Synthesis of (±)-Methyl 5-(1′,2′-Epoxy-2′,6′-dimethylcyclohexyl)-3-methyl-(2Z,4E)-2,4-pentadienoate

The effect of tripropyltin chloride (TPT) on transport systems in E. coli was investigated. The inhibition on uptakes of ¹⁴C-l-leucine, l-proline, adenine and methyl-(α-d-gluco)pyrano-side (α-methylglucoside) by TPT was examined. The active uptake of l-leucine which utilized ATP molecule as an energy source was 100% inhibited at the concentration of 10 µg/ml TPT. On the other hand, the uptake of l-proline which was generated by an “energied” membrane state of the cells was inhibited only 40% at the same concentration of TPT. α-Methylglucoside uptake was scarcely inhibited. Adenine uptake was intensely inhibited at 20 µg/ml TPT. The effect of the delayed addition of TPT on transport systems was also examined. l-Leucine incorporated into cells was completely released from cells by TPT. Leucine binding protein (LBP) was prepared from E. coli cells and the effect of TPT on LBP activity was examined. TPT scarcely inhibited LBP activity.     

Discovery of (3S,4S)-3-methyl-3-(4-fluorophenyl)-4-(4-(1,1,1,3,3,3-hexafluoro-2-hydroxyprop-2-yl)phenyl)pyrrolidines as novel RORγt inverse agonists

A novel series of cis-3,4-diphenylpyrrolidines were designed as RORγt inverse agonists based on the binding conformation of previously reported bicyclic sulfonamide 1. Preliminary synthesis and structure–activity relationship (SAR) study established (3S,4S)-3-methyl-3-(4-fluorophenyl)-4-(4-(1,1,1,3,3,3-hexafluoro-2-hydroxyprop-2-yl)phenyl)pyrrolidine as the most effective scaffold. Subsequent SAR optimization led to identification of a piperidinyl carboxamide 31, which was potent against RORγt (EC₅₀ of 61 nM in an inverse agonist assay), selective relative to RORα, RORβ, LXRα and LXRβ, and stable in human and mouse liver microsomes. Furthermore, compound 31 exhibited considerably lower PXR Y_max (46%) and emerged as a promising lead. The binding mode of the diphenylpyrrolidine series was established with an X-ray co-crystal structure of 10A/RORγt.     

(2R,3S,4S)-2-(N,N-二乙氨基)甲酰氧基-3-苯基-4-苯甲酰基-N-甲基-γ-内酰胺的合成及工艺研究

目的：通过对黄皮酰胺全合成中间体（2R,3S,4S）-2-羟基-3-苯基-4-苯甲酰基-N-甲基-γ-内酰胺（化合物A）2位羟基的酯化,提高脂水分配系数（kP）,考察对谷丙转氨酶活性的影响。方法：以化合物A为原料,通过酰化反应合成（2R,3S,4S）-2-（N,N-二乙氨基）甲酰氧基-3-苯基-4-苯甲酰基-N-甲基-γ-内酰胺（化合物B）,重点考察了摩尔比、反应温度、反应时间等条件对反应的影响。化合物B结构已经元素分析、红外光谱、质谱及核磁共振氢谱确证。结果：化合物A和酰化剂以摩尔比2：3,在160℃下反应1h,目标化合物B。收率78．42％。结论：本合成路线及具体反应方法,具有试剂廉价易得、反应条件温和、后处理简便等优点,是一种较为实用的合成方法。     

2′-(E)-O-p-coumaroylgalactaric acid and 2′-(E)-O-feruloylgalactaric acid in citrus

2′-(E)-O-p-Coumaroyl- and 2′-(E)-O-feruloylgalactaric acids, hitherto unknown in nature, have been isolated and identified from orange peel.     

