African Journal of
Pure and Applied Chemistry

  • Abbreviation: Afr. J. Pure Appl. Chem.
  • Language: English
  • ISSN: 1996-0840
  • DOI: 10.5897/AJPAC
  • Start Year: 2007
  • Published Articles: 357

Full Length Research Paper

Electronic and steric effects in the control of the Anilinium chloride catalyzed condensation reaction between Aldones and 4-Phenylthiosemicarbazide

Urbain C. Kasséhin1, 2, Fernand A. Gbaguidi3*, Coco N. Kapanda1, Christopher McCurdy4,  André K. Bigot2 and Jacques H. Poupaert1
  1Medicinal Chemistry, Louvain Drug Research Institute, Université catholique de Louvain. 73, Bte B1.73.10, Av. E. Mounier B-1200 Bruxelles, Belgium. 2Unité de Formation et de Recherches en Pharmacie, Faculté des Sciences de la Santé, Université d’Abomey- Calavi, BP-188, Cotonou, Bénin. 3Laboratoire de Pharmacognosie/UAC/CBRST ; Porto-Novo, BP 06 Oganla, Benin. 4Medicinal Chemistry, School of Pharmacy, 419 Faser hall, P. O. BOX 1848, University, M S 386771848, USA.
Email: [email protected]

  •  Accepted: 26 August 2013
  •  Published: 30 September 2013

Abstract

 

A concise series of aldehydes and ketones were reacted in a condensation reaction with 4-phenylthiosemicarbazide in order to assess the relative influence of the steric and electronic effects in the control of this reaction. While steric effects had a modest impact, electronic effects and in particular the mesomeric donating effect delivered by a phenyl ring produced a strong passivating influence on the reactivity of these aldones. Additionally, the cyclopropyl substituent totally passivated the reaction via the interfering factor of its inherent sigma-aromaticity. When reacted with cyclopropyl-phenylketone, under our standard conditions, 4-phenylthiosemicarbazide gave in 82%, an original 1, 4-dihydrotetrazine via a double consecutive self-condensation.

 

Key words: Thiosemicarbazone, electronic effect, steric effect, ion catalysis aniline, sigma, aromaticity.