Esters => alkyl halides

Nylons 46, 6, 66, 610, 11 and 12 are polar crystalline materials with exceptionally good resistance to hydrocarbons. Esters, alkyl halides, and glycols have little effect. Alcohols generally have some swelling action and may in fact dissolve some copolymers (e.g. nylon 66/610/6). There are few solvents for the nylons, of which the most common are formic acid, glacial acetic acid, phenols and cresols. 

C-Alkylation of malonic acid esters Malonic acid esters, alkyl halides... 

Preparation of esters Alkyl halide reacts with sodium carhoxylate (R C02Na) to give ester via 8 2 reaction. The formation of ester follows a similar mechanism to the formation of alkyne. 

Mill T., Haag, W., Penwell, P., Pettit, T. and Johnson, H. Environmental Fate and Exposure Studies. Development of a PC-SAR for Hydrolysis Esters, Alkyl Halides and Epoxides, EPA Contract No. 68-02-4254, SRI International, Menlo Park, CA. (1987). 

Kimura l r)=aebe (0= T/T, 7d=abs. b.p. a, b, constants). (31) for various classes of organic liquids (hydrocarbons, ethers, ketones, esters, alkyl halides, etc.), and also binary mixtures. 

The relationship between log A ow and log S for various classes of organic compounds is shown schematically in Fig. 1, along with the ideal line for the octanol-water system. The data for organic liquids (classes 1-9) are those of Hansch et al. (44), in which most partition coefficients are calculated values. Imprecise as some of these data may be, they nevertheless form a useful basis for illustrating the characteristic behavior of organic liquids in the octanol-water system. Alcohols and ethers approach ideal behavior apparently because their structure and polarity are similar to octanol. Over the range of the solute solubility reported, the deviation of ketones, esters, alkyl halides, alkynes, and... 

A previous report demonstrated that esters, alkyl halides, vinyl ethers, acetic anhydride and epoxides did not react under MBH reaction conditions or give intractable mixtures however, many kinds of electrophiles have been... 

Non-hydrolytic Aprotic Reactions. Actually, rigorously non-hydrolytic conditions are more surely preserved by the use of aprotic condensation reactions (excluding hydroxyl groups), which involve the elimination of ester, alkyl halide or ether. 

NaOCHjCHa. White solid (Na in EtOH). Decomposed by water, gives ethers with alkyl halides reacts with esters. Used in organic syntheses particularly as a base to remove protons adjacent to carbonyl or sulphonyl groups to give resonance-stabilized anions. 

The alkyl halides are also of great importance in synthetic operations (e.g.) using Grigard reagents (p. 280). acetoacetic ester (p. 269) and malonic ester (p. 2- S)-... 

When an alkyl halide is heated with a trialkyl phosphite, an ester of a phos-phonic acid is produced. This is known as the Arbusov Reaction ... 

Strictly speaking the alkyl halides are esters of the halogen acids, but since they enter into many reactions (t.g., formation of Grignard reagents, reaction with potassium cyanide to yield nitriles, etc.) which cannot be brought about by the other eaters, the alkyl halides are usually distinguished from the esters of the other inorganic acids. The preparation of a number of these is described below. 

The sodio derivative, which is prepared by mixing alcoholic solutions of the ester and of sodium ethoxide, condenses with alkyl halides to yield mono-alkyl C-substituted products, for example ... 

The sodiocompound may be written [CHtCOOCjHjij] Na, and it must always be home in mind that the anion is mesomeric. The system reacts smoothly with an alkyl halide to give a C-substituted malonic ester, evidently through the carbanion (I) ... 

If only the monocarboxybc acid is required, the ester after hydrolysis with potash may be strongly acidified with sulphuric acid and the mixture heated under reflux the mineral acid promotes decarboxylation at a temperature just above 100°. The net result is the replacement of the halogen atom of the alkyl halide by —CH COOH thus in the above example ... 

The monosubstituted malonic ester still possesses an activated hydrogen atom in its CH group it can be converted into a sodio derivative (the anion is likewise mesomeric) and this caused to react with an alkyl halide to give a C-disubstituted malonic ester. The procedure may accordingly be employed for the synthesis of dialkyImalonic and dialkylacetic acids ... 

Where R and R are identical, the dialkylmalonic ester may be prepared in one operation by treating 1 mol of ethyl malonate with 2 mots each of sodium ethoxide and the alkyl halide (usually bromide or iodide). 

Esters are alkylated in the presence of strong bases in aprotic solvents. A common combination is LDA in tetrabydrofuran at low temperatures. Equimolar amounts of base are sufficient and only the mono-carbanion Js formed. After addition of one mole of alkyl halide the products form rapidly, and no dialkylation, which is a problem in the presence of excess base, is possible. Addition of one more mole of LDA and of another alkyl halide leads to asymmetric dialkylation of one or-carbon atom in high yield (R.J. Cregge, 1973). 

Alkylation of aldol type educts, e.g., /3-hydroxy esters, using LDA and alkyl halides leads stereoselectively to erythro substitution. The erythro threo ratio of the products is of the order of 95 5. Allylic and benzylic bromides can also be used. The allyl groups can later be ozonolysed to gjve aldehydes, and many interesting oligofunctional products with two adjacent chiral centres become available from chiral aldol type educts (G. Prater, 1984 D. Seebach, 1984 see also M. Nakatsuka, 1990, p. 5586). 

Alkyl Halides, Polyhalides, a-Halo Ketones and Esters... 

Particularly alkyl halides which have a perfluoroalkyl group at the /3-position undergo smooth carbonylation. Probably the coordination of fluorine to form a five-membered chelate ring accelerates the reaction. Double carbonylation to give the a-keto amide 915 is possible in Et NH with the fluorine-bearing alkyl iodide 914[769,770]. The ester 917 is obtained by the carbonylation of the /3-perfluoroalkyl iodide 916 in ethanol. 

Carboxylate ion (RC—O ) An ester IS formed when the negatively charged oxygen of a carboxylate re places the halogen of an alkyl halide... 

Alkyl sulfonate esters resemble alkyl halides m their ability to undergo ehmma tion and nucleophilic substitution... 

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