2-Butanone, condensation with diethyl

Another three-step synthesis of cerpegin (118) was described by Villemin and Liao (236). Condensation of 3-hydroxy-3-methyl-2-butanone (365) with diethyl malonate in the presence of cesium carbonate, and with Aliquat as... 

Fluorenylamine, 40,5 Formaldehyde, reaction with diethyl malonate to form diethyl bis-(hydroxymethyl)malonate, 40,27 Formamide, condensation with 4,4-dimethoxy-2-butanone to give 4-methylpyrimidine, 43, 77 Formic acid, and hydrogen peroxide, with indcne, 41, 53... 

The preparation of tebufenpyrad and tolfenpyrad (see below) are outlined in Scheme 28.3.4. The pyrazole ring is prepared from a Claisen condensation of 2-butanone with diethyl oxalate followed by treating the resulting acylpyruvate with hydrazine [45, 46]. The pyrazole ring is then alkylated with dimethyl sulfate at 50-60 °C without base to give, selectively, the l-methylpyrazole-5[Pg.893]

A. 2-Methyl-4-eihoxalylcyclopenlane-l,3,5-trione. A solution of sodium ethoxide is prepared in a 2-1. three-necked, round-bottomed flask fitted with a mercury-sealed stirrer, a reflux condenser carrying a drying tube, and a stopper by the addition of 69.0 g. (3 moles) of sodium to 950 ml. of absolute ethanol. The solution is cooled to 0-5° in an ice bath and stirred. The stopper is replaced by a dropping funnel, and a cold mixture (5-15°) of 108 g. (1.50 moles) of freshly distilled 2-butanone and 482 g. (3.30 moles) of diethyl oxalate (Note 1) is added gradually over a... 

Reaction of N-substituted bromomethanesulfonamides with 2 equiv of potassium carbonate and an cr-haloketone, ester, or nitrile leads directly to the /3-sultams 187 substituted at the C-3 position by an EWG. This base-promoted condensation can be used with a-halo ketones, esters, and nitriles where a second Sn2 intramolecular displacement can operate in tandem fashion (Scheme 60). This domino alkylation sequence exhibits a reactivity order where ketone > nitrile > ester (Table 14). The process is particularly efficient when diethyl bromomalonate or 3-chloro-2-butanone are involved <2004CJC113>. 

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