Synthesis and plant growth inhibitory activities of (+)- and (−)-(2Z,4E)-5-(1′,2′-epoxy-2′,6′,6′-trimethylcyclohexyl)-3-methyl-2,4-pentadienoic acid

Chiral (+)- and (?)-enantiomers of (2Z,4E)-5-(1′,2′-epoxy-2′,6′,6′-trimethylcyclohexyl)-3-methyl-2,4-pentadienoic acid have been synthesized from the chiral epoxy alcohols (+)- and (?)-1′,2′-dihydro-1′,2′-epoxy-β-ionone, which were prepared by Katsuki-Sharpless' asymmetric epoxidation of β-cyclogeraniol. The (+)-enantiomer showed strong inhibitory activity in a rice seedling and lettuce germination assay, whereas the (?)-enantiomer was 10³-times less active.     

Selective synthesis of cerebrosides: (2S, 3R, 4E)-1-O-β-d-galactopyranosyl-N-(2′R and 2′S)-2′-hydroxytetracosanoyl-sphingenine

The cerebrosides were first isolated by Thudicum in 1874 and the structures were established by Carteret al. in 1950 (for review, see [2]). In 1961 Shapiro and Flowers [3] reported the first total synthesis of a cerebroside1 (Fig. 1) which was identified with the natural sample, only through comparison of their i.r. data. In order to confirm the absolute configuration at C-2 of natural cerebroside1, we describe here an unambiguous synthesis of two stereoisomeric cerebrosides1 and2, and found that the¹H-NMR spectra of the synthetic1 (Fig. 2) was completely identical with that of the natural cerebroside reported recently by Dabrowskiet al. [4].In planning the synthetic route, the target structures1 and2 were disconnected at the dotted lines to give three key synthetic intermediates3, 4 and5 or6 (Fig. 1).Abbreviations Bu butyl - Ph phenyl - t-BuPh₂SiCl t-butyldiphenylsilyl chloride - MTPA -methoxy--trifluoromethylphenylacetic acid - THF tetrahydrofuran Part 36 in the series Synthetic Studies on Cell-surface Glycans, for part 35, see [1]     

Total synthesis of cerebrosides: (2S, 3R, 4E)-1-O-β-d-galactopyranosyl-N-(2′R and 2′S)-2′-hydroxytetracosanoylsphingenine

Total syntheses of both (2S, 3R, 4E)-1-O-β-d-galactopyranosyl-N-(2′R)-2′-hydroxytetracosanoylsphingenine 23 and the (2′S) stereoisomer were performed in an unambiguous way by employing either (2S, 3R, 4E)-N-(2′R)-2′-(tert-butyl-diphenylsilyloxy)tetracosanoylsphingenine or its (2′S) stereoisomer as the key glycosyl acceptors. The synthetic cerebroside 23 was shown to be identical with the natural product through comparison of their 400-MHz, ¹H-n.m.r. spectra, thus providing synthetic evidence for the 2′R configuration of the natural cerebroside.     

Synthesis,in vitro β-glucuronidase inhibitory activity and in silico studies of novel (E)-4-Aryl-2-(2-(pyren-1-ylmethylene)hydrazinyl)thiazoles

Current research is based on the synthesis of novel (E)-4-aryl-2-(2-(pyren-1-ylmethylene)hydrazinyl)thiazole derivatives (3–15) by adopting two steps route. First step was the condensation between the pyrene-1-carbaldehyde (1) with the thiosemicarbazide to afford pyrene-1-thiosemicarbazone intermediate (2). While in second step, cyclization between the intermediate (2) and phenacyl bromide derivatives or 2-bromo ethyl acetate was carried out. Synthetic derivatives were structurally characterized by spectroscopic techniques such as EI-MS, ¹H NMR and ¹³C NMR. Stereochemistry of the iminic double bond was confirmed by NOESY analysis. All pure compounds 2–15 were subjected for in vitro β-glucuronidase inhibitory activity. All molecules were exhibited excellent inhibition in the range of IC₅₀ = 3.10 ± 0.10–40.10 ± 0.90 μM and found to be even more potent than the standard d-saccharic acid 1,4-lactone (IC₅₀ = 48.38 ± 1.05 μM). Molecular docking studies were carried out to verify the structure-activity relationship. A good correlation was perceived between the docking study and biological evaluation of active compounds.     

Synthesis and screening of (E)-1-(β-D-galactopyranosyl)-4-(aryl)but-3-ene-2-one against Mycobacterium tuberculosis

A series of galactose-derived aryl enones were synthesised and screened against Mycobacterium tuberculosis H₃₇Rv. Preliminary results were promising with MIC values in the range 1.56-12.5 μg/mL.     

