Double Hydroamination of Terminal Alkynes over Beta Zeolite-Supported CuO Catalyst

An effective and novel heterogeneous beta zeolite supported CuO (Cu beta) catalyzed double hydroamination of alkynes for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones has been achieved in a solvent-free condition. Cu beta zeolite was synthesized by impregnation method. The synthesized Cu beta was characterized by X-ray diffraction, Fourier transformation infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. Pure H beta (18 % yield) or Nano CuO (44 % yield) displayed poor catalytic activity, whereas 1 % Cu beta (96 % yield) showed higher catalytic activity for double hydroamination of alkynes due to the synergistic effect of CuO and H beta zeolite in the reaction. The new protocol offers an appealing approach to a number of di-substituted quinazolinones with decent to excellent yields. The catalyst has been successfully recycled for up to 5 consecutive cycles. An efficient heterogeneous 1 % Cu beta zeolite catalyzed double hydroamination of terminal alkynes for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones is achieved in a solvent-free environment. This method offers an appealing approach to a number of di-substituted quinazolinones with decent to excellent yields.image