Design, synthesis and in vitro evaluation of novel chroman-4-one, chroman, and 2H-chromene derivatives as human rhinovirus capsid-binding inhibitors

As part of an effort to generate broad-spectrum inhibitors of rhinovirus replication, novel series of (E)-3-[(E)-3-phenylallylidene]chroman-4-ones 1a–e, (E)-3-(3-phenylprop-2-yn-1-ylidene)chroman-4-ones 2a and 2b, (Z)-3-[(E)-3-phenylallylidene]chromans 3a–e, and (E)-3-(3-phenylprop-1-en-1-yl)-2H-chromenes 4a–d were designed and synthesized. All the compounds were tested in vitro for their efficacy against infection by human rhinovirus (HRV) 1B and 14, two representative serotypes for rhinovirus group B and A, respectively. Most of the analogues were found to be potent and selective inhibitors of both HRVs, although HRV 1B was generally more susceptible than HRV 14. Mechanism of action studies of (E)-6-chloro-3-(3-phenylprop-1-en-1-yl)-2H-chromene 4b, the most potent compound on HRV 1B infection, suggested that 4b behaves as a capsid-binder probably acting at the uncoating level.     

Microbial transformation of hydrocortisone by two fungal species Fusarium fujikuroi PTCC 5144 and Rhizomucor pusillus PTCC 5134

Abstract

This paper examines the biotransformation of hydrocortisone (1) by Fusarium fujikuroi and Rhizomucor pusillus. These species have not previously been tested for hydrocortisone biotransformation. The metabolites produced during hydrocortisone biotransformation by these two fungi were 11β,17α,20β,21-tetrahydroxypregn-4-en-3-one (2) and 11 β-hydroxyandrost-4-en-3,17-dione (3). Chemical structures were determined by spectroscopic methods. A time course study revealed that the disappearance of hydrocortisone was accompanied by the formation of metabolites 2 and 3. Metabolite 2 was produced as the major metabolite with high yield but the transformation to metabolite 3 was considerably lower, as determined by HPLC.     

Biotransformation of mestanolone and 17-methyl-1-testosterone by Rhizopus stolonifer

Abstract

Microbial transformation of mestanolone (1) using the plant pathogenic fungus, Rhizopus stolonifer, resulted in the production of two known metabolites, identified as 11α-hydroxymestanolone (3) and 6α-hydroxymestanolone (4). Transformation of 17-methyl-1-testosterone (2) by R. stolonifer yielded two known metabolites, methandrostenolone (5) and 11α,17β- dihydroxy-androsta-1,4-diene-3-one (6). These transformations included α-hydroxylations at C-11 and C-6, dehydrogenation at C-4, androsta and a demethylation at C-17 positions. Structures of transformed products were determined using spectroscopic techniques.     

Novel 2′-Deoxy Pyrazine C-Nucleosides Synthesized VIA Palladium-Catalyzed Cross-Couplings

Abstract

The palladium-catalyzed cross-couplings of 2-chloro-3,5-diamino-6-iodopyrazine (1a) and methyl 3-amino-6-iodopyrazine-2-carboxylate (1b) with 1,4-anhydro-3,5-O-bis[(tert-butyl)dimethylsilyl]-2-deoxy-D-erythro-pent-1-enitol (2) followed by desilylation and stereospecific reduction of the 2′-deoxy-3′-keto adduct leads to the formation of 2-chloro-6-(2-deoxy-ß-D-ribofuranosyl)-3,5-diaminopyrazine (4a) and methyl 3-amino-6-(2-deoxy-ß-D-ribofuranosyl)pyrazine-2-carboxylate (4b) in 58% yield and 21% yield, respectively. These are the first syntheses of the heretofore unknown 2′-deoxy pyrazine C-nucleosides and demonstrate the utility of a convergent approach for the synthesis of pyrazine C-nucleosides.     