秦艽1-羟基-2-甲基-2-(E)-丁烯基-4-焦磷酸还原酶基因(GmHDR)的克隆和表达分析

龙胆苦苷(gentiopicroside)等裂环烯醚萜苷类化合物是中药秦艽中主要的有效成分,属于萜类化合物的衍生物,1-羟基-2-甲基-2-(E)-丁烯基-4-焦磷酸还原酶(1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate reductase,HDR)是植物萜类物质合成的关键酶之一。该研究在实验室高通量测序的基础上,采用RT-PCR方法克隆了秦艽HDR基因(即Gm HDR基因),利用生物信息学的方法分析了Gm HDR编码氨基酸序列的理化性质、信号肽、转运肽、亚细胞定位、保守结构域和高级结构等特征,并采用实时定量PCR分析了HDR的表达模式。结果表明:秦艽Gm HDR基因包含一个完整的长1 392 bp的ORF框,编码463个氨基酸;Gm HDR与萝芙木、艾菊等植物HDR蛋白具有很高的一致性(≥84%),无跨膜结构域,有叶绿体转运肽等结构,主要定位于叶绿体中。实时定量PCR结果显示,Gm HDR基因在秦艽的花中进行表达量高,在叶、茎和根等部位表达较低。Gm HDR在序列上与其他植物的HDR蛋白序列特征上存在很大的相似性;Gm HDR基因主要在秦艽花中表达,可能主要参与花中萜类物质的合成。该研究结果可为今后研究秦艽环烯醚萜类化合物的生物合成机制提供依据。     

Enantioselective enzymatic acetylation of racemic [4-[4α,6β (E)]]-6-[4,4-bis(4-fluorophenyl)-3-(1-methyl-1H-tetrazol-5-yl)-1,3-butadienyl]-tetrahydro-4-hydroxy-2H-pyran-2-one

Summary A chiral compound [4R-[4,6ß(E)]]-6-[4,4-bis(4-fluorophenyl)-3-(1-methyl-1H-tetrazol-5-yl)-1,3-butadienyl]-tetrahydro-4-hydroxy-2H-pyran-2-one (R-(+)-1) was prepared by the lipase-catalysed stereoselective acetylation of racemic 1 in an organic solvent. Chiral R-(+)-1 is a hydroxymethyl glutaryl coenzyme A (HMG CoA) reductase inhibitor and a potential anticholesterol drug candidate. Among various lipases evaluated, lipase PS-30 from Pseudomonas species efficiently catalysed acetylation of the undesired enantiomer of racemic 1 to yield the S-(–)-acetylated product 2 and unreacted desired R-(+)-1. A reaction yield of 48 mol% and an optical purity of 98% were obtained for R-(+)-1 when the reaction was conducted in toluence as solvent in the presence of isopropenyl acetate as acyl donor. Lipase PS-30 was immobilized on Accurel polypropylene (PP) and the immobilized enzyme was reused (five cycles) in the acetylation reaction without loss of enzyme activity, productivity, or optical purity of the R-(+)-1. The enzymatic acetylation process was scaled-up to 501 and a 640-l volume (preparative batches) at a substrate concentration of 4 g/l. R-(+)–1 was recovered from the preparative batches in 68–71% recovery yield with 98.5% gas chromatography homogeneity index and 98.5% optical purity. The S-(–) acetate 2 produced by the acetylation reaction was enzymatically hydrolysed by lipase PS-30 in a biphasic system to prepare the corresponding S-(–)-1.Correspondence to: R. N. Patel     

Microbiological synthesis of 5-ethyl- and (E)-5-(2-bromovinyl)-2′-deoxyuridine

Summary The title compounds were prepared by an enzymatic transdeoxyribosylation from 2 dGuo or 2 dThd to the respective heterocyclic bases, 5-ethyluracil and (E)-5-(2-bromovinyl)uracil, using the whole bacterial cells ofEscherichia coli as a biocatalyst.     

