When keto-enol tautomerism occurs through the addition of base, it proceeds through the formation of an intermediate enolate before being protonated and converted to the enol form. Since the aldehyde / ketone (pKa = 17-19) is a weaker acid than H2O (pKa 15) the equilibrium lies mostly to ...
The solvent effect on the ground-state energy difference of meridine (enol form) and meridin-12(13H)-one (keto form) is examined by use of AM1 and COSMO methods. The results show that solvents stabilize the keto form more than the enol form. In apolar solvents, the enol form is the...
The post-synthetic modification featuring the flexibility of topological arrangement allows the incorporation of majority types of linkers and functional groups into COFs without damaging the periodic structure [129]. Meanwhile, similar to the enol-to-keto tautomerization, it provides a promising approach...
This increases the tendency to form polyhydroxylated fullerenes (fullerenols). The structural stability is analyzed in terms of the calculated formation enthalpy of each species. Also, a careful examination of the electron density of states for different fullerenols shows the possibility of ...
Solubility and stability of scorodite, FeAsO/sub 4/. 2H/sub 2/O: Reply This report presents evidence that, although thermodynamically favored, ferric hydroxides do not form during the solution of scorodite owing to inhibition ... J Rimstidt,P Dove...
The ionization of oligomer structures led to mass fragments of main monomers present in Okoume condensed tannins which appeared in the ionized [M-H]− form. The results obtained with an output predominance around 40–60 and 60–85 minutes were collected (Figs. 1–2) and compared to those...
Paclitaxel as an anticancer agent:isolation, activity, synthesis and stabilityecules using a Shapiro and McMurry coupling to form the B ring. Further reactions were carried out to produce the final product of paclitaxel. Holton et al. started with (-)-borneol, which they converted to an unsatur...
composition or kit according to any one of the preceding claims;b) contacting one or more from (a) with zearalenone and/or a derivative thereof. Description: This application contains a Sequence Listing in a computer readable form, which is incorporated herein by reference....
wehavesuccessfullyovercomethisproblem byintroducing-OHfunctionalitiesadjacenttotheSchiffbase centersinCOFsbyusingamethodologyofcombined reversibleandirreversibleorganicreactions. [8] Theexpected enol-imine(-OH)formundergoesirreversibleprotontauto- merismtotheketo-enamineform,whichisstableandremains crystallineinacid(...
(1) o-hydroxybenzophenone - the most important uv absorber A hydroxyl group must be contained in the carbonyl adjacent position to form a hydrogen bond chelation ring, which is used to absorb and release energy through the interaction of ketone and enol. The greater the strength of hydrogen ...