Search

In order to exploit the 430-cavity in the active sitesof neuraminidases,22 zanamivir analogs with C-1 and C-4 modification were synthesized,and their inhibitory activities against both group-1 (H5N1, H1N1)and group-2 neuraminidases (H3N2) were determined. Compound 9fexerts the most potency, with IC50value of0.013, 0.001, and 0.09 μM against H3N2, H5N1, and H1N1, whichis similar to that of zanamivir (H3N2 IC50= 0.0014 μM,H5N1 IC50= 0.012 μM, H1N1 IC50= 0.001μM). Pharmacokinetic studies of compound 9finrats showed a much longer plasma half-life (t1/2) than that of zanamivir following administration (po dose).Molecular modeling provided information about the binding model betweenthe new inhibitors and neuraminidase, with the elongated groups atthe C-1-position being projected toward the 430-loop region. Thisstudy may represent a novel starting point for the future developmentof improved antiflu agents. [ABSTRACT FROM AUTHOR]

This report describes the gold-catalyzed synthesis of fused polycyclic indoles from substituted 2-(1H-indol-1-yl) alkylamines and alkynoic acids in water under microwave irradiation. This protocol proceeds in high atom economy and leads to the generation of two rings, together with the formation of one new C–C bond and two new C–N bonds in a single operation. The advantages of the method include a short reaction time, excellent yield, easy work-up, and the use of microwave irradiation and an environmentally benign solvent. [ABSTRACT FROM AUTHOR]

RhoA is a member of Rho GTPases, a subgroup of the Ras superfamily of small GTP-binding proteins. RhoA, as an important regulator of diverse cellular signaling pathways, plays significant roles in cytoskeletal organization, transcription, and cell-cycle progression. The RhoA/ROCK inhibitors have emerged as a new promising treatment for cardiovascular diseases. However, to date, RhoA inhibitors are macromolecules, and to our knowledge, small molecular-based inhibitors have not been reported. In this study, a series of first-in-class small molecular RhoA inhibitors have been discovered by using structure-based virtual screening in conjunction with chemical synthesis and bioassay. Virtual screening of ∼200,000 compounds, followed by SPR-based binding affinity assays resulted in three compounds with binding affinities to RhoA at the micromolar level (compounds 1–3). Compound 1was selected for further structure modifications in considering binding activity and synthesis ease. Fourty-one new compounds (1, 12a–v, 13a–h, and 14a–j) were designed and synthesized accordingly. It was found that eight (12a, 12j, 14a, 14b, 14d, 14e, 14 g, and 14h) showed high RhoA inhibition activities with IC50values of 1.24 to 3.00 μM. A pharmacological assay indicated that two compounds (14gand 14 h)demonstrated noticeable vasorelaxation effects against PE-induced contraction in thoracic aorta artery rings and served as good leads for developing more potent cardiovascular agents. [ABSTRACT FROM AUTHOR]

An Au(I)-catalyzed tandem cyclization reaction of substituted indolylalkylamines (I), (IV), (VI) and (VIII) and alkynoic acids (II), (IX) under microwave irradiation is described. [ABSTRACT FROM AUTHOR]

Review: 96 refs. [ABSTRACT FROM AUTHOR]

A highly efficient organocatalyzed Michael addition of 2-oxindole-3-carboxylate esters to nitroolefins using a Cinchona alkaloid-thiourea and an achiral Brønsted acid as cooperative organocatalysts is reproted that affords significantly improved enantioselectivity and diastereoselectivity. It also provides an efficient approach to the synthesis of spirooxindole derivatives with high enantioselectivity. [ABSTRACT FROM AUTHOR]

Abstract: With the introduction of bioisosteres of the guanidinium group together with scaffold hopping, 35 zanamivir analogs with C-4-modification were synthesized, and their inhibitory activities against both group-1 and group-2 neuraminidase (H5N1 and H3N2) were determined. Compound D26 exerts the most potency, with IC50 values of 0.58 and 2.72 μM against N2 and N1, respectively. Further preliminary anti-avian influenza virus (AIV, H5N1) activities against infected MDCK cells were evaluated, and D5 exerts ∼58% protective against AIV infection, which was comparable to zanamivir (∼67%). In a rat pharmacokinetic study, compound D5 showed an increased plasma half-life (t 1/2) compared to zanamivir following either intravenous or oral administration. This study may represent a new start point for the future development of improved anti-AIV agents. [Copyright &y& Elsevier]

The 2009 H1N1 influenza pandemic (pH1N1) led to record sales of neuraminidase (NA) inhibitors, which has contributed significantly to the recent increase in oseltamivir-resistant viruses. Therefore, development and careful evaluation of novel NA inhibitors is of great interest. Recently, a highly potent NA inhibitor, laninamivir, has been approved for use in Japan. Laninamivir is effective using a single inhaled dose via its octanoate prodrug (CS-8958) and has been demonstrated to be effective against oseltamivir-resistant NA in vitro. However, effectiveness of laninamivir octanoate prodrug against oseltamivir-resistant influenza infection in adults has not been demonstrated. NA is classified into 2 groups based upon phylogenetic analysis and it is becoming clear that each group has some distinct structural features. Recently, we found that pH1N1 N1 NA (p09N1) is an atypical group 1 NA with some group 2-like features in its active site (lack of a 150-cavity). Furthermore, it has been reported that certain oseltamivir-resistant substitutions in the NA active site are group 1 specific. In order to comprehensively evaluate the effectiveness of laninamivir, we utilized recombinant N5 (typical group 1), p09N1 (atypical group 1) and N2 from the 1957 pandemic H2N2 (p57N2) (typical group 2) to carry out in vitro inhibition assays. We found that laninamivir and its octanoate prodrug display group specific preferences to different influenza NAs and provide the structural basis of their specific action based upon their novel complex crystal structures. Our results indicate that laninamivir and zanamivir are more effective against group 1 NA with a 150-cavity than group 2 NA with no 150-cavity. Furthermore, we have found that the laninamivir octanoate prodrug has a unique binding mode in p09N1 that is different from that of group 2 p57N2, but with some similarities to NA-oseltamivir binding, which provides additional insight into group specific differences of oseltamivir binding and resistance. [ABSTRACT FROM AUTHOR]

Abstract: A simultaneous stereoselective 2-O-deacetylation and 4-amination reaction of peracetylated Neu5Ac 1 has been established with cyclic secondary amines, such as 1-N-Boc-piperazine. Four C 2-symmetric and two asymmetric sialic acid dimers with (4→4)-piperazine derivatives linked were synthesized. They may serve as precursors of unnatural polysialic acids. [Copyright &y& Elsevier]

An efficient approach to the dehydrative sialylation of various substrates with C-4-aminated sialyl-hemiketal donors by using the reagent combination of diphenyl sulfoxide and triflic anhydride is reported. By using a C-4-hindered non-nucleophilic amine auxiliary, excellent yields and high a-stereoselectivities were obtained for coupling with a wide range of primary and secondary acceptors. [ABSTRACT FROM AUTHOR]

The reaction proceeds with moderate dia- and high enantioselectivity. [ABSTRACT FROM AUTHOR]