Extraction of Acetals of Phenyl-Propargyl Aldehyde Using the Metod of Liquid Column Chromotography

The interreaction of substrates containing cyclopropane fragment with initial allyl and butyl alcohol, the influence of bromide atom in a gem-dichlorocyclopropane ring on the direction of the reaction with alcohol. The reaction of O-alkyllation 2-bromide-2-phenyl-gem-dichlorocyclopropane with alcohol in dimethylformamide with solid sodium hydroxide and without a phase transfer catalyst occurs selectively and produces the corresponding acetals of phenyl-propargyl aldehyde. The optimal conditions were selected for the reaction. It was researched and established that gem-dichlorocyclopropanes with a bromide atom in the cycle can also participate in such transformations. Acetals of phenyl-propargyl aldehyde were extracted from the reaction mix using the method of liquid column chromotography

In order to identify the prospects of the synthesis of polygalogencyclopropanes, the interreaction of substrates with cyclopropane fragment and initial allyl and butyl alcohol was analysed.
The previous research showed only synthetic capabilities of polychloro-and polybromidecyclopropanes, while the influence of a bromide atom in the gem-dichlorocyclopropane ring on the direction of the reaction with alcohols has never been studied [11][12][13].
The obtained compounds were extracted using the method of column chromotography, as it is one of the most important methods to divide liquid mixes and solid organic substances on the preparative scale. The division was carried out in a column, or a glass tube filled with a sorbing agent (silicagel) that acts as a porous layer, with the moving phase going through it (eluting the mix of solvents, hexane:ethyl acetate at the ratio of 98:2). The eluent for the column chromatography was chosen using thin layer chromatography. The mix was chromotographed in several eluents and for the column chromotography was used the one with the largest distance between spots. The divided part was put into the upper part of the column where it was absorbed by the stationary phase and then the eluent was continually fed through the column. Every component of the mixture was transferred down the column by the moving phase (eluent) with the speed that depends on the affinity with the sorbing

Results and discussions
The reaction of O-alkyllation 2-bromide-2-phenyl-gem-dichlorocyclopropane with alcohols in dimethylformamide with solid sodium hydroxide and without a phase transfer catalyst at 100 °С occurs selectively and produces the corresponding acetals of phenyl-propargyl aldehyde ( Figure 1). The methodology of the interreaction of 2-bromide-2-phenyl-gem-dichlorocyclopropane with alcohols: put 0.012 moles of substituted alcohol (0.67 g allyl alcohol, 0.89 g butyl alcohol) into a fourneck vial with a mechanical mixer, thermometer, a backflow condenser and a dropfunnel; gradually add 0.001 moles (0.02 g) sodium metal. Add to the obtained sodium alcoholate 0.005 moles (1.33 g) 2-bromide-2-phenyl-gem-dichlorocyclopropane in drops and then heat up to 100°С for 8 hours The reaction mass is diluted with water, separated by chloroform, washed with water, the solvent was boiled out, the target products were extracted on the silica-gel using the method of liquid column chromatography. Hexane:ethyl acetate ratio in the eluent 9:1 correspondingly.
It was established that the interreaction of gem-dichlorocyclopropane with allyl and butyl alcohol leads to the opening of the cyclopropane ring and the formation of the corresponding acetylene acetals. The product output on the basis of butyl alcohol was 30%, and on the basis of allyl alcohol it was 70% The formation of acetals of phenyl-propargyl aldehyde during the reaction of 2-bromide-2-phenylgem-dichlorocyclopropane with alcohols is supposedly associated with the elimination of hydrogen bromide and the formation of cyclopropene's derivatives that suffer the substitution of allyl chlorine atoms with alkoxy group and further cyclopropane fragment fission (Figure 2).  The opening of the cyclopropane ring of polysubstituted gem-dichlorocyclopropanes without a bromide atom in the reaction with alcohols accompanied by the formation of propargyl esters was described in the works of R.R.Kostikov and L.K. Sydnesс [14][15][16][17][18].
The research allowed to establish for the first time that gem-dichlorocyclopropanes with a bromide atom in the cycle can also participate in such transformations.
As a result of the research it was proved that the main factor influencing the direction of the reaction of alcohols and substituted gem-dichlorocyclopropanes is the nature and position of the substitute in the cyclopropane ring.
The structure of the obtained compounds was established on the basis of NMR spectral data 1 Н and 13 С and confirmed by the mass spectrometric analysis method. The special feature of the NMR range

Conclusions
Compounds of cyclopropane range have biological activity of broad spectrum of activity and are of interest in what concerns synthesis of important difficult to access carbo-and heterocycles. Substituted gem-dichlorocyclopropane play a special role in organic synthesis, that have both a cyclopropane ring and other functional groups. Galogen-, alkenyl-gem-dichlorocyclopropanes are such polyfunctional compounds that are used as valuable reagents in the synthesis of polysubstituted cyclopropanes, olefins, diens and allens. Moreover, interphase catalyst for the generation of digalocarbens in the reactions of cycloaddition allows to obtain gem-dichlorocyclopropanes different in form and with high output [19][20][21][22][23].
Synthetic potential of substituted gem-dichlorocyclopropanes that have chloroalkyl groups, alkenyl groups and galogen atoms basically have never been studied. In this regard the research of synthetic capabilities of polychlor-, bromidecyclopropanes obtained on the basis of industrially accessible galogenolefins as well as the development of convenient methods for the synthesis of biologically active polyfunctional compounds is an important and pertinent task. Alcohols with gem-dichlorocyclopropane and dimethylsulfoxide and solid alkali at 20°С do not interreact. It was experimentally established that the optimal temperature for this reaction is 100 °С.
AlcoholatealcoholateAcetals of phenyl-propargyl aldehyde are synthesized by adding 2-bromide-2phenyl-gem-dichlorocyclopropane to the alcoholate obtained in the reaction of sodium metal and alcohols.
Thus the present research has shown that the interreaction of 2-bromide-2-phenyl-gemdichlorocyclopropane with alcohols takes place with the opening of the cyclopropane ring and the formation of the corresponding acetals of phenyl-propargyl aldehyde.