Alginic acid in water at room temperature: a natural combination for the environmental benign synthesis of 2,3-dihydroquinazolin-4(1H)-ones

We have successfully synthesized 2,3-dihydroquinazolin-4(1H)-ones (DHQs) using naturally sourced alginic acid as a solid acid catalyst. Our synthetic method was performed in pure water at room temperature and yielded good to excellent results. We achieved this by directly cyclo-condensing anthranilamide with various aldehydes or ketones in the presence of alginic acid in water at room temperature. Furthermore, the alginic acid can be easily separated from the reaction mixture and reused up to five times with consistent yields and reaction time. This method is energy efficient and can be applied on a large scale, with excellent green credentials. Our evaluation of green metrics highlights the sustainable features of the alginic acid-catalyzed DHQ synthesis process. [GRAPHICS] .