L-valine(link:https://www.bloomtechz.com/synthetic-chemical/api-researching-only/valine-powder-cas-72-18-4.html) is one of the twenty protein amino acids. From a nutritional perspective, valine is also an essential amino acid. The English name Valine is derived from Valerian, and the Chinese name is therefore also called Valine. Its codons are GUU, GUA, GUC, and GUG. It is a non polar amino acid. In sickle type red blood cell disease, the valine in hemoglobin replaces the hydrophilic amino acid glutamate: because valine is hydrophobic, hemoglobin cannot fold correctly. Valine is completely electrically neutral, and when its side chains are also neutral, and the charges generated by its amino and carboxyl groups are exactly balanced, this molecule is called a zwitterion. Food sources rich in valine include white cheese, fish, poultry, cattle, peanuts, sesame seeds, and lentils.
Synthesis L-valine
There are many methods for synthesizing L-valine:
Method 1:
Aminoisobutyl alcohol is prepared from isobutyraldehyde and ammonia, and then reacted with hydrogen cyanide to generate aminoisobutyronitrile. Finally, L-valine is obtained through hydrolysis reaction. The following are the detailed steps and their chemical equations:
1. Isobutyraldehyde and ammonia generate aminoisobutanol:
React isobutyraldehyde with ammonia in appropriate solvents and reaction conditions to produce aminoisobutyl alcohol.
Chemical reaction formula: (CH3) 2CHCHO+NH3 → (CH3) 2CHCH2OHNH2
2. Synthesis of aminoisobutyronitrile from aminoisobutyl alcohol and hydrogen cyanide:
React aminoisobutyl alcohol with hydrogen cyanide under acidic conditions to undergo a condensation reaction, producing aminoisobutyronitrile.
Chemical reaction formula: (CH3) 2CHCH2OHNH2+HCN → (CH3) 2CHCH2CN+H2O
3. Hydrolysis of aminoisobutyronitrile to produce L-valine:
React aminoisobutyronitrile with an alkaline aqueous solution (such as sodium hydroxide) to undergo a hydrolysis reaction, producing L-valine.
Chemical reaction formula: (CH3) 2CHCH2CN+2H2O → (CH3) 2CHCH2COOH+NH3
Method 2:
It is a hydroxyisobutyronitrile synthesized from isobutyraldehyde and hydrogen cyanide, which reacts with ammonia and hydrolyzes to produce aminoisobutyronitrile.
Due to the fact that the direct reaction of isobutyraldehyde with hydrogen cyanide to generate hydroxyisobutyronitrile is highly unstable and dangerous, there is no conventional chemical synthesis route. In laboratory synthesis, other methods are usually used to prepare hydroxyisobutyronitrile.
Starting from hydroxyisobutyronitrile, it reacts with ammonia to produce aminoisobutyronitrile, which is then hydrolyzed to obtain L-valine. The following are the detailed steps and chemical equations of the synthesis route:
1. Synthesis of hydroxyisobutyronitrile:
Use appropriate methods (such as oxidation reaction) to oxidize isobutyraldehyde to hydroxyisobutyronitrile.
Chemical reaction formula: (CH3)2CHCHO+[O] → (CH3)2C(OH) CN
2. Aminoisobutyronitrile reacts with ammonia to produce aminoisobutyronitrile:
React hydroxyisobutyronitrile with ammonia to generate aminoisobutyronitrile under appropriate reaction conditions.
Chemical reaction formula: (CH3) 2C(OH)CN+NH3 → (CH3)2CHCNH2
3. Hydrolysis of aminoisobutyronitrile to produce L-valine:
React aminoisobutyronitrile with an alkaline aqueous solution (such as sodium hydroxide) to undergo a hydrolysis reaction, producing L-valine.
Chemical reaction formula: (CH3)2CHCNH2+2H2O → (CH3)2CHCOOH+NH3
Method 3:
It can also be directly synthesized from isobutyraldehyde, sodium cyanide, and ammonium chloride, and then hydrolyzed.
1. Under anhydrous and oxygen free conditions, isobutyraldehyde and sodium cyanide are reacted to produce isobutyronitrile, with the reaction equation as follows:
CH3CH (CH3)CHO+NaCN → CH3CH(CH3)CN+NaOCHO
2. React the NaOCHO generated in the previous reaction with ammonium chloride to produce N-carbamoyl L-valine, with the reaction equation as follows:
NH4Cl+NaOCHO → N-carbamoyl L-valine+NaCl+H2O
3. Treat the N-aminoacyl-L-valine generated in the previous reaction with concentrated hydrochloric acid to hydrolyze it. The reaction equation is:
Hydrolyzed product of N-aminoacyl-L-valine+HCl+H2O → N-aminoacyl-L-valine+NaOH
4. Separate and purify the hydrolysis product generated in the previous reaction to obtain L-valine.
The yields of the above three methods are all 36% to 40%. It can also be synthesized by hydrolysis of isobutyraldehyde, sodium cyanide, and ammonium carbonate. The yield of this method is approximately 49%. There are also various methods for the resolution of racemes, such as hydrolysis with acyl DL amino acid enzymes, and separation using poorly soluble free amino acids and acylated products. The valerian amino acids produced by fermentation are all L-type and do not require optical separation. The strains used for fermentation are Micrococcus glutamicum, Bacillus ammoniae, Escherichia coli, and Aerobacterium. Use media such as glucose, urea, inorganic salts, etc.