Elaboration of 2-(trifluoromethyl)indoles via a cascade coupling/condensation/deacylation process

CuI/l-proline-catalyzed coupling of 2-halotrifluoroacetanilides with beta-keto esters in anhydrous DMSO under the action of Cs2CO3 at 40-80 degrees C produces polysubstituted 2-(trifluoromethyl)indoles in good to excellent yields. This reaction is suggested to occur via a novel coupling/condensation/deacylation mechanism, and many functional groups are tolerated under these conditions.

CCDC134, a novel secretory protein, inhibits activation of ERK and JNK, but not p38 MAPK

In this study, we report a novel gene, CCDC134 (coiled-coil domain containing 134), that encodes a secretory protein that can inhibit the MAPK pathway as a novel human MAPK-regulating protein. The CCDC134 mRNA contains 1280 nucleotides, encoding a protein of 229 amino acids. CCDC134 is a classical secretory protein. Expression profile analysis by Northern blot, RT-PCR, immunohistochemistry and Western blot reveals that CCDC134 is widely expressed in normal adult tissues, tumor tissues and cell lines. Functional investigation reveals that overexpression of CCDC134 and its purified protein significantly inhibit transcriptional activity of Elk1 and phosphorylation of Erk and JNK/SAPK but not p38 MAPK. Conversely, specific siRNA against CCDC134 activates Elk1 transcriptional activity and promotes Erk and JNK/SAPK phosphorylation. These results clearly indicate that CCDC134 is a novel member of the secretory family and down-regulates the Raf-1/MEK/ERK and JNK/ SAPK pathways.

Cascade Coupling/Cyclization Process to N-Substituted 1,3-Dihydrobenzimidazol-2-ones

Assembly of N-substituted 1,3-dihydrobenzimidazol-2-ones is achieved starting from methyl o-haloarylcarbamates via a CuI/amino acid catalyzed coupling with amines and subsequent condensative cyclization. A number of functional groups are tolerated by these reaction conditions, including vinyl, nitro, carboxylate, amide, ester, ketone, and silyl ether groups.

CuI-catalyzed domino process to 2,3-disubstituted benzofurans from 1-bromo-2-iodobenzenes and beta-keto esters

CuI-catalyzed coupling of 1-bromo-2-iodobenzenes with beta-keto esters in THF at 100 degrees C leads to 2,3-disubstituted benzofurans. This domino transformation involves an intermolecular C-C bond formation and a subsequent intramolecular C-O bond formation process. Benzofurans with different substituents at the 5- and 6-position are accessible by employing the corresponding 1-bromo-2-iodobenzenes.

Assembly of Conjugated Enynes and Substituted Indoles via CuI/Amino Acid-Catalyzed Coupling of 1-Alkynes with Vinyl Iodides and 2-Bromotrifluoroacetanilides

Cross-coupling of 1-alkynes with vinyl iodides occurs at 80 degrees C in dioxane catalyzed by CuI/N,N-dimethylglycine to afford conjugated enynes in good to excellent yields. Heating a mixture of 2-bromotrifluoroacetanilide, 1-alkyne, 2 mol % of CuI, 6 mol % of L-proline, and K(2)CO(3) in DMF at 80 degrees C leads to the formation of the corresponding indole. This conversion involves a CuI/L-proline-catalyzed coupling between aryl bromide and the 1-alkyne followed by a CuI-mediated cyclization process. An ortho-substituent effect directed by NHCOCF3 enables the reaction to proceed under these mild conditions. Both aryl acetylenes and O-protected propargyl alcohol can be applied, leading to 5-, 6-, or 7-substituted 2-aryl and protected 2-hydroxymethyl indoles in good yields. With simple aliphatic alkynes, however, lower yields were observed.

Asymmetric total syntheses of marine cyclic depsipeptide halipeptins A-D

Halipeptins A-D (1 a-d) are a family of natural cyclic depsipeptides isolated from marine sponges. Total syntheses of these four compounds are detailed in this report. The key elements in this synthesis include the elaboration of the polysubstituted decanoic acid parts by two asymmetric aldol reactions, assembly of the N-methyl-delta-hydroxyisoleucine residue by using either aza-Claisen rearrangement or methylation of aspartates as the key steps, and macrocyclization at the polysubstituted decanoic acid alanine site.

