2-Methylacetoacetate

Alkyl ketones can be prepared by the carbonylation of alkyl iodides in the presence of organoboranes. The carbonylation of iodocyclohexane with 9-octyl-9-BBN at 1 atm gives cyclohexyl octyl ketone in 65% yield[386]. This reaction is treated in Section 1.1.3.3. Methyl o-methylacetoacetate (919) is obtained by the reaction of the 2-bromopropionate 918, which has a /9-hydrogen, with CO and Me4Sn. PhjAs as a ligand gives better results than Ph3P[771]. 

Most methods used for the production of the commercially important a-amino penicillins, such as ampicillin and amoxicillin, are based on modifications of an enamine process employing the appropriate phenylglycine and methylacetoacetate followed by coupling with 6-APA (64). Other aspects of the fermentation, strain maintenance, equipment, inoculum development, media, and procedures used in the production of penicillin are well covered in previous editions of the Enyclopedia. Developments in these areas have been reviewed (65). 

Earlier reported syntheses have been shown to give isoxazolin-5-ones. Other isoxazolin-3-ones have been prepared by the reaction of methylacetoacetic esters and hydroxylamine. An additional synthesis was reported by the action at 0°C of hydroxylamine on ethyl -benzoylpropionate to produce an insoluble hydroxamic acid which cyclized on acid treatment. The hydroxamic acid acetal was similarly transformed into the isoxazolin-3-one (Scheme 149) (71BSF3664, 70BSF1978). 

Hydroxy-2-methyl-4//-pyrido[l,2-n]pyrimidin-4-one was prepared in the reaction of 2-amino-3-benzyloxypyridine and ethyl acetoacetate at 60 °C, then at 100 °C for 3 h in 22% yield (96MIP1). Reaction of 2-amino-3-hydroxypyridine and ethyl 2-methylacetoacetate in a 1 2 mixture of... 

Cas/liquid reaction 5 [CL 5] Fluorination of ethyl 2-methyl-3-oxobutanoate (ethyl-2-methylacetoacetate) [16]... 

The same complex functions as the catalyst in the Rhone-Poulenc process (Mercier and Chabardes, 1994) for the manufacture of the vitamin A intermediate geranylacetone, via reaction of myrcene with methylacetoacetate in a biphasic system (Fig. 2.28). 

Catalytic asymmetric hydrogenation is a relatively developed process compared to other asymmetric processes practised today. Efforts in this direction have already been made. The first report in this respect is the use of Pd on natural silk for hydrogenating oximes and oxazolones with optical yields of about 36%. Izumi and Sachtler have shown that a Ni catalyst modified with (i ,.R)-tartaric acid can be used for the hydrogenation of methylacetoacetate to methyl-3-hydroxybutyrate. The group of Orito in Japan (1979) and Blaser and co-workers at Ciba-Geigy (1988) have reported the use of a cinchona alkaloid modified Pt/AlaO.i catalyst for the enantioselective hydrogenation of a-keto-esters such as methylpyruvate and ethylpyruvate to optically active (/f)-methylacetate and (7 )-ethylacetate. 

Methyl monoethyl malonate and 2-methylacetoacetic acid, however, did not give definite condensation products. 

Figure 1.18 STM image (4 nm x 4 nm) showing the 2D cocrystalline structure consisting of an ordered array of 1 1 H-bonded complexes of (R,R)-tartrate and methylacetoacetate species on Ni l 1 1 givingachiral (3 11-3 4) structure. (Adapted with permission from Ref. [62], Copyright 2002, Elsevier.)...

Effects of Ethyl 2-Methylacetoacetate (EMA) on the Algal Antioxidant Enzymes Activity 150... 