Heteroatom-Containing Antibacterial Phenolic Metabolites from a Terrestrial Ampelomyces Fungus

Two new sulfur-containing phenolic compounds, 7-hydroxy-5-hydroxymethyl-2H-benzo[1,4]thiazin-3-one (1) and 2,5-dihydroxy-3-methanesulfinylbenzyl alcohol (2), along with two known compounds, 3-chloro-2,5-dihydroxybenzyl alcohol (3) and 2-hydroxy-6-methylbenzoic acid (4), were isolated from the mycelial solid culture of a soil-derived Ampelomyces fungus by antibacterial assay-guided fractionation. Their structures were elucidated on the basis of spectroscopic analysis. Compounds 1–3 showed structure and microbial dependent antibacterial activities.     

Biotransformation of (20S)-20-hydroxymethylpregna-1,4-dien-3-one by four filamentous fungi

Microbial transformation of (20S)-20-hydroxymethylpregna-1,4-dien-3-one (1) by four filamentous fungi, Cunninghamella elegans, Macrophomina phaseolina, Rhizopus stolonifer, and Gibberella fujikuroi, afforded nine new, and two known metabolites 2–12. The structures of these metabolites were characterized through detailed spectroscopic analysis. These metabolites were obtained as a result of biohydroxylation of 1 at C-6β, -7β, -11α, -14α, -15β, -16β, and -17α positions, except metabolite 2 which contain an O-acetyl group at C-22. These fungal strains demonstrated to be efficient biocatalysts for 11α-hydroxylation. Compound 1, and its metabolites were evaluated for the first time for their cytotoxicity against the HeLa cancer cell lines, and some interesting results were obtained.     

Biosynthesis of Coumarin Glycosides by Transgenic Hairy Roots of Polygonum multiflorum

To investigate the substrate specificity and regio-selectivity of coumarin glycosyltransferases in transgenic hairy roots of Polygonum multiflorum, esculetin (1) and eight hydroxycoumarins (2–9) were employed as substrates. Nine corresponding glycosides (10–18) involving four new compounds, 6-chloro-4-methylcoumarin 7-O-β-D-glucopyranoside (15), 6-chloro-4-phenylcoumarin 7-O-β-D-glucopyranoside (16), 8-hydroxy-4-methylcoumarin 7-O-β-D-glucopyranoside (17), and 8-allyl-4-methylcoumarin 7-O-β-D-glucopyranoside (18), were biosynthesized by the hairy roots.     

Biotransformation of pseudolaric acid B by Chaetomium globosum

Pseudolaric acid B (1) is a natural product with potent antifungal activity. We discovered that pseudolaric acid B did not kill but only suppress the growth of the filamentous fungus Chaetomium globosum. It was proposed that pseudolaric acid B was converted to metabolites with decreased antifungal activities. In this study, a scaled-up biotransformation of pseudolaric acid B by C. globosum produced five metabolites, including three new compounds, pseudolaric acid I (2), pseudolaric acid B 18-oyl-alanine (4) and pseudolaric acid B 18-oyl-serine (6), together with two known compounds, pseudolaric acid F (3) and pseudolaric acid B 18-oyl-glycine (5). The structures were characterized by NMR and MS spectroscopy. The major biotransformation reaction was conjugation with amino acids. None of the metabolites showed inhibitory effects on the growth of Candida albicans. The results suggested that biotransformation might be a detoxification process for fungi to resist antifungal drugs.     

谷氨酸脱氢酶与醇脱氢酶的共表达及其在制备(R)-2-氯-1-苯乙醇中的应用

【背景】醇脱氢酶AdhS能催化不对称还原反应制备(R)-2-氯-1-苯乙醇,但由于自身再生辅酶NADH的能力不足,需要辅酶再生酶协助其再生NADH。谷氨酸脱氢酶能以谷氨酸为底物,再生辅酶NAD(P)H,具有辅酶再生酶的潜力。【目的】克隆表达谷氨酸脱氢酶基因gdhA,构建谷氨酸脱氢酶GdhA与醇脱氢酶AdhS的大肠杆菌共表达体系,提高AdhS制备(R)-2-氯-1-苯乙醇的转化效率。【方法】从枯草芽孢杆菌(Bacillus subtilis) 168中克隆基因gdhA,并在大肠杆菌(Escherichia coli) BL21(DE3)中表达,分析辅酶再生活力;再与醇脱氢酶AdhS共表达,优化表达条件;分析不同辅酶再生方案对制备(R)-2-氯-1-苯乙醇的转化效率的影响。【结果】谷氨酸脱氢酶GdhA再生NADH的比活力为694 U/g。经GdhA与AdhS的共表达及表达条件优化后,制备(R)-2-氯-1-苯乙醇的转化效率达465 U/L。经比较,GdhA协助再生辅酶NADH,可使AdhS制备(R)-2-氯-1-苯乙醇的转化效率提高到约3倍。【结论】谷氨酸脱氢酶GdhA为NADH高效再生酶,与醇脱氢酶AdhS共表达可显著提高AdhS制备(R)-2-氯-1-苯乙醇的转化效率。     

