ABSTRACT
Sitafloxacin is a newly developed fluoro-quinolone anti-bacterial drug. The crystal studied, C(19)H(18)ClF(2)N(3)O(3)·CH(3)OH, consists of one mol-ecule of sitafloxacin and one methanol solvent mol-ecule. The mol-ecule of sitafloxacin is a zwitterion with a protonated primary amine group and a deprotonated carboxylate group. The cyclopropane ring and the CO(2) group make dihedral angles of 79.5â (3) and 35.4â (4)°, respectively, with the fused ring system. The supra-molecular structure is defined by N-Hâ¯O and O-Hâ¯O hydrogen bonds.
ABSTRACT
This communication describes the facile synthesis of tetracyanoresorcin[4]arene and its high and pH dependent affinities toward biologically important acetylcholine in the physiological pH region.
Subject(s)
Acetylcholine/chemistry , Calixarenes/chemistry , Calixarenes/chemical synthesis , Receptors, Cholinergic/chemistry , Resorcinols/chemistry , Resorcinols/chemical synthesis , Binding Sites , Hydrogen-Ion Concentration , Molecular StructureABSTRACT
A pH sensitive artificial ion channel, tetracyanoresorcin[4]arene, whose pK(a1) to pK(a3) are around pH 7, was synthesized. Conductivities for potassium ion were increased by the progress of dissociation at the channel mouth.
