Paul C. Anderson

An NS3 protease inhibitor with antiviral effects in humans infected with hepatitis C virus

Hepatitis C virus (HCV) infection is a serious cause of chronic liver disease worldwide with more than 170 million infected individuals at risk of developing significant morbidity and mortality. Current interferon-based therapies are suboptimal especially in patients infected with HCV genotype 1, and they are poorly tolerated, highlighting the unmet medical need for new therapeutics. The HCV-encoded NS3 protease is essential for viral replication and has long been considered an attractive target for therapeutic intervention in HCV-infected patients. Here we identify a class of specific and potent NS3 protease inhibitors and report the evaluation of BILN 2061, a small molecule inhibitor biologically available through oral ingestion and the first of its class in human trials. Administration of BILN 2061 to patients infected with HCV genotype 1 for 2 days resulted in an impressive reduction of HCV RNA plasma levels, and established proof-of-concept in humans for an HCV NS3 protease inhibitor. Our results further illustrate the potential of the viral-enzyme-targeted drug discovery approach for the development of new HCV therapeutics.

Stereoelectronic effects in the ring cleavage of methyl glycopyranosides using dimethylboron bromide

Abstract Treatment of methyl D-glycopyranosides with dimethylboron bromide followed by a nucleophile gives acyclic products resulting from selective cleavage of the ring carbon-oxygen bond. The results are rationalized based on stereoelectronic considerations.

Discovery of non-peptidic P2-P3 butanediamide renin inhibitors with high oral efficacy.

A new series of non-peptidic renin inhibitors having a 2-substituted butanediamide moiety at the P2 and P3 positions has been identified. The optimized inhibitors have IC50 values of 0.8 to 1.4 nM and 2.5 to 7.6 nM in plasma renin assays at pH 6.0 and 7.4, respectively. When evaluated in the normotensive cynomolgus monkey model, two of the most potent inhibitors were orally active at a dose as low as 3 mg/kg. These potent renin inhibitors are characterized by oral bioavailabilities of 40 and 89% in the cynomolgus monkey. Inhibitor 3z (BILA 2157 BS) was selected as candidate for pre-development.

Biosynthesis of porphyrins and related macrocycles : Part 27. Syntheses of modified hydroxymethylbilanes and studies of their chemical and biological properties

Abstract The biosynthetic pathway to uroporphyrinogen-III, the parent macrocycle for all the pigments of life, involves the formation and ring-closure of an hydroxymethylbilane. The non-enzymic ring-closure of this bilane is studied under different pH conditions. Also octamethyl esters of related bilanes are synthesised which have either a cyano or a methyl group blocking position-19 which is free on the terminal ring-D of the natural bilane. Studies are made of the ring-closure of these substituted bilanes under acidic conditions. The conclusion is reached that there is a strong preference for non-enzymic ring-closure of an hydroxymethyebilane to occur at the terminal carbon atom (position-19). The octa-acids derived from the cyano and methyl substituted bilanes inhibit the action of cosynthetase on the natural hydroxymethylbilane.

Ring cleavage of THP and THF ethers using dimethylboron bromide

Abstract The reaction of dimethylboron bromide with THP and THF ethers was studied. Under conditions of kinetic control, these reactions proceed by selective cleavage of the ring carbon—oxygen bond to give acyclic α-bromo ethers. Treatment of these intermediates with a variety of nucleophiles gives ring-opened products.

Preparation of enantiopure 4-oxygenated pipecolic acid derivatives

Abstract Two approaches to enantiopure 4-oxo- and 4-( R )-hydroxypipecolic acid derivatives from protected L-aspartic acid were developed. The first route exploits an intramolecular Michael addition on the stable enaminone 8 . Hydrogenation and concomitant decarboxylation gave the 4-oxo derivative 11 which was reduced selectively to the 4-( R )-hydroxy derivative 12 . The second route starts with a Michael addition followed by an intramolecular Dieckmann condensation to build the piperidine ring. The 4-oxo derivatives 11 and 19 are thus obtained in an expeditious manner on large scale without any chromatographic purification. Both sequences proved to be highly stereoselective.

Discovery of BI 207524, an indole diamide NS5B thumb pocket 1 inhibitor with improved potency for the potential treatment of chronic hepatitis C virus infection.

The development of interferon-free regimens for the treatment of chronic HCV infection constitutes a preferred option that is expected in the future to provide patients with improved efficacy, better tolerability, and reduced risk for emergence of drug-resistant virus. We have pursued non-nucleoside NS5B polymerase allosteric inhibitors as combination partners with other direct acting antivirals (DAAs) having a complementary mechanism of action. Herein, we describe the discovery of a potent follow-up compound (BI 207524, 27) to the first thumb pocket 1 NS5B inhibitor to demonstrate antiviral activity in genotype 1 HCV infected patients, BILB 1941 (1). Cell-based replicon potency was significantly improved through electronic modulation of the pKa of the carboxylic acid function of the lead molecule. Subsequent ADME-PK optimization lead to 27, a predicted low clearance compound in man. The preclinical profile of inhibitor 27 is discussed, as well as the identification of a genotoxic metabolite that led to the discontinuation of the development of this compound.

Novel small renin inhibitors containing 4,5- or 3,5-dihydroxy-2-substituted-6-phenylhexanamide replacements at the P2P3 sites

Renin inhibitors containing a 4,5- or a 3,5-dihydroxy-2-substituted-6-phenylhexanamide fragment at the P2-P3 sites have been prepared and evaluated. The four possible diastereomeric diols of the two series of inhibitors were synthesized to determine the optimal configuration of the carbinol centers for these replacements. The most potent inhibitors of each series, la and 2c have a molecular weight of only 503 and IC50 values of 23 and 20 nM in a human plasma renin assay at pH 6.0. Their very low aqueous solubility limited their further evaluation. The efficacy of these P2-P3 replacements is a result of their ability to maintain the important hydrogen-bonds with the enzyme. Due to conformational differences with the dipeptide, adjustment at the P2 side chain was required. These 4,5- and 3,5-dihydroxyhexanamide segments could be seen as novel N-terminal dipeptide replacements.