1,3,5-triazinylpiperazines

A series of 2-amino-4-(4-methylpiperazin-1-yl)-1,3,5-triazines was designed based on previously published 2-amino-4-benzyl-(4-methylpiperazin-1-yl)-1,3,5-triazines in order to evaluate the role of a linker between the triazine moiety and an aromatic substituent for the human serotonin 5-HT₆ receptor affinity. As new linkers two carbon atoms (ethyl or ethenyl) or an oxyalkyl chain (methoxy, 2-ethoxy, 2-propoxy) were introduced. Affinities of the compounds for the 5-HT₆R as the main target, and for the 5-HT_1AR, 5-HT₇R and D₂R as competitive ones, were determined in the radioligand binding assays. Docking to the 5-HT₆R homology model was performed to support SAR analysis. Results showed that the branching of the methoxyl linker increased affinity for the human 5-HT₆R whereas an unsaturated bond within the linker dramatically reduced desirable activity. Both experimental and theoretical studies confirmed the previously postulated beneficial role of the aromatic size for interaction with the 5-HT₆R. Thus, the largest naphthyl moiety yielded the highest activity. In particular, 4-(4-methylpiperazin-1-yl)-6-(1-(naphthalen-1-yloxy)ethyl)-1,3,5-triazin-2-amine (24), the most potent 5-HT₆R agent found (K_i = 23 nM), can be a new lead structure for further search and development.     

Potent CCR4 antagonists: synthesis, evaluation, and docking study of 2,4-diaminoquinazolines

A series of CC chemokine receptor-4 (CCR4) antagonists were examined in a previous report in an attempt to improve metabolic stability in human liver microsomes. In this study, the cycloheptylamine moiety of N-cycloheptyl-6,7-dimethoxy-2-(4-pyrrolidin-1-ylpiperidin-1-yl)quinazolin-4-amine 1 was replaced with the p-chloroaniline moiety, and the resulting compound, N-(4-chlorophenyl)-6,7-dimethoxy-2-(4-pyrrolidin-1-ylpiperidin-1-yl)quinazolin-4-amine (8c), retained its potency ([(35)S]GTPgammaS-binding inhibition and CCL22-induced chemotaxis in humans/mice). Based on the structure-activity relationships (SAR), a homology model was constructed for CCR4 to explain the binding mode of 8c. Overall, there was good agreement between the docking pose of the CCR4 homology model and the human [(35)S]GTPgammaS assay results. Administration of 8c in a murine model of acute dermatitis showed anti-inflammatory activity (oxazolone-induced contact hypersensitivity test).