Studies on Geobacillus stearothermophilus – Part V: Transformation of 11α-hydroxyprogesterone

The influence of a hydroxyl group on the biotransformation of 11α-hydroxyprogesterone mediated by the thermophile Geobacillus stearothermophilus, was investigated. Bacterial transformation of 11α-hydroxyprogesterone resulted in the formation of previously reported six hydroxylated progesterone metabolites, identified as 11α-hydroxy-5α-pregnane-3, 6, 20-trione 1, 11α, 20α-dihydroxypregnene-3-one 2, 11α, 6β-dihydroxyprogesterone 3, 11α, 6α-dihydroxyprogesterone 4, 11α, 6β, 20α-trihydroxypregnene-3-one 5, 11α, 6α, 20α-trihydroxypregnene-3-one 6. All transformation products were identified through their spectral data and comparison with reference compounds.     

Synthesis of a Base-Protected xylo-LNA Adenine Nucleoside

Abstract

Synthesis of (1S,3R,4R,7R)-7-hydroxy-1-hydroxymethyl-3-(6-N-benzoyl-adenin-9-yl)-2,5-dioxabicyclo[2.2.1]heptane (2), a base-protected xylo-LNA adenine nucleoside, has been accomplished using a convergent synthetic strategy starting from 1,2-di-O-acetylfuranose 3.     

An Improved Synthesis of 1-(2-Deoxy-β-D-erythro-pentofuranosyl)quinazoline-2,4(3H)-dione and Its Incorporation Into G-Rich Triple Helix Forming Oligonucleotides

Abstract

A convenient synthesis of 1-(2-deoxy-β-D-erythro-pentofuranosyl)quinazoline-2,4(3H)-dione ( 6 ) has been accomplished. The structural conformation of ( 6 ) was derived by 2D NMR, COSY and NOESY experiments. Nucleoside ( 6 ) was incorporated into G-rich triplex forming oligonucleotides (TFOs) by solid-support, phosphoramidite method. The triplex forming capabilities of modified TFOs (S2, S3 and S4) has been evaluated in antiparallel motif with a target duplex (duplex-31) 5′d(GTCACTGGCCCTTCCTCCTTCCCGGTCTCAG)3′-5′d(CAGTGACCGGGAAGGAGGAAGGGCCAGAGT)3′ (D1) at pH 7.6. The parallel triplex formation of a shorter TFO (S6) containing Q has also been studied with a target duplex-11 (D2) at pH 5.0.     

Synthesis of new pyridothienopyrimidinone derivatives as Pim-1 inhibitors

Four series of pyridothienopyrimidin-4-one derivatives were designed and prepared to improve the pim-1 inhibitory activity of the previously reported thieno[2,3-b]pyridines. Significant improvement in the pim-1 inhibition and cytotoxic activity was achieved using structure rigidification strategy via ring closure. Six compounds (6c, 7a, 7c, 7d, 8b and 9) showed highly potent pim-1 inhibitory activity with IC₅₀ of 4.62, 1.18, 1.38, 1.97, 8.83 and 4.18?μM, respectively. Four other compounds (6b, 6d, 7b and 8a) showed moderate pim-1 inhibition. The most active compounds were tested for their cytotoxic activity on three cell lines [MCF7, HCT116 and PC3]. Compounds 7a [the 2-(2-chlorophenyl)-2,3-dihydro derivative] and 7d [the 2-(2-(trifluoromethyl)-phenyl)-2,3-dihydro derivative] displayed the most potent cytotoxic effect on the three cell lines tested consistent with their highest estimated pim-1 IC₅₀ values.     

