. 18-Crown-6 (264 mg, 1.0 mmol) and thiourea (304 mg, 4.0 mmol) were refluxed for 30 min in 5 mL of methanol and then evaporated to dryness. The crystalline residue was recrystallized from acetone or methanol/ethyl acetate (1:1): yield 186 mg (32.7%); mp 168-174 °C.

No abstract

The cis-macrocyclic configuration in the phenol-pendant-[l 31aneN4 [I 1-(2'-hydroxyphenyl)-I ,4,7,1 O-tetra-azacyclotridecane] complex with Nil1 rapidly rearranges to a 'square planar' form upon oxidation to Ni l 11 at ca.

No abstract

Three new proton‐ionizable macrocyclic polyether ligands containing the 4‐pyridone subcyclic group have been prepared. Two of these ligands contain lipophilic n‐octyl substituents, the other ligand contains a phenyl substituent. The 15‐crown‐5 ligand containing both a 4‐pyridone subcyclic unit and an n‐octyl substituent selectively transported lithium cations in a water‐methylene chloride‐water bulk liquid membrane system. Five crown compounds containing the 4‐pyridone subcyclic unit were converted to the 4‐thiopyridono‐crown compounds when treated with Lawesson's Reagent. The crystal structure of 4‐thiopyridono‐18‐crown‐6 shows a carbon‐sulfur double bond and a molecule of water hydrogen bonded inside the macrocycle cavity.