Über die Reduktionsprodukte des Thebains

Abstract

und Edmund Speyer: Ober die Reduktionsprodukte des Thebains.(nach Versuchen von ]:rust G u t t m a n n ) . Ihlitteiliiiig au5 dem Clicm. Iiistitut dor Universitiit FrankFurt-Main.j (Eingegangen am 2. Oktoher 1920.) Infolge der Saure-Empfindlichkeit des T h e b a i n s war es bisher nur moglich, die R e d u k t i o n desselben i n a l k a l i s c h e r L o s u n g ~o r z u n e h m e n .~ F r e u n d ') erhielt beim Behandeln des Thebains rnit Siltrium in alkoholischer Losung ein D i h y d r o -t h e b a i n von der %usarnmenset'zung C19 IIa3 NO,. Eine Mcthoxyl-Bestimmung dieser h s e erpab das Vorhandensein zweier Methosylgruppen, wie im Thebain. Ein wesentlicber Uoterscbied der reduzierten Base im Vergleich zum Ausgangsmaterial bestand vor allem in der Alkaliloslichkeit. Die Entstehung dieses Dihydro-thebains findet ihre Erklarung i n der Aufnabme von 1 Xlol. Wasserstoff an die Sauerstoffbrucke unter Hildung einer Phenolbase. Legt man dern Thebain die von K n o r r rorgesohlagene Formulicrung (I.) zugrunde, so kann man dern Dihydro-thebain Formel (11.) zuschreiben. C11 CH,O.C:-". CH Wir haben n u n gcfunden, dalJ beim Behandeln einer e s s i gs n u r e n L i j s u u g d e s T h e b a i n s rnit P l a t i n r n o h r (bereitet nacb L o e w -W i l l s t a t t e r ) u n d W a s s e r s t o E f ein Gemisch verschiedener Bnsen gebildet wird, aus welchen eine gut krystallisierende, alkaliunliisliche, tertiare Base rorn Schmp. 163-163O uod der Zusammencetzung ClaH23 NOS neben einem 0 1 isoliert werden konnte. Dieses so erhaltene D i h y d r o -t h e b a i n ist rnit dem friiher beechriebenen Dibydro-tbebain i s o m er. Es lieferte eio gut krystallisierendes Cblorhydrat von der Formel ClsIIzaNOs, HCI, ein Pikrat von der Zusarnmensetzung C1~II23N03, C G H~( N O~)~. O H und ein J o d m e t h y l a t von der Formel CIsHt3 NO3, CIL J. Dieses Jodrnethylat wurde dern A b b a u n a c h H o f m a n n unterworfen. -.___-'1 M. F r e i i n d , B. 82, 19'2 118991.

Recrystallization effect during the dehydration of magnesium hydroxide

“…8,1975 phase. Elsewhere it has been discussed [16] that the average size of these particles can be calculated from the elastic constants of Mg(OH)~ and the relative lattice contraction upon defect phase formation.…”

DARK Classics in Chemical Neuroscience: Opium, a Historical Perspective

“…80 Later, in 1920, it was shown by using the Zeisel determination that there were two methoxys in thebaine. 99 A year later in 1921, thebaine was determined to have two double bonds by examining the products of palladium catalyzed hydrogenation. 100 These experiments showed that thebaine differs from morphine by two methoxy groups and an extra double bond, so once the structure morphine was determined, so was thebaine.…”

“…To start, Knorr demonstrated that acids convert thebaine into codeinone ( 13 ) . Later, in 1920, it was shown by using the Zeisel determination that there were two methoxys in thebaine . A year later in 1921, thebaine was determined to have two double bonds by examining the products of palladium catalyzed hydrogenation .…”

A practical synthesis of codeine from dihydrothebainone

“…In the thebaine synthesis7 both of these difficulties were eliminated in a single reaction. While bromination of 4a results first in bromination at C-l, reaction of dihydrocodeinone methyl enol ether (15) with methyl hypobromite gave selective reaction at C-7 and produced 7-bromodihydrocodeinone dimethyl ketal (16) in moderate yields. Since the ketal now lowers the reactivity of the system, conventional dehydrobromination conditions were employed and good yields of codeinone dimethyl ketal (17) were obtained.…”

“…However, heating a solution of 19 and ptoluenesulfonic acid in CHCI3 gave nearly quantitative yields of 15, and crystallization gave an 82% yield for the two steps from 4a. The addition of CHsOBr to 15 proceeded best when the HBr salt was employed, conveniently prepared by the two-phase reaction of 15 in CHCI3 with stoichiometric amounts of concentrated (48%) HBr. Methyl hypobromite then gave crude bromoketal 16 in nearly quantitative yield.…”