柯拉斯那沉香的生物活性成分研究

为了解柯拉斯那(Aquilaria crassna)的化学成分,从其所产沉香中分离得到10个化合物,经波谱分析分别鉴定为:6,8-羟基-2-(2-苯乙基)色酮(1),6,8-二羟基-2-[2-(4-甲氧基苯)乙基]色酮(2),rel-(1a R,2R,3R,7b S)-1a,2,3,7b-tetrahydro-2,3-dihydroxy-5-(2-phenylethyl)-7H-oxireno[f][1]benzopyran-7-one(3),rel-(1a R,2R,3R,7b S)-1a,2,3,7b-tetrahydro-2,3-dihydroxy-[2-(4-methoxyphenyl)-ethyl]-7H-oxireno[f][1]benzopyran-7-one(4),rel-(1a R,2R,3R,7b S)-1a,2,3,7b-tetrahydro-2,3-dihydroxy-5-[2-(3-hydroxy-4-methoxyphenyl)-ethyl]-7H-oxireno[f][1]benzopyran-7-one(5),oxidoagarochromone B(6),oxidoagarochromone C(7),(5S,6R,7S,8R)-2-[2-(3′-hydroxy-4′-methoxyphenyl)ethyl]-5,6,7,8-tetrahydroxy-5,6,7,8-tetrahydrochromone(8),6,7-cis-dihydroxy-2-(2-phenylethyl)-5,6,7,8-tetrahydrochromone(9),N-trans-feruloyltyramine(10)。化合物3~5和8~10为首次从柯拉斯那沉香中分离得到。化合物1,3,6,7,9和10对乙酰胆碱酯酶具有一定的抑制活性,化合物4对人慢性髓原白血病细胞株K-562和人胃癌细胞株SGC-7901均具有较小的抑制作用,化合物1和3对人肝癌细胞株BEL-7402也有抑制活性。     

Definitive Solution Structures for the 6-Formylated Versions of 1-(βD-Ribofuranosyl)-, 1-(2′-Deoxy-β-D-Ribofuranosyl)-, and 1-β-D-Arabinofuranosyluracil,and of Thymidine

Abstract

ROESY and NOESY NMR spectroscopic analyses of the ribofuranosyl (1a), 2′-deoxyribofuranosyl (1b), and arabinofuranosyl (1c) derivatives of 6-formyluracil in (CD₃)₂SO and D₂O solutions have established that each exclusive 7,05′-cyclic hemiacetal diastereomer of 1a,b and the major 7,O2′-cyclic hemiacetal diastereomer of 1c possess the 7R configuration. In addition, (7R)-1c has been shown to be thermodynamically more stable than (7S)-1c, contrary to our previous indication. A new, higher yielding synthetic route to 1a has been developed, 1b has been obtained for the first time in crystalline form, the route to 1c has been modified to better accommodate large scale preparations, and a new, fourth member of this class, 6-formylthymidine (1d), has been synthesized and its solution structures in (CD₃)₂SO, D₂O, and CD₃OD have been determined. Antitumor and antiviral evaluations of 1a-c have revealed no significant levels of activity.     

Reaction of Retinol with Peroxynitrite

The reactivity of retinol with peroxynitrite, which is a strong oxidant and has been reported to induce several biological damages, was investigated. 13-cis-14-nitroretinol (1), 13-trans-14-nitroretinol (2), 13-apo-β-carotenone (3), retinal (4), 11,14-epoxyretinol (5), and 11,15-epoxyretinol (6) were identified as reaction products of retinol with peroxynitrite. From these results, it was observed that retinol can undergo a nitration reaction with peroxynitrite. Furthermore, the formation mechanisms of 1, 2, and 3 from retinol with peroxynitrite are discussed.     

Efficient Synthesis of a New L-Shaped Dimer of Naphthalene,and Its Analogs

Efficient syntheses of 14H-dinaphtho[1,8-bc:1′,8′-fg]oxocin-14-one (2), 14H-dinaphtho[1,8-bc:1′,2′-f]oxepin-14-one (3), and 2,2′(2H,2′H)-spirobi[naphtho[1,8-bc]furan] (9) are described. The putative structure of 2 has been reported previously, but the synthetic route was not reproducible. 7H-Dibenzo[c,h]xanthen-7-one (4), a known compound, was obtained by a different method. Possible reaction mechanism are proposed.     

