Synthesis of quaternary ammonium salts | SpringerLink
A novel class of tartaric acid-derived N-spiro quaternary ammonium salts was synthesised starting from known TADDOLs. These compounds were found to catalyse the asymmetric α-alkylation of glycine Schiff bases with high enantioselectivities and in good yields.
Synthesis and properties of quaternary ammonium salts …
The use of chiral phase-transfer catalysts (PTCs) for asymmetric reactions has attracted considerable interest over the last three decades. Among the different catalytically active structural motives like crown ethers, ammonium salts, and phosphonium salts, chiral quaternary ammonium salts have found the most widespread applications. Following the seminal reports of Wynberg and a group of Merck scientists describing the successful use of chiral quaternary ammonium salts for asymmetric epoxide formation or methylation of a phenylindanone derivative, cinchona-based PTCs have been thoroughly investigated in the 1990s.- Due to their high catalytic potential and broad application scope, these catalysts still belong to the most commonly employed and most powerful PTCs as shown in several recent reports.,
AB - Novel functionalized quaternary ammonium curcuminoids have been synthesized from piperazinyl curcuminoids and Baylis-Hillman reaction derived allyl bromides. These molecules are found to be highly water soluble with increased cytotoxicity compared to native curcumin against three cancer cell lines MIAPaCa-2, MDA-MB-231, and 4T1. Preliminary in vivo toxicity evaluation of a representative curcuminoid 5a in healthy mice indicates that this molecule is well tolerated based on normal body weight gains compared to control group. Furthermore, the efficacy of 5a has been tested in a pancreatic cancer xenograft model of MIAPaCa-2 and has been found to exhibit good tumor growth inhibition as a single agent and also in combination with clinical pancreatic cancer drug gemcitabine.
derivatives are 3-chloro 2 hydroxypropyl quaternary ammonium salts ..
AB - A simple method of wide scope for the synthesis of substituted indolium, quinolinium, isoquinolinium, and benzoazepinium salts has been developed from readily available starting materials. Quaternary ammonium compounds possessing a β-alkenyl substituent and an arylmethyl group readily cyclized in the presence of 115% polyphosphoric acid (PPA) at 300°C for 1 h to furnish the substituted isoquinolinium and benzoazepinium salts in respectable yields (55-67%). On the other hand, alkenylanilinium salts cyclized at 130-140°C for 1 h to give indolium and quinolinium salts in modest yields (18-38%). However, workup simply involved addition of the reaction mixture to ice-water to produce a homogeneous solution followed by the treatment with saturated aqueous KPF6 and extraction of the salt formed with HCCl3 or CH2Cl2. Spectral and elemental analyses supported the structures of the heterocyclic derivatives. A plausible mechanism involving the alkylation of a cation intermediate by the arene in a typical electrophilic substitution process is suggested for the salts carrying an arylmethyl group. In the case of the alkenylanilinium salts, the mechanism is not clear but rearrangements of the Claisen type appear to be operative.
Study on the synthesis of quaternary ammonium salts …
N2 - Novel water-soluble conjugates of 1,2,4,5-tetraoxane bis(quaternary ammonium salts) were synthesized in a relatively stable crystalline form via four steps starting from methyltrioxorhenium-catalyzed endo-peroxidation of ethyl 4-oxocyclohexanecarboxylate with hydrogen peroxide in hexafluoro-2- propanol. The assay for the in vitro toxicity of water-soluble tetraoxanes 5a-5d to malaria parasites indicate that they were inactive against the Plasmodium falciparum FCR-3 strain.
2 – Chiral Quaternary Ammonium Salts in Organocatalysis
AB - Novel water-soluble conjugates of 1,2,4,5-tetraoxane bis(quaternary ammonium salts) were synthesized in a relatively stable crystalline form via four steps starting from methyltrioxorhenium-catalyzed endo-peroxidation of ethyl 4-oxocyclohexanecarboxylate with hydrogen peroxide in hexafluoro-2- propanol. The assay for the in vitro toxicity of water-soluble tetraoxanes 5a-5d to malaria parasites indicate that they were inactive against the Plasmodium falciparum FCR-3 strain.