Biomedical subjects
Publications and source records attributed to Gurdip Bhalay.
The enzymatic desymmetrization of 2,2- and 2,5-disubstituted pyrroline compounds is reported in a procedure which gives access to both enantiomers in excellent enantiomeric excess and good yield. The enzyme reaction precursors are formed easily from two readily available substituted pyrroles using both ammonia (Na/NH3) and ammonia-free (Li/DBB) Birch reduction conditions.
[reaction: see text] The partial reduction of 2,5-pyrrole diester 1 followed by enantioselective protonation in situ to furnish synthetically useful building blocks is described. An enantiomeric excess of up to 74% was achieved using (-)-ephedrine and related analogues as chiral proton sources. The pyrroline product obtained could be recrystallized to give enantiomerically pure material.
A solid-phase approach was used to prepare 20 cystine amide derivatives with disulfide bond formation resulting from an intra-site reaction between neighbouring cysteine residues. Library members were screened as potential organogelators in a range of solvent mixtures and resulted in the identification of a potent gelator able to rigidify water/DMSO mixtures at concentrations as low as 1.3 mM.
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Dyad beads, bearing both a substrate and a catalyst, were prepared to enable direct split and mix bead based screening for catalysis.
[reaction: see text] Catalytic Sc(OTf)(3) greatly increases the efficiency of hydrogen peroxide mediated monooxidation of alkyl-aryl sulfides and methyl cysteine containing peptides. The method is high yielding, compatible with many widely used protecting groups, suitable for solid-phase applications and proceeds with minimum over-oxidation.
In clinical studies, several inhibitors of phosphodiesterase 5 (PDE5) have demonstrated utility in the treatment of erectile dysfunction. We describe herein a series of 8-aryl xanthine derivatives which function as potent PDE5 inhibitors with, in many cases, high levels of selectivity versus other PDE isoforms.
PDE5 inhibitors based upon the xanthine scaffold 8 have been expediently synthesized using a solid-phase route. Attachment of the xanthine scaffold 8 using the Rink chloride linker 4 and N-1 functionalization using Mitsunobu chemistry is described. A library of compounds was produced in multi-milligram quantities with excellent purities and acceptable yields. The compounds were tested for their PDE5 inhibitory activity.
The currently available therapy for asthma is highly effective and is able to control the disease in the majority of patients. There are two types of treatments for asthma: rapid relief of symptoms, used as needed and long-term control, used on a regular basis. Rapid relief is provided by short-acting beta2-agonists and anticholinergics. The control of asthma is achieved by treatment with inhaled corticosteroids (ICS), theophylline, long acting beta2-agonists and antileukotrienes. Beta2-agonists and corticosteroids dominate asthma therapy, with over 65% of the market share. Corticosteroids are the most effective drugs available to clinicians for the control of inflammation in patients with asthma. ICS have revolutionized the treatment of asthma and are now the first-line treatment for chronic asthma in all ages.
Ion-extraction mass spectrometry of ladders of mixtures of isotopically labeled compounds from single beads allows the unambiguous sequencing of bead-based peptides and offers significant advantages over traditional methods of library analysis.