Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Use of Dimethysulfoxide in the Benzoin Condensation

IP.com Disclosure Number: IPCOM000092649D
Original Publication Date: 1967-Feb-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 3 page(s) / 20K

Publishing Venue

IBM

Related People

Cox, RJ: AUTHOR [+2]

Abstract

Benzoin condensation is the treatment of an aromatic aldehyde with potassium or sodium cyanide to form a class of benzoin compounds. This reaction can be generalized by the following equation: Ar CHO + Ar' CHO --------> Ar' CHOHCO Ar in which Ar and Ar' may be the same, symmetrical benzoins or different, unsymmetrical benzoins.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 3

Use of Dimethysulfoxide in the Benzoin Condensation

Benzoin condensation is the treatment of an aromatic aldehyde with potassium or sodium cyanide to form a class of benzoin compounds. This reaction can be generalized by the following equation: Ar CHO + Ar' CHO -------->
Ar' CHOHCO Ar in which Ar and Ar' may be the same, symmetrical benzoins or different, unsymmetrical benzoins.

Normally, this reacton is carried outin aqueous ethanol but the synthesis of o,o' and p,p'-dialkoxy-substituted benzoins is quite difficult to prepare with this reaction solvent. By using dimethylsulfoxide as the reaction solvent, the yields of these dialkoxy-substituted benzoins are improved. The reaction time is shortened. The workup and isolation of the product are simplified.

The following examples illustrate the preparation of a number of these dialkoxy-substituted benzoins. 1) 2,2'-Dimethoxybenzoin 51.7 g. of o- methoxybenzaldehyde (0.38 mole) 100 m 1. of dimethylsulfoxide 10.4 g. of potassium cyanide 20 m 1. of water are charged to a 3-necked, 250 m 1. round- bottomed flask equipped with stirrer and condenser. The reaction mixture is heated with stirring on a steam bath for one hour, and then poured into ice water. The precipitate is filtered, pressed dry and recrystallized from ethanol. The white solid weighs 33.2 g. after drying in a vacuum oven and melts at 98-99 degrees
C. This weight represents a 64.3% yield of 2,2'- dimethoxybenzoin. 2) 2,2'- Diethoxybenzoin 45 g. of o-ethoxybenzaldehyde (0.30 mole) 79 m 1. of dim ethylsulfoxide 8.2 g. of potassium cyanide 16 ml. of water are charged to a 3- necked, 250 ml. round-bottomed flask and heated, with stirring, on a steam bath for two hours. The reaction mixture is poured into about 1200 ml. of ice water and allowed to stand at room temperature overnight. The precipitate i...