1. Chemical and physical properties of thiamin
Domina Petric, MD

2. Essential features of the chemical structure:
Conjoined pyrimidine and thiazole rings.
Thiazole ring contains a quaternary nitrogen, an open C-2, and a phosphorylatable alkyl group on C-5.
Amino group on C-4 of the pyrimidine ring.
November 20, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

3. Chemical structure of thiamin:
Thiamin (free base)
Thiamin pyrophosphate
Thiochrome
November 20, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

4. Softschools.com
November 20, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

5. Thiamin nomenclature
The term thiamin is the trivial designation of the compound 3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-5-(2-hydroxyethyl)-4-methylthiazolium, known also as vitamin B1, aneurine and thiamine.
November 20, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

6. Chemical and physical properties of thiamin
Free thiamin is unstable because of its quaternary nitrogen.
In water it is cleaved to the thiol form.
For this reason the hydrochloride and mononitrate forms are used in commerce.
November 20, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

7. Chemical and physical properties of thiamin
Thiamin hydrochloride (thiamin chloride hydrochloride) is a colorless crystal that is very soluble in water (1 g/ml, thus making it a very suitable form for parenteral administration), soluble in methanol and glycerol, but practically insoluble in acetone, ether, chloroform and benzene.
November 20, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

8. Chemical and physical properties of thiamin
The protonated salt has two positive charges:
one associated with the pyrimidine ring
one associated with the thiazole ring
The mononitrate form is more stable than the hydrochloride form, but it is less soluble in water (27 mg/ml).
It is used in food/feed supplementation and in dry pharmaceutical preparations.
November 20, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

9. Chemical and physical properties of thiamin
Free thiamin is easily oxidized to thiamin disulfide and other derivatives, including thiochrome.
Thiochrome is yellow biologically inactive product with strong blue fluorescence that can be used for the quantitative determination of thiamin.
The thiazole hydroxyethyl group can be phosphorylated in vivo to form thiamin mono-, di- and triphosphates.
November 20, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

10. Chemical and physical properties of thiamin
Thiamin diphosphate (thiamin pyrophosphate) is the metabolically active form sometimes referred to as cocarboxylase.
November 20, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

11. Literature
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc
November 20, 2018