Experiments on the biogenesis of vitamin B1

WE have recently suggested The fact that yeast, which is pre-eminently able to effect this type of degradation, is a rich source of aneurin added plausibility to this hypothesis. The synthesis of the amino-acid (II) was described in our last communi- cation. It has now been found that the compound II is in fact broken down by yeast to give 4-methyl-5-(,B-hydroxyethyl)-thiazole (I) which was isolated as the picrate; the yield amounted to nearly 60 % on the assumption that only one of the optical isomerides was attacked.