Tricyclic pharmacophore-based molecules as novel integrin alpha(v)beta3 antagonists. Part 2: synthesis of potent alpha(v)beta3/alpha(IIb)beta3 dual antagonists

We synthesized 4-aminopiperidine derivatives of our prototype integrin alpha(v)beta3 antagonist 1 in an attempt to increase the activity and water solubility. Introduction of one or two hydrophilic moieties into the central aromatic ring and/or the benzene ring at the C-terminus of 1 increased water solubility and enhanced inhibition of cell adhesion. The results of a structure-activity relationships (SAR) study indicated that the torsion angle between the central aromatic ring and the piperidine ring, and the acidity at the sulfonamide moiety, might be important for alpha(v)beta3 receptor binding activity. Some of these compounds are novel and potent alpha(v)beta3/alpha(IIb)beta3 dual antagonists with acceptable water solubility and a satisfactory early absorption, distribution, metabolism, excretion, and toxicity (ADMET) profile.

Tricyclic pharmacophore-based molecules as novel integrin alpha(v)beta3 antagonists. Part III: synthesis of potent antagonists with alpha(v)beta3/alpha(IIb)beta3 dual activity and improved water solubility

In order to optimize our novel integrin alpha(v)beta3/alpha(IIb)beta3 dual antagonists, spatial screening at the N-terminus was performed. The alpha(v)beta3 antagonistic activity varied depending on the space that was occupied by the N-terminus, but high potency against alpha(IIb)beta3 was well maintained. The (3S)-aminopiperidine analogue had the strongest activity against alpha(v)beta3, and the S isomer at piperidine was more potent than the R isomer. Compounds selected on the basis of SAR analysis of a novel lead compound showed acceptable early absorption, distribution, metabolism, excretion, and toxicity (ADMET) profiles and sufficient water solubility for use as infusion drugs. Docking studies with the alpha(v)beta3 receptor were performed to confirm the SAR findings.

Raman, hyper-Raman, hyper-Rayleigh, two-photon luminescence and morphology-dependent resonance modes in a single optical tweezers system

We present a setup of optical tweezers combined with linear and nonlinear microspectroscopies that enhances the capabilities of capture and analysis of both techniques. We can use either a continuous-wave (cw) Ti:sapphire laser for Raman measurements or a pulsed femtosecond Ti:sapphire laser that permitted the observation of nonlinear results such as hyper-Raman, hyper-Rayleigh, and two-photon luminescence. Only the high peak intensity of the femtosecond laser allows the observation of all these nonlinear spectroscopies. The sensitivity of our system also permitted the observation of morphology-dependent resonance (MDR) modes of a single stained trapped microsphere of 6 microm. The possibility of performing spectroscopy in a living microorganism optically trapped in any desired neighborhood would mean that one can dynamically observe the chemical reactions and/or mechanical properties changing in real time.

A proof of the specificity of kanamycin-ribosomal RNA interaction with designed synthetic analogs and the antibacterial activity

The binding specificity of designed synthetic kanamycins with model RNA sequences (wild-type and point-mutated type) derived from the 16S ribosomal A-site was evaluated using surface plasmon resonance imaging. It was observed that kanamycins have nonspecific and multiple interactions with RNA hairpins and that the binding potency is not always proportional to the antimicrobial activity.

Synthesis and biological evaluation of novel leucomycin analogues modified at the C-3 position. I. Epimerization and methylation of the 3-hydroxyl group

The synthesis and biological evaluation of sixteen-membered macrolides modified at the C-3 position are described. 3-Epi-leucomycin A7 (9), 3-O-acyl-3-epi-leucomycin A7 analogues (11a-11e), 3-O-acylleucomycin A7 analogues (13b-13e) and 3-O-methylleucomycin analogues (16a, 16b and 22) were synthesized via fully protected intermediates (7, 5a, 5b and 20). After appropriate modification, subsequent deprotections were performed to furnish a variety of leucomycin analogues. Methylation of the 3-hydroxyl group was found to improve the pharmacoprofile of leucomycin antibiotics. 3-O-Methylrokitamycin (16b) showed enhanced antibacterial activity in vitro and 3,3''-di-O-methyl-4''-O-(3-methylbutyl)leucomycin V (22) exhibited improved metabolic stability in rat plasma in vitro.

Direct electrophilic radiofluorination of a cyclic RGD peptide for in vivo alpha(v)beta3 integrin related tumor imaging

The association of the alpha(v)beta(3) integrin with tumor metastasis and tumor related angiogenesis has been suggested. Therefore, by imaging the alpha(v)beta(3) receptor with PET, information concerning the tumor status could be obtained. Cyclic peptides including the RGD sequence, were radiolabeled by direct electrophilic fluorination with [(18)F]AcOF. In tumor-bearing mice, the labeled peptides accumulated at the tumor with a high tumor to blood ratio. These findings suggest that an assessment of tumor characteristics may be obtained by using these (18)F-labeled peptides.

