Friday, February 05, 2021

History of caffeine

Caffeine is a simple purine base compound and it is a moderately soluble about 2 g/100 mL in water at room temperature. It tastes bitter, white, odorless substance with melting point 235-238 °C. Coffee and tea have owed stimulant properties to caffeine, a simple trimethyl purine derivative.

“The Canon of Medicine”, written in 1025 by the Persian physician Avicenna, is the first text mentioning coffee as a medication. At the time, coffee was used to “clean the skin, dry up the humidities that are under it, and give a better odor to the body”.

In 1819, the German chemist Friedrich Ferdinand Runge (1795-1865) first time isolated pure caffeine in laboratory; he also called it as "Kaffebase" that exists in coffee. According to Runge, he did this at the request of Johann Wolf-Gang von Goethe, a German writer and statesman who had gifted Runge with a case of coffee beans.

In 1821, caffeine was isolated both by the French chemist Pierre Jean Robiquet and by further another pair of French chemists, Pierre-Joseph Pelletier and Joseph Bienaimé Caventou, according to a journal article by Jöns Jacob Berzelius. Further experiments were done according to Berzelius.

Berzelius stated that the French chemists had made their discoveries independently of any knowledge of Runge's work or of each other’s work. Berzelius states ‘caffeine is a substance in coffee’, which simultaneously, in 1821, was discovered by Robiquet and by Pelletier and Caventou, by whom however nothing was made known about it in print.

Robiquet was one among the first to isolate and outlined the properties of pure caffeine whereas Pelletier was the first to execute an elemental analysis.

In 1827, M Oudry isolated "theine" from tea, but it was later proved by Mulder and Carl Jobst that theine was the same as caffeine.

In 1895, German chemist Hermann Emil Fischer (1852-1919) first synthesized caffeine from its chemical components and that was a total synthesis. Then two years later, he as well derived the structural formula of the compound. The study of caffeine was also his first major effort, published when he was 29 30 years of age. Using oxidation with moist chlorine, he found that caffeine had a similar heterocyclic skeleton as uric acid. He then found that it was a trimethylxanthine, but he struggled for some time to clarify the structure of xanthine. However, it was only when Fischer turned to a synthetic approach to structure that he finally correctly realized that the xanthine structure proposed by Ludwig Medicus (1847-1915) prior to Fischer was the correct one.

Fischer was awarded the Nobel Prize in 1902.
History of caffeine

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