Triethylamine 1,1-dimethyl

Dimethyl sulfoxide Methyl sulfoxide (8) Methane, sulfinylbis- (9) (67-68-5) N,N-Diisopropylethylamine Triethylamine, 1,1 -dimethyl- (8) 2-Propanamine, N-ethyl-N-(1-methylethyl)- (9) (7087-68-5)... 

ETHYL ESTER (10601-80-6), 69, 238 Ethyldiisopropylamine Triethylamine, 1,1 -dimethyl- (7087-68-5), 68, 162 Ethyl 2-(diphenylmethylsilyl)decanoate Decanoic acid, 2-(methyldiphenylsilyl)-, ethy ester (89638-16-4), 67, 125 Ethylene, 69, 144 Ethylenediamine, 69, 33... 

Auch organische Basen (z. B. Triethylamin, Dimethyl-pyridine) konnen als Saureakzepto-ren verwendet werden. Die Reaktionen werden in Toluol, Benzol, Diethylether oder Te-trachlormethan durchgefuhrt5S 5s4 z.B. ... 

Triethylamine, dimethyl malonate, and rhodium(ll) acetate dimer were purchased from Aldrich Chemical Company, Inc., and used without further purification. 

A variety of sulfating agents has been used for preparing sulfuric esters of polysaccharides. " The methods employed include use of adducts of sulfur trioxide with such aprotic solvents as triethylamine, dimethyl... 

The octahedral dipyridyl Rh(III) complexes 9a-c (Scheme 2) were shown to be stable in solution for extended periods of time. Attempts to promote the back reaction (reductive elimination) by the addition of hard ligands such as triethylamine, dimethyl sulfoxide, or NA -dimethylaminopyridine were unsuccessful. This observation was rationalized in terms of hard/soft acid base theory. The resulting soft Rh(I) species would be unstable when coordinated to hard ligands. 

Water reducible, or water thinnable, synthetic polymers are usually acidic, typically containing carboxyl groups built into the polymer chain. These require neutralisation with a base, with ammonia, triethylamine, dimethyl aminoethanol being typical, and often the use of cosolvents, such as glycol ethers, to produce complete compatibility with water. 

THF, tetrahydrofuran DMSO. dimethylsulfoxide TEA, triethylamine DMF. dimethyl-formamid. 

Certain base adducts of borane, such as triethylamine borane [1722-26-5] (C2H )2N BH, dimethyl sulfide borane [13292-87-OJ, (CH2)2S BH, and tetrahydrofuran borane [14044-65-6] C HgO BH, are more easily and safely handled than B2H and are commercially available. These compounds find wide use as reducing agents and in hydroboration reactions (57). A wide variety of borane reducing agents and hydroborating agents is available from Aldrich Chemical Co., Milwaukee, Wisconsin. Base displacement reactions can be used to convert one adduct to another. The relative stabiUties of BH adducts as a function of Group 15 and 16 donor atoms are P > N and S > O. This order has sparked controversy because the trend opposes the normal order estabUshed by BF. In the case of anionic nucleophiles, base displacement leads to ionic hydroborate adducts (eqs. 20,21). 

With l,3-dimethyl-2,l-benzisoxazolium salts, however, considerable reactivity has been reported. Condensation occurs readily with aldehydes, ketones, orthoesters and diazonium salts to yield styryl, cyanine and azo compounds, respectively (78JOC1233). In the presence of triethylamine, dimerization was observed, and the reactions of the cation were considered to involve the intermediacy of the anhydro base (77JOC3929). 

The reaction of tertiary alkylthioenyne alcohols (205) with carbon dioxide [70-73 atm, 70-75°C, Cu(I) salts, triethylamine] leads to 4,4-dimethyl-5-(alkyl-thioethenylmethylene)-l,3-dioxolan-2-ones (206) (79KGS1617 79ZOR1319). 

Upon addition of a base—triethylamine is often used—the sulfonium salt 7 is deprotonated to give a sulfonium ylide 8. The latter decomposes into the carbonyl compound 2 and dimethyl sulfide 9 through /3-elimination via a cyclic transition state. 

Aminobenzenethiol undergoes a Michael reaction with methyl 5,5-dimethyl-2-oxo-2,5-dihyd-rofuran-3-carboXylate (4) to give the adduct 5, which cyclizes to the tricyclic benzothiazepinone 6 under the influence of triethylamine hydrochloride.426... 

