Carboxylic acid and ether

Esters, Carboxylic Acids, and Ethers.—The rates of hydrolysis of 3(3- and 6(3-acetoxy-4 ,5 -epoxides and 1 a-acetoxy-2(3,3 (3-epoxides were observed to be accelerated relative to those acetates not containing a neighbouring epoxide group.24 Bile acid methyl esters were readily prepared from the carboxylic acids by reaction with methanol in the presence of toluene-p-sulphonic acid.25 Bile acids were readily converted into the amino-amides (14) by successive reaction with Bu N- 

Bu OCOCl and 1,2-diaminoethane.26 A number of side chain keto-steroids were obtained by reactions of the carboxylic acid chlorides with organomanganous iodides and the reactions are exemplified by the conversion of the acid chloride (15) into the 24-keto-compound (16) using isobutylmanganous iodide.27 The 16a,17a-(alkoxymethylenedioxy)-steroids (18) were prepared from the 16a-formyloxy-17a-hydroxy-compounds (17) with acetals and P205.28 The major product of thermal decarboxylation of the 3,17-dioxo-4(3,5(3-epoxyandrostan-19-oic acid (19) was the hydroxy-enone (20).29 

Digitoxigenin 3-alkyl ethers were prepared by BF3-Et20-catalysed alkylation of digitoxigenin with diazoalkanes, AgBF4-assisted solvolysis of 3-desoxy-3a-iodo-digitoxigenin, and MCPBA-induced oxidative solvolytic displacement on the 3-desoxy-3a-iodo-compound in alcohols.30 

Treatment of oestrone with tetraphenylbismuth monotrifluoroacetate gave oestrone phenyl ether and exemplified, in part, a new procedure for aryl ether formation.31 A detailed study was reported of the formation of benzyl ethers by sequential reaction of alcohols with chloro(phenylmethylene)dimethylammonium chloride and sodium hydrogen telluride.32 Steroidal alcohols, inter alia, were converted into hydrolytically stable silyl ethers by reaction with B N Sil or BulPh2I which were generated in situ from the selenosilane and iodine.33 The 5a-hydroxycholestane (21) was protected in this way. 

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Flood gun conditions, 0.3 ma, 5 eV. The C-Is alkyl line was approximately 279.0 eV the spectra above are charge-referenced to 284.0 eV for the alkyl carbon line. Spectrum A is the as-received material note the presence of the aromatic satellite at 6.7 eV from the main carbon line at 284.0. Note also the absence of any carbon-oxygen functionalities as evidenced by the lack of structure between 284 and 290 (a) as-received material (b) methanol-cleaned (c) oxygen plasma-treated material. Note the decrease in the satellite line at 297 eV it has disappeared to nearly background level. Also note the presence now of two carbon-oxygen functionalities as evidenced by apparent peaks at about 288.6 and 286.4 eV, characteristic of ester or carboxylic acid, and ether or hydroxyl carbon, respectively. 

The next several chapters deal with the chemistry of various oxygen containing func tional groups The interplay of these important classes of compounds—alcohols ethers aldehydes ketones carboxylic acids and derivatives of carboxylic acids— IS fundamental to organic chemistry and biochemistry... 

The /-propyldimethylsilyl ester is prepared from a carboxylic acid and the silyl chloride (Et3N, 0°). It is cleaved at pH 4.5 by conditions that do not cleave a tetrahydropyranyl ether (HOAc-NaOAc, acetone-H20, 0°, 45 min - 25°, 30 min, 91% yield). ... 

Production and Uses of Aliphatic Compounds II Ether, Epoxide and Pnlyeiher, Carboxylic Acids and Their Denvatives, Sulfonic Acids, Toxicological Data of Aliphatic Fluorine Compounds (Ger) Liebig, H, Ulm, K Chem Ztg 100 3-14 270... 

During electrochemical fluorination retention of important functional groups or atoms in molecules is essential. Acyl fluorides and chlorides, but not carboxylic acids and anhydrides (which decarboxylate), survive perfluorination to the perfluorinated acid fluorides, albeit with some cyclization in longer chain (>C4) species [73]. Electrochemical fluorination of acetyl fluoride produces perfluoro-acetyl fluoride in 36-45% yields [85]. Electrochemical fluorination of octanoyl chloride results in perfluorinated cyclic ethers as well as perfluorinated octanoyl fluonde. Cyclization decreases as initial substrate concentration increases and has been linked to hydrogen-bonded onium polycations [73]. Cyclization is a common phenomenon involving longer (>C4) and branched chains. a-Alkyl-substituted carboxylic acid chlorides, fluorides, and methyl esters produce both the perfluorinated cyclic five- and six-membered ring ethers as well as the perfluorinated acid... 

Notable examples of general synthetic procedures in Volume 47 include the synthesis of aromatic aldehydes (from dichloro-methyl methyl ether), aliphatic aldehydes (from alkyl halides and trimethylamine oxide and by oxidation of alcohols using dimethyl sulfoxide, dicyclohexylcarbodiimide, and pyridinum trifluoro-acetate the latter method is particularly useful since the conditions are so mild), carbethoxycycloalkanones (from sodium hydride, diethyl carbonate, and the cycloalkanone), m-dialkylbenzenes (from the />-isomer by isomerization with hydrogen fluoride and boron trifluoride), and the deamination of amines (by conversion to the nitrosoamide and thermolysis to the ester). Other general methods are represented by the synthesis of 1 J-difluoroolefins (from sodium chlorodifluoroacetate, triphenyl phosphine, and an aldehyde or ketone), the nitration of aromatic rings (with ni-tronium tetrafluoroborate), the reductive methylation of aromatic nitro compounds (with formaldehyde and hydrogen), the synthesis of dialkyl ketones (from carboxylic acids and iron powder), and the preparation of 1-substituted cyclopropanols (from the condensation of a 1,3-dichloro-2-propanol derivative and ethyl-... 

