Ketones ethyl 2- propanoate

A) Propanol B) Dimethyl ether C) Acetone D) Ethyl methyl ketone E) Propanoic acid... 

The ease with which alcohols are oxidized to aldehydes, ketones, or carboxylic acids (depending on the alcohol that you start with and the conditions that you employ), coupled with the ready availability of alcohols, provides the pathway necessary to many successful s)mthetic transformations. For example, let s develop a method for synthesizing ethyl propanoate, using any inorganic reagent you wish but limiting yourself to organic alcohols that contain three or fewer carbon atoms ... 

The enolates of other carbonyl compounds can be used in mixed aldol condensations. Extensive use has been made of the enolates of esters, thioesters, and amides. Of particular importance are several modified amides, such as those derived from oxazolidinones, that can be used as chiral auxiliaries. The methods for formation of these enolates are similar to those for ketones. Lithium, boron, tin, and titanium derivatives have all been used. Because of their usefulness in aldol additions and other synthetic methods (see especially Section 6.4.2.3, Part B), there has been a good deal of interest in the factors that control the stereoselectivity of enolate formation from esters. For simple esters such as ethyl propanoate, the E-enolate is preferred under kinetic conditions using a strong base such as EDA in THE solution. Inclusion of a... 

Ester enolates usually exist as mixtures oiE- andZ-isomers (see Chapter 9, Section 9.4.3). An example is the enolate anion generated from ethyl propano-ate, where the two priority groups (see Chapter 9, Section 9.3.1) of the C=C unit are the methyl group on one sp carbon and the OEt group on the other sp carbon atom. When the priority groups are on opposite sides, as in 64, this is an E-enolate anion. The other enolate anion is 65, the Z-isomer. Methods are available for the reaction that will lead to selectivity in the formation of E- or Z-isomers, but those methods are not discussed. Assume that both 64 and 65 are present in the reaction. Assume also that formation of this mixture has no influence on the subsequent reaction. This is not entirely correct because there may be stereochemical issues in the product, but it simplifies the fundamental concepts. As mentioned in Section 22.4.2, enolate anions from ketones may also exist as E- and Z-isomers. Enolate anion 39 in that section is drawn as the Z-isomer, but both are formed. 

Once an ester enolate is generated, it can react with another ester in a Claisen condensation however, it may also react with the carbonyl of an aldehyde or ketone. The ester enolate anion is a nucleophile and it reacts with an aldehyde or ketone via acyl addition. Kinetic control conditions are the most suitable for this reaction in order to minimize Claisen condensation of the ester with itself (self-condensation). If ester 74 (ethyl propanoate, in green in the illustration) is treated first with LDA and then with butanal (21, in violet), for example, the initial acyl addition product is 78. The new carbon-carbon bond is marked in blue and treatment with dilute aqueous acid converts the alkoxide to an alcohol in the final product of this sequence, 79. Compound 79 is a P-hydroxy ester, which is the usual product when an ester enolate reacts with an aldehyde or a ketone. Ester enolate anions react with ketones in the same way that they react with aldehydes. 

Figure 9.2. An aldehyde (propanai, CH3CH2CHO), ketone (propanone, acetone, dimethyl ketone, DMK, CH3COCH3) and carboxylic acid (propanoic acid, propionic acid, CH3CH2CO2H). An acid chloride (propanoyi chloride, propionyl chloride, CH3CH2COCI), amide (propanamide, propionamide, CH3CH2CONH2), and ester (ethyl propanoate, ethyl propionate, CH3CH2CO2CH2CH3), typical carboxylic acid derivatives, are also shown.

According to Fig. 2, one of the steps in chain formation with propanoate will result in the formation of an a-methyl-P-ketoacyl moiety A, which, similarly to an acetogenin (Fig. 1), may be converted to the acid precursor D, via reduction to B and dehydration to C, followed by hydrogenation. Alternatively, after another two cycles, decarboxylation would provide an ethyl ketone like 4,6-dimethylnonan-3-one, III, a component of the pheromone bouquet of caddis flies, Potamophylax spp. [43]. 

