B. C. P. Jansen was a Dutch chemist and biochemist. In the Dutch Indies, with his colleague W. F. Donath, he isolated in crystalline form an anti-beriberi factor (known as vitamine B1 or aneurin) from rice polishings and christinaed it thiamine

Thiamine

Thiamine or thiamin or vitamin B1 , named as the "thio-vitamine" is a water-soluble vitamin of the B complex. First named aneurin for the detrimental neurological effects if not present in the diet, it was eventually assigned the generic descriptor name vitamin B1. Its phosphate derivatives are...

(sulfur-containing amine). It was the first vitamine to be obtained in pure form.