Eduard Felder

Fluoroolefin dipeptide isosteres -II. : Enantioselectlve synthesis of both antipodes of the phe-gly dlpeptide mimic☆

Abstract The addition of optically active ester enolatas to α-fluoro-α,β-unsaturated aldehydes and formal S N 2′ substitution of an allylic hydroxyl group thus formed by a trichloro-acetamido group via Overman rearrangement constitutes a new general route to fluoroofefin dipeptide isosteres in enantiomerically pure form. This methodology was applied for the preparation of both enantiomars of the Phe…(CFCH)Gly dipeptide mimic which were further elongated to substance P analogues.

Solid support synthesis of highly functionalized pyrazoles and isoxazoles; Scaffolds for molecular diversity

Abstract A scope and limitations study on a 4 steps reaction sequence including a Claisen condersation, an α-alkylation, and a cyclization of a β-diketone with monosubstituted hydrazines for the generation of variably substituted pyrazoles and isoxazoles on solid phase is described. The ample choice of reactants compatible with the reaction scheme points out its potential in combinatorial chemistry.

The TPM3-NTRK1 rearrangement is a recurring event in colorectal carcinoma and is associated with tumor sensitivity to TRKA kinase inhibition.

The NTRK1 gene encodes Tropomyosin‐related kinase A (TRKA), the high‐affinity Nerve Growth Factor Receptor. NTRK1 was originally isolated from a colorectal carcinoma (CRC) sample as component of a somatic rearrangement (TPM3‐NTRK1) resulting in expression of the oncogenic chimeric protein TPM3‐TRKA, but there has been no subsequent report regarding the relevance of this oncogene in CRC. The KM12 human CRC cell line expresses the chimeric TPM3‐TRKA protein and is hypersensitive to TRKA kinase inhibition. We report the detailed characterization of the TPM3‐NTRK1 genomic rearrangement in KM12 cells and through a cellular screening approach, the identification of NMS‐P626, a novel highly potent and selective TRKA inhibitor. NMS‐P626 suppressed TPM3‐TRKA phosphorylation and downstream signaling in KM12 cells and showed remarkable antitumor activity in mice bearing KM12 tumors.

Entrectinib, a Pan-TRK, ROS1 and ALK Inhibitor with Activity in Multiple Molecularly Defined Cancer Indications

Activated ALK and ROS1 tyrosine kinases, resulting from chromosomal rearrangements, occur in a subset of non–small cell lung cancers (NSCLC) as well as other tumor types and their oncogenic relevance as actionable targets has been demonstrated by the efficacy of selective kinase inhibitors such as crizotinib, ceritinib, and alectinib. More recently, low-frequency rearrangements of TRK kinases have been described in NSCLC, colorectal carcinoma, glioblastoma, and Spitzoid melanoma. Entrectinib, whose discovery and preclinical characterization are reported herein, is a novel, potent inhibitor of ALK, ROS1, and, importantly, of TRK family kinases, which shows promise for therapy of tumors bearing oncogenic forms of these proteins. Proliferation profiling against over 200 human tumor cell lines revealed that entrectinib is exquisitely potent in vitro against lines that are dependent on the drugs pharmacologic targets. Oral administration of entrectinib to tumor-bearing mice induced regression in relevant human xenograft tumors, including the TRKA-dependent colorectal carcinoma KM12, ROS1-driven tumors, and several ALK-dependent models of different tissue origins, including a model of brain-localized lung cancer metastasis. Entrectinib is currently showing great promise in phase I/II clinical trials, including the first documented objective responses to a TRK inhibitor in colorectal carcinoma and in NSCLC. The drug is, thus, potentially suited to the therapy of several molecularly defined cancer settings, especially that of TRK-dependent tumors, for which no approved drugs are currently available. Mol Cancer Ther; 15(4); 628–39. ©2016 AACR.

Discovery of Entrectinib: A New 3-Aminoindazole as a Potent Anaplastic Lymphoma Kinase (Alk), C-Ros Oncogene 1 Kinase (Ros1), and Pan-Tropomyosin Receptor Kinases (Pan-Trks) Inhibitor.

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase responsible for the development of different tumor types. Despite the remarkable clinical activity of crizotinib (Xalkori), the first ALK inhibitor approved in 2011, the emergence of resistance mutations and of brain metastases frequently causes relapse in patients. Within our ALK drug discovery program, we identified compound 1, a novel 3-aminoindazole active on ALK in biochemical and in cellular assays. Its optimization led to compound 2 (entrectinib), a potent orally available ALK inhibitor active on ALK-dependent cell lines, efficiently penetrant the blood-brain barrier (BBB) in different animal species and highly efficacious in in vivo xenograft models. Moreover, entrectinib resulted to be strictly potent on the closely related tyrosine kinases ROS1 and TRKs recently found constitutively activated in several tumor types. Entrectinib is currently undergoing phase I/II clinical trial for the treatment of patients affected by ALK-, ROS1-, and TRK-positive tumors.

