Mannich‐Type Condensation and Domino Quinazolinone‐Amidine Rearrangement Affords Ring‐Fused Mackinazolinones with Anti‐Amoebic Activity

Abstract

A three‐step synthesis of anti‐amoebic, ring‐fused mackinazolinones has been developed. A Mannich‐type reaction between quinazolin‐4‐ones and N‐Cbz propanal in the presence of AgOTf afforded quinazolinones (19–94% isolated yield) bearing a newly formed heterocycle with an alkylamine appendage that, upon N‐Cbz deprotection and basification, triggered a domino rearrangement to afford 45 separable, ring‐fused products. Several compounds inhibited growth of Naegleria fowleri parasites that can cause a lethal human brain infection. Thus, the methodology provides immediate access to a promising anti‐amoebic scaffold.