1,8-Diazabicyclo[5.4.0]undec-7-ene CAS 6674-22-2 DBU
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- Appearance: Yellow liquid
- Assay: 99. 0%min
- Stock: In stock
- Sample: Available
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1,8-Diazabicyclo[5.4.0]undec-7-ene: The Complete Guide
DBU for Sale
Basic Info of DBU
Organic Intermediates; Daily Chemicals; Pharmaceutical raw materials
What is DBU?
1,8-Diazabicyclo [5.4.0] undec-7-ene is a bicyclamidine base. In natural chemistry, it is a non nucleophilic, sterically impeded tertiary amine base. It is reported that it is superior to amine drivers in Baylis Hillman response and can advertise the methylation response of phenol, indole as well as benzimidazole with dimethyl carbonate under mild conditions.
1,8-Diazabicyclo [5.4.0] undecanon-7-ene, referred to as DBU, is a type of amidine with a dual heterocyclic framework. It is an anemic or light yellow liquid at space temperature level, as well as can be dissolved in water, ethanol, acetone as well as other natural solvents. It is normally saved listed below 30 ℃.
DBU, as a natural strong base with one-of-a-kind structure, has actually been used in several synthesis reactions, showing the catalytic effect that solid bases can not play. It has the features of mild response conditions, basic synthesis actions, high item selectivity and also high yield. It can be predicted that with the growing of people’s understanding of DBU, DBU will certainly be extensively made use of in enhancing the existing synthesis process, establishing brand-new organic synthesis approaches and synthesizing new items.
1,8-Diazabicyclo [5.4.0] undec-7-ene is utilized as catalyst, complicated ligand as well as non nucleophilic base in natural synthesis. It is utilized as a protective representative for the synthesis of cephalosporins and a stimulant for polyurethane. 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) can be utilized for:
- DBU used as a catalyst for carboxylic acid esterification with dimethyl carbonate in the synthesis of dokacin and also CC-1065 analogues.
- DBU used of as catalyst in aza Michael enhancement and also knovenegal condensation responses.
- As the basis for dehalogenation of halogenated Diels alder adducts, Yamamoto reagent (ch3cu · BF3) was used to regionally and stereodirectionally Michael enhancement camptothecin to the gotten activated 2,4-diene in the synthesis of a new ABCD ring system
1,8-Diazabicyclo [5.4.0] undec-7-ene can be utilized as a stimulant for dissolving as well as turning on cellulose with the reversible reaction of its hydroxyl group with co2. This dissolved cellulose system can be obtained to form cellulose mixed esters.
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Application of DBU
DBU is a strong basic reagent, but it is a weak nucleophile, which is easy to combine with protons but not easy to combine with carbon atoms. Therefore, the application of DBU is mainly used as a strong basic reagent to transfer protons and act as a base or catalyst. effect. The characteristic of DBU participating in the reaction is that it generally requires the same amount of DBU, and the applied reactions are mainly concentrated in some reactions with proton transfer, such as elimination, isomerization, addition, esterification, etherification, amidation, diazotization chemical reactions.
DBU has been applied to a variety of elimination reactions to introduce unsaturated bonds into reagent molecules, as intermediates and raw materials for organic synthesis, just to name a few examples is enough to see the application of DBU in elimination reactions.
- Haloalkanes eliminate hydrogen halide
A typical reaction is that 1,1-diiodobutane is heated to reflux with an equivalent amount of DBU until a brown solid appears, and the product (E)-1-iodo-1-butene is obtained by distillation and separation from the reaction mixture. The yield is is 80%. Usually DBU is difficult to dehydrohalogenate vinyl halides to alkynes, but the special structure (E)-vinyl bromide and DBU are refluxed in benzene, almost quantitatively converted to the corresponding alkynes, while (Z)-form isomerization The body does not have such a reaction. The use of DBU for the dehydrohalogenation of halocarbons is numerous enough to demonstrate that DBU is a very efficient haloalkane dehydrohalogenation reagent.
- N-halogenated amides to eliminate hydrogen halide
Under the action of DBU, N-halogenated amides can successfully remove hydrogen halide, and then rearrange into isocyanates. Under the action of DBU, N-chlorobenzamides can be rearranged to obtain benzene isocyanates with a yield of more than 90%. However, it is difficult to obtain benzene isocyanate by replacing DBU with an organic base such as triethylamine.
