Weinreb amidation as the cornerstone of an improved synthetic route to A-ring-modified derivatives of luotonin A

Molecules. 2012 Sep 25;17(10):11363-78. doi: 10.3390/molecules171011363.

Abstract

Weinreb amidation of ethyl 4-oxo-3,4-dihydroquinazoline-2-carboxylate with aromatic amines provides a significantly improved route to anilide-type key intermediates for the synthesis of the anticancer alkaloid, luotonin A, and new A-ring-modified derivatives thereof. This method has advantages concerning overall yield, brevity, and versatility with regard to the aromatic amine component, even if the latter has less favourable nucleophilicity, solubility and/or stability properties. This is demonstrated by the concise synthesis of a small library of luotonin A analogues, including a novel thiophene isostere of the alkaloid.

MeSH terms

  • Decarboxylation
  • Hydrolysis
  • Pyrroles / chemical synthesis*
  • Pyrroles / chemistry
  • Quinones / chemical synthesis*
  • Quinones / chemistry

Substances

  • Pyrroles
  • Quinones
  • luotonin A