Ethyl diisopropylamine

Alkyl-4-hydroxybutenolides. This group is present in some marine sponges and is believed to arise from 3-alkylfurans. This transformation can be realized in vitro by singlet oxygen oxidation in the presence of a hindered base such as ethyl-diisopropylamine. ... 

Being a diastereomer of 450 with respect to the configuration of the sulfur atom, 458 was liberated from the triflate 457 by ethyl diisopropylamine and trapped by furan (Scheme 6.93). The resulting [4+ 2]-cycloadduct 459 was isolated in 62% yield and is a diastereomer of 451 [155, 171b], Typical for virtually all furan adducts of six-membered cyclic allenes, 451 and 459 display the mdo-configuration with respect to the 7-oxanorbornene skeleton. 

The reaction of methyl ester of D-alanine 185 with 4-methoxy-2-nitrobenzenesulfonyl chloride 186 in presence of ethyl diisopropylamine gave the sulfonamide 187, which was alkylated with allyl bromide 188 to afford 189 (Scheme 41). Ozonolysis of 189 resulted in the formation of aldehyde 190, and the subsequent reductive cyclization with zinc and AcOH led to the benzothiadiazepine 120 through intramolecular reductive alkylation. Using similar reaction sequence, the 1,2,5-thiadiazepines 191 and 192 were also synthesized <2003JME1811>. 

Boron trifluoride diethyl etherate Sodium bicarbonate Palladium on charcoal Sodium periodate Hydroperoxide, 1,1-dimethylethyl Titanium tetraisopropoxide Ethyl diisopropylamine Triethylamine Ammonium sulfate Trimethylsilyl triflate d-3-oxo-a-D-gluco-pyranoside -oxo-a-D-erythro-hexopyranoside... 

A 3 M solution of t-butylhydroperoxide in toluene (0.042 ml, 0.12 mmol), titanium tetraisopropoxide (0.008 ml, 0.02 mmol) and ethyl diisopropylamine (0.014 ml, 0.08 mmol) were added to a stirred solution of 40 mg (0.074 mmol) of phenyl 4,6-di-0-benzoyl-2,3-dideoxy-3,3-difluoro-l-seleno-a-D-erythro-hexopyranoside in 4 ml of anhydrous dichloromethane at room temperature. The reaction was complete within 6 h, and the solvent was then evaporated to dryness and the residue was quickly purified by preparative TLC to give 20 mg (72%) of l,5-anhydro-4,6-di-0-benzoyl-2,3-dideoxy-3,3-difluoro-D-erythro-hex-l-enitol. 

Similarly, an intramolecular variant utilizing carbamates 26 derived from allylic alcohols has been developed using an amine like Hunigs base (ethyl diisopropylamine) as additive [21], The products were obtained with complete regio- and diastereocontrol, but surprisingly, only in racemic form when chiral ligands like (DHQ PHAL, being established for the AA, were employed. 

Fucoxanthin and its metabolites Egg yolk Normal phase, Silica gel column Acetone hexane gradient Normal phase, Silica gel column Hexane, Dichlormethane, 2-Propanol and Ethyl-diisopropylamine (90.9 7 3 0.1 v/v/v/v) isocratic Reverse phase, C18 column Methanol and Water (67 33 v/v) isocratic Bonded nitrile column Hexane, Isopropyl acetate, Acetone, Methanol (76 17 7 0.1 v/v/v/v) isocratic Strand et al., 1998... 

Triphenyl-pyrylium salts and ring substituted phenylnitromethane derivatives similarly rearrange to the phenols 6 or nitrobenzenes 7. When the ringsubstituted phenylnitromethane is reacted with the 2,4,6-arylated pyrylium salt in t-butanol with one mole of potassium t-butylate, 5 is the suspected intermediate. It rearranges to the phenol 6 when heated in 1,2-dichlorobenzene with one mole of ethyl-diisopropylamine and to the nitro compound 7 with an excess of potassium t-butylation in t-butanol (47-81 % yield l38). Some similar examples are shown in Table 1. 

Cossement et al. [9] s)nithesized the enantiomers of l-(p-chlorobenzhy-diyl)-4-(p-methylphenyl)sulfonyl piperazine 3 and used it as an intermediate for fhe preparation of buclizine 6 and other histamines. The enantiomers of (+)- and (—)-l-(p-chlorobenzhydryl)-4-(p-foluene sulfo-nyl)piperazine 3 were prepared and converted by hydrolysis to the enantiomers of (+)- or (—)- of p-chlorobenzhydryl piperazine 4. Compound 3 was prepared by refluxing p-chlorobenzhydrylamine 1 with N-bis-2-chloroethyl-p-toluene sulfonamide 2 with ethyl diisopropylamine. Reaction of p-ferf-bufylbenzyl chloride 5 wifh p-chlorobenzhydryl piperazine 4 gives buclizine 6. 

