SU142644A1 - Method for preparing aminooxyalanine esters - Google Patents

Description

The known method of synthesizing p-aminooxyalanine ester from acetoxim and dichloropropionic acid methyl ester is unsuitable for practice, since it provides p-aminooxyalanine with a yield of 3% of the theoretically possible.

The proposed method for the preparation of E-aminooxyalanine esters is that, in order to increase the yields and simplify the process, the haloacrylic acid ester is oxyiminoacetic ester.

The preparation of p-aminooxyalanine ethyl ester according to the described method is carried out according to the following scheme.

 X, G, R;

l,., ..........,., ....

CH, h

".C NOCIbCHCOOH - HsNOCliH-HCOOR

RO / I

 -V H

- 2INMij

Where; R, R and R are hydrocarbon residues.

I ether p-aminooxyalanine. II ester of a-haloacrylic acid.

IIIoxyimine ester.

IV ester of p- (ethylidenethoxy) aminooxy a-halo-propionic

acid. V P- (ethylidenethoxy) -aminooxyalanine.

P. Example 1. Preparation of methyl ester; p- (ethylideneethoxy) aminooxy a-bromopropionic acid.

15 g of oxyiminoacetic ester is mixed with 25 ml of absolute isopropyl alcohol containing 0.1 g of metallic sodium, and 16.5 g of a-bromoacrylic acid methyl ester is added to the reaction mixture with stirring and cooling at a rate such that the temperature of the reaction mixture is - 5-0 °. Then the reaction mixture is stirred for 1-2 hours at 0 ° and 24 hours at 5-8 °, diluted with water, benzene is removed, benzene is distilled off, the residue is distilled in vacuum and the fraction with boiling point 96-98 ° is collected at 3 mm residual pressure; yield 21.5 g (80% of theoretically possible). Product identified by elemental analysis. For C8Hi4O4NBr,% N is calculated - 5.22; Br - 29.81; found in% N - 5.41; 5.23 and Br - 30.09 and 29.74.

Example 2. Getting ip- (ethylidenethoxy) -amnooxialine.

First option. To 0.27 g of methyl P- (ethylideneethoxy) -aminoxy-α-bromopropionic acid ester was added at 130-35 ° and stirring a solution of 4.1 g of sodium hydroxide in 10 ml of water. The resulting homogeneous solution is heated in the appropriate apparatus with 50 g of liquid ammonia at 30-35 ° for 48 hours. After evaporation of ammonia, 13 g of p- (ethylideneethoxy) -amino oxyalanine are obtained. T. pl. 240 ° (with decomposition). The product is identified by elemental analysis. For C5ni4O4N2, calculated in%: N - 14.73; found fl%; N - 14.52; 14.67. Output - 65% of theoretically possible.

The second option. 27 g of P- (ethylidenethoxy) aminooxy-a-bromopropionic acid methyl ester are saponified as described above, then acidified with 20% hydrochloric acid at a temperature of 10-15 °; the oil that is separated out is extracted with ether, dried over magnesium sulfate and the ether is distilled off. The residue is stirred in an autoclave and heated for 16-18 hours at 50-60 ° C with 70 ml of liquid ammonia, the ammonia is evaporated and P- (ethylideneethoxy) -amino-oxyalanine is obtained with a yield of 80% of the theoretically possible.

Example 3. Preparation of p-aminooxyalanine ethyl ester.

25 ml of absolute ethanol containing 25 g of dry hydrogen chloride are added to 27 g of p- (ethylidene-ethoxy) -aminooxyalanine, and the reaction mixture is heated for 3 hours at 110 °, then filtered, then equilibrated to dryness; the residue is dissolved in 50 ml of absolute ethanol and dry ethladate is added until crystallization begins. Obtain 22 g of ethyl ester | 3-aminooxyalkane with so pl. 152-153 °. Yield 70% of theoretically possible.

The described method for the preparation of β -aminoxyalanine ester can be used in the development of an industrial method for the synthesis of cyclostrol.

Subject invention

A method for the preparation of p-aminooxyalanine esters, characterized in that, in order to increase the yields and simplify the process, eacrylate acrylic acid acts on hydroxyacetate ester.

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