p-Toluenesulfonic acid → methyl 5-hydroxy-2,3-dihydro-1H-indene-1-carboxylate

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Reaction Conditions

Reaction Steps

In a 20-liter reactor with a mechanical stirrer, 1.6 kg of 2,3-dihydro-5-hydroxy-1H-inden-1-carboxylic acid were dissolved with 7.2 l of absolute methanol, 9 g of p-toluenesulphonic acid were added and then refluxed under stirring in oil bath heated at 90° C. for 24 hours. The mixture was allowed to cool, the excess of methanol was evaporated at vacuum, the residue was diluted with 1.5 l of water, 1.5 l of sodium bicarbonate saturated solution and 5 l of toluene and then stirred for 30 minutes. The insoluble material was filtered, washed twice with 1 l of toluene; the aqueous phase was extracted with 2 l of toluene, and the organic phases were filtered using a filter paper and washed with water. The toluene phase was concentrated at vacuum to give a blackish, viscous liquid residue weighing 1.391 kg (88%), which was distilled at vacuum to give 1.1 kg (70%) of colourless liquid at 124°-137° C./0.03-0.025 tors, nD20 =1.5533, IR and 1H-NMR spectra were consistent with structure.

Provenance & Evidence