Diastereoselective synthesis of new psi[(E)-CH=CMe]- and psi[(Z)-CH=CMe]-type alkene dipeptide isosteres by organocopper reagents and application to conformationally restricted cyclic RGD peptidomimetics

Diastereoselective synthesis of new psi[(E)-CH=CMe]- and psi[(Z)-CH=CMe]-type alkene dipeptide isosteres corresponding to dipeptides having one N-methylamino acid, and application to bioactive peptides, are described. In a key reaction introducing the chiral alpha-alkyl group of the isosteres, organocopper-mediated alkylation of syn-beta-methylated gamma-mesyloxy-alpha,beta-enoate 26a afforded E- and Z-isomers of anti-S(N)2' products in a solvent-dependent manner. The resulting two isosteres, D-Phe-psi[(E)-CH=CMe]-L-Val 27a and D-Phe-psi[(Z)-CH=CMe]-L-Val 28b, which corresponded to trans- and cis-conformers of D-Phe-L-MeVal, respectively, were utilized in a structure-activity relationship study on cyclic RGD peptides 1 and 2, in company with a psi[(E)-CH=CH]-type alkene dipeptide isostere, D-Phe-psi[(E)-CH=CH]-L-Val. The cyclic isostere-containing pseudopeptides 3, 4, and 40 were synthesized and biological activity against integrin alpha(V)beta(3) and alpha(IIb)beta(3) receptors were also evaluated.

Synthesis and structure-activity relationships of new non-steroidal progesterone receptor ligands

In order to study structure-activity relationships, a series of new non-steroidal progesterone receptor ligands based on PF1092A was synthesized with structural modifications (mostly introduction or removal of a methyl group) at the 3-, 4-, 5-, 7- or 9-position in the 6-acetoxy-4a, 5, 6, 7-tetrahydro-3, 4a, 5-trimethylnaphtho[2,3-b]furan-2(4H)-one skeleton. Critical positions for high binding affinity to the progesterone receptor were identified.

Cladinose analogues of sixteen-membered macrolide antibiotics. VI. Synthesis of metabolically programmed, highly potent analogues of sixteen-membered macrolide antibiotics

Five novel 3-hydroxyl derivatives of sixteen-membered macrolide possessing 4-O-acyl-alpha-L-cladinose as a neutral sugar moiety were synthesized by using a combination of structurally stable silyl acetal protection and selective hydrogenolysis of a 3"-methylthiomethyl ether to a 3"-OMe group. Several derivatives having n-butyryl, i-butyryl and n-valeryl substituent at the 4"-OH group exhibited significant antibacterial activity in vitro. One of them, 4"-O-n-butyryl-3"-O-methylleucomycin V, showed improved therapeutic effect in mice.

Cladinose analogues of sixteen-membered macrolide antibiotics. IV. Improved therapeutic effects of 4-O-acyl-L-cladinose analogues of sixteen-membered macrolide antibiotics

Six derivatives of sixteen-membered macrolides possessing 4-O-acyl-alpha-L-cladinose as a neutral sugar were synthesized via 3"-methylthiomethyl ether intermediates in reasonable yield. Introduction of a methyl group on the 3"-hydroxyl group of midecamycin A1 was effective for enhancing its antibacterial activity. All these derivatives exhibited excellent therapeutic effects in mice, and some of them showed improved pharmacokinetics compared with the natural antibiotics (mycarose type) in mice. Facile synthesis of 9-O-acylated analogues are also described.

Cladinose analogues of sixteen-membered macrolide antibiotics. III. Efficient synthesis of 4-O-alkyl-L-cladinose analogues: improved antibacterial activities compatible with pharmacokinetics

The synthesis and biological evaluation of sixteen-membered macrolides possessing a 4-O-alkyl-alpha-L-cladinosyl moiety as a neutral sugar are described. These potent novel derivatives have been efficiently synthesized avoiding glycosylations. Two hydroxyl groups in mycarose of the tri-(tert-butyldimethylsilyl) ether intermediate were successively alkylated. Sequential deprotections of silyl groups afforded 4-O-alkyl-L-cladinose analogues and 3,4-di-O-alkyl-L-mycarose analogues of leucomycin V. Some 4-O-alkyl-L-cladinose analogues exhibited potent antibacterial activities. The most active derivative, 3"-O-methyl-4"-O-(3-methylbutyl)leucomycin V, showed improved metabolic stability in rat plasma in vitro and extremely high concentrations in serum after oral administrations in mice and in hamsters.

Cladinose analogues of sixteen-membered macrolide antibiotics. I. Synthesis of 4-O-alkyl-L-cladinose analogues via glycosylation

The synthesis and biological evaluation of sixteen-membered macrolides possessing a 4-O-alkyl-alpha-L-cladinosyl moiety as the neutral sugar are described. The nine novel derivatives have been synthesized by glycosylation with 1-thio sugars. The most active derivative of them showed prolonged antibacterial activity in rat plasma in vitro and improved pharmacokinetics.

Sequence-selective carbohydrate-DNA interaction: dimeric and monomeric forms of the calicheamicin oligosaccharide interfere with transcription factor function

The synthetic oligosaccharide moiety of the antibiotic calicheamicin and the head-to-head dimer of this oligosaccharide are known to bind to the minor groove of DNA in a sequence-selective manner preferring distinct target sequences. We tested these carbohydrates for their ability to interfere with transcription factor function. The oligosaccharides inhibit binding of transcription factors to DNA in a sequence-selective manner, probably by inducing a conformational change in DNA structure. They also interfere with transcription by polymerase II in vitro. The effective concentrations of the oligosaccharides for inhibition of transcription factor binding and for transcriptional inhibition are in the micromolar range. The dimer is a significantly more active inhibitor than is the monomer.