Synthesis,conformation and biological activity of centrally modified pseudopeptidic analogues of For-Met-Leu-Phe-OMe

Summary. For-Met-βAlaψ[CSNH]-Phe-OMe (3), For-Met-βAlaψ[CH₂NH]-Phe-OMe (5), For-Met-NH-pC₆H₄-SO₂-Phe-OMe (8a), For-Met-NH-mC₆H₄-SO₂-Phe-OMe (8b) and the corresponding N-Boc precursors (2, 4, 7a, b) have been synthesized and their activity towards human neutrophils has been evaluated in comparison with that shown by the reference tripeptide For-Met-Leu-Phe-OMe (fMLF-OMe). Chemotaxis, lysozyme release and superoxide anion production have been measured. ¹H NMR titration experiments and IR spectra have been discussed in order to ascertain the preferred solution conformation adopted by the tripeptide 3 with particular reference to the presence of a folded conformation centred at the centrally positioned thionated β-residue.     

Synthesis of “Reversed” Methylenecyclopropane Analogues of Antiviral Phosphonates

Synthesis of “reversed” methylenecyclopropane analogues of nucleoside phosphonates 6a,7a, 6b, and 7b is described. 1-Bromo-1-bromomethylcyclopropane 8 was converted to the bromocyclopropyl phosphonate 9 by Michaelis-Arbuzov reaction with triisopropyl phosphite. Base-catalyzed β-elimination and deacetylation gave the key Z- and E-hydroxymethylcyclopropyl phosphonates 10 and 11 separated by chromatography. The Mitsunobu type of alkylation of 10 or 11 with adenine or 2-amino-6-chloropurine afforded phosphonates 12a, 12b, 13a, and 13b. Acid hydrolysis furnished the adenine and guanine analogues 6a, 7a, 6b, and 7b. The E and Z configuration was assigned on the basis of NOE experiments with phosphonates 6b and 7b. All Z- and E-isomers were also distinguished by different chemical shifts of CH₂O or CH₂N (H₄ or H_4′). Significant differences of the chemical shifts of the cyclopropane C_3(3’) carbons and coupling constants ³J_P,C2(2’) or ³J_P,C3(3’) selective for the Z- or E-isomers were also noted. Phosphonates 6a, 7a, 6b, and 7b are devoid of significant antiviral activity.     

A facile synthesis of (1S,5R,6S)-5-azido-6-benzyloxycyclohex-2-en-1-ol

A facile and short synthesis of (1S,5R,6S)-5-azido-6-benzyloxycyclohex-2-en-1-ol (1) has been achieved in high yield starting from 4,5-epoxycyclohex-1-ene by using a catalytic asymmetric allylic oxidation reaction.     

Mutational biosynthesis of neomycin analogs by a mutant of neomycin-producing <Emphasis Type="Italic">Streptomyces fradiae</Emphasis>

Neomycin, produced by Streptomyces fradiae, has been widely used for the treatment of bacterial infections in clinical and agricultural applications. In this study, a neomycin nonproducing mutant of S. fradiae was obtained by gene disruption technique for mutational biosynthesis. A crucial gene neoC (neo7) which encodes 2-deoxystreptamine (2-DOS) synthases was disrupted. The mutant could resume producing neomycin in the presence of 2-DOS. Salen derivatives of 2-DOS were synthesized and individually added to cultures of the mutant. Antibacterial activity of the mutasynthesis products against Staphylococcus aureus and four plant pathogenic bacteria (Pseudomonas solanacarum, Erwinia carotovora, Xanthomonas oryzae, and Xanthomonas campestris) was detected quantitatively by Oxford cup method. It is suggested that all 2-DOS derivatives were incorporated by the mutant into new active neomycin analogs except for 2-DOS derivative 2d ((1R,2r,3S,4R,6S)-4,6-bis((E)-3,5-di-tert-butyl-2-hydroxybenzylideneamino)cyclohexane-1,2,3-triol). Neomycin analogs produced by feeding 2-DOS derivative 2a ((1R,2r,3S,4R,6S)-4,6-bis((E)-2 hydroxybenzylideneamino)cyclohexane-1,2,3-triol) to cultures of the mutant displayed a similar antibacterial activity with neomycin produced by wild strain.     

