An efficient method for the synthesis of functionalized phosphonopyrazolines has been developed. The procedure involved the microwave-assisted cycloaddition of diisopropyl diazomethylphosphonate to dipolarophiles, such as a,b-unsaturated-nitriles and -esters, performed in neat conditions. By oxidative aromatization the phosphonopyrazolines, thus obtained, were converted into the corresponding phosphonopyazoles. Alternatively, phosphonopyazoles could be obtained by a one-pot, two step procedure directly from dipolarophiles, thus avoiding the isolation of the intermediate pyrazolines. Full spectroscopic characterization of the compounds has been also reported.
Microwave-assisted cycloaddition of diisopropyl diazomethylphosphonate to electron-deficient alkenes: synthesis of multifunctionalized phosphonopyrazolynes and phosphonopyrazoles
MARINOZZI, Maura;
2014
Abstract
An efficient method for the synthesis of functionalized phosphonopyrazolines has been developed. The procedure involved the microwave-assisted cycloaddition of diisopropyl diazomethylphosphonate to dipolarophiles, such as a,b-unsaturated-nitriles and -esters, performed in neat conditions. By oxidative aromatization the phosphonopyrazolines, thus obtained, were converted into the corresponding phosphonopyazoles. Alternatively, phosphonopyazoles could be obtained by a one-pot, two step procedure directly from dipolarophiles, thus avoiding the isolation of the intermediate pyrazolines. Full spectroscopic characterization of the compounds has been also reported.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