Synthesis,Protonation Behavior,Conformational Analysis,and Regioselective Enzymatic Acylation of the Novel Diamino Analogue of (E)-5-(2-Bromovinyl)-2′-deoxyuridine (BVDU)

Abstract

(E)-3′,5′-Diamino-5-(2-bromovinyl)-2′,3′,5′-trideoxyuridine (5), the diamino analogue of BVDU (1), was synthesized from BVDU. The protonation behavior of 5 has been studied by means of pH-metric measurements and NMR spectroscopy. This study allows the determination of the basicity constants and the stepwise protonation sites. Thus, the main species at physiological pH is the monoprotonated form. The conformational analysis of this nucleoside analogue was also carried out through ¹H NMR spectroscopy. In addition, a convenient synthesis of N-3′ and N-5′ acylated derivatives was developed by regioselective enzymatic acylation. Thus, Candida antarctica lipase B (CAL-B) selectively acylated the 5′-amino group, thus furnishing nucleosides 8. On the other hand, immobilized Pseudomonas cepacia lipase (PSL-C) exhibited the opposite selectivity, conferring acylation at the 3′-amino group, thus affording derivatives 9.     

(2E,4 E)-N-(2-氨基乙基-5-(苯并[d][1,3][二氧杂环戊烯]-5基)戊-2,4-二烯酰胺的合成及其降血脂作用

以金属钠为催化剂,加热回流合成(2E,4E)-N-(2-氨基乙基-5-(苯并[d][1. 3][二氧杂环戊烯]-5基)戊-2,4-二烯酰胺(C14H16N2O3,胡椒酸乙二胺,EPA),利用XRD、IR、1H、13C NMR对产物结构进行了表征和确认。以EPA的产率为指标,研究其最佳合成工艺参数。实验结果表明:当催化剂用量为1. 0 g(通氮气保护),加热回流温度65~70oC,反应时间45~48 h,为较好的合成工艺条件,EPA的合成收率达62. 93%以上,论文研究结果可为工业化生产提供设计依据。同时,EPA能显著降低高脂血症大鼠的血清TC、TG和LDL-C水平,且呈剂量依赖性; 2. 5 mg/kg剂量时显著升高HDL-C水平;并能显著升高高脂血症大鼠血清SOD和GSH-PX活力降低MDA含量。由此可知,降血脂作用与传统降血脂药物辛伐他汀相比,以降LDL-C作用更为明显。EPA具有一定的辅助降血脂功能及抗氧化作用。     

Stereoselective Synthesis of (2R, 3S)-2-Benzyl-2-hydroxy-3- (3,4-methylenedioxybenzyl)-γ-butyrolactone from L-(+)-Arabinose

As a model experiment for the stereoselective synthesis of optically active cis-α,β-dibenzyl-α-hydroxy-γ-butyrolactone, (2R, 3S)-2-benzyl-2-hydroxy-3-(3,4-methylenedioxybenzyl)-γ-butyrolactone (3) was stereoselectively synthesized from L-(+)-arabinose.     

巴西橡胶树4-羟基-3-甲基-2-(E)-丁烯基-4-磷酸还原酶基因(Hb-HDR)的克隆及表达分析

4-羟基-3-甲基-2-(E)-丁烯基-4-磷酸还原酶(4-hydroxy-3-methyl-2-(E)-butenyl-4-diphosphatereductase,HDR)是异戊烯基焦磷酸合成途径之一甲基赤藓糖磷酸(methylerythritol phosphate,MEP)途径中的最后一个酶,催化4-羟基-3-甲基-(2E)-丁烯基-4-磷酸生成异戊烯基焦磷酸.根据植物HDR的同源序列设计引物,通过RT-PCR结合RACE的方法在橡胶树中获得了与其相应的HDR基因,命名为HbHDR.序列分析表明HbHDR长1 627 bp,编码462个氨基酸,属于LYTB家族,该氨基酸序列与烟草、长春花、胡黄连、拟南芥、银杏和火炬松的HDR同源性为79.1%、78.4%、76.5%、75.3%、72.2%和70.9%.半定量RT-PCR结果显示,乙烯诱导胶乳HbHDR的表达.     

