Process for producing 1,2-propanediol

Details Process for producing 1,2-propanediol Process for producing 1,2-propanediol

1999-12-20

2000-12-05

Reamer, James H.

Organic compounds -- part of the class 532-570 series

Organic compounds

Oxygen containing

C07C 3118

Patent

active

061569410

DESCRIPTION:

BRIEF SUMMARY
TECHNICAL FIELD

The present invention relates to a process for producing 1,2-propanediol, particularly, optically active substances thereof, which are useful compounds as a synthetic intermediate of medicines, agricultural chemicals and the like.


BACKGROUND OF THE INVENTION

1,2-Propanediol is a known substance as an industrially useful compound. As a conventional process for producing the compound, it is reported that 1) 3-chloro-1,2-propanediol is converted into glycidol in a solution of potassium hydroxide-methanol and then glycidol is catalytically hydrogenated to give the object substance (M. Ochiai, Biochem. Z., 293 (1935)).
Known processes for producing optically active substances of 1, 2-propanediol are 2) reduction of natural ethyl lactate (J. Amer. Chem. Soc., 107, 5210 (1985)), 3) reduction of hydroxyacetone in the presence of a chiral catalyst (J. Amer. Chem. Soc., 110, 629 (1988)), 4) asymmetry reduction of hydroxyacetone with yeast (Japanese Laid-open Patent Publication No. 059592/1995), 5) resolution of racemate with enzyme (Japanese Laid-open Patent Publication No. 030790/1994), etc.
In the case of the above-mentioned conventional processes, however, since 1.2 equivalents of the base is used to the starting compound in the process 1), it leads to forming by-products such as polymers and 3-methoxy-1,2-propanediol. Since it is difficult to separate these by-products from the object substance, the yield of the object substance is low (72%). Actually, when the reaction 1) was carried out on a large scale, the yield was lower (47% (see Comparative Example 2 mentioned later)). The process 2) has disadvantages in that both of optically active substances of 1,2-propanediol cannot arbitrarily be obtained because the starting material is a natural optically active substance and in that it is necessary to use lithium aluminium hydride, which is difficult to handle in a practical use and expensive, as a reducing agent. In the process 3), the optical purity of the obtained object substance is low (92%ee), and it needs troublesome steps wherein the optical purity is improved by recrystallization after conversion into a derivative in order to obtain the object substance having high optical purity. In the processes 4) and 5), only one optically active substance is obtained.
In view of the above-mentioned various problems, the object of the present invention is to provide a process for obtaining 1,2-propanediol or the optically active substances thereof, both arc the object substance, in high yields and at a low cost, using a readily available compound as a starting material.


DISCLOSURE OF THE INVENTION

Doing studies continuously to attain the above-mentioned object, the inventors found a process for producing 1,2-propanediol, particularly, optically active substances thereof advantageously using 3-halogeno-1,2-propanediol as a starting compound and accomplished the present invention.
The present invention relates to a process for producing 1,2-propanediol characterized in that 3- halogeno-1,2-propanediol represented by the following general formula [I] is catalytically hydrogenated in an alcoholic solvent having two or more carbon atoms in the presence of a base of 0.9 to one mole with respect to one mole of 3-halogeno-1,2-propanediol to give 1,2-propanediol represented by the following formula [II]. In the general formula [I], X stands for a halogen atom. ##STR2##
3-Halogeno-1,2-propanediol [I] can be obtained by any processes. Optically active 3-halogeno-1,2-propanediol can easily be prepared according to processes described in Japanese Examined Patent Publication Nos. 73998/1992 and 73999/1992.
The halogen atom X of 3-halogeno-1,2-propanediol [I] is preferably a chlorine atom or a bromine atom. Accordingly, preferred 3-halogeno-1,2-propanediol, which is the starting material, is 3-chloro-1,2-propanediol or 3-bromo-1,2-propanediol.
The "alcoholic solvent" means a solvent which comprises alcohol(s) having two or more carbon atoms in the present specification. Namely, the solvent can contain the othe

REFERENCES:
patent: 5616817 (1997-04-01), Schuster et al.
Biochem. Z., 293 (1935) and English abstracts thereof.
J. Am. Chem. Soc. 1985, 107, 5210-5219, Diethoxytriphenylphosphorane: A Mild, Regioselective Cyclodehydrating Reagent for Conversion of Diols to Cyclic Ethers: Stereochemistry, Synthetic Utility and Scope, Philip L. Robinson et al.
J. Am. Chem. Soc. 1988, 110, 629-631, Homogeneous Asymmetric Hudrogenation of Functional Keytones, M. Kitamura et al.

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