Synthesis of 2‐(3‐methyl‐5‐oxo‐4,5‐dihydro‐1H‐pyrazol‐1‐yl) quinazolin‐4(3H)‐one derivatives

A simple, synthesis of 2‐(3‐methyl‐5‐oxo‐4, 5‐dihydro‐1h‐pyrazol‐1‐yl) quinazolin‐4(3H)‐one 6(a‐d) derivatives, an easy, clean, and economical methodology has been defined. The development of a new pathway for the preparation of substituted derivatives of Quinazoline Pyrazole is highlighted in this report. The mild, inexpensive polyphosphoric acid has proven to be an effective catalyst for excellent yields in the above multi‐component reaction. Widely available and mostly benign catalyst and easy purification are among the several attractive features.