Efficient Syntheses of (E)-5-(2-Bromovinyl)-2′-deoxy-4-thiouridine; A Nucleoside Analogue with Potent Biological Activity

Abstract

(E)-5-(2-Bromovinyl)-2′-deoxy-4′-thiouridine (S-BVDU) is a potent antiherpesvirus agent and its use in gene therapy as an anticancer agent has recently been described. We here outline 2 efficient methods for the synthesis of S-BVDU. The decision as to which method is to be used depends upon the starting materials available but starting from BVU, an overall yield of β-nucleoside of 35% can be expected. From 5-ethyl-2′deoxy-4-thiouridine, radical bromination using bromine will give a quantitative conversion to S-BVDU if unreacted starting material is recycled (50%) or using N-bromosuccinimide, a one step yield in excess of 80% can be obtained.     

Stereospecific Synthesis and Anti-HIV Activity of (Z)2′- and (E)3′-Deoxy-2′(3′)-C-(chloromethylene) Pyrimidine Nucleosides

Abstract

Reaction of 1-[2,5(and 3,5)-di-O-trityl-β-D-erythro-pentofuran-3 (and 2)-ulosyl]uracil derivatives 5 and 6 with (chloromethyl)triphenylphosphorane resulted in the stereoselective formation of (E)-3′- and (Z)-2′-chloromethylene derivatives 7 (69%) and 8 (53%), respectively, deprotection of which gave 9 and 10. Transformation of the uracil nucleoside 7 into cytosine one followed by deprotection yielded 12. The latter was converted into the arabinoside 14. The fully deprotected chloromethylene nucleosides were tested for their activity against HIV-1 and HIV-2.     

Theoretical studies on all-metal binuclear sandwich-like complexes M2(η4-E4)2 (M=Al, Ga, In; E=Sb, Bi)

A series of all-metal binuclear sandwich-like complexes with the formula M(2)(η(4)-E(4))(2) (M=Al, Ga, In; E=Sb, Bi) was studied by density functional theory (DFT). The most stable conformer for each of the M(2)(η(4)-E(4))(2) species is the staggered one with D (4d) symmetry. The centred metal-metal bond in each M(2)(η(4)-E(4))(2) species is a covalent single bond, with the main contributors to these covalent bonds being the a(1) and e orbitals. For all these species, the interactions between the centred metal atoms and the all-metal ligands are covalent; η(4)-Sb (4) (2-) has a stronger ability to stabilize metal-metal bonds than η(4)-Bi (4) (2-). Nucleus-independent chemical shifts (NICS) values and molecular orbital (MO) analysis reveal that the all-metal η(4)-Sb (4) (2-) and η(4)-Bi (4) (2-) ligands in M(2)(η(4)-E(4))(2) possess conflicting aromaticity (σ antiaromaticity and π aromaticity), which differs from the all-metal multiple aromatic unit Al (4) (2-). In addition, all of these M(2)(η(4)-E(4))(2) species are stable according to the dissociation energies of M(2)(η(4)-E(4))(2)?→?2 M(η(4)-E(4)) and M(2)(η(4)-E(4))(2)?→?2 M?+?2E(4), and these stable species can be synthesized by two-step substitution reactions: CpZnZnCp?+?2E (4) (2-) →?[E(4)ZnZnE(4)](2-)?+?2Cp(-) and [E(4)ZnZnE(4)](2-)?+?2 M (2) (+) →?E(4)MME(4)?+?2Zn(+).     

Synthesis,Molecular Conformation and Activity Against Herpes Simplex Virus of (E)-5-(2-Bromovinyl)-2′-Deoxycytidine Analogs

Analogs of (E)-5-(2-bromovinyl)-2 ′-deoxycytidine (BrVdCyd) (1) by substitution at N⁴ were synthesized to impart resistance against deamination. The anti-HSV-1 activity and solution conformation of these analogs were determined. N⁴-Acetyl-BrVdCyd (2) was a potent inhibitor of HSV-1 replication whereas N⁴-propanoyl-BrVdCyd (3) had good activity and N⁴-Butanoyl-BrVdCyd (4) had only low activity against HSV-1 replication. N⁴-Methyl-BrVdCyd (5) was devoid of activity against HSV-1.