Design, synthesis and biological evaluation of pyrido[2,3-d]pyrimidin-7-(8H)-ones as HCV inhibitors

Overcoming Paradoxical Kinase Priming by a Novel MNK1 Inhibitor

Targeting the kinases MNK1 and MNK2 has emerged as a valuable strategy in oncology. However, most of the advanced inhibitors are acting in an adenosine triphosphate (ATP)-competitive mode, precluding the evaluation of different binding modes in preclinical settings. Using rational design, we identified and validated the 4,6-diaryl-pyrazolo[3,4-b]pyridin-3-amine scaffold as the core for MNK inhibitors. Signaling pathway analysis confirmed a direct effect of the hit compound EB1 on MNKs, and in line with the reported function of these kinases, EB1 only affects the growth of tumor but not normal cells. Molecular modeling revealed the binding of EB1 to the inactive conformation of MNK1 and the interaction with the specific DFD motif. This novel mode of action appears to be superior to the ATP-competitive inhibitors, which render the protein in a pseudo-active state. Overcoming this paradoxical activation of MNKs by EB1 represents therefore a promising starting point for the development of a novel generation of MNK inhibitors.

1,6-Naphthyridin-2(1H)-ones: Synthesis and Biomedical Applications

Naphthyridines, also known as diazanaphthalenes, are a group of heterocyclic compounds that include six isomeric bicyclic systems containing two pyridine rings. 1,6-Naphthyridines are one of the members of such a family capable of providing ligands for several receptors in the body. Among such structures, 1,6-naphthyridin-2(1H)-ones (7) are a subfamily that includes more than 17,000 compounds (with a single or double bond between C3 and C4) included in more than 1000 references (most of them patents). This review will cover the analysis of the diversity of the substituents present at positions N1, C3, C4, C5, C7, and C8 of 1,6-naphthyridin-2(1H)-ones, the synthetic methods used for their synthesis (both starting from a preformed pyridine or pyridone ring), and the biomedical applications of such compounds.

A captured room temperature stable Wheland intermediate as a key structure for the orthogonal decoration of 4-amino-pyrido[2,3-d]pyrimidin-7(8H)-ones

Wheland intermediates are usually unstable compounds and only a few have been isolated at very low temperatures. During our work on tyrosine kinase inhibitors, we studied the bromination of 7 in order to obtain a dibromo substituted pyrido[2,3-d]pyrimidin-7(8H)-one which could be orthogonally decorated. Surprisingly, treatment of 7 with 3 equiv. of Br2 in acetic acid (AcOH) afforded 12, a captured room temperature stable Wheland bromination intermediate stabilized by the bromination of the imino tautomer of the amino group at C4 of the pyridopyrimidine skeleton. The structure was confirmed by crystal structure determination from powder X-ray diffraction data. Treatment of 12 with DMSO afforded the dibromo substituted compound 13 presenting a bromine atom at C6 and C5-C6 unsaturation. 13 was directly accessed by treating 7 with N-bromosuccinimide (NBS), a protocol extended to other compounds using NBS or N-iodosuccinimide (NIS) to afford 6-halo substituted systems. 26, bearing an iodine at C6 and a p-bromophenylamino at C2, allows the orthogonal decoration of pyridopyrimidines.

Design of novel small molecule base-pair recognizers of toxic CUG RNA transcripts characteristics of DM1

Myotonic Dystrophy type 1 (DM1) is an incurable neuromuscular disorder caused by toxic DMPK transcripts that carry CUG repeat expansions in the 3' untranslated region (3'UTR). The intrinsic complexity and lack of crystallographic data makes noncoding RNA regions challenging targets to study in the field of drug discovery. In DM1, toxic transcripts tend to stall in the nuclei forming complex inclusion bodies called foci and sequester many essential alternative splicing factors such as Muscleblind-like 1 (MBNL1). Most DM1 phenotypic features stem from the reduced availability of free MBNL1 and therefore many therapeutic efforts are focused on recovering its normal activity. For that purpose, herein we present pyrido[2,3-d]pyrimidin-7-(8H)-ones, a privileged scaffold showing remarkable biological activity against many targets involved in human disorders including cancer and viral diseases. Their combination with a flexible linker meets the requirements to stabilise DM1 toxic transcripts, and therefore, enabling the release of MBNL1. Therefore, a set of novel pyrido[2,3-d]pyrimidin-7-(8H)-ones derivatives (1a-e) were obtained using click chemistry. 1a exerted over 20% MBNL1 recovery on DM1 toxic RNA activity in primary cell biology studies using patient-derived myoblasts. 1a promising anti DM1 activity may lead to subsequent generations of ligands, highlighting a new affordable treatment against DM1.

An overview on synthetic and pharmaceutical prospective of pyrido[2,3-d]pyrimidines scaffold

Pyrido[2,3-d]pyrimidine, a fused hetero-bicyclic nucleus containing pyridine and pyrimidine rings has attained the momentary attention in the sphere of multicomponent synthetic protocol and medicinal chemist. Pyrido[2,3-d]pyrimidine derived drugs have manifested diverse pharmacological activities, particularly, anti-inflammatory, cytotoxic, antimicrobial, phosphodiesterase inhibitors and cytokine inhibitors etc. The present review illustrates various modern synthetic strategies adopted, the structure-activity relationship (SAR) aspects and discloses the extensive crucial biological properties (anticancer, anti-infectious, anti-diabetics and CNS agents) of pyrido[2,3-d]pyrimidines.

Pyrido[2,3-d]pyrimidin-7(8H)-ones: Synthesis and Biomedical Applications

Pyrido[2,3-d]pyrimidines (1) are a type of privileged heterocyclic scaffolds capable of providing ligands for several receptors in the body. Among such structures, our group and others have been particularly interested in pyrido[2,3-d]pyrimidine-7(8H)-ones (2) due to the similitude with nitrogen bases present in DNA and RNA. Currently there are more than 20,000 structures 2 described which correspond to around 2900 references (half of them being patents). Furthermore, the number of references containing compounds of general structure 2 have increased almost exponentially in the last 10 years. The present review covers the synthetic methods used for the synthesis of pyrido[2,3-d]pyrimidine-7(8H)-ones (2), both starting from a preformed pyrimidine ring or a pyridine ring, and the biomedical applications of such compounds.

Chemoselective One-Pot Synthesis of Functionalized Amino-azaheterocycles Enabled by COware

Functionalized bicyclic amino-azaheterocycles are rapidly accessed in a one-pot cross-coupling/reduction sequence enabled by the use of COware. Incompatible reagents are physically separated in a single reaction vessel to effect two chemoselective transformations-Suzuki-Miyaura cross-coupling and heteroarene reduction. The developed method allows access to novel heterocyclic templates, including semisaturated Hedgehog and dual PI3K/mTOR inhibitors, which show enhanced physicochemical properties compared to their unsaturated counterparts.