DEPENDENCE OF THE BIOLOGICAL-ACTIVITY AND MASS-SPECTROMETRIC PATTERN ON THE STRUCTURE PECULIARITIES OF THE MOLECULE OF ALKYLATING DRUG THIOTEPA

Structural and electronic parameters of the chemotherapeutic alkylatin g drug thiotepa obtained by MNDO and MINDO/3 quantum mechanical calcul ations are used to explain some physical, chemical and biological prop erties of this compound. On the basis of the revealed difference betwe en the preferential conformations of the thiotepa molecule in crystal and vacuum, a conclusion is made concerning the precautions in the cho ice of the appropriate molecular geometry in the search of structure-a ctivity correlations. The theoretical data are also applied to the exp lanation of some peculiarities of soft ionization mass spectra of thio tepa, in particular its sensitivity to high field effects and the abse nce of protonation. The modeling of some reactions of thiotepa directl y in the conditions of field ionization mass spectrometric experiment is discussed.