When 2,2-dimethylpropanal is used to prepare the azomethine moiety, the corresponding azaallyl anion may be obtained when l,8-diazabicyclo[5.4.0]undec-7-ene/lithium bromide is used as base. The subsequent addition to various enones or methyl ( )-2-butenoate proceeds with anti selectivity, presumably via a chelated enolate. However, no reaction occurs when triethylamine is used as the base, whereas lithium diisopropylamide as the base leads to the formation of a cycloadduct, e.g., dimethyl 5-isopropyl-3-methyl-2,4-pyrrolidinedicarboxylate using methyl ( )-2-butenoate as the enone84 89,384. 

A one-pot synthesis of thiohydantoins has been developed using microwave heating [72]. A small subset of p-substituted benzaldehydes, prepared in situ from p-bromobenzaldehyde by microwave-assisted Suzuki or Negishi reactions, was reacted in one pot by reductive amination followed by cyclization with a thioisocyanate catalyzed by polystyrene-bound dimethyl-aminopyridine (PS-DMAP) or triethylamine, all carried out under microwave irradiation, to give the thiohydantoin products in up to 68% isolated yield (Scheme 16). 

N-silylated imines 509 react with the Li salts of tosylmethylisonitriles to give 4,5-disubstituted imidazoles in moderate yields [93]. Acetylation of N-trimethylsilyl imines 509 with acetyl chloride and triethylamine affords 72-80% of the aza-dienes 510 these undergo readily Diels-Alder reactions, e.g. with maleic anhydride at 24 °C to give 511 [94] or with dimethyl acetylenedicarboxylate to give dimethyl pyridine-3,4-dicarboxylates [94] (Scheme 5.29). 

N,N-Bis(trimethylsilyl)carbodiimide 328, which is readily accessible in 81% yield on silylation of cyanamide with TCS 14/triethylamine [124] and which is apparently in equilibrium with N,N-bis(trimefhylsilyl)cyanamide 553, reacts readily with non-enolizable ketones such as 554 or 2,5-dimethyl-p-quinone in the presence of CsF or TiCL., probably via 553, to N-cyanoimines such as 555 or 556, in 47 and 89% yield, respectively, and HMDSO 7 [125, 126] whereas the enohzable ketone... 

Substituted pyrimidine N-oxides such as 891 are converted analogously into their corresponding 4-substituted 2-cyano pyrimidines 892 and 4-substituted 6-cya-no pyrimidines 893 [18]. Likewise 2,4-substituted pyrimidine N-oxides 894 afford the 2,4-substituted 6-cyano pyrimidines 895 whereas the 2,6-dimethylpyrimidine-N-oxide 896 gives the 2,6-dimethyl-4-cyanopyrimidine 897 [18, 19] (Scheme 7.6). The 4,5-disubstituted pyridine N-oxides 898 are converted into 2-cyano-4,5-disubsti-tuted pyrimidines 899 and 4,5-disubstituted-6-cyano pyrimidines 900 [19] (Scheme 7.6). Whereas with most of the 4,5-substituents in 898 the 6-cyano pyrimidines 900 are formed nearly exclusively, combination of a 4-methoxy substituent with a 5-methoxy, 5-phenyl, 5-methyl, or 5-halo substituent gives rise to the exclusive formation of the 2-cyanopyrimidines 899 [19] (Scheme 7.6). The chemistry of pyrimidine N-oxides has been reviewed [20]. In the pyrazine series, 3-aminopyrazine N-ox-ide 901 affords, with TCS 14, NaCN, and triethylamine in DMF, 3-amino-2-cyano-pyrazine 902 in 80% yield and 5% amidine 903 [21, 22] which is apparently formed by reaction of the amino group in 902 with DMF in the presence of TCS 14 [23] (Scheme 7.7) (cf. also Section 4.2.2). Other 3-substituted pyrazine N-oxides react with 18 under a variety of conditions, e.g. in the presence of ZnBr2 [22]. 

In this work, various Ru-BINAP catalysts immobilized on the phosphotungstic acid(PTA) modified alumina were prepared and the effects of the reaction variables (temperature, H2 pressure, solvent and content of triethylamine) on the catalytic performance of the prepared catalysts were investigated in the asymmetric hydrogenation of dimethyl itaconate (DMIT). 

