Pyridoxine-

Pyridoxine (peer-ih-DOCK-seen) is also known as 3-Hydroxy-4,5-bis(hydroxymethyl)- -methyl pyridine 3-hydroxy-4,5-dime-thylol-2-methylpyridine and vitamin B6. It is a white, odorless, crystalline compound with a slightly bitter taste. The term pyridoxine is also used as a generic term for three compounds with biological activity classified under the term Vitamin Bfc. The three compounds are pyridoxine, pyridoxal, and pyridoxamine. Pyridoxine is usually produced commercially as the hydrochloride, CH3CSHN(0H)(CH20H)2-HC1, which has somewhat different physical characteristics from pyridoxine itself. 

Pyridoxin. Red atoms are oxygen white atoms are hydrogen black atoms are carbon and blue atom is nitrogen. Ring of alternating white and dark sticks is a benzene ring, publishers 

The first component of vitamin B6, pyridoxine, was first synthesized, also in 1938, by the Austrian-German chemist Richard Kuhn (1900-1967). Its chemical structure was determined a year later by American chemists Karl August Folkers (1906-1997) and S. A. Harris (dates not available) at the 

Because pyridoxine is water soluble, it dissolves when 

Merck chemical corporation. Pyridoxine is the most stable form of the vitamin, so it is the form used in vitamin supplements and as a food additive. 

5-hydroxy-6-methyl-3,4-bis(hydroxymethyl)pyridine (1) which usually comprises only a fraction of the total amount of vitamin B ia aatural sources. The older term pyridoxol is seldom used. 

Substance Stmcture number CAS Registry Number Formula Mol wt Form Mp ia water, °C Solubihty, g/100 ml. piC values 

Kirk-Othmer Encyclopedia of Chemical Technology (4th Edition) 

Salts and Derivatives. Generally the vitamers are high melting crystalline soHds that are very soluble in water and insoluble in most other solvents. Properties of the common forms are Hsted in Table 1. The only commercially important form of vitamin B is pytidoxine hydrochloride (7). This odorless crystalline soHd is composed of colorless platelets melting at 204—206°C (with decomposition). In bulk, it appears white and has a density of - 0.4 kg/L. It is very soluble in water (ca 0.22 kg/L at 20°C), soluble in propylene glycol, slightly soluble in acetone and alcohol (ca 0.014 kg/L), and insoluble in most lipophilic solvents. A 10% water solution shows a pH of 3.2. Both the hydrochloride and corresponding free base sublime without decomposition (16). 

Vitamin B was found in the 1940s during the unraveling of the mysteries of the nitrogen-base B vitamin complex. A diet-induced peUagra-Hke condition in rats was shown to be cured by a water-soluble base, later differentiated from the known vitamins B and named vitamin B by Gyoigy 

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The related compounds pyridoxamine and pyridoxal, in which the CH2OH group in the 4-position is replaced by CH2NH2 and CHO respectively, also possess vitamin activity and for certain bacteria are much more active than pyridoxine. 

In the following decades, chemists tried to utilize more and more the knowledge on reactions which had already been gained. A number of landmark syntheses represent the change to modern chemistry, such as the synthesis of the estrogenic steroid equilenin (W. Bachmann, 1939), of pyridoxine (K. Folkers, 1939), and of quinine (R.B. Woodward, W. von E. Doering, 1944) [23]. 

Description of Method. The water-soluble vitamins Bi (thiamine hydrochloride), B2 (riboflavin), B3 (niacinamide), and Be (pyridoxine hydrochloride) may be determined by CZE using a pH 9 sodium tetraborate/sodlum dIhydrogen phosphate buffer or by MEKC using the same buffer with the addition of sodium dodecyl-sulfate. Detection Is by UV absorption at 200 nm. An Internal standard of o-ethoxybenzamide Is used to standardize the method. 

Uses. Butanediol is used to manufacture the insecticide Endosulfan, other agricultural chemicals, and pyridoxine (vitamin B ) (see Vitamins) (116). Small amounts are consumed as a diol by the polymer industry. 

Oxa2oles react with dienophiles to give pyridines after dehydration or other aromatization reactions (69,70). A commercially important example is the reaction of a 5-aLkoxy-4-methyloxa2ole with 1,4-butenediol to yield pyridoxine (55), which is vitamin... 

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