Dialkylamide

An extension of these calculations to cationic dialkylamide salts required an even more complex model [Adolf et al. 1995]. These molecules have the general formula (CH3)2N [(CH2) iCH3][(CH2)m-iCH3]CK and the isomer with m = m = 18 is one of the main active ingredients in commercial fabric softeners. The presence of two long alkyl... 

Alkyllithium bases are generally less suitable for deprotofiation of compounds with strongly electron-withdrawing groups such as C=0, COOR and CsN. In these cases lithium dialkylamides, especially those with bulky groups (isopropyl, cyclohexyl), are the reagents of choice. They are very easily obtained from butyllithium and the dialkylamine in the desired solvent. 

Ester enolates generated by proton abstraction with dialkylamide bases add to aldehydes and ketones to give (3 hydroxy esters... 

Lithium dialkylamides are excellent bases for making ketone enolates as well Ketone enolates generated m this way can be alkylated with alkyl halides or as illus trated m the following equation treated with an aldehyde or a ketone... 

Complexes. In common with other dialkylamides, highly polar DMAC forms numerous crystalline solvates and complexes. The HCN—DMAC complex has been cited as an advantage ia usiag DMAC as a reaction medium for hydrocyanations. The complexes have vapor pressures lower than predicted and permit lower reaction pressures (19). 

Acylation. Aliphatic amine oxides react with acylating agents such as acetic anhydride and acetyl chloride to form either A[,A/-diaLkylamides and aldehyde (34), the Polonovski reaction, or an ester, depending upon the polarity of the solvent used (35,36). Along with a polar mechanism (37), a metal-complex-induced mechanism involving a free-radical intermediate has been proposed. 

The most useful general method for the C-acylation of pyrroles is the Vilsmeier-Haack procedure in which pyrrole is treated with the phosphoryl chloride complex (55a, b) of an AiA-dialkylamide (54). The intermediate imine salt (56) is hydrolyzed subsequently under mildly alkaline conditions to give the acylated pyrrole (57). On treatment of the imminium salt (56 R =H) with hydroxylamine hydrochloride and one equivalent of pyridine and heating in DMF, 2-cyanopyrrole (58) is formed (80CJC409). 

The nonsymmetrie dimethylhydrazine adds exelusively to the triple bond of the ynaminoketones (70-75°C, THF, CH2CI2, 3 h) to form A,A-dialkylamides of 3-oxobutanohydrazonie aeid, whieh exist in solution as a tautomerie mixture of the hydrazonie (371) and enhydrazinie (372) forms, yields 49-54% (87ZOR1635). 

The deprotonation of the (1-oxopropyl) group of these compounds is achieved either by treatment with lithium dialkylamides or by the use of dialkylboron triflates in the presence of trialkylamines. In each case, exclusive generation of the corresponding (Z)-cnoiate results. 

A further improvement utilizes the compatibility of hindered lithium dialkylamides with TMSC1 at —78 °C. Deprotonation of ketones and esters with lithium dialkylamides in the presence of TMSC1 leads to enhanced selectivity (3) for the kinetically generated enolate. Lithium t-octyl-t-butyl-amide (4) appears to be superior to LDA for the regioselective generation of enolates and in the stereoselective formation of (E) enolates. 

To a solution of the lithium dialkylamide (1.1 mmol) in THF (2 ml) cooled to -78°C was added a solution to TMSC1 (5-10mmoI) in THF (2ml), also cooled to -78 °C. This was followed by dropwise addition of the carbonyl compound (lmmol) in THF (2ml). After lmin, triethylamine (2ml) was added, followed by quenching with saturated sodium hydrogen carbonate solution. The product was extracted into pentane, and these extracts were... 

Lithium bis(trimethylsilyl)cuprate, 29. 52 Lithium dialkylamides, 100 Lithium l-(dimethylamino)naphthalenide (LDMAN), 68,69,77 Lithium dimethylcopper, 131 Lithium hexamethyldisilazide, 73, 78 Lithium t-octyl-t-butylamide, 100 2.6-Lutidine, 93. 94... 

Das wenig selektive Lithiumalanat reduziert nur aktivierte Carbonsaure-amide mit gu-ten Ausbeuten zu Aldehyden. Fiir einfache Dialkylamide miissen selektivere Hydride eingesetzt werden. Besonders geeignet ist die Kombination eines aktivierten Carbonsau-re-amids mit einem selektiven Hydrid. 

The reaction of the chloride with nitrogen has also been used.P lPO] Lower deposition temperature is possible by MOCVD via the pyrolysis of a dialkylamide at 500-800°C.PO... 

Homoleptic lanthanide(III) tris(amidinates) and guanidinates are among the longest known lanthanide complexes containing these chelating ligands. In this area the carbodiimide insertion route is usually not applicable, as simple, well-defined lanthanide tris(alkyls) and tris(dialkylamides) are not readily available. A notable exception is the formation of homoleptic lanthanide guanidinates from... 

The microgels could be conveniently isolated by precipitation as white powders, readily redispersable in many different organic solvents such as dialkylamides, nitriles, dichloromethane, acetone and THF. Further to this, the DMAA-based microgels exhibited a rather amphiphilic character and were also soluble in water and in alcohols such as methanol or ethanol in contrast, their counterparts based on MMA turned out to be more lipophilic and therefore insoluble in water and alcohols but soluble in organic solvents of low polarity such as toluene. 

Furthermore, the injection of organic aromatic solvents and soaking is a feasible method to remove the precipitates [924]. The precipitation of asphalt from crude oil can be reduced by adding an N,N-dialkylamide of a fatty acid [1525,1527]. When asphaltenes are precipitated out, they can be removed from the walls of a well, pipeline, and so forth by washing with a hydrocarbon solvent. However, it has been shown that isopropyl benzoate is exceptionally useful as a solvent for asphaltene removal [1583]. 

Compositions of a N,N-dialkylamide of a fatty acid in a hydrocarbon solvent and a mutual oil-water solvent are useful for the prevention of sludge formation or emulsion formation during the drilling or workover of producing oil wells [1526,1528,1529]. 

J. Romocki. Application of N,N-dialkylamides to reduce precipitation of asphalt from crude oil. Patent WO 9418430,1994. 

J.Romocki. Application ofN,N-dialkylamides to control the formation of emulsions or sludge during drilling or workover of producing oil weUs. Patent WO 9522585,1995. 

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