Abstract
1). Addition of 3 moles of sodium hydroxide to the aqueous solution of thiamine hydrochloride to form the sodium salt of thiol-type thiamine, followed by the addition of aqueous solution of cyanogen bromide, and immediate basification with 30% sodium hydroxide afford colorless hydrate crystals of m. p. 109.5°, which give a dehydrated compound of m. p. 134-136° by drying over phosphorus pentoxide.
2). Addition of 3 moles of sodium hydroxide to the aqueous solution of thiamine hydrochloride to form the sodium salt of thiol-type thiamine and application of 1 mole of cyanogen bromide to it affords colorless hydrate crystals of m. p. 78-80°. Recrystallization from dehydrated ethanol gives N-(1-methyl-2-thiocyanato-4-hydroxy-l-butenyl)-N-[(2-methyl-4-amino-5-pyrimidinyl)methyl]formamide (III) as crystals melting with decomposition at 150.5-151.5°. This substance is decomposed by hydrochloric acid into 2-methyl-4-amino-5-aminomethylpyrimidine and formic acid, by sodium hydroxide into thiamine, thiamine disulfide, and a substance of m. p. 134-136°, and reduced by sodium sulfide or cysteine hydrochloride into thiamine. The substance of m. p. 134-136° is identical with the unknown substance obtained by Yurugi by the pyrolysis of thiamine disulfide.
