Process for the preparation of 1-Propyl-2, 4, 5- trimethoxybenzene from toxic beta-asarone of Acorus calamus or from crude calamus oil containing beta-asarone

Abstract

The invention relates to a process for the preparation of 1-Propyl-2, 4, 5-trimethoxybenzene useful as a aroma molecule and as a starting material and intermediate for preparation of various drugs. The process comprises providing crude calamus oil or beta-asarone in a solvent, hydrogenating the solution in the presence of a catalyst, filtering the catalyst and removing the solvent under reduced pressure, subjecting the reduced calamus oil to column of silica gel chromatography using an eluent to obtain the desired product in liquid form with 85-97% purity.

Description

[0001] The present invention relates to an improved process for the preparation of 1-Propyl-2,4,5-trimethoxybenzene of the formula I 1[0002] from the toxic compound .beta.-asarone of Acorus calamus or from crude calamus oil containing .beta.-asarone. The present invention also relates to a process for the preparation of 1-Propyl-2,4,5-trimethoxybenz-ene from toxic compound .beta.-asarone of Acorus calamus or from crude calamus oil containing .beta.-asarone and useful as a new kind of aroma molecule. The present invention also relates to a process for the preparation of salicylamide based antipsychotic drug from 1-Propyl-2,4,5-trimethoxybenzene, and other uses thereof.[0003] .beta.-asarone (cis-2,4,5-trimethoxy-1-propenylbenzene) is found in a number of plants such as Orthodon calveriei Level and Acorus gramineus (Nguyen, X. D.; Ladinh, M.; Vuviet, N.; Luudam, C. and Leclercq, P. A., J. of Essential Oil Research 7(1):111-112 (1995) and Perrett, S. and Whitfield, P. J., Phytotherapy R...

AI Technical Summary

Benefits of technology

[0017] Another object of the present invention is to provide a simple process for isolation of .beta.-asarone in high purity from Acorus calamus oil.

[0040] In yet another embodiment of the present invention a simple catalytic process is described to convert other asarones rich plants such as Asarum europaeum, Crowea angustifolia and Heterotropa yakusimensis into useful products such as 1-Propyl-2,4,5-trimethoxybenzene for various applications.

Problems solved by technology

However, all the above uses and medicinal potential of Acorus calamus have been hampered because of carcinogenic effect of .beta.-asarone (Opdyke, D. L. J., Food Cosmet. Toxicol., 15: 623, (1997)).

However, these methods do not effectively lower the high percentage (70 to 90%) of asarone content of tetraploid or hexaploid varieties.

While supercritical gas extraction of calamus oil (americanus variety) with fractionated separation has been reported (Keller, K. and Stahl, E., Planta Medica 47(2): 71-74 (1983)) to make .beta.-asarone free calamus oil, fractionation will not be cost effective with tetraploid or hexaploid varieties having very high percentage of .beta.-asarone (70 to 90%).

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