Human trachea primary epithelial cells express both sialyl(α2-3)Gal receptor for human parainfluenza virus type 1 and avian influenza viruses, and sialyl(α2-6)Gal receptor for human influenza viruses

We reported previously that the dominant receptors of influenza A and B viruses, and human and murine respiroviruses, were sialylglycoproteins and gangliosides containing monosialo-lactosamine type I-and II-residues, such as sialic acid-α2-3(6)-Galβ1-3(4)-GlcNAcβ1-. In addition, the Siaα2-3Gal linkage was predominantly recognized by avian and horse influenza viruses, and human parainfluenza virus type 1 (hPIV-1), whereas the Siaα2-6Gal linkage was mainly recognized by human influenza viruses (Paulson JC in “The Receptors' [Conn M Ed] 2, 131–219 (1985); Suzuki Y, Prog Lipid Res 33, 429–57 (1994); Ito T, J Virol 73, 6743–51 (2000); Suzuki Y, J Virol 74, 11825–31 (2000); Suzuki T, J. Virol 75, 4604–4613 (2001); Suzuki Y, Biol. Pharm. Bull. 28, 399–408 (2005)). To clarify the distribution of influenza virus receptors on the human bronchial epithelium cell surface, we investigated a primary culture of normal human bronchial epithelial (NHBE) cells using two types of lectin (MAA and SNA), which recognize sialyl linkages (α2-3 and α2-6), using fluorescence-activated cell-sorting analysis. The results showed that both α2-3- and α2-6-linked Sias were expressed on the surface of primary human bronchial epithelial cells. The cells infected by hPIV-1 bound to MAA, confirming that cells targeted by hPIV-1 have α2-3-linked oligosaccharides. We also compared the ability of hPIV-1 and human influenza A virus to infect primary human bronchial epithelial cells pre-treated with Siaα2-3Gal-specific sialidase from Salmonella typhimurium. No difference was observed in the number of sialidase pre-treated and non-treated cells infected with human influenza A virus, which binds to Siaα2-6Gal-linked oligosaccharides. By contrast, the number of cells infected with hPIV-1 decreased significantly upon sialidase treatment. Thus, cultured NHBE cells showed both α2-3-linked Sias recognized by hPIV-1 and avian influenza virus receptors, and α2-6-linked Sias recognized by human influenza virus receptors.     

A facile synthesis of novel pyrazolopyrimidine thioglycosides as purine thioglycoside analogues

The easy, convenient and high yielding preparation of new thioglycosides incorporating mercaptopyrazolo[1,5-a]pyrimidine moieties from readily accessible starting materials has been reported. The main step of this protocol is the formation of 7-mercaptopyrazolo[1,5-a]pyrimidine-6-carbonitrile derivatives 4a-d by condensation of sodium 2-cyano-3-ethoxy-3-oxoprop-1-ene-1,1-bis(thiolate) 1 with 4-(aryldiazenyl)-1H-pyrazole-3,5-diamines 3a-d to form target compounds 4a-d, which coupled with tetra-O-acetyl-α-D-glycopyranosyl bromides 5a,b in the presence of basic medium to provide the corresponding product purine thioglycoside analogs 6a-h. Ammonolysis of the latter compounds 6a-d at ambient temperature for 10 minutes, led to the free glycoside derivatives 7a-h, which were obtained in approximately quantitative yields. Their structures were created based on the spectroscopic and elemental data.     

