Bases Quina alkaloids

Leaves of Cinchona succirubra Pav. from a trial plantation in the north of Thailand have been reported to contain the typical bases of quinoline alkaloids (cinchonine, cinchonidine, quinidine, quinine, di-hydroquinidine, and dihydroquinine) together with the indole bases quina-mine and 3-epiquinamine (97,98). 10-Methoxycinchonamine (92) has also been isolated from this plant for the first time. Except for the inclusion of alkaloid 92, the alkaloid pattern in C. succirubra is the same as that in the cross-species C. succirubra x C. ledgeriana from Guatemala. 

The central. CHOH. group in the cinchona alkaloids seems to be essential to anti-malarial activity Conversion into quinicines [quinatoxines (I) — (VII)] destroys activity and so do such changes as. CHOH. — . CHCl. (cinchona chlorides) or. CHOH. — . CHj. (deoxy-cinchona bases) or. CHOH. — . CO. quina-ketones), or acylation of the hydroxyl group except in the case of quinine ethylcarbonate. 

The cinchona tree, from the bark of which these alkaloids are obtained, was originally found only on the eastern slope of the Andes in South America. The cultivation of this species, and other species of the same genus, was introduced into Java, India, Ceylon, Jamaica and Australia. At present the production of bark in Java is greater than in any other country. As early as 1639 the cinchona bark was introduced into Europe but it was not until 1792 that an impure alkaloid was isolated and a little later given the name quina. In 1820 this impure alkaloid was separated into two compounds named quinine and cinchonine. The bark contains about 3 per cent quinine combined with acids, tannic and quinic, from which it is set free by the action of lime. The free base is then extracted with petroleum ether or... 

Quinoline is a high-boiling liquid isoquinoUne is a low-melting solid each has a sweetish odour. Both bases have been known for a long time quinoline was first isolated from coal tar in 1834, isoquinoUne from the same source in 1885. Shortly after the isolation of quinoline from coal tar, it was also recognised as a pyrolytic degradation product of cinchonamine, an alkaloid closely related to quinine, from which the name quinoline is derived the word quinine, in turn, derives from quina, a Spanish version of a local South American name for the bark of quinine-containing Cinchona species. 

Alkaloids are classified into two main groups heterocyclic and non-heterocyclic. In this work, authors will only deal with the heterocyclic alkaloids that have a quinoUne nucleus (tryptophan derivatives), which include the alkaloids of quina, and the group of diverse alkaloids, specifically the xanthine bases or purine alkaloids. 

---