Bei der Umsetzung von cis-Benzoltrioxid (1) mit Guanidin in gepufferter tert-Butylalkohol-Losung werden mit 88 -91 % (9-12%) Ausbeute die aus der 1,3(1,2)-Uberbruckung in 1 hervorgehenden 1 : 1 -Addukte ~~-( l a , 2 B , 4 P , 5 a , 6 a , 10a)-8-1mino-3-oxa-7,9-diazatricyclo[4.3.1 .d*4]decan-5,lO-diol (13 a) und DL-(~ u ,2u ,3f3 ,5f3,6c( ,7~)-9-Imino-4-oxa-8,1O-diazatricyclo[ 5.3 .0.03i5]decan-2,6-diol(12a) gewonnen. Auch Trifluoracetamidin (Acetamidin) wird an 1 bevorzugt 1 Jaddiert. Aus 13a gcwinnt man durch jeweils regiospezifische Hydrolyse (26a), Thiolyse (30a, d), Ammonolyse (34a), Hydrazinolyse (34d) und HCI/HBr-Addition (39a, c) Zugang zu hochfunktionalisierten 2,4-Diazabicyclo[3.3.l]nonan-Derivaten. Bei der fur 26a und 34d beobachteten ,,Ring-Ketten-Tautomerie" (28a, 36d) sind die adamantoiden Orthokohlensaure-Intermediate (27a, 35d) nicht nachweisbar. Die u. a. wegen der konformativen Flexibilitat der Geruste nicht immer eindeutigen spektroskopischen Strukturzuordnungen werden durch Rontgenstrukturanalysen f u r 29f, 36e, 38 und 43 gesichert. 2,4-Diazabicyclo[3.3. Ilnonane Skeletons from &Benzene TrioxideBy treating &-benzene trioxide (1) with guanidine in buffered tert-butyl alcohol solution the 1 : 1adducts ~~-(la,2~,4~,5a,6~,l0a)-8-imino-3-oxa-7,9-diazatricyclo[4.3.l.d~~]decane-5,lO-dio (13a) and ~~-(1a,2c(,3~,5(j,6a,7~)-9-imino-4-oxa-8,1O-dia~atricyclo[5.3.0.0~'~]decane-2,6-diol (12a) resulting from 1,3(1,2)-bridging in 1 are obtained in 88-91% (9-12Vo) yields. Trifluoroacetamidine (acetamidine) is also selectively 1,3-added to 1. From 13a via generally regiospecific hydrolysis (26a), thiolysis (30a, d), ammonolysis (34a), hydrazinolysis (34d), and HCI-/HBraddition (39a, c) access to highly functionalised 2,4-diazabicyclo[3.3.l]nonane derivatives is opened. During the "ring-chain tautomerism" observed for 26a and 34d (28a, 36d) the adamantoid orthocarbonic acid intermediates (27a, 35d) cannot be identified directly. The spectroscopic structure elucidations (not always unequivocal because i.a. of conformational flexibility of the skeletons) are confirmed by X-ray structural analysis for 29f, 36e, 38, und 43. Fur cis-Trioxa-tris-o-homobenzol (1) (,,cis-Benzoltrioxid" , Trisanhydro-cis-inosit) und seine einfach-bzw. zweifach Allyl-(a-epoxy)-substituierten Epoxycyclohexan-/Diepoxycyclohexan-Vorprodukte wurden ausgehend von Benzol okonomische Synthesen ausgearbeitet. Damit waren diese funf-bzw. sechsfach funktionalisierten Cyclohexane fur unterschiedliche Zielsetzungen interessant: (i) Zum Aufbau heteroanaloger (Aza-*), Thia-3), Carba-4))-o-Homobenzole. (ii) Zur Herstellung neuartiger 1 ,4-Diheterocine (u. a. 1,4-Dihydro-1 ,4-diazocine5), 4H-1 ,4-Oxazocine6)) 0 VCH Veriagsgesellschaft rnbH, D-6940 Weinheim, 1985Chem. Ber. II8(1985) 134' W. Fritsche-Lang, P. Wilharm, E. Hadicke, H. Fritz und H. Prinzbach den (Tab. 1/2). Zur Trennung und Derivatisierung wird das Rohgemisch mit einem Uberschurj an Acetanhydrid/Pyridin bei 25 C acetyliert. Unter standardisierten Bedingungen fallt ein zur Trennung genugend ein...
SynopsisLow molecular weight /j, 1 + 4-glucans (cellodextrins) are favorably prepared by cleavage of cellulose in liquid hydrogen fluoride at temperatures between -15 and -30° C. This is due to the suppression of the reversion reaction in that low temperature range. Under conditions favorable for reversion the presence of water leads to a competing hydrolysis and lowers the average degree of polycondensation. For the preparation of defined 0-glycosides from glucose and alcohols, hydrogen fluoride is not'suitable as a reaction medium. Under reversion conditions, monohydroxy compounds are inferior in their reactivity to the competing carbohydrate molecules, and polyols like sorbitol furnish mixtures of isomeric glycosides. Gaseous hydrogen fluoride represents a highly suitable agent for the degradation of carbohydrate and lignin containing biomass, such as waste wood, for the purpose of providing fermentation raw material. As a model, lignocellulose was studied and the heat of reaction of the hydrogen fluoride sorption and desorption processes were examined. The practically important desorption value was found to be approximately 870 kJ/kg HF:
Bei der Umsetzung der Titelverbindung (I) mit Guanidin (II) werden die l :l‐Addukte (III) und (IV) (Racemate) gebildet.
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