The preparation of magnetic iron oxide nanoparticles within microreactors is reported. The proportion of γ-Fe2O3 and Fe3O4 in the sample was determined, an important parameter for reproducibility in applications.
Continuous-flow methodologies have been applied to the synthesis of a number of fluorinated alkynyl arenes and heteroarenes. Through a series of optimizations reagent stoichiometry and reaction time were improved and substrate specificity was interrogated. Using optimized conditions under copper-free Sonogashira type couplings readily available arene building blocks were derivatized with fluoroalkynyl side chains in <10 min. Given the rapidity of the process and the enhanced purity profile of the products an immediate application of the work is in the development of 18F labeled versions of the agents for subsequent use in positron emission tomography (PET) imaging. A homolog of the Alzheimer's disease imaging agent Fallypride® was prepared using the methodology and additional analogs was identified.
A facile and benign route to N-heterocycles, including triazoles and triazolopyrimidines, has been developed. Using continuous-flow microreactor technology, organic azides are prepared in situ and reacted with cyanoacetamide in a [3+2] cycloaddition to produce a variety of substituted 1,2,3-triazoles, which can be elaborated into useful building blocks. A benzyl-substituted triazole was further functionalized to an analog of the core structure of the antiplatelet agent Brilinta®. The methodology lends itself well to flow chemistry, where reaction volumes are minimized, heating and mixing are consistent, and the need for intermediate azide isolation bypassed. The scope of the process is wide, and the efficiency is high, suggesting this as a practical, green route for the production of triazolo-based heterocycles.