Synthesis of 2‐amino‐7,8‐dihydro‐6(5 H )‐quinazolinone, 2,4‐diamino‐7,8‐dihydro‐6(5 H )‐quinazolinone, 5,6,7,8‐tetrahydro‐2,6‐quinazoline‐diamine and 5,6,7,8‐tetrahydro‐2,4,6‐quinazolinetriamine derivatives

N ‐(2‐Amino‐5,6,7,8‐tetrahydro‐6‐quinazolinyl)acetamide ( 9 ) and N ‐(2,4‐diamino‐5,6,7,8‐tetrahydro‐6‐quinazolinyl)acetamide ( 6 ) were synthesized from N ‐(4‐oxocyclohexyl)acetamide ( 5 ) as novel peptidomimetic building blocks. With similar purpose, N ‐(6‐oxo‐5,6,7,8‐tetrahydro‐2‐quinazolinyl)acetamide ( 18 ) and N ‐[2‐(acetylamino)‐6‐oxo‐5,6,7,8‐tetrahydro‐4‐quinazolinyl]acetamide ( 14 ) were prepared from cyclohexane‐1,4‐dione monoethylene ketal ( 11 ).