ChemisTris
(Hive Bee)
07-10-03 15:43
No 446181
      Mathews’ rxn(MW): carboxylic acids from nitriles
(Rated as: excellent)
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Towards the rehabilitation of the Mathews’ ‘dry’ hydrolysis reaction using microwave technology
Farid Chemat
Tetrahedron Letters 43 (2002) 5555–5557
DOI:10.1016/S0040-4039(02)01127-9
pdf: http://mishmashblue.tripod.com/tlphenaacid.pdf

Abstract
The Mathews’ reaction is a one-pot preparation of carboxylic acids from their corresponding nitriles or amides by a
‘dry’ hydrolysis with phthalic acid or anhydride in the absence of water and solvent. Excellent isolated yields and selectivity (up
to 99%) were attained within short reaction times (typically, 30 minutes) when the reaction was performed under microwave
heating.

e.g. phenylacetonitrile to phenylacetic acid
R: PhCH2CN
Reaction time: 30 min
Yield: 99%
Selectivity: 99%

In a typical run, the nitrile (30 mmol) and phthalic acid (30 mmol) were introduced in the microwave reactor and heated under stirring. At the desired reaction time, the reactor was rapidly cooled down in a water/ice mixture, and chloroform (30 mL) is added. The
mixture is stirred for 5 min, and the solid filtered off. The chloroform solution contains unreacted nitrile, amide and carboxylic acid. The residual solid contains unchanged phthalic acid, phthalic anhydride and phthalimide. The volume of the chloroform solution is adjusted to 50 mL and naphthalene is added as internal standard. The resulting solution is analyzed by GC/MS.

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