Synthesis of 2′,3′-Dideoxy- and 3′-Azido-2′,3′-dideoxy-pyridazine Nucleosides as Potential Antiviral Agents

Abstract

The synthesis of 4-methoxy-, 4-amino-3-chloro-, and 4-amino-1-(2,3-dideoxy-B-D-glycero-pentofuranosyl)pyridazin-6-one nucleosides, 6,19 and 20 is described. The synthesis of 3,4-dichloropyridazin-6-one (10) was accomplished in 44% overall yield using bromomaleic anhydride (17) as the starting material. The condensation of the silylated base of 10 with the halogenose 12 in the presence of trimethylsilyl triflate as a catalyst afforded a mixture of3,4-dichloro-1-(3,5-di-O-p-toluoyl-2-deoxy-B-D-erythro-pentofuranosyl)pyrridazin-6-one (13) in 67% and its α-anomer 14 in 12% yield, respectively. A series of 3′-sulfonate esters were prepared to explore the synthesis of 3-chloro-4-hydroxy-1-(3-azido-2,3-dideoxy-B-D-erythro-pentofuranosyl) pyridazin-6-one (32) via 6,3-anhydronucleoside analogues. Compounds 15, 19 and 20 were evaluated against human immunodeficiency virus, human cytomegalovirus, and herpes simplex virus type 1 but were inactive.     

Method for the Synthesis of Uric Acid Derivatives

Abstract

A general procedure to obtain tetra-substituted uric acid by stepwise N-alkylation is described. 2,6-Dichloropurine (1) was condensed with 1-propanol by Mitsunobu reaction to give 9-propyl congener (2). Treatment of 2 with ammonia gave adenine derivative (4a), which was converted to the 8-oxoadenine (5b) in 3 steps. Methylation of 5b proceeded site-specifically to give 6-amino-2-chloro-7,8-dihydro-7-methyl-9-propylpurin-8-one (6) as a sole product. Compound 6 was successively treated with NaNO₂ and iodomethane to give 2-chloro-1,6,7,8-tetrahydro-1,7-dimethyl-9-propylpurin-6,8-dione (9) accompanied by the O ⁶-methyl product (8) in 75% and 6.9%, respectively. After nucleophilic substitution of 9 with NaOAc, the product (11) was reacted with iodomethane to give the uric acid (12) and the 2-methoxy product (13) in 46% and 15.5%, respectively. However, the reaction of 11 with the benzylating agents gave only O-benzyl products (14a,b).     

Biotransformation of prednisolone to hydroxy derivatives by Penicillium aurantiacum

Prednisolone, a synthetic adrenal corticosteroid drug, is known to have anti-inflammatory and autoimmune activity. Biotransformation of prednisolone was carried out to obtain more bioactive prednisolone derivatives. Among six different fungi, Penicillium aurantiacum proved to be the best prednisolone hydroxylator. As a result of prednisolone biotransformation by P. aurantiacum, whole cells four different prednisolone derivatives were investigated. 20β-Hydroxyprednisolone (1) and 21,21-dimethoxy-11β-hydroxypregn-1,4-dien-3,20-dione (2) were detected as the main metabolites. These metabolites together with other two metabolites, 11β-hydroxyandrost-1,4-dien-3,17-dione (3) and 11β,17β-dihydroxyandrost-1,4-dien-3- one (4), were purified and assigned by an interpretation of their spectral data using mass spectroscopy (MS), proton nuclear magnetic resonance (¹H-NMR), carbon nuclear magnetic resonance (¹³C-NMR) and infrared spectroscopy (IR) analyses. The best fermentation conditions for production of compounds 1–4 were as follows: medium (3) consisting of (g/l): glucose 20; l-asparagine 0.7; MgSO₄.7H₂O 0.5; KH₂PO₄ 1.52; KCl 0.52; Cu (NO₃)₂ traces; ZnSO₄.7H₂O traces, supplemented with prednisolone concentration of 0.3?mg/ml, inoculated by 10% of microorganism and incubated for 72?h. Under these optimized conditions, ～94.8% of the added prednisolone was converted to aforementioned derivatives, which have the potential to be used in industrial production of important pharmaceutical compounds.     

