Methyl (2-chloroethyl)aminocarbonyldiazenecarboxylate reacted with either 4-fluorophenol or 2-chlorophenol in the presence of ZrCl4 to give 2-chlorophenol, aminated at the position 4 with regard to the OH group. These results clearly indicated that the aminations of 4-fluorophenol was not only an electrophilic process. A plausible reaction pathway seems to involve an ion pair intermediate, followed by an ipso attack of the nitrogen electrophile at position 4. The next step is probably the elimination of ZrCl4Fâ and the entrance of the chloride ion leading to the tautomer of the final product.
COBISS.SI-ID: 25767941
We have studied a novel tandem hydration of alpha-thiocyanatoketones to thiocarbamates followed by in situ cyclodehydration to fused 2-oxo-3-thiazolines. This work represents a new and one of the rare strategies for the preparation of fused 2-oxo-3-thiazolines. Its importance is demonstrated by the recent discovery of structurally related 2-arylthiazolo[4,5-c]quinolin-4(5H)-ones exhibiting high affinity for the GABA receptors.
COBISS.SI-ID: 26055941
We have investigated the Diels-Alder cycloaddition reaction of 2H-pyran-2-ones with alkynes yielding substituted derivatives of aniline and ortho-phenylenediamine under thermal and high-pressure conditions. All the reactions were completely regioselective, but the reactivity was strongly dependent on the substitution patterns of the starting 2H-pyran-2-ones and of acetylenes. The importance of the synthesized compounds is high as they represent useful multifunctional building blocks for further transformations toward more complex products.
COBISS.SI-ID: 25825029
Triethylammonium triazenides reacted with alkyl propiolates to give the alkoxycarbonylvinyltriethylammonium triazenides in excellent yields. The products are prone to transesterification at rt. Namely, when dissolved in the selected alcohol with the solution being kept at room temperature they can easily be transformed into the appropriate esters. Transesterification is a reversible process as indicated by a number of conversions. The triazenide counterion plays an important role in transesterification. The same triazenides can also serve as promoters for some other transesterifications.
COBISS.SI-ID: 27535109
The collaboration of researchers from UCLA, UL FKKT, and UL MF resulted in the assessment of FDDNP applicability in labeling protein deposits in fixed brain tissue sections of selected neurodegenerative disorders. We found significant agreement between amyloid histochemical properties and FDDNP labeling of the deposits. Radiolabeled FDDNP will be used with PET to extend the method for assessment of the protein deposits to living brain of patients with various neurodegenerative diseases.
COBISS.SI-ID: 21354457