Vitus: The pseudoephedrine isomerization article has been retrieved:
Post 425116 (missing)
(Flogiston: "Èçîìåðèçàöèÿ ïñåâäîýôåäðèíà â ýôåäðèí.", Russian HyperLab)Here is a rough machine tanslation (courtesy of
Promt Online
(
http://translation2.paralink.com)) which creates a document readable to me at least, but the experimental part contained too many technical words for the translation to be useful. We'll have to ask one of our Russian friends to edit this translation for clarity, and to translate the experimental part in its entirety.
IZOMERIZATSIJA PSEVDOEFEDRINA IN EFEDRINM.I.Gorjaev, E.I.Satdarova For last decade efedrin has found wide application in
To medical practice, in particular at treatment of a bronchial asthma and as the agent stimulating blood circulation [1]; diastereoizomer it alkaloida ? psevdoefedrin ? on action it is similar with efedrinom, but is much weaker and consequently in medicine it is not applied.
Efedrin and psevdoefedrin usually accompany each other in plants. These alkaloidy are widely enough distributed; they meet in efedre and in other kinds of plants [2,3,4,5,6]. From them only the few have industrial value. Now in a plenty two kinds are prepared: Åphedra equisetina and Åðhådra intermedia which contain up to 3 % alkaloidov (efedrina and psevdoefedrina). Other kinds contain less alkaloidov and besides are insufficiently investigated in chemical botanical attitudes.
In prepared efedre on a share psevdoefedrina 80 % and about 20 % on efedrin are necessary on the average.
Now it is established, that psevdoefedrin and connections of its lines have treo-ksnfiguratsiju, and efedrin ? an eritro-configuration [7,8].
Ability to mutual transformation of these alkaloidov has been established for a long time. In 1906. Schmidt [9] at attempt to prepare ratsemat efedrina kipjacheniem from 25-percents a hydrochloric acid has received psevdoefedrin. From here there was an idea on an opportunity of transformation efedrina in psevdoefedrin and back. Mutual izomerizatsija these alkaloidov long time it was studied by Schmidt and Emde [10,11,12,13].
It is necessary to note work Kallisa and Schmidt [14] whom as they assert, it was possible to transform completely psevdoefedrin in efedrin, heating up a hydrochloride psevdoefedrina in the sealed - in tubes with baritovoj water at addition of powder Va (IT) 2; within 8 hours sweat pressure at temperature 170-180.
Now it is necessary to consider established, that transformations of these alkaloidov are connected to inversion of It-group at the carbon atom located about fenilnsgo of a radical as at restoration both alkaloida pass in same dszoksiefedrin
[15,16].
Izomerizatsija, connected to inversion of It-group, can be osushchestvleva various ways. So, at processing N-àöåòèëýôåäðèíà by a hydrochloric acid boiling by 5-percents the mix of hydrochlorides efedrina and psevdoefedrina in a provisional parity 38:62 [18] turns out. Mitchel [19] has received the same results, but only alkaloidy have been submitted in a return parity (2 parts efedrina and 1 part psevdoefedrina).
This izomerizatsija, touching alpha-carbon atom at efedrina, does not meet at N-àöåòèëïñåâäîýôåäðèíà which at acid and shelochaom hydrolysis gives only psevdoefedrin. It is typical, that similar izomerizatsija it was observed Kanao [20] at heating with concentrated hydrochloric acid N-áåíçîèë-íîð-dl-ýôåäðèíà. As a result of reaction it turned out only Î-áåíçîèë-íîð-dl-ïñåâäîýôåäðèí; Reaction was accompanied by migration benzoilnoj groups from N to About.
At hydrolysis individual chlorine both bromproizvodnyh efedrina and psevdoefedrina, turning out at replacement with haloid gidroksila, also is formed a mix efedrina and psevdoefedrina.
From works Emde [21, 22] it is visible, that chloride and bromide psevdoefedrina are steadier at hydrolysis, than the same derivatives efedrina.
However these data demand additional check whereas the parity alkaloidov was defined only on the basis of specific rotation of a mix after hydrolysis chlorine and bromproizvodnyh.
In some cases izomerizatsija psevdoefedrina and efedrina it is accompanied by formation of by-products which are investigated in an insufficient degree.
So, the cold sulfuric acid forms with both alkaloidami the same ether psevdoefedrina [12, 14, 17] which at hydrolysis in boiling water or with a hydrochloric acid gives a mix efedrina and psevdoefedrina [13]. At more long action of the concentrated sulfuric acid (5 days, at 15 °) turn out some by-products among which, in particular, has been found metilamin and Others.
At a usual, factory method izomerizatsii psevdoefedrina in 50-percents the sulfuric acid manages 10?15 % of pitch and other products of irreversible change which studying can give a material for finding-out of the mechanism izomerizatsii psevdoefedrina in efedrin. It is possible, that izomerizatsija to mineral acids occurs with
obrazevaniem intermediate products, such, as hlorefedringidrohlorid at action of a hydrochloric acid, bromefedringidrobromid with bromistovodorodnoj an acid and a corresponding ether at action of a sulfuric acid. Hlorefedringidrohlorid easily enough it turns out At action of a smoking hydrochloric acid on efedringidrohlorid [22].
Similar should be, apparently, and action of alkalis on efedrin and psevdoefedrin, however message Kallisa and Schmidt [14] about full transformation psevdoefedrina in efedrin under action of hydrate okisi barium has not proved to be true our experiences and experiences of others
Authors [23].
From the patent literature it is known, that efedrin and psevdoefedrin it is easy ratsemizirujutsja at heating with alkaline alkogoljatami. From ratsematov it is possible to receive again initial opticheski active components [24, 25, 26].
Complex connections of metals and their salts with alkaloidami efedry, probably, influence also on a course of reaction izomerizatsii.
Complex connections of these alkaloidov with ÑuSÎ4 (is more true, with Ñu (IT) 2â presence of alkali) are received and described Grade Tung-fengom [27];
To regret, the author ve results their structure.
Formation of complex connection, probably, is connected to obligatory presence of two functional groups at these alkaloidov ? it and-NÍÑÍ3; so, according to Hailey [28], dezoksiefedrin this complex does not give.
The question about izomerizatsii psevdoefedrina in efedrin has got from us great value after works of Item. Ñ. Màññàãåòîâà [29, 30], opened in 30th years in Kazakhstan and Central Asia big promyshlen nye thrickets efedry.
The method izomerizatsii, used on Chimkent himfarmzavode, developed VNIHFI, leads to to loss up to 50 % psevdoefedrina. With the purpose of improvement of an output efedrina at izomerizatsii psevdoefedrina the given work also has been undertaken.
Experimental partWork on izomerizatsii psevdoefedrina in efedrin was carried out in three directions.
1. Izomerizatsija psezdoefedrina in efedrin in exact conformity with a factory method with a potion of definition of possible blanks in factory technology and receptions of products of irreversible change,
Which should give a material for construction of a hypothesis about the mechanism izomerizatsii.
2. Izomerizatsija from 50-percents a sulfuric acid, as well as in the previous case, but at entering various additives as additional catalysts. As additives various substances which could give complex connections on metilaminnoj and gidroksilnoj to groups have been tested, creating stericheskie obstacles for connection gidroksila from party SNz-MN-gruppy.
3. Studying influence of other agents promoting izomerizatsii psevdoefedrina in efedrin.
