Transcript QUININE
QUININE -CHEMISTRY BEHIND THE ANTI-MALARIAL DRUG WHAT IS QUININE? • Natural, white crystalline alkaloid • Possesses antipyretic, antimalarial , analgesic and anti-inflammatory properties • Bitter taste • Stereoisomer of quinidine • Possesses 2 major ring systems: aromatic quinoline , bicyclic quinuclidine. BIOLOGICAL SOURCES AND HISTORY • Cinchona species (Rubiaceae) • Obtained from cinchona or peruvian bark • First discovered by Quechua of Peru and Bolivia • First used antimalarial drug CHEMICAL STRUCTURE (R)-(6-Methoxyquinolin-4-yl)((2S,4S,8R)-8-vinylquinuclidin-2-yl)methanol CHARACTERISTICS • Fluoresces in direct sunlight • Sublimes in vacuum at 443-453k. • Dissociation constants Pk1=5.07 and pK2=9.7 • pH of saturated solution=8.8 • Fluoresces with a blue colour especially in sulphuric acid. FUNCTIONAL GROUPS • It's functional groups are: * alkene * tertiary amine (the quinuclidine bicyclic system) * secondary alcohol * quinoline (an aromatic system, specifically 1azanaphthalene) * phenolic ether (or perhaps simply an aromatic ether) TYPES OF BONDS PRESENT IN QUININE • All the bonds present in quinine are covalent bonds. R AND S FORMS Powdered Bark - Alk. CaO + NaOH + H2O - Reflux with benzene & - Filtration while hot Benzene filtrate (Alkaloidal bases) dilute H2SO4 Acidic aqueous layer (Alkaloidal bisulphates) pH to 6.5 with Na2CO3 Precipitate Quinine (monosulphate) Hot water, Na2CO3 Aqueous solution (Monosulphates) quinidine, cinchonine & cinchonidine NaOH, ether Quinine Ether layer Quinidine & Cinchonidine Aqueous layer -HCl PH=7, Na, K Tart. salt - filter Precipitate Cinchonidine tartrate Filtrate Quinidine tartrate Cinchonine RABE AND KINDLER PROCESS • In 1918 Paul Rabe and Karl Kindler obtained a three step preparation of quinine from dquinotoxine IDENTIFICATION TESTS a)Colour Tests: 1.Oxygenated Acids : Strong, blue fluorescence in sulphuric acid, acetic acid,etc. 2. Herpathite Test: boiling mixture of quinine(0.3g)+ 7.5ml glacial acetic acid+ 5 drops of conc. H2SO4 in 3ml ethanol(0.9v/v)+3.5 ml of I2 solution(0.01w/v) in ethanol—dark crystals of sulphate of iodoquinine (herpathite) obtained. ( ( c) Thalleioquin Test: Br2 water+2-3 ml of weakly acidic solution of quinine salt+0.5-1 ml of strong ammonia solution—distinct emerald green colouration. (d) Erythroquinine Test(Rosequin Test): Quinine+ dil. Acetic acid+ freshly prepared Br2 water+ 10% solution of [K4Fe(CN)6]+ conc. NH4OH soln—red colouration. USES • Flavour in carbonated beverages. • Antimalarial agent. • Skeletal muscle relaxant. • Used to treat hemorrhoids and varicose veins • Oxytocic agent. • Prophylactic for flu. DERIVATIVES OF QUININE 1)Quinine Trihydrate 2)Quinine bisulphate heptahydrate 3)Quinine dihydrochloride 4)Quinine hydrochloride dehydrate 5)Quinine sulphate dehydrate QUININE TRIHYDRATE • It has a melting point of 330 K • It becomes anhydrous at 398 K QUININE BISULPHATE HEPTAHYDRATE • It is obtained as bitter crystals • Also known as Quinbisan, Dentojel. QUININE DIHYDROCHLORIDE • Also known as quinine dichloride, Quinine bimuriate • Slightly soluble in chloroform and very slightly soluble in ether • Aqueous solutions are found to be higly acidic with a pH of 2.6 QUININE HYDROCHLORIDE DIHYDRATE • Obtained as silky needles of bitter taste • It effloresces on exposure to warm air. • Forms anhydrous solution at 373 K. QUININE SULPHATE DIHYDRATE • Also known as Quinsan, Quine and Quinate • Its is obtained as dull needles or rods making a light and readily compressible mass. • Losses water of crystallization at 383 K. • Slightly soluble in ether and chloroform QUININE ISOMER : QUINIDINE (S)-(6-Methoxyquinolin-4-yl)((2R,4S,8R)-8-vinylquinuclidin-2-yl)methanol Powdered Bark - Alk. CaO + NaOH + H2O - Reflux with benzene & - Filtration while hot Benzene filtrate (Alkaloidal bases) dilute H2SO4 Acidic aqueous layer (Alkaloidal bisulphates) pH to 6.5 with Na2CO3 Precipitate Quinine (monosulphate) Hot water, Na2CO3 Aqueous solution (Monosulphates) quinidine, cinchonine & cinchonidine NaOH, ether Quinine Ether layer Quinidine & Cinchonidine Aqueous layer -HCl PH=7, Na, K Tart. salt - filter Precipitate Cinchonidine tartrate Filtrate Quinidine tartrate Cinchonine PROPERTIES • It is optical isomer of quinine • It is a diastereomer of quinidine • It is found as white powder or crystals • Insoluble in water • It melts at 441 K USES • It is an antiarrhythmic agent • It helps in keeping the heart rate normal for the people with certain heart rhythm disorders. DONE BY DHRUVI, RUTVI, SIDDHARTH