SU1035026A1 - Process for preparing selenolane - Google Patents

Abstract

THE METHOD OF OBTAINING SELENSSHCHANA /, -to tl and h and y with the fact that, in order to simplify the process and increase the yield of the target product, bis

Description

The invention relates to a new method for producing selenolane, which may find application in preparative organic chemistry.

Known methods for producing selenol, for example, by the interaction of tetrahydrofuran with hydrogen selenium in a strong current of the latter at 400 ° C in the presence of alumina as a catalyst. Yield 54%.

The disadvantages of this method include the use of toxic selenium hydrogen and a catalyst, the use of high temperatures and low yield of the target product.

Closest to the proposed is a method for producing selenolane, which consists in the fact that about ol _r vdihalogenbutane is subjected to interaction. with sodium dislenide, which is preliminarily obtained by treating selenium with alkali water while boiling in the presence of rongalite as a catalyst at 100 ° C. Yield 70%.

The disadvantages of this method are multi-stage, the use of hard-to-reach starting reagents (sodium dislenide), the use of a catalyst (rongalite) and the process at high temperature, which all complicates the process, as well as the relatively low yield of the target product.

The aim of the invention is to simplify the process and increase the yield of the target product.

The goal is achieved in that according to the method for producing selenolane, bis- (2-bromoethyl) selendibromide is reacted with. zinc powder in ethanol in a nitrogen atmosphere at 50 ~ 70 ° C.

The process is carried out within 1-3 hours. • The process proceeds according to the scheme

SKSN-VG _{7 and} N.S-SI „ _X ta, 10 g (0.022 mol) of bis- (2-bromoethyl) selendibromide in 40 ml of ethanol are charged under reflux. Then, to the contents of the flask with neper stirring in a nitrogen atmosphere, 3 g of zinc powder are added in portions over 15 minutes, while maintaining the temperature not higher than 30 ° C. The reaction mixture was continued to stir, raising the reaction temperature to 60 ° C for two hours. At the end of the reaction, ethanol is distilled off, the target product is extracted with pentane. The residue is treated with water, the unreacted bis- (2-bromoethyl) selendibromide in an amount of 0.9 g is filtered off, so pl. 118-120 ° C. The pentane extract is subjected to distillation in a Klaisen flask and the target product is isolated with boiling point. 136,137 ^l C / 760 mm in an amount of 2.4 g (82% of theory). The remainder of 0.2 g (resin), loss of 0.3 g. P ^ ° 1.54 62;

d | ° 1.4721. A characteristic band for the C-Se group at 742-724 cm * '' ’· was found in the IR spectrum

The starting bis- (2-bromoethyl) selendibromide with a melting point of 119-120 ° C. was prepared according to a known method.

The process is preferably carried out at 60 ° C for 2 hours. The yield of selenolane reaches 82% of theory.

Example 1. In a three-necked round-bottom flask equipped with a stirrer, thermometer, tube for feeding azo Example 2. The experiment is carried out under conditions similar to example 1; but at 50 ° C. From 10 g (0.022 mol) bis. - (2-bromoethyl) selendibromide receive

2.2 g (74% of theory). Return of bis- (2-bromoethyl) selendibromide 1.9 g, residue 0.2 g, loss 0.2 g.

Sample The experiment is carried out under conditions similar to example 1, but at 70 ^r C. From 10 g (0.022 mol) of bis- (2-bromoethyl) selendibromide receive

2.3 g (77% of theory). Return of bis- (2-bromoethyl) selendibromide 1 <, 2 g, residue 0.25 g, loss 0.2 g.

Example 4. The experiment was carried out under conditions similar to example 1, but within 1 h. Of 10 g (0.022 mol) of bis- (2-bromoethyl) selendibromide, 2.14 g (72% of theory) was obtained. Return bist (2-bromoethyl) selendibromide 2.3 g, residue 0.2 g, loss 0.3 g.

Example 5. The experiment is carried out under conditions similar to example 1, but for 3 hours. From 10 g (0.022 mol) of bis- (2-bromoethyl) selendibromide, 2.3 g (79% of theory) are obtained. Return. bis- (2-bromoethyl) selendibromideIda is 0.9 g, residue 0.3, loss 0.3 g.

Thus, the new method allows to obtain selenolan without subsequent special purification with a higher yield of 82% (against 70% in the prototype) in one stage at more than 60. low temperature of 50-70 ° C (against 100 ° C in the prototype).

VNIIIPI Order 5751/21

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Branch of PPP Patent, Uzhgorod, Project 4,

Claims (1)

METHOD FOR PRODUCING SELENOLANE, characterized in that, in order to simplify the process and increase the yield of the target product, bis (2-bromoethyl) selendibromide is reacted with zinc powder in ethanol in an atmosphere of nitrogen at 50-70 ° C.