Adamantylation and Adamantylalkylation of Amides, Nitriles and Ureas in Trifluoroacetic Acid
作者:Elvira Shokova
DOI:10.1055/s-1997-1304
日期:1997.9
A new preparative method for N-adamantylation of carboxylic acid amides, ureas and for C5-adamantylation of barbituric acid in trifluoroacetic acid (TFA) is proposed. Tertiary 1-adamantanols and 1-(1-adamantyl)alkanols were used as adamantylating agents. The reaction of 1-(1-adamantyl)alkanols with nitriles in TFA solution was employed for the first time for the preparation of N-[1-(1-adamantyl)alkyl]amides.
Direct Access to Acyl Fluorides from Carboxylic Acids Using a Phosphine/Fluoride Deoxyfluorination Reagent System
作者:Socrates B. Munoz、Huong Dang、Xanath Ispizua-Rodriguez、Thomas Mathew、G. K. Surya Prakash
DOI:10.1021/acs.orglett.9b00197
日期:2019.3.15
A fast and simple method for deoxyfluorination of carboxylicacids is presented. The protocol employs commodity chemicals (PPh3, NBS, fluoride), affording products in excellent yields under mild conditions. Acyloxyphosphonium ion, the key reaction intermediate, was identified by NMR spectroscopic methods. Brønsted acidic conditions are essential for efficient C–F bond formation. The protocol displays
Shokova; Musulu, Tasula; Luzikov, Russian Journal of Organic Chemistry, 1999, vol. 35, # 6, p. 844 - 856
作者:Shokova、Musulu, Tasula、Luzikov、Kovalev
DOI:——
日期:——
Cavitand−Porphyrins
作者:Stephen D. Starnes、Dmitry M. Rudkevich、Julius Rebek
DOI:10.1021/ja010038r
日期:2001.5.1
The synthesis and characterization of new nanoscale container molecules 7 and 8 are described. They are covalent hybrids of deepened, self-folding cavitands and metalloporphyrins. In receptor 7, the Zn-porphyrin wall is directly built onto the cavitand skeleton. Host 8 features a large unimolecular cavity containing two cavitands attached with the Zn-porphyrin wall. Its dimensions, similar to 10 x 25 Angstrom, place it among the largest synthetic hosts prepared to date. A series of adamantyl- and pyridyl-containing guests 14-20 of various lengths were prepared and used to determine the hosts' binding abilities in solution using UV/vis and H-1 NMR spectroscopy. Intramolecular hydrogen bonds at the upper rims of the cavitands resist the unfolding of the inner cavities and thereby increase the energetic barrier to guest exchange. The exchange is slow on the NMR time scale (at less than or equal to 300 K), and kinetically stable complexes result. When the cavities and metalloporphyrins participate simultaneously in the binding event, very high affinities for guests are found (-DeltaG(295) up to 10 kcal mol(-1) in toluene), to which the porphyrin fragments contribute significantly (-DeltaG(295) up to 6 kcal mol(-1)). The pairwise selection of two different guests by molecular container 8 is reported, and the termolecular complex formed raises the possibility of metal-catalyzed bimolecular reactions in these containers.