Chinazolincarbonsäuren. VII. Mitteilung . Ein einfacher Zugang zu (4‐Oxo‐3,4‐dihydrochinazolin‐3‐yl)‐alkansäuren, (4‐Oxo‐3,4‐dihydro‐1,2,3‐benzotriazin‐3‐yl)‐alkansäuren und deren Estern

Quinazoline Carboxylic Acids. An Easy Route to (4‐Oxo‐3,4‐dihydroquinazolin‐3‐yl)‐alkanoic Acids, (4‐Oxo‐3,4‐dihydro‐1,2,3‐benzotriazin‐3‐yl)‐alkanoic Acids and their Esters A new route was found for the synthesis of (4‐Oxo‐3,4‐dihydroquinazolin‐3‐yl)‐alkanoic acids ( 8 ) and (4‐Oxo‐3,4‐dihydro‐1,2,3‐benzotriazin‐3‐yl)‐alkanoic acids ( 6 ) by cyclization of the N ‐(2‐aminobenzoyl)amino acids 5 with HCOOH or HNO 2 . 2 H ‐3,1‐Benzoxazine‐2,4(1 H )‐diones ( 1 ) reacted with glycine esters to 2 , which were cyclized by HNO 2 to the esters 4 . Ester 4 was hydrolyzed to 6 (X = CH 2 ). Diones 1 reacted with the most common amino acids (as the ammonium salt of tertiary amine) to amino‐alkanoic acids 5 , which were cyclized with orthoformate to 7 or 8 depending on the reaction conditions.