Organic compounds -- part of the class 532-570 series – Organic compounds – Silicon containing
Patent
1998-07-29
1999-11-30
Shaver, Paul F.
Organic compounds -- part of the class 532-570 series
Organic compounds
Silicon containing
C07F 708
Patent
active
059945729
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a process for producing 1-alkoxy-1-trimethylsilyloxycyclopropane which is useful as an intermediate for medicines, an intermediate for agricultural chemicals, or an intermediate for production of perfumes, etc.
BACKGROUND ART
1-Alkoxy-1-trimethylsilyloxycyclopropanes are known to be an important raw material used in synthesis of N-cyclopro-pylamines which are raw materials in synthesis of medicines and agricultural chemicals (Chem. Comm., 1987, p. 897; Tetrahedron Lett., 1995, p. 7399). Since showing a very characteristic reactivity of homoenolate anion equivalent in a carbon-carbon bond-forming reaction, they are also known to become an important intermediate in synthesis of perfumes, etc. (J. Amer. Chem. Soc., Vol. 108, p. 3745, 1986).
As to the process for synthesis of 1-alkoxy-1-trimethylsilyloxycyclopropane, a process is well known which comprises reacting 3-chloropropionic acid ester with sodium sand in the presence of trimethylchlorosilane in an ether solvent (Org. Synthesis, Vol. 63, p. 147, 1984).
The process, however, has a problem of complicated operation such as the following. That is, metallic sodium is heat-melted in toluene or xylene and stirred, followed by cooling to form sodium sand; only the supernatant portion of the solvent is taken out; the residual metallic sodium is washed a plurality of times to change the solvent to ether. Further, the above process can be conducted in a laboratory flask but has been difficult to carry out on an industrial scale for the following reasons, for example. In this procedure, metallic sodium catches fire easily when water comes in; and the ether used as a reaction solvent has a low flash point and is difficult to recycle, and when the ether is used in a large amount, it easily forms a peroxide which is explosive.
Meanwhile, it is described in Synlett, p. 89, 1990 that the above reaction, when an ultrasonic is applied to the reaction system, proceeds without making metallic sodium as sand-like one by heat-melting or the like. However, use of ultrasonic in industrial production requires a special apparatus, which is disadvantageous in cost and not practically suitable for industrial production.
DISCLOSURE OF THE INVENTION
The object of the present invention is to provide a process for producing 1-alkoxy-1-trimethylsilyloxycyclopropane, which has industrial applicability and which is thoroughly satisfactory in yield, purity and cost.
The present inventors made a study in order to solve the above-mentioned problems of conventional laboratory processes for synthesis. As a result, the present inventors surprisingly found out that when microgranular metallic sodium dispersed in a hydrocarbon solvent (such sodium is easy to handle industrially) is used, industrial production of 1-alkoxy-1-trimethylsilyloxycyclopropane is possible, it is not necessary to use any ether solvent (the ether solvent has various problems in safety), the reaction proceeds sufficiently to a yield at least equal to that obtained when an ether solvent is used, and the production cost of intended product is favorable. The present invention has been completed based on the above finding.
The above object of the present invention has been achieved by providing a process for producing 1-alkoxy-1-trimethylsilyloxycyclopropane represented by the following general formula: ##STR3## (wherein R.sup.1 and R.sup.2 are each independently a hydrogen atom or a lower alkyl group; R.sup.3 is a lower alkyl group), by reacting microgranular metallic sodium dispersed in a hydrocarbon solvent, .beta.-halogenocarboxylic acid ester represented the following general formula: ##STR4## (wherein R.sup.1, R.sup.2 and R.sup.3 are as defined above; and X is a halogen atom), and chlorotrimethylsilane.
BEST MODE FOR CARRYING OUT THE INVENTION
In the present invention, by using microgranular metallic sodium dispersed in a hydrocarbon solvent, the solvent used can be a hydrocarbon alone and no ether solvent is used which is usable in laboratory but whose use in in
REFERENCES:
patent: 5412134 (1995-05-01), Singh et al.
Salaun et al; "Cyclopropanone Ethyl Hemiacetal from Ethyl 3-Chloropropanoate"; J. Org. Synthesis; vol. 63, pp. 147-153 (1984).
Ihara Chemical Industry Co., Ltd
Shaver Paul F.
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