The procedure for the elimination of HBr from the dibromo ester is a modification of the method of Lawton and co-workers for sui generis generation of the methyl or ethyl ester during a reaction. Methyl a-(bromomethyl)acrylate has also been prepared by bromination of methyl methacrylate in 700°C steam and by dehydrohalogenation with sodium acetate in acetic acid. Ethyl a-(bromomethyl)acrylate has been prepared by dehydrohalogenation with the monosodium salt of ethylene glycoP and ethyl diisopropylamine." The latter reaction was reported by Ohler et al. with no experimental details for the elimination reaction. The use of triethylamine as reported in this procedure appears to be the most efficient and convenient method for dehydrobromination to these acrylate esters. 

Swern oxidation provided the intermediate dicarbonyl derivative 32, which spontaneously cyclized into cyclohexene 33 under the action of ethyl diisopropylamine in a 50% overall yield. The resulting unsaturated ketone was reduced, desilylated and hydrogenated to separately afford 5a-carba-a- and (3-L-idopyranose, as well as 5a-carba-a- and (3-L-glucopyranose [31]. 

Polymer 4A (15 g) was reacted with 4-chlo-romethylsalicylaldehyde (21 g, 123 mmol) in CHCl 3 (150 ml) at reflux for 24 hours (4-chlo-romethylsalicylaldehyde reacts with alcohols in refluxing CHCl3, in the presence of NEtj or NaHCOj (AD-357. 367) excess 4-chloro-methylsalicylaldehyde can be isolated after 3 days reaction with 4A, in CHCl3, with ethyl diisopropylamine (RS-lOO) consequently, Amberlyst A-21 (N, A-diethylpolybenzyl-... 

The conjugated thionium ylids are prepared by the Pummerer reaction of an allyl sulphoxide, with trimethylsilyl triflate in the presence of ethyl diisopropylamine, and give products of ketone allylation [equation (52)... 

Ring opening of l,3-thiazole-5(4ff)-one 91 with a-aminoalkyl esters 92 in the presence of 1-hydroxybenzotriazole and iV-ethyl diisopropylamine gives the endothiotripeptide 93 (Eq. 32) [54]. The starting compound 91 is prepared by the ( )-camphor-10-sulfonic acid-catalyzed cydization of endodipeptide.The reaction with 92, where a bulky alkyl group is introduced to the carbon atom... 

Acylation of alkenes. In the presence of a nonnucleophilic base e.g., ethyl-diisopropylamine), the reagent reacts with alkenes in CH2CI2 at -50 to -25° under kinetic control to form 3,y-unsaturated ketones in moderate to high yield. Examples ... 

C-Silylated cyclohexyl diazo esters can be prepared from the appropriate diazo acetates by treatment with TMSOTf and ethyl diisopropylamine in ether at -78 °C (eq A9) ... 

A series of aryl chloroformates 69, which are very unstable at room temperature, being readily decomposed by amines, acids, protic solvents, and atmospheric moisture, could be prepared with diphosgene and triphosgene in the presence of ethyl diisopropylamine (Table 4.3) [44]. 

The other amines listed in Table 1 also displayed unique resonances in the NMR. Although no acyl ammonium salt was observed for the very hindered N-ethyl diisopropylamine (entry 12), peak broadening of the methylene protons and the methine protons was again observed. The sterically unhindered amine, MeNEt2, reacts completely with phenyl chloroformate to form the acyl ammonium salt, and produces two nonequivalent sets of methylenes (multiplets at 4.98 ppm and 4.11 ppm) indicative of a single conformational isomer, unlike the triethylamine case. 

Use of these various amines in cyclization reactions produced results which correlated well with the NMR data. The extremely sterically hindered N-ethyl diisopropylamine, which produced no acyl ammonium salt by NMR, left the chloroformate virtually unreacted under standard cyclization reaction conditions. Although tributylamine does form acyl ammonium salts, it has an equilibrium constant nearly an order of magnitude lower than triethylamine when compared at the same temperatures (Table 1, entries 7 and 4). This amine produced cyclics, but required much higher catalyst loadings, similar to tripropylamine which was aphically represented in Figure 1. The equilibrium constant for N-ethylpiperidine was twice the value for triethylamine at similar temperatures (Table 1, entries 8 and 4), and affords an optimum yield of cyclics at half the amine concentration required for triethylamine. 

Hooz reaction of boranes with diazo compds. 24,817 Huang Minion rednctimi s. Wolff-Kishner Hiinig base s. Ethyl-diisopropylamine Hydantoin ring,... 

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