The chemical constituents of Piper kadsura and their cytotoxic and anti-neuroinflammtaory activities

The n-hexane and CHCl₃ soluble fractions of the MeOH extract of the aerial parts of Piper kadsura were found to potently inhibit nitric oxide (NO) production in LPS-activated BV-2 cells, a microglial cell line. From the active fractions, a new stereoisomer of guaiane sesquiterpene, 1α,5β-guai-4(15)-ene-6β,10β-diol, kadsuguain A (1) and a new cyclohexadienone, kadsuketanone A (2), together with twelve known compounds (3–14) were isolated. The structures of these compounds were elucidated by extensive NMR spectral studies. The absolute configuration of 2 was determined by circular dichroism (CD) spectra. Compounds 2, 6, and 11–14 significantly inhibited both nitric oxide (NO) and prostaglandin E₂ (PGE₂) production in the LPS-activated microglia cells. In addition, compounds 4, 6, and 11–14 exhibited cytotoxicity against the A549, SK-OV-3, SK-MEL-2, and HCT15 human tumour cells.     

Design and synthesis of novel cell wall inhibitors of Mycobacterium tuberculosis GlmM and GlmU

GlmM and GlmU are key enzymes in the biosynthesis of UDP-N-acetyl-d-glucosamine (UDP-GlcNAc), an essential precursor of peptidoglycan and the rhamnose–GlcNAc linker region in the mycobacterial cell wall. These enzymes are involved in the conversion of two important precursors of UDP-GlcNAc, glucosamine-6-phosphate (GlcN-6-P) and glucosamine-1-phosphate (GlcN-1-P). GlmM converts GlcN-6-P to GlcN-1-P, GlmU is a bifunctional enzyme, whereby GlmU converts GlcN-1-P to GlcNAc-1-P and then catalyzes the formation of UDP-GlcNAc from GlcNAc-1-P and uridine triphosphate. In the present study, methyl 2-amino-2-deoxyl-α-d-glucopyranoside 6-phosphate (1α), methyl 2-amino-2-deoxyl-β-d-glucopyranoside 6-phosphate (1β), two analogs of GlcN-6-P, were synthesized as GlmM inhibitors; 2-azido-2-deoxy-α-d-glucopyranosyl phosphate (2) and 2-amino-2,3-dideoxy-3-fluoro-α-d-glucopyranosyl phosphate (3), analogs of GlcN-1-P, were synthesized firstly as GlmU inhibitors. Compounds 1α, 1β, 2, and 3 as possible inhibitors of mycobacterial GlmM and GlmU are reported herein. Compound 3 showed promising inhibitory activities against GlmU, whereas 1α, 1β and 2 were inactive against GlmM and GlmU even at high concentrations.     

Synthesis and Biological Properties of 2-Amino-3-fluoro-2,3-Dideoxy-D-Pentofuranosides of Natural Heterocyclic Bases

Abstract

The oxidation of methyl 5–0-benzyl-3-deoxy-3-fluoro-α-D-arabi-nofuranoside (1) with DMSO/Ac₂o afforded a ～ 2:1 mixture of 2-keto derivatives with erythro and threo configuration resulting from isomerization at C3. Successive treatment of the above mixture with MeONH₂, LiA1H₄, and S-ethyl trifluoroacetate followed by silica gel chromatography afforded methyl 5–0-benzyl-2, 3-dideoxy-3-fluoro-2-(trifluoroacetamido)-α-D-ribofuranoside (6b) and its lyxo isomer 7b in a total yield of 25% and 5%, respectively. The arabino analogue 25 was prepared from 6b. Compounds 6b, 7b and 25 were converted to the corresponding 5–0-benzoyl derivatives 8a, 9 and 26. A series of 2′-amino-2′, 3′-dideoxy-3′-fluoro-β-D-ribo- and-α-D-lyxofuranosides of natural heterocyclic bases have been synthesized starting from 8a and 9. None of the test compounds had any antiviral activity. 3′-Fluoro-2′-amino-2′, 3′-dideoxycytidine (16) was the only compound showing inhibition of murine L1210 and human Molt/4F cell proliferation (50% effective concentration: 39–42μg/m1).     

