Ultrasonic‐Assisted One‐Pot Batch Simultaneous Synthesis of Two Different Types of Heterocyclic Derivatives and DFT Study

A green method called “one‐pot batch synthesis” has been developed for the simultaneous synthesis of two different types of heterocyclic derivatives, oxazolo [3, 2‐c] pyrimidines and hydroxyl ethyl dihydropyrimidones. The reaction was conducted under ultrasonic irradiation in green bio‐based solvent lactic acid without any additional catalysts and additives. From β‐hydroxyethyl urea, acetoacetyl esters/amines and aromatic aldehydes, fifteen oxazolopyrimidine and eleven hydroxyl ethyl dihydropyrimidones were synthesized using the method for the first time. The generation mechanism of two different kinds of products under ultrasonic irradiation from the same reaction conditions was explained by Density Functional Theory. All products were obtained in high yields and characterized by IR, NMR, ESI MS, and X‐ray diffraction. Described a method for the one‐pot batch simultaneous synthesis of two different types of heterocyclic derivatives, oxazolo [3,2‐c] pyrimidines and hydroxyl ethyl dihydropyrimidones, and calculated the possible reaction mechanisms using the density functional methods.