Enantiotopically Selective Oxidation of 1,5-Diols with Gluconobacters Preparation of (S)-Mevalonolactone

(±)-(2Z,4E)-α-Ionylideneacetic acid (2) was enantioselectively oxidized to (?)-(l′S)-(2Z,4E)-4′-hydroxy-α-ionylideneacetic acid (3), (+)-(1′R)-(2Z,4E)-4′-oxo-α-ionylideneacetic acid (4) and (+)-abscisic acid (ABA) (1) by Cercospora cruenta IFO 6164, which can produce (+)-ABA and (+)-4′-oxo-α-acid 4. This metabolism was confirmed by the incorporation of radioactivity from (±)-(2-¹⁴C)-(2Z,4E)-α-acid 2 into three metabolites. (?)-4′-Hydroxy-α-acid 3 was a diastereoisomeric mixture consisting of major 1′,4′-trance-4′-hydroxy-α-acid 3a and minor 1′,4′-cis-4′-hydroxy-α-acid 3b. These structures, 3a and 3b, were confirmed by ¹³C-NMR and ¹H-NMR analysis. Also, the enantioselectivity of the microbial oxidation was reexamined by using optically pure α-acid (+)-2 and (?)-2, as the substrates.     

Synthesis and characterization of quinazoline derivatives: search for hybrid molecule as diuretic and antihypertensive agents

Abstract

To explore the pharmacological and structure–activity relationship of a series of N-substituted-(4-oxo-2-substituted-phenylquinazolin-3-(4H)-yl), substituted benzene sulfonamide derivatives (1–25) were synthesized from substituted anthranilic acids derived amino quinazolines and substituted benzene sulphonamides. All the synthesized compounds were evaluated for their diuretic (by Lipschitz et al. method), antihypertensive activity by non-invasive blood pressure (NIBP) using the tail-cuff method and anti-diabetic potential in rats. Six compounds showing significantly excellent activity were compared with metolazone, prazosin and diazoxide as standards. Compound N-[7-chloro-2-(4-methoxyphenyl)-4-oxoquinazolin-3(4H)-yl]-4 nitrobenzenesulfonamide (20) exhibited most potent of the series.     

Semisynthesis and cytotoxic activities of andrographolide analogues

Andrographolide 1, a diterpenoid lactone of the plant Andrographis paniculata, known to possess antitumour activity in in vitro and in vivo breast cancer models was subjected to semisynthesis leading to the preparation of a number of novel compounds. These compounds exhibited in vitro antitumour activity with moderate to excellent growth inhibition against MCF-7 (breast) and HCT-116 (colon) cancer cells. Compounds 3,19-(2-chlorobenzylidene)andrographolide(5), 3,19-(3-chlorobenzylidene)andrographolide(6), 3,19-(3-fluorobenzylidene)andrographolide(7), 3,19-(4-fluorobenzylidene)andrographolide(8), 3,19-(2-fluorobenzylidene)andrographolide(10), 3,19-(2-chloro-5-nitrobenzylidene)andrographolide (21), 3,19-(4-chlorobenzylidene)andrographolide(30) and 3,19-(2-chloro-4-fluorobenzylidene) andrographolide(31) were also screened against 60 NCI (National Cancer Institute, USA) human tumour cell lines derived from nine cancer cell types.     

