Discrepancies in the results may arise from different ways of handling salts, mixtures, tautomers
, and stereoisomers, generating 3-D coordinates with stochastic algorithms, and so on.
Kurtoglu, Computational and experimental studies of 2-[(E)-hydrazinylidenemethyl]-6-methoxy-4-[(E)-phenyldiazenyl] phenol and its tautomers
Acetone has two types of tautomers
, keto and enol forms.
Sayin, "The investigation of corrosion inhibition efficiency on some benzaldehyde thiosemicarbazones and their thiole tautomers
: Computational study," Journal of the Taiwan Institute of Chemical Engineers, vol.
Sulfonphthaleins (Scheme 1) are anionic dyes; their structure has two tautomers
present in equilibrium.
At neutral to basic pH solutions there are two tautomers
: 4-methylimidazole and 5-methylimidazole exist in equilibrium .
It is suggested that the two tautomers
are plausible in equilibrium due to strong acidic nature of the sulphonic acid group.
The minimized internal energies (total energy and binding energy) beside the formation energy (Tables 1 and 2) of 21 tautomers
suggest their high stability which outweigh their production from the coupling reaction and indicate that the most stable tautomer
This analysis can be done with the use of FICTS rules to modify structures by (F) removing small organic fragments, (I) ignoring isotopic labels, (C) neutralizing charges, (T) generating canonical tautomers
, (S) ignoring stereochemistry.
Original states of ionization were retained; tautomers
and conformations were generated by the Monte Carlo method as implemented in MacroModel version 9.8, 2010 , using OpLs-2005 force field.
of lithium bis(trimethylsilyl)amide (LiHMDS) in THF at -78[degrees]C and with a temperature increase to room temperature for 1 day produced intermediates comprising mixtures of tautomers
. These intermediates were subjected to acid cyclodehydration and deprotection with 0.5% [H.sub.2]S[O.sub.4] in acetic acid at 100[degrees]C for 4.5 h.
Furthermore the binding site was evaluated 15 [Angstrom] around the cocrystal and the histidine tautomers
were protonated to ND1H state as was observed in the crystal structure.