Diethyl dicarbonate

Chromium(II) chloride, 4052 Cyclohexanone oxime, 2452 l,4-Dicyano-2-butene, 2311 Diethyl dicarbonate, 2444 Diethyl sulfate, Iron, Water, 1710 (Difluoroamino)difluoroacetonitrile, Hydrazine, 0630 Difluoroammonium hexafluoroarsenate, 0098 1,1-Difluorourea, 0398 Dihydroxymaleic acid, 1447 f Diketene, Acids, or Bases, or Sodium acetate, 1441 /V. /V-Dimcthylacctamidc. 1656... 

Di- jjL-carbonylhexacarbonyldicobalt, 99 Diethyl dicarbonate, 110 Carbomethoxylation Palladium(II) acetate-Triphenylphos-phine, 233... 

Ethylpyridine-4-carbothioamide, 2976 Ethyl pyrocarbonate, see Diethyl dicarbonate, 2438 Ethyl sodioacetoacetate, 2398 Ethylsodium, 0873... 

Gejvall [114] analysed low-molecular-weight amines in the form of urethanes produced by their reaction with diethyl dicarbonate (Scheme 5.12). The reaction can be carried out in aqueous solution. A 10-mg amount of diethyl dicarbonate was allowed to react with 0.05—0.7 mg of the amine at room temperature for 30—40 min, the pH being adjusted to 9.5 with NaOH. A good separation with symmetric peaks was obtained by using SE-30 as the stationary phase. 

In general, lower reaction temperatures are used to increase selectivity and to avoid side reactions. The reaction of cyclohexanone with diethyl dicarbonate (18) led to the O-acylated product 19 at —78°C (Figure 5.7), with the C-acylated product 20 being produced at about 80°C [17]. Cooling a lipase-mediated esterification to — 40°C enriched the product ester 21 to 97% ee (Figure 5.7) [18]. Reaction rates slow with decreasing temperatures, and the rule of thumb is that increasing the reaction temperature by 10°C will usually double the reaction rate. 

Hellou,J. Kingston, J. F. Fallis, A. G., Diethyl Dicarbonate A Convenient Reagent for the Preparation of P-Ketoesters. Synthesis 1984,1014. 

A variety of reagents will effect the conversion C(XTH2 - C(XrHC02R the decarbonylation of glyoxalate esters was described above. The most recently described reagent, methyl cyanoformate, reported by Mander and Sethi in 1983, allows the conversion of a preformed lithium enolate to the 3-keto ester in high yield (Scheme 68). Diethyl dicarbonate with potassium hydride in benzene effects the same reaction wiA symmetrical ketones, and with lithium dicyclohexylamide in ether introduces the ethoxycarbonyl group into the a -position of a,3-unsaturated ketones (Scheme 69)."" Diethyl carbon-... 

N-(l-Alkoxyalkyl)-aniides or -carbamates (2 X = OR), most frequently used as stable precursors for A -acyliminium ions, are usually prepared by one of the following routes (equations 7-13). For five- or six-membered cyclic cases a simple acid-catalyzed solvolysis of the hydroxy compound provides the alk-oxy derivative (equation 7). A silicon-assisted approach involves the TMSOTf-catalyzed reaction of bis(trimethylsilyl)formamide with aldehydes (equation 8). /V-(l-Trimethylsilyloxyalkyl)formamides are thus formed in good yields, which on TMSOTf-catalyzed solvolysis lead to the /V-( 1-alkoxyalkyl)form-amides. A third method is based on the NaBH4 reduction of imidates (equation 9), and has proved useful for a total synthesis of the insect poison pederine. Addition of reactive acid derivatives to imines constitutes another method (equations 10 and 11). Acylation with acid chlorides followed by treatment with ethanol in the presence of base leads to N-(l-alkoxyalkyl)amides. A one-step protocol using diethyl dicarbonate provides the corresponding carbamates. 2... 

Diethyl dicarbonate Pyrocarbonic acid diethyl ester CeHioOs 1609-47-8 162.140 93 1.120 1.3960 vs ace, EtOH, lig... 

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