A versatile route to 3-(pyrimidin-4-yl)-imidazo[1,2-a]pyridines and 3-(pyrimidin-4-yl)-pyrazolo[1,5-a]pyridines

A two-step synthesis of 3-(2-chloropyrimidin-4-yl)imidazo[1,2-a]pyridines is presented. The late stage elaboration of the imidazopyridine through a cyclocondensation allows a rapid access to a variety of substitution patterns. The intermediate enol ethers were obtained from inexpensive reagents in a ligand-free Heck coupling. This methodology has been extended to the formation of pyrazolo[1,5-a]pyridines via a formal 1,3-dipolar cycloaddition.     

Quantification of ignition time uncertainty based on the classical ignition theory and Fourier analysis

This study aims at modeling the effect of incoming heat flux fluctuations, on solid material ignition. In order to propose a general methodology based on the classical ignition theory that can be applied to any kind of solid target, kernels accounting for the target temperature response regarding an incoming heat flux are considered for thermally thick and thin solids with low or high thermal inertia. A Fourier decomposition of the incoming heat flux is then used to calculate the target response to harmonic heat fluxes. Finally, effects of harmonic fluctuations on ignition are discussed based on the previous analytical results, allowing us to discriminate situations where ignition time is expected to be rather predictable from situations where ignition time is expected to be less predictable thanks to an uncertainty quantification of the ignition time.     

Strategic studies in the syntheses of novel 6,7-substituted quinolones and 7- or 6-substituted 1,6- and 1,7-naphthyridones

This paper describes the different strategies devised and applied to overcome the selectivity issues in the syntheses of 6,7-disubstituted-1H-quinolin-4-one, 7-substituted-1H-1,6-naphthyridin-4-one and 6-substituted-1H-1,7-naphthyridin-4-one derivatives. They allowed us to improve the overall yields and the scaling-up feasibility. Several examples illustrate these strategies with their advantages and drawbacks.     

Fischer synthesis of isomeric thienopyrrole LHRH antagonists

As part of a structure–activity exploration into LHRH antagonists, structures containing the thieno[2,3-b]pyrrole core were identified as potent antagonists. This letter describes the employment of the Fischer synthesis to access this thienopyrrole and isomeric final compounds.     

Discovery and application of iminotriphenylphosphorane as a formal aromatic primary amine protecting group

During our efforts to selectively synthesise N-arylated benzotriazole fragments, we developed a new primary aromatic amine protecting group strategy showing significant advantages over recognised protecting groups.