The pterins xanthopterin (2-amino-4:6-dihydroxypteridine) (Koschara, 1936) and biopterin (2amino 4 hydroxy-6-[1: 2-dihydroxypropyl (L-erythro)]-pteridine) (Patterson, Saltza & Stokstad, 1956) have been isolated from human urine. It has been suggested that the pterins 2-amino-4-hydroxypteridine-6-carboxylic acid, 2-amino-4-hydroxypteridine and isoxanthopterin (2-amino-4:7-dihydroxypteridine) are...

BACKGROUND The utility of N-heterocyclic bases to obtain molecular complexes with carboxylic acids is well studied. Depending on the solid state interaction between the N-heterocyclic base and a carboxylic acid a variety of neutral or ionic synthons are observed. Meanwhile, pyridines and pyrimidines have been frequently chosen in the area of crystal engineering for their multipurpose functional...

A comprehensive study pertaining to the emulsion liquid membrane (ELM) extraction process to enrich dilute aqueous solutions of silver salt is presented. The study has highlighted the importance and influence of membrane composition for maximizing the extraction of Ag+ ions. The liquid membrane was made up of Cyanex-302 as an extractant and the industrial solvent mainly consists of p...

A new series of 5-substituted-3-methylsulfanyl-1-(2,4-dinitro phenyl)-1H-pyrazole-4-carboxylic acid ethyl esters were synthesized by reacting the amino group of 5-amino-3-methylsulfanyl-1-(2,4-dinitro phenyl)-1H-pyrazole-4carboxylic acid ethyl ester with acid anhydrides, acid chlorides and phenyl dithiocarbamates. The title compounds were investigated for analgesic, anti-inflammatory and ulcero...

Polypeptoids bearing carboxylic acid groups on the N-substituent are useful building blocks for construction of peptidomimetic supramolecular assemblies with stimuli-responsive properties.