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AZ9RBAYCAN KIMYA JURNALI № 4 2017
UCD 543.547
IMMOBILIZED CROWN COMPOUNDS AS ADSORBENT IN THE COLUMN
CHROMATOGRAPHY
A.L.Shabanov, U.A.Hasanova, E.A.Abdullayeva, P.F.Huseynova*
Research Institute "Geotechnological problems of oil, gas and chemistry" of Azerbaijan
State Oil and Industry University
*Ganja State University
The racemate of L-a-alanine ester-2-butanol, propylene oxide were separated into their individual diastereoisorners, using immobilized crown ether as adsorbent by column chromatograpy. The resulting diastereoisomers were hydrolyzed and converted into the enantiomers. The structure of the enantiomers have been confirmed by physico-chemical methods.
Keywords: crown ether, enantiomer, diastereoisomer, oligomer, immobilized crown, column
chromatography, optical selectivity, eluent.
The study of enantiospecific reactions in analytical chemistry of optically active isomers contributed to serious progress. One of the major achievements of chemistry of crown compounds are innovative works of the Crimea and its employees about compounds tike like "host-guest" type [1]. Separation of the optically active isomers into the antipodes with participation of the chiral adsorbents in the column chroma-tography, extended the possibilities of preparative analytical chemistry. Separation of the optically active isomers into antipodes in analytical chemistry, organic chemistry and organic synthesis is one of the most important problems. At present in the methods for separation of optical isomers, there are observed serious drawbacks. The implementing of these methods, in many cases, met with serious difficulties [2]. Taking into account all above mentioned, we have developed the methods for the separation of a number of the compounds into individual enantiomers, of practical importance. The method consists in the fact that the compounds having hydroxyl or other functional groups in the macrocyclic ring, join to L(S)-amine acid. The obtained racemic diastereoisomers by passing through a chromatographic column are separated and converted into the individual diastereoiso-mers. During the chromatographic separation as adsorbent immobilized crown compounds were used. Applying immobilized crown on ethers was based on their high optical selectivity. For the preparation of the adsorbent crown an ether molecule is attached tacked to monomer which
readily polymerizes [3] and crown ether turns in the corresponding oligomer. By oligomerization of a synthesized glycidyloxy crown ether it is possible to obtain immobilized crown ether (I)
nn
O O
O i
CH I
—( 0-CH-CH2 -n I
and this gives an opportunity to use it as an adsorbent in chromatography.
Using mentioned adsorbents, we have developed an original method in this field, namely the separation of the optical isomers of the compounds of 2-butanol and propylene oxide into antipodes. The offered method is based on the action of the L(S)-alanine to the mixture of optical isomers with obtaining the corresponding diastereoisomers of esters. The racemic mixture obtained diastereoisomers were separated into the individual diastereoisomers by the column chromatography method. Specifically, during the passage of the racemate diastereoisomer ester obtained by reacting 2-butanol with L(S)-alanine [4] (R,S- and S,S-) through a chromatographic column is filled with the adsorbent (I), the structure of individual diastereoisomers with the immobilized crown ether is described below:
AЗЕРБАЙДЖАНСКИЙ ХИМИЧЕСКИЙ ЖУРНАЛ № 4 2017
-(-O-CH-CH2 -n
II
iii
The method of column chromatography and the separation mechanism of diastereoisomers is consists in that these isomers according to the principle "host-guest" with immobilized crown ether by the dipole-dipole interaction lead to the formation of the complex. On the basis of this principle diastereoisomers are held by various non-covalent forces in the hollow spaces of (II) and (III) of immobilized crown ethers. For this reason marked diastereoisomers leave the chromatography column at different times. As the eluent the methylene chloride is used. The first come from the column S,S-diastereoisomers, later come R,S-diastereoisomers. Basing on the results of the elemental analysis it is confirmed that these compounds are isomers. In the area of 3450 cm-1
in IR spectrum of both diastereoisomers there are absorption bands, and it characterizes existence of hydroxyl groups in the diastereoisomers. The resulting S,S-diastereoisomers and R,S-diaste-reoisomers hydrolyzed in a basic medium, turn respectively in S-2-butanol ([a]max = -730) and R-2-butanol ([a]max = + 590). Both optical isomers of butanol are of great interest in organic synthesis. Both optically active substances are used in the preparation of optically active esters, various drugs and so on [5].
Vinyl ester obtained by condensation of these optically active compounds with the acetylene gives an opportunity to obtain optical polymer.