Compounds with neuroprotective activity from the medicinal plant Machilus thunbergii

The dichloromethane fraction of the bark of Machilus thunbergii Sieb. et Zucc. (Lauraceae) significantly protected primary cultures of rat cortical cells exposed to the excitotoxic amino acid, L-glutamate. Through the activity-guided isolation from the CH₂Cl₂ fraction, (+)-9′-hydroxygalbelgin (1), isogalcatin B (2), (7S,8S,8′R)-3′,4′-dimethoxy-3,4,-methylenedioxylignan-7-ol (3), 1-hydroxy-7-hydroxymethyl-6-methoxyxanthone (4), 5,7-dimethoxy-3′,4′-methylenedioxyflavan-3-ol (5), (+)-(3S,4S,6R)-3,6-dihydroxypiperitone (6), protocatechuic acid methyl ester (7) and tyrosol (8) were obtained. All of them had significant neuroprotective activities against glutamate-induced neurotoxicity in primary cultures of rat cortical cells at concentrations ranging from 0.1 μM to 10.0 μM and were comparable to MK-801, a well-known inhibitor of glutamate receptor.     

Synthesis and Biological Evaluation of 1,3-Oxathiolane 5-Azapyrimidine, 6-Azapyrimidine,and Fluorosubstituted 3-Deazapyrimidine Nucleosides

Abstract

(2R,5S)-5-Amino-2-[2-(hydroxymethyl)-1,3-oxathiolan-5-y1]-1,2,4-triazine-3(2H)-one (8) and (2R,5R)-5-amino-2-[2-(hydroxymethyl)-1,3-oxathiolan-5-y1]-1,2,4-triazine-3(2H)-one (9) have been synthesized via a multi-step procedure from 6-azauridine. (2R,5S)-4-Amino-1-[2-(hydroxymethyl)-1,3-oxathiolan-5-y1]-1,3,5-triazine-2(1H)-one (11) and (2R,5R)-4-amino-1-[2-(hydroxymethyl)-1,3-oxathiolan-5-y1]-1,3,5-triazine-2(1H)-one (12), and the fluorosubstituted 3-deazanucleosides (19–24) have been synthesized by the transglycosylation of (2R,5S)-1-{2-[[(tert-butyldiphenylsilyl) oxy]methyl]-1,3-oxathiolan-5-y1} cytosine (2) with silylated 5-azacytosine and the corresponding silylated fluorosubstituted 3-deazacytosines, respectively, in the presence of trimethylsilyl trifluoromethanesulfonate as the catalyst in anhydrous dichloroethane, followed by deprotection of the blocking groups. These compounds were tested in vitro for cytotoxicity against L1210, B₁₆F₁₀, and CCRF-CEM tumor cell lines and for antiviral activity against HIV-1 and HBV.     

Hydroxylation of (+)-menthol by Macrophomina phaseolina

Abstract

Biotransformation of (+)-menthol with Macrophomina phaseolina led to hydroxylations at C-1, C-2, C-6, C-7, C-8 and C-9, with the C-8 position being preferentially oxidized. The resulting metabolites were identified as 8-hydroxymenthol (2), 6R-hydroxymenthol (3), 1R-hydroxymenthol (4), 9-hydroxymenthol (5), 2R,8-dihydroxymenthol (6), 8S,9-dihydroxymenthol (7), 6R,8-dihydroxymenthol (8), 1R,8-dihydroxymenthol (9) and 7,8-dihydroxymenthol (10). Metabolites 6–10 are described here for the first time. Their structures were characterized by spectroscopic analysis.