Benzil benzilic acid rearrangement

Benzilic acid rearrangement. The benzilic acid rearrangement is formally the 1,2-rearrangement of 1,2-diketones to form α-hydroxy–carboxylic acids using a base. This reaction receives its name from the reaction of benzil with potassium hydroxide to form benzilic acid.

1. Benzil Benzilic Acid Rearrangement Syed touseef haidar

2. Benzil Benzilic Acid Rearrangement ꬰ -Diketones ( benziles ) undergo a base-catalyzed reaction called benzil benzilic acid rearrangement. The salts of alfa-hydroxy acids initially formate or acidification yield the hydroxyl carboxylic acids.

3. Example: Benzil (1) on treatment with KOH followed by acidification yields benzylic acids (2). Reaction :

4. Mechanism :

5. Applications: Doering extended the reaction to the formation of the corresponding ester by replacing the normal alkali by alkoxides. Thus benzil may directly be converted into alkyl benzilate by treatment with sodium alkoxide.

6. The reaction may be used for the preparation of α-hydroxy acids from the easily accessible starting materials . it is important to note that as the ethoxide and isopropoxide ions reduce benzil to benzoin these reagents do not carry out benzilic rearrangement . Application:

7. Applications: Benzilic acid is used in the manufacture of  glycollate   pharmaceuticals including  clidinium ,  dilantin ,  flutropium , and  mepenzolate  which are  antagonists  of the  muscarinic acetylcholine receptors . It is used in manufacture of the  incapacitating agent   3-quinuclidinyl benzilate  (BZ) and is regulated by the Chemical Weapons Convention. It is also monitored by law enforcement agencies of many countries, because of its use in the manufacture in  hallucinogenic drugs .

8. Applications: The benzylic acid arraignments of Furil , 9,10-phenanthrenequinone have been describe below.

9. Hazardous of Benzilic Acid Potential Acute Health Effects: Very hazardous in case of skin contact (irritant), of eye contact (irritant). Hazardous in case of ingestion, of inhalation. Inflammation of the eye is characterized by redness, watering, and itching. Skin inflammation is characterized by itching. Chemical stability : Stable under recommended storage conditions. Hazardous combustion products : Under fire conditions, hazardous fumes will be present and product flammable at h i gh tem perature and prod u ct of c o mbustion (CO , C O 2 ) .

10. References: Selman, S.; Eastham, J. (1960). "BENZILIC ACID AND RELATED REARRANGEMENTS“ Bowden, K.; Fabien, W. M. F. (2001). "Reactions of carbonyl compounds in basic solutions. Part 36:The base- catalysed reactions of 1,2-dicarbonyl compounds“ Gill, G. B. (1961). "Benzyl- benzilic acid rearrangements“ Shinichi Yamabe ; Noriko Tsuchida & Shoko Yamazaki (2006). "A FMO-Controlled Reaction Path in the Benzil-Benzilic Acid Rearrangement.

11. Thank you ` Touseef Haidar [phone] [email protected]