Esters and acid fluorides give88 product mixtures very similar to those produced from ketones. Cobalt(III) fluoride again causes complete degradation, but potassium tetrafluoro-cobaltate(lll) gives polyfluoro acid fluorides, which are isolated by conversion to their ethyl esters yields are poor (ca. 20%) in all cases. Methyl propanoate reacts with potassium tetra-fluorocobaltate(III) at 350 CC to give a 5 2 2 mixture of ethyl 2,2-difluoropropanoate, ethyl... 

The 1,3-proton shift reaction has also been applied to the synthesis of a-(perfluoroalkyl)-a-amino acids, specifically 3.3,3-trifluoroalanine.2 -26 Attempts to prepare the A-benzylimine of ethyl 3,3.3-trifluoro-2-oxopropanoate by direct condensation with benzylamine were very difficult due to the exceptionally high stability of the intermediate a-amino alcohol, which fails to dehydrate. By contrast, 1-phenylethanamine reacted with ethyl 3,3,3-trifluoro-2-oxo-propanoate to form ketimine 33 in 83 % yield.26 The 1,3-proton shift reaction of 33 is much faster than those of ketimines derived from perfluoroalkyl ketones or perfluoroaldehydes (see Table 5). Complete conversion in triethylamine required 6 hours at room temperature and afforded the isomeric Shiff base 34 in 92 % yield. Mild hydrolysis of Shifif base 34 gives a-amino ester 35, which in turn hydrolyzes to 3,3,3-trjfluoroalanine hydrochloride (36). 

SYNTHESIS OF ALKYL PROPANOATES BY A HALOFORM REACTION OF A TRICHLORO KETONE PREPARATION OF ETHYL 3,3-DIETHOXYPROPANOATE (Propanoic acid, 3,3-dlethoxy-, ethyl ester)... 

A reaction which is applicable to the synthesis of imidazoles substituted at C-4 by sulfur substituents is the interaction of a-chloro-a-phenyl thioketones (prepared from the corresponding diazoketones) with ammonia and carboxylic acids. Although the detailed reaction course is yet uncertain, it bears a close resemblance to the reactions of a-chloro ketones with amides. The method has been used to prepare 2-ethyl-4-methyl-5-phenylthioimidazole (145) using ammonia, propanoic acid and 1-chloro-l-phenylthiopropanone (Scheme 82). 

Solubility determinations were used to characterize the polymorphism of 3-(((3-(2-(7-chloro-2-quinolinyl)-( )-ethenyl)-phenyl)-((3-dimethylamino-3-oxopropyl)-thio)-methyl)-thio)-propanoic acid. " The solubility of Form II was found to be higher than that of Form I in both isopropyl alcohol (IPA, solubility ratio equal to 1.7 over the range of 5-55°C) and methyl ethyl ketone (MEK, solubility ratio equal to 1.9 over the range of 5-55°C), indicating that Form I is the thermodynamically... 

Synthesis of Alkyl Propanoates by Haloform Reaction of Trichloro Ketones Preparation of Ethyl 3,3-Diethoxypropanoate... 

Judging from the number of incorrect names that appear in the chemical literature, it s probably safe to say that relatively few practicing organic chemists are fully conversant with the rules of organic nomenclature. Simple hydrocarbons and monofunctional compounds present few difficulties because the basic rules for naming such compounds are logical and easy to understand. Problems, however, are often encountered with polyfunctional compounds. Whereas most chemists could correctly identify hydrocarbon 1 as 3-ethyl-2,5-dimethylheptane, rather few could correctly identify poly functional compound 2. Should we consider 2 as an ether As an ethyl ester As a ketone As an alkeae It is, of course, all four, but it has only one correct name ethyl 3-(4-methoxy-2-oxo-3-cyclohexenyl)propanoate. 

Ans. (a) 2-Methylpropanoic acid, (b) butanone or ethyl methyl ketone, (c) benzoic anhydride, (e) 1-methoxypropanone or methoxyacetone, (/) methyl propanoate, (g) hydroxymethyl phenyl ketone, (A) phenylacetic acid, and (/) propanoyl chloride. 

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