Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Patent
1993-11-19
1995-01-17
Lone, Werren B.
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
568583, C07C 43205, C07C20537
Patent
active
053827023
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to processes for producing 5-alkoxy-2,4-dinitroalkylbenzenes of the general formula (I) ##STR2## where R.sup.1 is a branched or unbranched C.sub.1 to C.sub.4 alkyl group and R is a branched or unbranched C.sub.1 to C.sub.6 alkyl group, a C.sub.2 to C.sub.4 hydroxyalkyl group or a C.sub.3 to C.sub.4 dihydroxyalkyl group, which can be used as dye precursor, etc., e.g. for hair dyes.
A number of processes for producing 5-alkoxy-2,4-dinitroalkylbenzenes of formula (I) are already known from the relevant literature. However, these processes are unsatisfactory in many respects.
For example, J. F. Corbett, Journal of the Chemical Society Perkin II, page 999 (1972), describes a process for producing 5-methoxy-2,4-dinitrotoluene in which 5-chloro-2,4-dinitrotoluene and methanol are heated under reflux in the presence of potassium hydroxide. However, the yield in this process is unsatisfactory.
Further, DE-OS 3 622 784 describes a process for the production of 5-alkoxy-2,4-dinitroalkylbenzenes in which 5-alkyl-2,4-dinitrophenol is reacted in an appropriate solvent with a suitable alkyl halide in the presence of a base and the product is then precipitated by adding water. Although the alkylation in this process produces satisfactory yields (50 to 77%), the overall production method involves some disadvantages. For example, the starting material required for this method must be produced by a three-step synthesis starting with 3-methyl-6-nitrophenol by introducing a mesyl protective group, nitration and subsequent separation of the protective group with a total yield of roughly 76%. Further, the alkyl halides, which are not without disadvantages, must be used as reagents for producing the alkyl compounds. Although the process described above for producing 5-alkoxy-2,4-dinitroalkylbenzenes of the general formula (I) can be carried out with a satisfactory yield technically, it nevertheless has disadvantages in economical and ecological respects. The large number of required reaction steps and the type of reagents that are used necessitate a high input of energy for carrying out the reactions. In addition, waste products are produced in every reaction step (by-products and solvent) which must be worked up and disposed of in an expensive manner to prevent additional environmental loading. These disadvantages are also shared in great measure by the process according to Corbett in which the proportion of by-products is greater than the proportion of desired reaction products.
SUMMARY OF THE INVENTION
Therefore, it is an object of the present invention to provide a process for the production of 5-alkoxy-2,4-dinitroalkylbenzenes of the formula (I) which enables a simple and economical production of these compounds and in which the aforementioned disadvantages are avoided.
Surprisingly, it has now been found that the proposed object is met in an outstanding manner in that the 5-alkoxy-2,4-dinitroalkylbenzenes of the general formula (I) are produced at low temperatures by nucleophilic substitution of 2,4-dinitro-5-fluoroalkylbenzenes.
The subject matter of the present invention is therefore a process for producing 5-alkoxy-2,4-dinitroalkylbenzenes of the general formula (I) ##STR3## where R.sup.1 is a branched or unbranched C.sub.1 to C.sub.4 alkyl group and R is a branched or unbranched C.sub.1 to C.sub.6 alkyl group, a C.sub.2 to C.sub.4 hydroxyalkyl group or a C.sub.3 to C.sub.4 dihydroxyalkyl group, in which a 3-fluoroalkylbenzene (II) is nitrated and the obtained 2,4-dinitro-5-fluoroalkylbenzene (III) is reacted with a suitable alcohol at -5.degree. C. to +25.degree. C. with the addition of sodium hydroxide or potassium hydroxide according to the following general reaction sequence: ##STR4##
In the process according to the invention, a 3-fluoroalkylbenzene of the general formula (II) is first nitrated according to the methods known from DE-OS 40 28 661. The obtained 2,4-dinitro-5-fluoroalkylbenzene of formula (III) is then reacted with a suitable alcohol and sodi
REFERENCES:
patent: 4537999 (1985-08-01), Ogawa et al.
Journal of the chemical society, Perkin Transactions Feb. 1972, John F. Corbett pp. 999-1005.
Balzer Wolfgang R.
Clausen Thomas
Weinges Alexa
Lone Werren B.
Striker Michael J.
Wella Aktiengesellschaft
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