R 1 R 1 Yields up to 95% 24 examples 0.24 to 2.3 g scale
AbstractA series of 5-aza-9-deaza-analogues of purine was effectively prepared using highly selective annulation of 1,3,5-triazine ring onto 5-aminopyrazole-4-carboxylates via a one-pot, multicomponent, microwave-assisted approach. The products were obtained in good yields and high purity. This catalyst-free method was demonstrated to be scalable and highly reproducible in different microwave reactors. Some structural features of the prepared compounds were studied in details using dynamic NMR spectroscopy and X-ray crystallography.
Highlights-A practical synthesis of adenine analogues -A new scalable and reproducible microwave-assisted synthesis -Hindered rotation study by dynamic NMR spectroscopy Keywords Pyrazole Purine isostere Multicomponent reaction Pyrazolo[1,5-a][1,3,5]triazine Dynamic NMR spectroscopy