In our previous research, we found that the antialgal allelochemical Ethyl 2-Methylacetoacetate (EMA) caused loss of cell membrane integrity. It hinted that EMA may cause a change in the membrane. It is reported that environmental stress may increase the concentration of ROS in plant cell. The excessive ROS may cause a decrease of antioxidation enzymes activity and lipid peroxidation. The effect of EMA on the activity of SOD and POD and lipid fatty acids of Chlorella pyrenoidosa, Chlorella vulagaris and Microcystis aeruginosa were evaluated to elucidate the mode of action of EMA. 

Plant. In plants, mevinphos is hydrolyzed to phosphoric acid dimethyl ester, phosphoric acid, and other less toxic compounds (Hartley and Kidd, 1987). In one day, the compound is almost completely degraded in plants (Cremlyn, 1991). Casida et al. (1956) proposed two degradative pathways of mevinphos in bean plants and cabbage. In the first degradative pathway, cleavage of the vinyl phosphate bond affords methylacetoacetate and acetoacetic acid, which may be precursors to the formation of the end products dimethyl phosphoric acid, methanol, acetone, and carbon dioxide. In the other degradative pathway, direct hydrolysis of the carboxylic ester would yield vinyl phosphates as intermediates. The half-life of mevinphos in bean plants was 0.5 d (Casida et ah, 1956). In alfalfa, the half-life was 17 h (Huddelston and Gyrisco, 1961). 

Di-/ -butyl phthalate 4-Methylacetanilide, p-Toluidine Methyl acetate, see Methvl tert-butvl ether Methylacetoacetate, see Mevinphos o-Methylacetophenone, see o-Xylene /n-Methylacetophenone, see ro-Xylene p-Methylacetophenone, see p-Xylene... 

Methyl Ethyl Ketone. 1 mole (20 g) of methylacetoacetic ester are refluxed with 250 cc of baryta water (saturated) until the oily layer disappears. Distill on a water bath to 90°. Stir violently or shake for three hours with a saturated solution of sodium bisulfate, and collect the crystals and distill with an excess of dilute sulfuric acid at 90°. The distillate is dried over calcium chloride and distilled again, retaining the fraction at 79-82°. Yield 70% theoretical (7 g). 

Similar investigations were reported by this group using /S-oxoesters as the precursors to be aminated products in the presence of CaO and 3n as amination reagent . Ethyl acetoacetate gave a-monoaminated and a-bisaminated products (Scheme 35) depending on the substrate base ratio. An A-aminated product was also obtained in the amination of ethyl a-methylacetoacetate. 

Nitrosohydroxylamino)-1-propanoic Acid or a-lsonitraminopropionic Acid a-[Nitroso-hydroxylamino] -propionsaure or a-Isonitra-mino-propionsaure HO.N(NO).CH(CH3 ).COOH mw 134.09, N 20.89%. It is stable only in solns. May be prepd by warming with soda the crude soln obtained by the action of nitric oxide on ethylic methylacetoacetate, until the alcohol is driven off the acid is then precipitated as the Lead Salt, PbC3H4N204, which is explosive Refs 1) Beil 4, 576 2) W. Traube, Ber 28,... 

Ethyl orthoacetate, 48 Ethyl orthobenzoate, 54 Ethyl orthobromoacetate, 60 Ethyl orthodibromoacetate, 60 Ethyl orthoformate, 50 Ethyl orthothioformate, 50 Ethyl a-phenylazo-a-methylacetoacetate, 299... 

In the recent patent literature a procedure is given for coupling a diazonium salt with ethyl a-methylacetoacetate to afford an azo compound which could be used as an acetylating agent because its acetyl group was readily cleaved under mild conditions [26], In the coupling reaction, relatively weak bases such as pyridine, picolines, quinoline, and collidine are said to be effective. The example is given here for illustration only. It is to be noted that this is a composition of matter patent. 

Most methods used for the production of the commercially important or-amiuo penicillins, such as ampicillin and ainuxicillin, are based on modifications of an enamine process employing the appropriate phenylglycine and methylacetoacetate followed by coupling with 6-APA. 

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