Bioreduction of α-chloroacetophenone by whole cells of marine fungi

The asymmetric reduction of 2-chloro-1-phenylethanone (1) by seven strains of marine fungi was evaluated and afforded (S)-(-)-2-chloro-1-phenylethanol with, in the best case, an enantiomeric excess of 50% and an isolated yield of 60%. The ability of marine fungi to catalyse the reduction was directly dependent on growth in artificial sea water-based medium containing a high concentration of Cl⁻ (1.2 M). When fungi were grown in the absence of artificial sea water, no reduction of 1 by whole cells was observed. The biocatalytic reduction of 1 was more efficient at neutral rather than acidic pH values and in the absence of glucose as co-substrate.     

Biotransformation of 5α-hydroxycaryophylla-4(12),8(13)-diene with Cunninghamella elegans and Rhizopus stolonifer

Abstract

Biotransformation of 5α-hydroxycaryophylla-4(12),8(13)-diene (1) was studied with Cunninghamella elegans and Rhizopus stolonifer. Incubation of 1 with C. elegans gave regioselective oxidative addition (hydration) and isomerization at the C-4(12) exocyclic double bond and hydroxylation at C-3 and C-15, and thus provided two polar metabolites, (3Z),8(14)-caryophylladiene-5α,(11R)-15-diol (2) and 3β,4β,5α-trihydroxycaryophylla-8(13)-ene (3). Incubation of 1 with R. stolonifer gave a transannular cyclization reaction and afforded 2β-methoxyclovan-9-one (4), clovan-2β-ol-9-one (5) and 8-methoxycaryolane-5α,13β-diol (6). Compounds 3 and 6 are new compounds described here for the first time; their structures were deduced with the help of different spectroscopic techniques.     

Design,synthesis and pharmacological evaluation of novel azole derivatives of aryl acetic acid as anti-inflammatory and analgesic agents

A series of substituted azole derivatives (3a–e, 4a–e and 5a–e) were synthesised by the cyclisation of N¹(diphenylethanoyl)-N⁴-substituted phenyl thiosemicarbazides under various reaction conditions. These compounds were tested in vivo for their anti-inflammatory activity. The compounds which showed activity comparable to the standard drug ibuprofen, were screened for their analgesic, ulcerogenic and lipid peroxidation activities. The compounds 5-(diphenylmethyl)-N-(4-fluorophenyl)-1,3,4-oxadiazol-2-amine (3b) and 5-(diphenylmethyl)-N-(3-chloro-4-fluorophenyl)-1,3,4-oxadiazol-2-amine (3c) emerged as the most active compounds of the series, and were moderately more potent than the standard drug, ibuprofen. (This abstract was published in Inflammation Research, Supplement 2, Volume 56, page A101, 2008.)     

SYNTHESIS OF PYRAZOLO[4,3-C]PYRIDINE C-RIBONUCLEOSIDES VIA AN EFFECTIVE TETRAZOLE TO PYRAZOLE TRANSFORMATION

Abstract

Methyl 2-[4-methoxycarbonyl-5-(β-D-ribofuranosyl)-1H-pyrazolyl-3]-acetate (7a) obtained from ribofuranosyltetrazole 3 by conjugative addition to dimethyl 1,3-allenedicarboxylate or dimethyl 3-chloro-2-pentenedioate after electrocyclization of 2-propenyltetrazole 5 was used as a suitable intermediate to provide pyrazolo [4,3-c]pyridine C-ribonucleosides 1 and 2 related to 7-substituted 3-deazaxanthosine and -guanosine analogs.     

Biotransformation of arenobufagin and cinobufotalin by Alternaria alternata

Abstract

The biotransformation of arenobufagin (1) and cinobufotalin (2), isolated from the natural medicine Chan Su, by Alternaria alternata AS 3.4578 was carried out. Incubation of 1 and 2 afforded six metabolites: 3-oxo-arenobufagin (1a), ψ-bufarenogin (1b), 3-oxo-ψ-bufarenogin (1c), 3-oxo-Δ⁴-derivative of cinobufotalin (2a), 3-oxo-cinobufotalin (2b) and 12β-hydroxycinobufotalin (2c). Among them, metabolites 1a, 1c and 2c are new compounds and their structures were characterized on the basis of their spectroscopic data (NMR, MS and IR). Compounds 1, 2, 1b, 2a and 2b were evaluated for their cytotoxicity against HepG2 and MCF-7 human cancer cells, and all of them showed significant inhibitory activities.