Using of the same compound tetramer (I) there was performed separation of propylene oxide on enantiomers. It is known that optical isomers of propylene oxide are of great practical interest in fine organic synthesis [6]. On their basis chemically strong stereoregular special polymers are obtained. At the same time, the optical isomers of propylene oxide are used as initial monomers in the synthesis of optically active macrocyclic compounds that have great perspective in creation of biosensors [7]. From this point of view, the separation of propylene oxidene on antipodes causes an actual scientific problem. To solve this problem, binding the (S)-alanine to a mixture of enantiomers of propyleneoxide there was obtained the racemate of the diastereo-isomeric ester [8]. The resulting racemic mixture is passed through a chromatographic column containing crown ether oligomer (1) deposited on the surface of the pumice. At this time, diaste-reoisomer esters (R,S- and S,S-) form wi th crown ether oligomer compound, which is shown below:
IV
62
A.L.SHABANOV et al.
Diastereoisomers are disposed between the parallel macrocyclic compounds in the oligomer chain of the crown ether. In this case, the hydrogen of amine group and the hydrogen of the hydroxyl group of diastereoisomer is held respectively by one crown compound and by the parallel disposed crown ether due to hydrogen bond.
Since the complexes formed by diastereo-isomers together with the oligomers of crown ethers have a various stability, they are held by various forces in the cavities of immobilized crown ethers [1]. For this reason, racemic diaste-reoisomers were removed from the chromato-graphic column in the form of individual diaste-reoisomers at different times. From column at first leaves S,S-diastereoisomer, and then R,S-diaste-reoisomer in the form of viscose liquid.
As the eluent dichloromethane was used. Individual diastereoisomers in a basic medium are subjected to hydrolysis.
So, the S,S-diastereoisomers added a solution of potassium hydroxide in DMSO. Thus the propylene oxide leaving the boiling solution in the form of gas is cooled and given to liquid. Twist angle of propylene oxide in the 7% solution of dioxane at 200C is -8.30. This indicates that propylene oxide is a left (S) enantiomer. Similarly is exposed to hydrolysis of R,S-dia-stereoisomer. Reaction conversion of S,S-diaste-reoisomers obtained R-enantiomer of propylene oxide, the twisting angle in the 7% solution of dioxane at temperature of 200C was +5.600.
Experimental part
6-glycidiloxi-2,3,9,10-dibenzo-1,4,8,11,14-pentaoxacyclohexadecane were obtained by A.Shabanov's reaction [9]. To 8.0 g of 6-glycidil-oxi-2,3,9,10-dibenzo-1,4,8,11,14-pentaoxacyclo-hexadecane (solution in ether) 0.5 ml of freshly made BF3 was added. During the reaction the rise of ambient temperature stopped. After reaction, the ester using water-vacuum pump was distilled, residue with «-octane was subjected to multiple-batch extraction. After removal of the extractant there were obtained white crystals with a melting point of 870C. Yield - 75%.
Separation of the racemate of 2-butanol with L(S)-diastereoisomers (II and III) of ala-
nine ester into individual isomers. The process is controlled on the shield "Sulifol". From a column two liquid fractions are selected separately. From the obtained fractions, the solvent was distilled off, then the residue was distilled in vacuum. It turns out the S,S-diastereoisomers and R,S-diastereoisomers respectively having a boiling point equal to 79-810C (10 mm Hg) and 96-970C (10 mm Hg). The yields of these diastereoisomers are respectively 4.54 and 3.7 g.
Separation of the racemate of propy-lene oxide with L(S)-diastereoisomers (IV) of alanine ester into individual isomers in the chromatographic column. Rasemate of S,S-and R,S-diastereoisomers dissolved in dichloro-methane in an amount 17 g is loaded into chro-matographic column.
Diastereoisomers (R,S-) and (S,S-) are removed from the column as a solution in di-chloroethane. From both samples dichlorome-thane was distilled off. The residual crystalline substances have the crystalline substances that have a melting temperature of 158-162 and 169-1730C. The resulting crystal substances are exposed to crystallization in dichloromethane and dioxane again. After deposition of the first sample of crystals there was obtained S,S-dia-stereoisomer having a melting point 161-1620C. From the second fraction (169-1730C) were separated crystals (R,S-diastereoisomers) with a melting point 170-1710C below there are offered the results of the elemental analysis of 1) S,S-diastereoisomers - found, %: C 54.67, H 9.87, N 10.75. C6H13O2N; calculated, %: C 54.96, H 9.92, N 10.69 and 2) R,S-diastereoisomers -found, %: C 54.66; H, 9.83; N 10,73. C6H13O2N; calculated, %: C 54.96, H 9.92, N 10.69.