Sorbitan esters of fatty acids are well known. Similar products can be made from ether carboxylic acids and sorbitol without an acid catalyst with a good color [39]. The advantage of these products is that the hydrophilicity can be adjusted by the polyethylene glycol content in the ether carboxylic acid. 

Esters of ether carboxylic acids (propylated and/or ethoxylated) and fatty alcohols or ethoxylated fatty alcohols are described [40], prepared by esterification of the ether carboxylic acid and the alcohol with an acid catalyst like H2S04 or p-toluenesulfonic acid under vacuum and at a temperature of about 130°C. The purpose of these esters is to mainly use them in cremes and lotions with better conditioning and moisture controlling properties. 

Diethylenetriamine and aminoethylethanolamine derivatives of mixtures of fatty acids and ether carboxylic acids are described as textile softeners for laundry baths with high electrolyte content [42]. 

In analogy to the well-known condensation products of fatty acids with protein hydrolysates, a patent has also been initiated for the condensation products of ether carboxylic acids and protein hydrolysates [43]. They are made by converting the ether carboxylic acids with thionyl chloride (SOCl2) to the corresponding acid chlorides followed by the condensation with a protein hydrolysate. 

A cooling, lubricating, and cleaning agent for use by the metalworking industry has been patented. It is produced by the condensation reaction of an excess diethanolamine or monoethanolamine with boric acid and an ether carboxylic acid or mixtures of ether carboxylic acids and fatty acids [46]. An advantage of these products is that they prevent the deposition of lime soaps. 

Mengerink et al. [243] describe for the analysis of ether carboxylic acids and mixtures thereof with ethoxylated alcohols an HPLC method with the use of a evaporative light-scattering detector (ELSD). 

Non-Kolbe Electrolysis of Carboxylic Acids to Ethers, Esters, and Alcohols... 

The cationic pathway allows the conversion of carboxylic acids into ethers, acetals or amides. From a-aminoacids versatile chiral building blocks are accessible. The eliminative decarboxylation of vicinal diacids or P-silyl carboxylic acids, combined with cycloaddition reactions, allows the efficient construction of cyclobutenes or cyclohexadienes. The induction of cationic rearrangements or fragmentations is a potent way to specifically substituted cyclopentanoids and ring extensions by one-or four carbons. In view of these favorable qualities of Kolbe electrolysis, numerous useful applications of this old reaction can be expected in the future. 

Figure 29 (a) Synthesis route of the molecule (b) (i) S8, NaOH, tetraethyleneglycol dimethyl ether, heat, (28%). (b) Adamantane upper rim derivative based on the thiacalix[4]arene platform. (c,d) The carboxylic acid and ester derivative of adamantane can also be used as substituents. Taken from Ref. [109] with permission. 

In the ease of very immatnre organie matter, or when the main research aim is to investigate polar fractions, a different analytical scheme may be applied (Figure 15.3). Prior to the fractionation, total concentrated extracts are treated with 14% BF3 in methanol or diazomethane in ether to esterify free carboxylic acids, and then they are snbjected to silica gel TLC using methylene chloride or a mixture of... 

Ruthenium tetroxide is a potent oxidant, however, and it readily attacks carbon-carbon double bonds.19 Primary alcohols are oxidized to carboxylic acids, methyl ethers give methyl esters, and benzyl ethers are oxidized to benzoate esters. 

The condensation reactions described above are unique in yet another sense. The conversion of an amine, a basic residue, to a neutral imide occurs with the simultaneous creation of a carboxylic acid nearby. In one synthetic event, an amine acts as the template and is converted into a structure that is the complement of an amine in size, shape and functionality. In this manner the triacid 15 shows high selectivity toward the parent triamine in binding experiments. Complementarity in binding is self-evident. Cyclodextrins for example, provide a hydrophobic inner surface complementary to structures such as benzenes, adamantanes and ferrocenes having appropriate shapes and sizes 12) (cf. 1). Complementary functionality has been harder to arrange in macrocycles the lone pairs of the oxygens of crown ethers and the 7t-surfaces of the cyclo-phanes are relatively inert13). Catalytically useful functionality such as carboxylic acids and their derivatives are available for the first time within these new molecular clefts. 

Benzyl esters of carboxylic acids are frequently used in organic synthesis for the protection of carboxyl groups. The C-O bond in benzyl esters can be cleaved more easily than the corresponding benzyl ether bond. The hydrogenolysis of an ester leads to carboxylic acid and toluene. Examples of debenzylation of benzyl esters of carboxylic acids on Pd/C catalysts are summarized in Table 4.4. 

Most ruthenium-initiated ROMP studies have been performed using (233) and strained cyclo-olefinic monomers such as norbornene688 and cyclobutenes,689 although several reports on the polymerization of 8-membered rings have also appeared.690-692 A wide range of functionalities are tolerated, including ethers, esters, amines, amides, alcohols, carboxylic acids, and ketones. 

Although the ability of microwaves (MW) to heat water and other polar materials has been known for half a century or more, it was not until 1986 that two groups of researchers independently reported the application of MW heating to organic synthesis. Gedye et al. [1] found that several organic reactions in polar solvents could be performed rapidly and conveniently in closed Teflon vessels in a domestic MW oven. These reactions included the hydrolysis of amides and esters to carboxylic acids, esterification of carboxylic acids with alcohols, oxidation of alkyl benzenes to aromatic carboxylic acids and the conversion of alkyl halides to ethers. 

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