Palladium(0) catalyzed alkenylation of 3′- or 4′-iodo- (or bromo-) benzocrown ethers are found to be a convenient procedure for the introduction of alkenyl groups (–CH=CH–R; R=Ph, COOEt and COOH). Iodination at 3′-position of benzocrown ethers could be achieved in good yield by the use of 4′-t-butyl derivatives.
Preparation of benzo- and polybenzocrown ethers by macrocyclization reactions
作者:Robert E. Hanes、Jong Chan Lee、Sheryl N. Ivy、Anna Palka、Richard A. Bartsch
DOI:10.3998/ark.5550190.0011.718
日期:——
the method was used for the preparation of monobenzocrown ethers. Interestingly, for the preparation of monobenzocrown ethers, [2+2] adducts were discovered to be significantly contaminating the products. Dimesylates were chosen as the leaving group due to their ease or preparation and the ability to use the unpurified products with no apparent impact on the macrocyclization.
Benzo-15-crown-5–Aluminium Chloride Complexes of Unusual Stability
作者:Fumio Wada、Tsutomu Matsuda
DOI:10.1246/bcsj.53.421
日期:1980.2
Among twelve crown ethers of 12, 15, 18, and 21 rings only benzo-15-crown-5 and those with an electron-releasing substituent formed the complexes with aluminium chloride which were stable in methanol.
A membrane electrode assembly for fuel cells includes a proton conducting membrane having a first side and a second side. The proton conducting membrane in turn includes a first polymer including cyclic polyether groups and a second polymer having sulfonic acid groups. The membrane electrode assembly further includes an anode disposed over the first side of the proton conducting layer and a cathode catalyst layer disposed over the second side of the proton conducting layer.