Author Topic: Direct Conversion of a Carbox. Acid Into a Nitrile  (Read 576 times)

0 Members and 1 Guest are viewing this topic.

pHarmacist

  • Guest
Direct Conversion of a Carbox. Acid Into a Nitrile
« on: March 15, 2003, 01:24:00 PM »
pHarmacist's voice: This is a general procedure for the conversion of carboxylic acids to corresponding nitriles.
 
In a 50-mL three-necked flask are placed the carboxylic acid (0.01 mol), ethyl polyphosphate (6 g, PPE) and purified chloroform (5 mL). The mixture is cooled in an ice bath and the flask is connected to a balloon containing amonia gas (approx. 3 liters). Air in the flask is replaced with ammonia and the mixture is mechanically stirred at 0-5°C for 30 minutes and then at room temperature for one and a half hours whereupon the mixture turns very viscous1. The balloon is removed and PPE (10 g) is added. The stirring is continued at 80°C until the reaction is complete (usually withinn several hours); the dehydration is monitored by T.L.C. analysis1. The mixture is stirred with aqueous 25% sodium carbonate solution (150 mL), and then extracted with benzene (3 x 40 mL). The combined organic extracts are dried with sodium sulphate and evaporated. The residual oil is passed through a short column packed with silica gel (approx. 20 g) and the product eluated with benzene. The eluate is evaporated and the residue purified by short path distillation under reduced pressure (Kugelrohr apparatus).

1: Formation of the amide and the nitrile may be monitored by T.L.C. analysis

Reference: Vogel's textbook of practical organic chemistry 5:th edition, page 1084


pHarmacist

  • Guest
Ring substituted phenylacetic acids
« Reply #1 on: March 15, 2003, 10:49:00 PM »
I'm sure this is very well-known, but still; Using the above method, ring substituted phenylacetic acids can be used to give corresponding nitriles that can be reduced to corresponding phenetylamines. Just yet another possibility.