Using pseudo amino acid composition to predict transmembrane regions in protein: cellular automata and Lempel-Ziv complexity

Transmembrane (TM) proteins represent about 20-30% of the protein sequences in higher eukaryotes, playing important roles across a range of cellular functions. Moreover, knowledge about topology of these proteins often provides crucial hints toward their function. Due to the difficulties in experimental structure determinations of TM protein, theoretical prediction methods are highly preferred in identifying the topology of newly found ones according to their primary sequences, useful in both basic research and drug discovery. In this paper, based on the concept of pseudo amino acid composition (PseAA) that can incorporate sequence-order information of a protein sequence so as to remarkably enhance the power of discrete models (Chou, K. C., Proteins: Structure, Function, and Genetics, 2001, 43: 246-255), cellular automata and Lempel-Ziv complexity are introduced to predict the TM regions of integral membrane proteins including both alpha-helical and beta-barrel membrane proteins, validated by jackknife test. The result thus obtained is quite promising, which indicates that the current approach might be a quite potential high throughput tool in the post-genomic era. The source code and dataset are available for academic users at liml@scu.edu.cn.

Genetic polymorphisms involved in toxicant-metabolizing enzymes and the risk of chronic benzene poisoning in Chinese occupationally exposed populations

Benzene is a recognized haematotoxin and leukaemogen, but its mechanism of action and the role of genetic susceptibility are still unclear. Cytochrome P450 2E1 (CYP2E1) and myeloperoxidase (MPO) are involved in benzene activation; and NAD (P)H:quinine oxidoreductase 1 (NQO1), glutathione S-transferase theta 1 (GSTT1) and glutathione S-transferase mu 1 (GSTM1) participate in benzene detoxification. The common, well-studied single-nucleotide polymorphisms (SNPs) were analysed in these genes drawn from the toxicant-metabolizing pathways. A total of 100 workers with chronic benzene poisoning (CBP) and 90 controls were enrolled in China. There was a 2.82-fold (95% CI = 1.42-5.58) increased risk of CBP in the subjects with the NQO1 609C > T mutation genotype (T/T) compared with those carrying heterozygous (C/T) and wild-type (C/C). The subjects with the GSTT1 null genotype had a 1.91-fold (95% CI = 1.05-3.45) increased risk of CBP compared with those with GSTT1 non-null genotype. There was no association of CYP2E1 and MPO genotype with CBP. A three genes' interaction showed that there was a 20.41-fold (95% CI = 3.79-111.11) increased risk of CBP in subjects with the NQO1 609C > T T/T genotype and with the GSTT1 null genotype and the GSTM1 null genotype compared with those carrying the NQO1 609C > T C/T and C/C genotype, GSTT1 non-null genotype, and GSTM1 non-null genotype. The study provides evidence of an association of a gene-gene interaction with the risk of CBP.

Platelet activation in acute pulmonary embolism

BACKGROUND

Platelet activation is implicated in thrombotic disorders, but has not been described in acute clinical pulmonary embolism (PE).

OBJECTIVES

To investigate the natural history of platelet activation in PE and associated markers of inflammation, thrombosis and cardiac dysfunction.

METHODS

Thirty-five consecutive patients (age 62 +/-17 years) with acute PE were prospectively enrolled and followed for 6 months. Platelet activation was assessed by flow cytometry [measuring expression of platelet P-selectin, conformational activation of glycoprotein IIb/IIIa complex (PAC-1) and formation of platelet-leukocyte complexes] and by plasma soluble P-selectin. Platelet activation, right ventricular (RV) function (assessed as RV ejection area by transthoracic echocardiography), D-dimer and high-sensitivity C-reactive protein (hs-CRP) were measured at presentation and repeated over 6 months follow-up.