Combinatorial compound libraries for enhanced drug discovery approaches

Publisher Summary This chapter focuses on combinatorial compound libraries for enhanced drug discovery approaches. The chapter describes the basic principles of combinatorial technologies such as arrays, combinatorial chemistry with split synthesis, expression libraries, highly diverse libraries, thematic libraries, analog series, and library formats. The chapter also covers the issues related to planning, design, and theoretical interpretation and illustrates how to manage screening and synthesis data, handling combinatorial structure information, searching through combinatorial data, statistical aspects of mixture libraries, assessing diversity, comparing combinatorial libraries, designing libraries, and evolutionary synthesis. The chapter also discusses the chemical libraries such as oligomer libraries, small-molecule libraries, and tagging, encoded libraries.

Discovery of 2-[1-(4,4-Difluorocyclohexyl)Piperidin-4-Yl]-6-Fluoro-3-Oxo-2,3-Dihydro-1H-Isoindole-4-Carboxamide (Nms-P118): A Potent, Orally Available and Highly Selective Parp- 1 Inhibitor for Cancer Therapy.

The nuclear protein poly(ADP-ribose) polymerase-1 (PARP-1) has a well-established role in the signaling and repair of DNA and is a prominent target in oncology, as testified by the number of candidates in clinical testing that unselectively target both PARP-1 and its closest isoform PARP-2. The goal of our program was to find a PARP-1 selective inhibitor that would potentially mitigate toxicities arising from cross-inhibition of PARP-2. Thus, an HTS campaign on the proprietary Nerviano Medical Sciences (NMS) chemical collection, followed by SAR optimization, allowed us to discover 2-[1-(4,4-difluorocyclohexyl)piperidin-4-yl]-6-fluoro-3-oxo-2,3-dihydro-1H-isoindole-4-carboxamide (NMS-P118, 20by). NMS-P118 proved to be a potent, orally available, and highly selective PARP-1 inhibitor endowed with excellent ADME and pharmacokinetic profiles and high efficacy in vivo both as a single agent and in combination with Temozolomide in MDA-MB-436 and Capan-1 xenograft models, respectively. Cocrystal structures of 20by with both PARP-1 and PARP-2 catalytic domain proteins allowed rationalization of the observed selectivity.

Rational optimization of a HIV-1 Tat inhibitor: Rapid progress on combinatorial lead structures

Lead molecules identified by combinatorial chemistry approaches are preferred starting points for straightforward improvements of compound profiles. Structure-guided rationales can be supported and complemented by systematic variations based on the modular nature of the molecules. A peptoidic compound (CGP 64222), previously identified from a sequential unrandomization process, was shown to specifically inhibit the interaction between the HIV-1 trans-activator Tat and its RNA response element TAR. To improve the compounds pharmaceutical attractiveness an approach to reduce both, size and number of charges was pursued. Because this resulted in activity decrease, parallel synthesis with variations on one rationally defined position aimed at the identification of structural determinants was undertaken to regain in vitro activity in biochemical and cellular Tat-TAR interaction assays. As a result CGP74026 was identified, a drastically simplified but highly active Tat antagonist, which is able to block HIV-1 replication even in primary human cells.

A new solid phase approach for rapid syntheses of oligonucleotides bearing a 3′-terminal phosphate group

Abstract Synthesis of pentanucleotide ApTpCpTpTp containing a 3′-terminal phosphomonoester group was accomplished with the help of the new phosphate-solid phase link 2-(4-carboxyphenyl-mercapto)ethanol; a similar molecule, 2-benzylsulfonylethanol, revealed interesting features as a temporary 3′-phosphate protecting group.

The generation of purinome-targeted libraries as a means to diversify ATP-mimetic chemical classes for lead finding

The generation of novel chemotypes in support of our oncology research projects expanded in recent years from a canonical design of kinase-targeted compound libraries to a broader interpretation of purinome-targeted libraries (PTL) addressing the specificity of cancer relevant targets such as kinases and ATPases. Successful screening of structurally diverse ATP-binding targets requires compound libraries covering multiple design elements, which may include phosphate surrogate moieties in ATPase inhibitors or far reaching lipophilic residues stabilizing inactive kinase conformations. Here, we exemplify the design and preparation of drug-like combinatorial libraries and report significantly enhanced screening performance on purinomic targets. We compared overall hit rates of PTL with a simultaneously tested unbiased collection of 200,000 compounds and found consistent superiority of the targeted libraries in all cases. We also analyzed the performance of the largest targeted libraries in comparison with each other and often found striking differences in how a specific target responds to various chemotypes and to whole collections.Graphical Abstract