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The geometries and vibrational frequencies of 11 training molecules containing the ammonium ion moiety were calculated at the MP2/6‐31+G* level of theory. Various torsional energy profiles were also calculated using this basis set. From those ab initio calculations, a molecular mechanics (MM3) force field was developed using our Parameter Analysis and Refinement Toolkit System (PARTS). Using this set of parameters, the MM3 force field was found to well reproduce the molecular geometries and vibrational spectra for the all training molecules. CPU time was reduced from days to seconds. The availability of this new force field dramatically increases the feasibility of the computer‐assisted drug design involving ammonium and protonated amino groups. © 1997 by John Wiley & Sons, Inc. J Comput Chem 18: 1371–1391, 1997

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1993 microwave chemistry, sonochemistry, mechanochemistry microwave chemistry, sonochemistry, mechanochemistry O 0170 -120Ultrasound Promoted Hypervalent Iodine Reactions: α-Tosyloxylation of Ketones with (Hydroxy(tosyloxy)iodo)benzene.-The α-tosyloxy ketones (III) or (V) are prepared in one-step by reaction of the ketones (I) and (IV) with the (tosyloxy)iodobenzene ( II) under sonication in acetonitrile. When 2-butanone (VI) is subjected to similar reaction conditions, a mixture of the sulfonates ( VII) and (VIII) is obtained. -(TUNCAY, A.; DUSTMAN, J. A.; FISHER, G.; TUNCAY, C. I.; SUSLICK, K. S.; Tetrahedron Lett. 33 (1992) 50, 7647-7650; Chem. Dep., Indiana Univ. Northwest, Gary, IN 46408, USA; EN)