Butyl acetoacetate

Submitted by Sven-Olov La wesson, Sitsanne Grohwall, and Rone Sandberg.  

CautionI This preparation should be conducted in a hood to avoid exposure to diketene, which is toxic and which may irritate mucous tissues such as those of the eyes the use of safety goggles is recommended. 

A 500-ml. three-necked flask is equipped with a sealed mechanical stirrer, a dropping funnel, and a two-armed addition tube, one arm of which bears a reflux condenser and the other arm of which is fitted with a thermometer. /erl-Butyl alcohol (79 g., 1.07 moles) (Note 1) is added to the flask and the thermometer arranged so that its bulb is immersed in the liquid but out of the path of the stirrer. The flask is heated by means of an electric mantle until the temperature of the liquid is 80-85, and the mantle then is removed. Anhydrous sodium acetate (0.4 g., 4.8 mmoles) is added with stirring, and then 96 g. (1.14 moles) of diketene (Note 2) is added dropwise over a period of 2.5 hours. The temperature of the solution drops to 60-70° during the first 15 minutes and then increases slowly to 110-115°. When all the 

Eastman Kodak white label grade is used without further purification. 

The submitters used material directly as supplied by Dr. Theodor Schuchardt and Co., Munich, Germany. The checkers used material directly as supphed by Aldrich Chemical Co., Milwaukee, Wisconsin. 

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The Ramberg-Backlund reaction has been utilized for the preparation of polyenes. 1,3-Butadienyl allyl sulfones 398 and 399 were transformed into the tri- and tetra-enes 400 and 401 by alkylcuprate addition and the Ramberg-Backlund-type S02 extrusion449. Julia and coworkers450 carried out the Michael addition of various nucleophiles such as ethanol, t-butyl acetoacetate and phenyl thioacetone to allyl dienyl sulfones 402 and then converted them to diallyl sulfones 403. The sulfones were transformed into isoprenoid, 404 by the Ramberg-Backlund reaction. 

C12H22O, 38965-26-3) see Dexamethasone ten-butylacetate Triamcinolone hexacetonide tert-butyl acetoacetate... 

The diazo transfer reaction between p-toluenesulfonyl azide and active methylene compounds is a useful synthetic method for the preparation of a-diazo carbonyl compounds. However, the reaction of di-tert-butyl malonate and p-toluenesulfonyl azide to form di-tert-butyl diazomalonate proceeded to the extent of only 47% after 4 weeks with the usual procedure." The present procedure, which utilizes a two-phase medium and methyltri-n-octylammonium chloride (Aliquat 336) as phase-transfer catalyst, effects this same diazo transfer in 2 hours and has the additional advantage of avoiding the use of anhydrous solvents. This procedure has been employed for the preparation of diazoacetoacetates, diazoacetates, and diazomalonates (Table I). Ethyl and ten-butyl acetoacetate are converted to the corresponding a-diazoacetoacetates with saturated sodium carbonate as the aqueous phase. When aqueous sodium hydroxide is used with the acetoace-tates, the initially formed a-diazoacetoacetates undergo deacylation to the diazoacetates. Methyl esters are not suitable substrates, since they are too easily saponified under these conditions. 

Butyl acetoacetate may be prepared from /-butyl alcohol and diketenc.4 The checkers obtained this material from Eastman Chemical Products, Inc. 

In a second Schlenk tube were placed under nitrogen tert-butyl acetoacetate and dry 2-propanol (14 mL). The mixture was degassed and added to the first solution. Finally, degassed potassium 2-propylate solution (1 mL) was added. The resulting orange solution was stirred at room temperature. 

Asymmetric [2 + 2] photocycloadditions. Acid-catalyzed condensation of t-butyl acetoacetate with (— )-menthone (1) results in two dioxacyclohexenones, 2 and 3, which are easily separable. Photocycloaddition of ( — )-2 with methylcyclo-butene gives mainly the adduct (4) which has the cis, anti, cis-configuration at the... 

Further proof that isoleucine has this constitution was given by Bouveault and Locquin in 1906. They synthesised it from sec. butyl-acetoacetic ester, which they prepared from sec. butyliodide and sodium-acetoacetic ester —... 

An improvement in this synthesis results from the use of the thallium salt of f-butyl acetoacetate in place of ethyl acetoacetate, and ethyl methylmalonyl chloride may replace the diacyl dihalide (75S259). 

Similar reactions of diethylaminosulfur trifluoride take place with 2,4-pentanedione (acetylacetone), with butyl acetoacetate, and with ethyl 3-oxooctanoate, giving the corresponding difluoro compounds as E/Z mixtures in the ratio of 1 1 [9]. 

The spectrum of terf-butyl acetoacetate (Figure 13-17) shows three types of protons the ferf-butyl protons (a), with a chemical shift of 8 1.5 the methyl protons (b), deshielded by an adjacent carbonyl group, with a chemical shift of 8 2.25 and the methylene protons (c), deshielded by two adjacent carbonyl groups, at 63.35. 

Draw the integral trace expected for the NMR spectrum of fcrf-butyl acetoacetate, shown in Figure 13-17. 

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