RESULTS

Soluble P-selectin (56 +/-19 ng mL(-1), anovaP < 0.0001) and PAC-1 (1.5 +/- 1.8%, anovaP = 0.005) were mildly but significantly increased in patients with acute PE relative to healthy young men (soluble P-selectin 33 +/- 13 ng mL(-1), P < 0.001; PAC-1 binding 0.5 +/- 0.6%, P < 0.01) and age-matched controls (soluble P-selectin 31 +/- 9 ng mL(-1), P < 0.001; PAC-1 binding 0.4 +/-0.4%, P < 0.05). Platelet P-selectin expression and platelet-leukocyte complexes were not increased during acute PE. Echocardiographic RV ejection area correlated inversely with soluble P-selectin (r = -0.47, P = 0.007) and positively with platelet P-selectin (r = 0.49, P = 0.0007), suggesting P-selectin is shed from activated platelets in proportion to the severity of RV dysfunction. Elevated soluble P-selectin, D-dimer and hs-CRP demonstrated a time-dependent return to normal during 6 months follow-up.

CONCLUSION

Platelet activation is evident after acute PE. Platelet activation correlates with the severity of RV dysfunction, and can persist for several months after acute PE.

Highly Convergent Route to Cyclopeptide Alkaloids. Total Synthesis of Ziziphine N

[structure: see text]. A highly convergent protocol to cyclopeptide alkaloids, as demonstrated by the first total synthesis of antiplasmodial agent ziziphine N, is developed. The key elements include construction of its aryl ether unit via Mitsunobu reaction, installation of its enamide part via CuI/N,N-dimethylglycine-catalyzed coupling reaction, and ring closure with coupling agents such as FDDP and DPPA.

Total synthesis of the cyclodepsipeptide apratoxin A and its analogues and assessment of their biological activities

A novel total synthesis of apratoxin A is described, with key steps including the assembly of its ketide segment through a D-proline-catalyzed direct aldol reaction and Oppolzer's anti aldol reaction and the preparation of its thiazoline unit in a biomimetic synthesis. An oxazoline analogue of apratoxin A has also been elaborated by a similar approach. This compound has a potency against HeLa cell proliferation only slightly lower than that of apratoxin A, whilst a C(40)-demethylated oxazoline analogue of apratoxin A displays a much lower cytotoxicity and the C(37)-epimer and C(37) demethylation product of this new analogue are inactive. These results suggest that the two methyl groups at C(37) and C(40) and the stereochemistry at C(37) are essential for the potent cellular activity of the oxazoline analogue of apratoxin A. Further biological analysis revealed that both synthetic apratoxin A and its oxazoline analogue inhibited cell proliferation by causing cell cycle arrest in the G1 phase.

Asynchronous administration of xenon and hypothermia significantly reduces brain infarction in the neonatal rat

BACKGROUND

Neonatal asphyxia causes long-term neurological and behavioural impairment in the developing brain. Concurrent administration of xenon and hypothermia synergistically reduces long-term damage in a rat model of neonatal asphyxia. This study sought to investigate whether asynchronous administration of xenon and hypothermia is capable of combining synergistically to provide neuroprotection.

METHODS

Seven-day-old rats were subjected to right common carotid artery occlusion followed by 90 min hypoxia with 8% oxygen. After a 1 h recovery period, rats received asynchronous administration of mild hypothermia (35 degrees C) and xenon (20%) with a 1 or 5 h gap between interventions, xenon (20%) alone, or mild hypothermia (35 degrees C) alone. Infarct volume in the brain was measured 4 days after injury.

RESULTS

Administration of hypothermia or xenon alone, 1 and 6 h after the hypoxic ischaemic insult, respectively, provided no neuroprotection. Asynchronous administration of xenon and hypothermia at a 1 h interval produced a significant reduction in infarct volume [93 (7) vs 74 (8); P < 0.05]. Reduction in infarct volume was also present when hypothermia and xenon were asynchronously administered with an intervening gap of 5 h [97 (5) vs 83 (3); P < 0.05].

CONCLUSIONS

This finding provides a rationale for investigating the combined use of hypothermia and xenon in a progressive manner for the management of neonatal asphyxia. Thus, hypothermia can be administrated at the site of delivery and xenon can be administered later.