1.5- Diazabicyclo octane

Hydroxy>3-meihyleneirldecan-2-one (2). A solution ol decanal 1 (3.12 g. 20 mmol), methyl vinyl ketone 2 (1.4 g, 20 mmol) and 1.4-diazabicyclo-octane (DABCO) (0 33 g. 

We note further studies concerning the ethanolysis of l-chloro-2-aza-adamantanes, the rearrangement " of iV-chloro-tropanes, the dealkylation " of (76) with PhSeH, the formation of a stable adduct between (77) and sulphur dioxide " and also between aaa-trifluoroacetophenone and 1,4-diazabicyclo-octane, "" and the use of (78) as an intermediate " in the synthesis of the antifungal antibiotic aristeromycin (79), which is a carbocyclic analogue of adenosine. The acid-catalysed cyclization "" of (80) gave (81) the structure of the product was determined by X-ray analysis. 

For the synthesis of 18 trichlorophosphine is alkylated to dichloro[bis(tri-methylsilyl)methyl]phosphine by means of the appropriate Grignard reagent. The subsequent elimination of HC1 can be achieved with, for example, diazabicyclo-octane (DABCO), however, the use of triethylamine is advantageous for the work-up.37,38... 

I have reviewed the scientific literature of the past 176 years on hydrogen peroxide hundreds of articles on such subjects as "Catalysis of single oxygen production in the reaction of hydrogen peroxide and hypochlorous acid by diazabicyclo octane."... 

Separation of relatively pure para-cresol from mixed cresols using an organic solvent and thereafter formation of a solid crystalline complex with the solvent has been reported. Piperazine and DABCO (diazabicyclo-octane) have been found to be very effective as extracting agents in this process of separation. There is very little effect of m-cresol in this process. The values of separation factor approach infinity as 100% p-cresol-base complex is crystallized. The yield of p-cresol was impressive with some aliphatic polar solvents, but... 

Details are given of the synthesis of new methacrylate monomers containing pendant quaternary ammortirrm moieties based on diazabicyclo-octane. The monomers were homopolymers using azobismethylpropionarrride dihydrochloride as initiator. The monomers and polymers were characterised by elemental analysis, TGA, DSC, FTIR and carbon 13 NMR. Antimicrobial activities were investigated against S.aureus and E.coli. 41 refs. 

Oxidation.— Two copper-catalysed reactions have been described for the degradation of the 22-aldehyde (298) to give a pregnan-20-one (299). Oxygenation of a solution of the aldehyde with the copper(n) acetate-2,2 -bipyridyl complex and diazabicyclo-octane in dimethylformamide gave the 20-ketone in 90% yield. A free-radical mechanism is proposed (Scheme 14). 

Figure 2.32 Examples of structures based on paddle wheel dimer units. In the copper trimesate HKUST-1, (top, left and right), dimeric copper units link four trimesate ligands into a three-dimensional framework, leaving the apical coordination site accessible to other ligands (such as water molecules). In the pillared layered zinc terephthalate of Dybtsev et al. porous planar zinc terephthalate sheets (shown) are linked via the diamine diazabicyclo-octane (N(C2H4)3N) coordinated at the apical sites.

Zeolite Beta is normally prepared at high alkaline pH with a templating mixture of Et4N and Na cations which in addition are not specific for this structure [72]. This synthesis can also be carried out in F" medium H = 7-10) with diazabicyclo-octane (DABCO) [73]. While with OH" anions the size of the crystals is generally below about 0.5 pm, in the presence of F" anions and without alkali cations, crystals have a pseudo octahedral morphology with a size up to 10 im(Figure 33.). 

The physical properties of polyurethane adhesives result from a special form of phase separation which occurs in the cross-linked polyurethane stmcture. The urethane portions of polyurethanes tend to separate from the polyol portion of the resin, providing good shear strength, good low temperature flexibiUty, and high peel strength. Catalysts such as dibutyltin dilaurate [77-58-7], stannous octoate [1912-83-0], l,4-diazabicyclo[2.2.2]octane... 

Conditions cited for Rh on alumina hydrogenation of MDA are much less severe, 117 °C and 760 kPA (110 psi) (26). With 550 kPa (80 psi) ammonia partial pressure present ia the hydrogenation of twice-distilled MDA employing 2-propanol solvent at 121°C and 1.3 MPa (190 psi) total pressure, the supported Rh catalyst could be extensively reused (27). Medium pressure (3.9 MPa = 566 psi) and temperature (80°C) hydrogenation usiag iridium yields low trans trans isomer MDCHA (28). Improved selectivity to aUcychc diamine from MDA has been claimed (29) for alumina-supported iridium and rhodium by iatroduciag the tertiary amines l,4-diazabicyclo[2.2.2]octane [280-57-9] and quiaucHdine [100-76-5]. 

More recently, Cheeseman and coworkers have investigated cycloaddition reactions of 2,6-dioxypyrazines (80jCS(Pl)1603). 2,6-Dihydroxy-3,5-diphenylpyrazine (77) reacts with electron deficient dienophiles such as iV-phenylmaleimide, diethyl maleate and diethyl fumarate (Scheme 26) to yield adducts of the 3,8-diazabicyclo[3.2.1]octane class such as (78). This reaction is believed to proceed by way of the betaine (79) and has precedent (69AG(E)604) in that photolysis of the bicyclic aziridine (80) generates analogous betaines which have been trapped in cycloaddition reactions. 

