Synthesis and characterization of organation (vi) desives of some biologically active compounds

Abstract

N-Maleoylamino acids prepared from maleic anhydride and amino acids, are biologically active compounds. Synthesis of N-Maleoylglycine is accomplished in two steps i.e. the reaction of maleic anhydride and glycine in glacial acetic acid giving maleamic acid, followed by the cyclization of the later to yield N-Maleoylglycine. Triorganotin carboxylates and dicarboxylato tetraorganodistannoxanes with general formulae R3SnL and [(R2SnL)20h respectively have been synthesized, where R = Me, Et, n-Bu, Ph and L = N-Maleoylglycine. The syntheses were carried out by the reaction of N-Maleoylglycine with organotin(IV) halides in stoichiometric ratios, in dry toluene. IR, IH NMR, \3CNMR, 119Sn NMR and Mass Spectrometry are successfully employed for the characterization of investigated compounds. These spectroscopic investigations reveal a dist0l1ed tetrahedral geometry for triorganotin carboxylates in solution and probably a polymeric structure with tin atom in trigonal bipyramidal envirolUnent in solid state. 11 9Sn NMR spectra of dimeric stannoxanes show the presence of two non-equivalent pentacoordinate tin sites, endocyclic and exocyclic. IH NMR and \3C NMR spectra of these compounds present pair of signals for al 'yl groups tt cJ d to do- and ex cyclic tin a oms. The fluxional behaviour of carboxylate groups is reflected in the \3C NMR spectra of dim~ric stallnoxanes which show single signal for these carboxylate groups. Low bond dissociation energies for these compounds result in considerable fragmentation in mass spectrometer and molecular ion peak is rarely observed with very small peak intensity.