TY  - JOUR
A1  - Klinka, Karel D.
A1  - Imrich, Jan
A1  - Danihel, I.
A1  - Bohm, Stanislav
A1  - Kristian, Pavol
A1  - Harnul'akova, S.
A1  - Pihlaja, Kalevi
A1  - Koch, Andreas
A1  - Kleinpeter, Erich
T1  - Configuration and E/Z interconversion mechanism of O(S)-allyl-S(O)-methyl-N-(acridin-9-yl)iminothiocarbonate
N2  - The configuration and dynamic behavior of O-allyl-S-methyl-N-(acridin-9-yl)iminothiocarbonate (1) and its S- allyl-O-methyl regioisomer (2) were studied using quantum chemical calculations and by applying a novel graphical method to scatter maps obtained from MD simulations for evaluation of an NOE-weighted internuclear distance (r(NOE)). Energy calculations indicated that the Z configuration was predominant for each compound and, further, this was supported both by the calculated chemical shifts and the rNOE. Both N-inversion- and rotation-type transition-state structures were also calculated for the E/Z isomerization process, the results indicating that the preferred interconversion mechanism for 1 is N-inversion, but contrastingly, interconversion via rotation is equally as probable as N-inversion for 2. This supports the notion that one or the other or both pathways can be active and each system needs to be assessed on a case- by-case basis. Copyright (c) 2005 John Wiley & Sons, Ltd
Y1  - 2005
SN  - 0749-1581
ER  - 
TY  - JOUR
A1  - Klinka, Karel D.
A1  - Balentova, Eva
A1  - Bernát, Juraj
A1  - Imrich, Jan
A1  - Vavrusova, Martina
A1  - Kleinpeter, Erich
A1  - Pihlaja, Kalevi
A1  - Koch, Andreas
T1  - Tautomerism, regioisomerism, and cyclization reactions of acridinyl thiosemicarbazides
N2  - The regioselectivities of methyl- and phenylhydrazine with acridin-9-yl isothiocyanate (thus yielding thiosemicarbazides with acridine substituted on the urea-type side) were examined. Methythydrazine regioselectivity was high with the alpha-nitrogen atom overwhelmingly more nucleophilic than the beta-nitrogen atom; phenylhydrazine regioselectivity was poor but varied with the solvent and only in the case of ethanol was nucleophilic predominance of the alpha-nitrogen atom pronounced. Of note, whilst both phenyl thiosemicarbazides were present in solution only as spiro forms, the methyl product was present as an equilibrium mixture of open-chain and spiro thiosemicarbazides. Reactions on the NH2 blocked analogue of methyl acridin-9-ylthiosemicarbazide (1-isopropylidene-2- methylthiosemicarbazide) were also examined. Interestingly, present in the starting material itself was a structural motif of novelty wherein a triazolethione represented the major species of an equilibrium between cyclic and open-chain forms
Y1  - 2006
UR  - http://www3.interscience.wiley.com/journal/121521817/toc
U6  - https://doi.org/10.1002/jhet.5570430317
SN  - 0022-152X
ER  -