B. Di-tert-butyl dicarbonate. A solution of 20.0 g. (0.076 mole) of di-i-butyl tricarbonate in 75 ml. of carbon tetrachloride is placed in a 600-ml. beaker fitted with a magnetic stirrer, and 0.10 g. (0.0009 mole) of freshly sublimed l,4-diazabicyclo[2.2.2]octane (DABCO) is added (Note 9). Rapid evolution of carbon dioxide begins at once. The reaction mixture is stirred at 25° for 45 minutes to complete the loss of carbon dioxide (Note 10), and then 35 ml. of water, containing sufficient citric acid to make the aqueous layer slightly acidic, is added. The layers are separated and the organic layer is dried over anhydrous magnesium sulfate and then concentrated at 25° with a rotary evaporator. The residual liquid is distilled under reduced pressure to separate 13.3-15.1 g. (80-91%) of di-butyl dicarbonate as a colorless liquid, b.p. 55-56° (0.15 mm.) or 62-65° (0.4 mm.) n T> 1.4071-1.4072 (Note 11). 

The submitters report that both l,4-diazabicyclo[2.2.2]octane and triethylamine have been used to catalyze this decomposition. Tri-ethylamine was less satisfactory as a catalyst because of its relatively rapid reaction with the solvent, carbon tetrachloride, to form triethylamine hydrochloride and because of difficulty encountered in separating triethylamine from the dicarbonate pi oduct. The 1,4-diazabicyclo-[2.2.2]octane was efficiently separated from the dicarbonate product by the procedure described in which the crude product was washed with very dilute aqueous acid. 

Hexafluoroacetone azine reacts with 2 equivalents of terminal olefins [194] and acetylenes [182] to give 1,5-diazabicyclo[3.3.0]octanes and 1,5-diazahicy-clo[3 3 0]octa-2,6-dienes, respectively (equation 44). 

Together with a shift of the proton from the a-carbon to the alkoxide oxygen, the tertiary amine is eliminated from the addition product to yield the unsaturated product 3. Early examples of the Baylis-Hillman reaction posed the problem of low conversions and slow reaction kinetics, which could not be improved with the use of simple tertiary amines. The search for catalytically active substances led to more properly adjusted, often highly specific compounds, with shorter reaction times." Suitable catalysts are, for example, the nucleophilic, sterically less hindered bases diazabicyclo[2.2.2]octane (DABCO) 6, quinuclidin-3-one 7 and quinuclidin-3-ol (3-QDL) 8. The latter compound can stabilize the zwitterionic intermediate through hydrogen bonding. ... 

By structural complementarity, dicationic l,4-diazabicyclo[2.2.2]octane (VII) provides an appropriate recognition site for phosphate ions and two stearyl side chains attached to the amines add lipophilic properties 59,60). Such a carrier model can selectively extract nucleotides from aqueous solution to chloroform solution via lipophilic salt formation. The order of nucleotide affinity is ATP > ADP > AMP. The selectivity ratios were 45 for ADP/AMP and 7500 for ATP/AMP at pH 3. The relative transport rate was ATP > ADP > AMP. The ratios were 60 for ATP/AMP and 51 for ADP/AMP. The modes of interaction of ADP and ATP are proposed to be as shown in Fig. 6. 

Treatment of the Z-aldehyde 9 (R1 = R2 = H) with trifluoroacetic acid in dichloromethane at — 10 C, then with l,4-diazabicyclo[2.2.2]octane or /V,/V-diethylpyridin-4-amine, constitutes the first synthesis of 27/-azepine (10, R1 = R2 = H) which was isolated, with great difficulty and in very low yield (1 %), as a highly volatile, unstable oil, the structure of which was confirmed by high field H and 13CNMR spectroscopy.290 Similar treatment of the Z-alkenones 9a-d furnishes the thermally unstable (5)-2/7-azepines lOa-d in much higher yields.291... 

In a study of the photoreduction of zinc(II) or magnesium chlorophyll derivatives 8 with ascorbic acid in the presence of l,4-diazabicyclo[2.2.2]octane (DABC-O), a 2,3-m-hydrogenated isobacteriochlorin 9 is formed which subsequently rearranges to a 3-ethylidenc derivative... 

The easiest access to most benzyllithium, -sodium, or -potassium derivatives consists of the deprotonation of the corresponding carbon acids. Hydrocarbons, such as toluene, exhibit a remarkably low kinetic acidity. Excess toluene (without further solvent) is converted into benzyllithium by the action of butyllithium in the presence of complexing diamines such as A. Af.Af.jV -tetramethylethylenediamine (TMEDA) or l,4-diazabicyclo[2.2.2]octane (DABCO) at elevated temperatures1 a procedure is published in reference 2. 

Diarylhydrazines, from ArNJ 195 Diarylmercury compounds 273 f. 1,4-Diazabicyclo [2.2.2]octane (DABCO) 360 Diazenes 6, 126, 192, 195, 211, see also Azo compounds... 

Triethylene diamine (TEDA also known as l,4-diazabicyclo[2.2.2]octane, or DABCO) is a powerful catalyst with a high selectivity for gellation. One reason... 

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