Synthesis and biological actIVity of new series of organotin(IV) esters with N,N-diacetylglycine

A bioactive N,N-diacetylglycine (NNDAG) and new organotin(IV) complexes (OTCs) (1-7) were synthesized. Spectroscopic techniques were employed to characterize NNDAG and OTCs. FTIR was employed to verify N,N protection of glycine by acetyl groups. The disappearance of υ(OH) at 3000-2600 cm^-1 showed de-protonation of free ligand. The Δυ 150<200 cm^-1 of OTCs 4-7 verified bidentate coordination with tetrahedral geometry. The Δυ of OTCs 1 and 3 was <200 cm^-1 exhibiting transoctahedral geometry while OTC 2 dimer was assigned a unique sinusoidal view. The ¹H NMR spectra of OTCs verified their synthesis by de-protonation of NNDAG and no chemical shift was found downfield for carboxylic acid proton. The ¹³C, ¹¹⁹Sn NMR and Mass spectrometric data also supported FTIR and ¹H NMR descriptions. The OTCs 4, 5, 6 and 7 (500 ppm) proved twice as active against Escherichia coli as the standard antibiotic enoxacin (1000 ppm). The promising property of the OTCs (4, 5, 6 and 7) is clearly due to their tetrahedral. The OTCs 4 and 5 exhibited excellent activity against M. minimum and good activity against T. castaneum. LD₅₀ of all the compounds were determined and OTCs 4, 5 and 7 were found to be active.