William H. Darlington

Oxidative cyclization of acyclic ureas with bis(trifluoroacetoxy)iodobenzene to generate N-substituted 2-benzimidazolinones

Abstract A facile method to synthesize N-substituted 2-benzimidazolinones from secondary aromatic amines is presented. Sequential treatment of a secondary aromatic amine with phosgene and methoxylamine afforded an acyclic 3-substituted 3-aryl-1-methoxy urea. Brief exposure of this urea to bis(trifluoroacetoxy)iodobenzene induced an oxidative cyclization to the ortho-position of the benzene ring, resulting in the formation of a 3-substituted 1-methoxy-2-benzimidazloinone. Hydrogenation over Pd C cleaves the methoxy group to afford the N-substituted 2-benzimidazolinone.

Synthesis of metabolically stable arylpiperazine 5-HT1A receptor agonists

Abstract Although N-alkylarylpiperazines as a class are finding use as anxiolytics and antidepressants, many of these arylpiperazines are highly metabolically labile at the n-alkyl-piperazine bond. We have found that cyclopropanating the n-butyl chain contained in the 5-HT1A receptor agonist ipsapirone (2) instills a resistance to this metabolism as well as providing information about the geometrical requirements of the 5-HT1A receptor.

Synthesis of 2,3-dihydro-1H-phenalene derivative by the intramolecular diels-alder reaction of benzyne with furan

Abstract 2,3-Dihydro-1H-phenalene derivative 1 was synthesized by the intramolecular Diels-Alder reaction ( 21 → 22 ). 2,5-Dimethylpyrrole was used as a protecting group for the primary amine.