SEARCH Articles Figures Tables Ammonium dimeric Cinchona Cinchona ammonium salts Cinchona derivatives Cinchona dimeric Cinchona dimerization Cinchona quaternary ammonium salts Cinchona salt Dimeric ammonium salts Dimeric quaternary ammonium salts Dimerization derivatives Dimerization salts Quaternary ammonium salts Quaternary cinchona-derived dimeric Quaternary salts