Glyoxylic Acid → Acetic Anhydride

反応式

[CH2:1]([O:3][C:4]1[CH:5]=[C:6]([CH:11]([OH:15])[C:12]([OH:14])=[O:13])[CH:7]=[CH:8][C:9]=1[OH:10])[CH3:2].[CH2:16]([O:18]C1C=CC=CC=1O)[CH3:17].[C:26]([OH:30])(=[O:29])[CH:27]=[O:28]>>[C:16]([O:15][CH:11]([C:6]1[CH:7]=[CH:8][C:9]([O:10][C:27](=[O:28])[CH3:26])=[C:4]([O:3][CH2:1][CH3:2])[CH:5]=1)[C:12]([OH:14])=[O:13])(=[O:18])[CH3:17].[C:1]([O:30][C:26](=[O:29])[CH3:27])(=[O:3])[CH3:2]

参加物

反応物 3

HCID 760Glyoxylic Acid

HCID 667552-Ethoxyphenol

HCID 1937923-Ethoxy-4-hydroxymandelic acid

生成物 2

HCID 7918Acetic Anhydride

HCID 20778781Acetoxy-(4-acetoxy-3-ethoxyphenyl)-acetic acid

反応条件

温度: 0 °C

実験手順

Intermediate 2, (3-ethoxy-4-hydroxyphenyl)hydroxy-acetic acid can be prepared by addition of base to an aqueous mixture of 2-ethoxyphenol and glyoxylic acid cooled to 0° C. Intermediate 3, acetoxy-(4-acetoxy-3-ethoxyphenyl)-acetic acid, can be formed by the addition of acetic anhydride to intermediate 2 dissolved in dichloromethane (DCM) and pyridine, cooled in an ice bath. Intermediate 3 dissolved in a short chain alcohol is reduced under hydrogen to provide intermediate 4, (4-acetoxy-3-ethoxyphenyl)-acetic acid, which is reacted with an excess of propanol and a catalytic amount of concentrated H2SO4 to form the propyl ester, intermediate 5, (3-ethoxy-4-hydroxyphenyl)-acetic acid propyl ester. Finally, intermediate 5 is reacted with a compound of the structure X—CH2C(═O)N(Et)2, where X is a leaving group, in the presence of potassium carbonate to provide the active agent, compound 1.