High-pressure S(N)Ar reaction was first applied to the synthesis of a new crown ether family, which incorporated various heteroaromatics as potential cation binding sites in a unique fashion. In a CH2Cl2 liquid membrane transport experiment, several diaza-crown ethers having thiazole, oxazole, pyrazine, and pyridazine rings exhibited a perfect Ag+ ion selectivity. Cation extraction and C-13 NMR titration experiments revealed that attachment of a unique heterocycle to the diaza-crown ring, if in the proper position, significantly offered excellent Ag+ ion specificity. Since the binding and transport selectivities of these crown ethers were apparently higher than those with conventional crown ethers, the high-pressure technique provided a useful method for synthesis of a new specific crown ether family.
Nucleophilic aromatic substitution reactions under aqueous, mild conditions using polymeric additive HPMC
作者:Niginia Borlinghaus、Tharique N. Ansari、Leon H. von Garrel、Deborah Ogulu、Sachin Handa、Valentin Wittmann、Wilfried M. Braje
DOI:10.1039/d1gc00128k
日期:——
nucleophilic aromatic subsitution (SNAr) reactions between various nucleophiles and electrophiles. The mild reactionconditions facilitate a broad functional group tolerance that can be utilized for subsequent derivatization for the synthesis of pharmaceutically relevant building blocks. The use of only equimolar amounts of all reagents and water as reaction solvent reveals the greenness and sustainability