Structure, elemental analysis, NMR of the obtained compounds are confirmed.
Conclusions
1. Using of immobilized crown ether as adsorbent racemate of diastereoisomers of 2-bu-tanol etherized with L(S)-alanine was subjected to column chromatography. It is shown that one of the formed diastereoisomers S,S- and R,S-create with a ring of crown ether ion-dipole and hydrogen ammonium group L(S)-alanine intra-
A3EPEAH#^AHCKHH XHMHHECKHH ^YPHAH № 4 2017
molecular hydrogen bond. For this reason, it is easily separated from the other diastereoisomers by column chromatography.
2. Using the regioselective conversion of propylene oxide with L(S)-alanine formed rasemate of diastereoisomers were separated into the individual isomers, using crown ethers oli-gomer as an adsorbent in the chromatographic column.
In the literature to name the optical isomers of alanine they used the model DL-(Ro-zanov), in the article for the name of the optical isomers we used this model (DL-) and SR-(Cannes-Ingold-Prelog) model [2].
References
1. Крам Д. Химия комплексов "гость-хозяин". М.: Мир, 1983. С. 38-41.
2. Марч Дж. Органическая химия. М.: Мир, 1987. С. 158-163.
3. Абдуллаева Э.А. Синтез краунзамещенных производных акрил- и метакрильных кислот // Азерб. хим. журн. 2003. № 1. С. 139-141.
4. Абдуллаева Э.А., Гусейнова П.Ф., Гасанова У.А. Применение иммобилизованных краун-соединений для хроматографического разделения оптических антиподов 2-бутанола // Азерб. хим. журн. 2003. № 3. С. 71-72.
5. Рубцов М.В., Байчиков А.Г. Синтетическая химическая фармацевтика. М.: Дом публикации "Медицина". 1971. С. 38-39 и 68.
6. Гаджиева С.Р., Абдуллаева Э.А., Кулиева Е.Г. Очистка пластовых вод от ионов переходных металлов с использованием олигомерных краун-соединений // Хим. пром-сть. 2014. № 5. С. 76-80.
7. Pedersen Ch. The syntheses of the dibenzocrown ethers // J. Amer. Chem. Soc. 1967. V. 89. No 26. P. 7017-7036.
8. Гусейнова П.Ф., Гасанова М.М., Абдуллаева Э.А. Разработка хроматографического метода разделения оптических изомеров окиси пропилена // Азерб. хим. журн. 2007. № 1. С. 140-142.
9. Шабанов А.Л. Перспективы синтеза и применения функциональнозамещенных краун-эфи-ров // Журн. Всесоюзного Менделеевского общества. Секция орган. химия. 1991. T. 36. № 4. С. 456-463.
iMMOBiLiZO OLUNMUS KRAUN BiRLO§MOLOR KOLONKALI XROMATOQRAFiYADA
ADSORBENT KiMi
O.L.§abanov, U.O.Hasanova, E.O.Abdullayeva, P.F.Huseynova
immobiliza olunmu§ kraun efirlardan adsorbent kimi istifada olunmaqla L-a-alaninla butanol-2 va propilen oksidinin kolonkali xromatoqrafiya ila muvafiq diastomerlara aynlmasi usulu i§lanib hazirlanmi§dir. Almmi§ diastomerlar hidroliz olunaraq enantiomerlara kegirilmi§dir. Enantiomerlarin qurulu§u fiziki-kimyavi usullarla tasdiq olunmu§dur.
Agar sozlzr: kraun efir, enantiomer, diastomer, oliqomer, immobiliza olunmu§ kraun, kolonkali xromatoqrafiya, optiki segicilik, elyuent.
ИММОБИЛИЗОВАННЫЕ КРАУН-СОЕДИНЕНИЯ КАК АДСОРБЕНТЫ В КОЛОНОЧНОЙ
ХРОМАТОГРАФИИ
А.Л.Шабанов, У.А.Гасанова, Э.А.Абдуллаева, П.Ф.Гусейнова
Разработан способ разделения смеси 2-бутанола с L-a-аланином и оксидом пропилена с образованием соответствующих диастомеров с применением иммобилизованных краун-эфиров как адсорбентов колоночной хроматографии. Образовавшиеся диастомеры были гидролизованы и переведены на энантиомеры. Структура энантиомеров была доказана физико-химическими методами.
Ключевые слова: краун-эфиры, энантиомер, диастомер, олигомер, иммобилизованные крауны, колоночная хроматография, оптическая селективность, элюент.