Derivatives are prepared from the appropriate acid anhydride, or occasionally the acid chloride, usually in the presence of a base such as pyridine, triethylamine, or N,N-dimethyl-4-amlnopyridine at elevated temperatures [474-482]. Acylation of amines and phenols (not alcohols) in aqueous solution in the presence of potassium carbonate has been demonstrated (448,483,484), but does not constitute m l practice as reactions are generally performed under i Arous conditions. 

Materials and Purification. Chemicals were purchased from Aldrich chemical company and used as received unless otherwise noted 1,1,1,3,3,3-hexamethyl disilazane, ethylene glycol, triphosgene, poly(ethylene oxide) (MW = 600), poly(tetramethylene oxide) (MW = 1000), poly(caprolactonediol) (MW = 530), toluene diisocyanate (TDI), anhydrous ethanol (Barker Analyzed), L-lysine monohydride (Sigma) and methylene bis-4-phenyl isocyanate (MDI) (Kodak). Ethyl ether (Barker Analyzer), triethylamine and dimethyl acetamide were respectively dried with sodium, calcium hydride and barium oxide overnight, and then distilled. Thionyl chloride and diethylphosphite were distilled before use. 

It is interesting to note that [(E)-2-phenylethenyl]-[018]phosphonic dichloride (116) upon treatment with (-)-ephedrine (42) in the presence of triethylamine afforded an equimolar mixture of (2S,4S,5R)- and (2/ ,4S, 5/ )-2,3-dimethyl-5-phenyl-2-[(E)-2-phenylethenyl]-l,3,2-oxazaphospholidin-2-[180]one 117a and 117b. The two diastereomers were completely separated by flash chromatography and the diastereomer 117b was hydrolyzed with water H20-170 to the corresponding monoester 118 which was finally converted to dihydro-(l,2-dibromo-2-phenyl- 1-ethyl) (R)-160,170,180 phosphonic acid 119 (Scheme 33) [66],... 

C. Methyl 3,3-dimethyl-4-oxobutanoate (3). A 50-mL flask, connected to a gas bubbler and equipped with a magnetic stirring bar, is charged with 20 mL of dichloromethane (or tetrahydrofuran), 2.16 g (10.0 mmol) of siloxycyclopropane 2 and 3.64 g (30.0 mmol) of triethylamine hydrofluoride (NEt3-HF) prepared in situ (Note 15). This mixture is stirred for 1 hr at room temperature (Note 16) and diluted with 20 mL of water. The aqueous phase is extracted with three 20-mL portions of dichloromethane. The combined organic phases are dried with magnesium sulfate, filtered, and concentrated on a rotary evaporator (bath temperature below 40°C). Crude product 3 is distilled with a Kugelrohr oven (oven temperature 105°C, 10 mm) to provide 1.26 g (87%) of pure 3 as a colorless liquid (Note 17). 

Besides the use of porphyrins as azomethinic ylide derivatives, the porphyrin macrocycle can also be used to generate porphyrinic nitrile oxides 55 (Scheme 17) <04RCB(E)2192>. Thus, the treatment of oxime 54 with /V-bromosuccinimide in the presence of triethylamine, led to the formation of nitrile oxide 55, which was trapped in 1,3-DC reactions with dimethyl maleate and 2,5-norbomadiene to afford 56 and 57, respectively. In the reaction with 2,5-norbomadiene, if an excess of 55 was used, then the corresponding bis-adduct was obtained in good yield. 

The groups of Giacomelli and Taddei have developed a rapid solution-phase protocol for the synthesis of 1,4,5-trisubstituted pyrazole libraries (Scheme 6.194) [356]. The transformations involved the cyclization of a monosubstituted hydrazine with an enamino-/8-ketoester derived from a /8-ketoester and N,N-dimethylformamide dimethyl acetal (DMFDMA). The sites for molecular diversity in this approach are the substituents on the hydrazine (R3) and on the starting j3-keto ester (R1, R2). Subjecting a solution of the /8-keto ester in DMFDMA as solvent to 5 min of microwave irradiation (domestic oven) led to full and clean conversion to the corresponding enamine. After evaporation of the excess DMFDMA, ethanol was added to the crude reaction mixture followed by 1 equivalent of the hydrazine hydrochloride and 1.5 equivalents of triethylamine base. Further microwave irradiation for 8 min provided - after purification by filtration through a short silica gel column - the desired pyrazoles in >90% purity. 

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