Double bond isomerization and epimerization reactions are extremely useful in organic synthesis, and DBU has a good catalytic effect in such isomerization reactions.
- Double bond isomerization reaction
Using DBU, β,γ-unsaturated esters can be converted into corresponding α,β-unsaturated esters. Under the action of DBU, 60% of 3-pentenoate is isomerized into stable 2-pentenoate; under the action of catalyst DBU, β,γ-unsaturated nitrile can also be isomerized into stable α,β-unsaturated Nitrile.
- Epimerization reaction
The mixture of stereoisomers was reacted with DBU for 1 h at room temperature, and its cis-3,4-isomer was converted to trans-3,4-isomer with a selectivity of 96%. This provides a way to synthesize compounds of special configurations.
DBU is an alkaline reagent that deprotonates active α-hydrogen compounds to form carbanions, among which Michael addition reaction is the most typical, with mild reaction conditions and few side reactions. In the reaction of cyclohexanone formate and methyl acrylate, DBU was used as an alkaline reagent to obtain the product with a yield of 96%:
DBU makes Michael reaction between nitro compound and styryl ketone containing double bond, and the yield is 95%; compound 15 undergoes Michael reaction with 2-cyclopentenone, and generates (+)-3-cyclopentenone after hydrolysis and decarboxylation Acetic acid with a total yield of 43% and an optical purity of 96%. The yield of the product obtained by using triphenyllithium or potassium tert-butoxide as a catalyst is close, but the optical purity is much lower, only 7% to 76%. In addition, in the Knovenagel condensation reaction between malonic acid and hexanal, DBU was used as a basic reagent, and the reaction was carried out at 90 °C for 10 h to obtain β, γ-unsaturated isomers with a selectivity of 94% and a yield of 56%. %.
DBU can be used as a catalyst for the preparation of esters and amine compounds from carboxylic acids, halogenated hydrocarbons, and the preparation of ethers, esters and carbamates from alcohols. This type of reaction is formed by deprotonation of carboxylic acid or alcohol with alkyl halide, acylating agent or other electrophilic reagents, wherein esterification and amidation reactions are generally carried out at room temperature, while etherification reactions are generally carried out at 60 ℃. at ~80°C.
When synthesizing 2,5-dimethyl-3-phenyl-2-cyclopentenone, using DBU as a catalyst, the yield reached 70%. In the synthesis of tetrahydropyrrole derivatives, it is also obtained by cycloaddition using DBU as a catalyst, and the yield is also over 90%.
Recently, it was found that DBU has a good catalytic effect in the synthesis of α-diazoketones and α-diazoesters. Under the catalysis of DBU, benzenesulfonyl azide compounds carry out diazotization reaction on the active sites of related compounds under mild conditions and high yields.
Preparation of DBU
A method for synthesizing 1,8-diazabicycloundec-7-ene, using epsilon caprolactam as a starting material, firstly reacting with hydroquinone in the presence of acrylonitrile, and then reacting with hydroquinone in an ice bath Dry hydrogen chloride gas was introduced into the toluenesulfonic acid until the solution was saturated, the reaction was continued for more than 10 hours under an ice bath, suction filtration under nitrogen protection, and benzyl chloride was added to react; the reaction product was mixed with sodium perborate, and then added to ethylenediaminetetraacetic acid. Reflux reaction in dichloromethane for 8h in the presence of conditions; then add 3-tert-butyl salicylaldehyde to it, add 3-phenylpropionic acid at 45°C under stirring conditions, keep the temperature unchanged and react until the raw materials disappear completely, then cool down At room temperature, add water to dilute 3 times, then add 4-nitrobenzyl chloride to stir the reaction, filter to obtain a solid, and extract the filtrate three times with ethyl acetate, collect the solid phase, dry with anhydrous magnesium sulfate, and dry under reduced pressure to obtain a crude product Wash with a mixed solution of acetone and petroleum ether to obtain DBU product.
Among them, the molar ratio of ε caprolactam, acrylonitrile and quinone is 1:4:2; the reaction conditions of ε caprolactam and hydroquinone are: react at 22° C. for 20 min under 2 atmospheres. The stirring conditions were accomplished using a magnetic stirrer. The molar ratio of 3-phenylpropionic acid to 4-nitrobenzyl chloride was 2:13. The collected solid phase was centrifuged at 4000 rpm for 20 min.