Synthesis of Pyrimidine Hybrids Based on 4H-Pyran and 4H-Chromene Privileged Structures

A combinatorial library of pyrimidine hybrids based on 4H-chromene and 4H-pyran privileged structures has been developed by reacting phenyl isothiocyanate with chromene derivatives 1a-j and pyranopyrazoles 2a-f in refluxing dry pyridine, respectively. Thus, the target pyrimidine hybrids 3a-j and 4a-f were obtained in good yields with a simple reaction strategy.