1,8-Diazabicyclo(5.4.0)undec-7-en Chemische Eigenschaften,Einsatz,Produktion Methoden
R-Sätze Betriebsanweisung:
R22:Gesundheitsschädlich beim Verschlucken.
R34:Verursacht Verätzungen.
R52/53:Schädlich für Wasserorganismen, kann in Gewässern längerfristig schädliche Wirkungen haben.
R35:Verursacht schwere Verätzungen.
S-Sätze Betriebsanweisung:
S26:Bei Berührung mit den Augen sofort gründlich mit Wasser abspülen und Arzt konsultieren.
S36/37/39:Bei der Arbeit geeignete Schutzkleidung,Schutzhandschuhe und Schutzbrille/Gesichtsschutz tragen.
S45:Bei Unfall oder Unwohlsein sofort Arzt zuziehen (wenn möglich, dieses Etikett vorzeigen).
S61:Freisetzung in die Umwelt vermeiden. Besondere Anweisungen einholen/Sicherheitsdatenblatt zu Rate ziehen.
S27:Beschmutzte, getränkte Kleidung sofort ausziehen.
Beschreibung
DBU is a bicyclic amidine base. It is non-nucleophilic, sterically hindered, tertiary amine base in organic chemistry. It is reported to be superior to amine catalyst in Baylis-Hillman reaction.It promotes the methylation reaction of phenols, indoles and benzimidazoles with dimethyl carbonate under mild conditions.
Chemische Eigenschaften
Colorless to yellow liquid
Occurrence
Although all commercially available DBU is produced synthetically, it may also be isolated from the sea sponge Niphates digitalis.The biosynthesis of DBU has been proposed to begin with 1,6-hexanedial and 1,3-diaminopropane.
Verwenden
DBU may be used:
- as catalyst for carboxylic acid esterification with dimethyl carbonate
- in the synthesis of duocarmycin and CC-1065 analogs
- as catalyst in aza-Michael addition and Knovenegal condensation reaction
- as base for dehalogenation of halogenated Diels-Alder adducts and the resulting activated 2,4-dienones were subjected to regio- and stereo-directed Michael additions, using Yamamoto′s reagent (CH3Cu · BF3)
- in a new synthesis of the ABCD ring system of Camptothecin
- DBU may be used as an catalyst for the dissolution and activation of cellulose by a reversible reaction of its hydroxyl groups with carbon dioxide. This dissolved cellulose system can be derivatized to form cellulose mixed esters.
- Used in a new synthesis of the ABCD ring system of Camptothecin.
Allgemeine Beschreibung
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Synthese
The synthesis of DBU is as follows:As a base, sodium hydroxide was used at a concentration of 25% by weight and 2.3 times molar equivalent. A stirrer was placed in a 100 mL screw tube, and 11.5 g (50 mmol) of DBU hydrochloride, 8.5 g of toluene and 18.5 g (116 mmol) of 25% sodium hydroxide aqueous solution were charged at room temperature. It was placed on a magnetic stirrer and mixed for 1 hour with stirring. The mixture was separated with a 100 mL separatory funnel to obtain 18.8 g of the upper layer containing DBU and 18.4 g of the lower layer of the aqueous layer. The upper layer portion was analyzed by gas chromatography and contained 31.9% by weight of DBU, and the yield was 6.0 g (39.4 mmol) in a yield of 78.8%.
läuterung methode
Fractionally distil DBU under vacuum. Also purify it by chromatography on Kieselgel and eluting with CHCl3/EtOH/25% aqueous NH3 (15:5:2) and checking by IR and MS. [Oediger et al. Chem Ber 99 2012 1962, Angew Chem, Int Ed Engl 6 76 1967, Guggisberg et al. Helv Chim Acta 61 1057 1978, Beilstein 23/5 V 271.]
1,8-Diazabicyclo(5.4.0)undec-7-en Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
