Acetic acid -, ethyl esters, preparation

Preparation of frans-(3,4-dimethyl-cyclopentylidene)-acetic acid ethyl ester... 

Pyridyl-3-butyrolactonyl ketones, conversion to quin-olizinaS/ 355 2-Fyridyl carbinols, 19 Di (a-pyridyl) carbonate, prepared from 2-pyridone and phosgene, 777, 781 2-Pyridylcinnamic acid, ethyl ester, preparation from ethyl pyridyl acetates, 344 stereochemistry of, 344 a-Pyridylcinnamic acids, decarboxylation to stilba-zoles, 340, 349... 

Reference values of the physical constants are available online and in the CRC Handbook of Chemistry and Physics. Submit a copy of the table prepared in your laboratory notebook to the instructor, after first tabulating the experimentally measured values of the physical properties, in addition to those reported in the literature for ethyl acetate (see acetic acid, ethyl ester if necessary). 

Cefazolin [25953-19-9], antibiotic, 54. The key intermediate, tetrazole-1-acetic acid ethyl ester 53 is prepared with pivaloyl chloride [44] or ethyl cyanofbrmate 50 (an effective dipolarophile undergoing 1,3-dipolar addition to azide 51) [45],... 

The next three procedures provide useful synthetic intermediates. A stereospecific synthesis of ETHYL (Z)-3-BROMO-2-PROPENOATE affords an alternative vinyl bromide partner for the coupling chemistry in the preceding procedure. A very simple but elegant illustration of the flash vacuum pyrolysis technique is used to prepare BENZOCYCLOBUTENONE from o-toluoyl chloride. Another member of the functionalized indole family of synthetic intermediates is presented in a four-step procedure for 5-METHOXYINDOLE-2-ACETIC ACID METHYL ESTER. 

Methyl- 1,3-cyclopentanedione is a key intermediate for the total synthesis of steroids.2 A number of methods have been described for its preparation, among them the condensation of succinic acid with propionyl chloride,3 and that of succinic anhydride with 2-buten-2-ol acetate,4 both in the presence of aluminum chloride. It has also been obtained from 3-methylcyclopentane-1,2,4-trione by catalytic hydrogenation5 and Wolff-Kishner reduction 6 The base-promoted cyclization of 4-oxohexanoic acid ethyl ester and diethyl propionylsuccinate with tertiary alkoxides was first reported by Bucourt.7 The present cyclization process provides an experimentally simple route to 2-methyl-1,3-cyclopentanedione. Using the same procedure, 4-oxoheptanoic acid ethyl ester has been cyclized to give 2-ethyl-l,3-cyclopentanedione in 46% yield... 

To 50 gms. (excess) of pure ethyl acetate (see Preparation 199) are added 23 gms. (excess) of sodium in the form of wire. The flask is cooled in ice, and, with slight shaking, 10 gms. (1 mol.) of benzaldehyde are gradually added. When all the sodium has gone into solution, the flask is set aside for 2 hours, when it is acidified with dilute acetic acid. The ester layer which separates is removed, shaken up with dilute sodium carbonate solution, and dried over calcium chloride. It is then distilled, the fraction 265°—275° being retained. 

Dipropyl acetic acid or valproic acid may be prepared the next way. Propylbromide is mixed with cyanacetic acid in the presence of sodium ethylate, made from absolute ethanol and sodium. By that prepared a,a-dipropylcyanacetic acid ethyl ester is saponified with equimolecular amounts of NaOH to give dipropylacetonitril. The desired dipropylacetic acid is produced by saponification of dipropylacetonitryl with aquatic NaOH. It is colorless liquid. BP 219°-220°C. 

In a third microreactor, the anion of 4-ferf-butyl l-ethyl-2-(diethox-yphosphoryl)succinate was prepared in situ using sodium ethoxide 237 (in EtOH) and the Wittig-Horner olefination with benzaldehyde 116 performed using a residence time of 47 min to afford (E)-ferf-butyl-l-ethyl-2-benzylidenesuccinate 238 in excellent selectivity (89% yield). In a fourth reactor, the acid-catalyzed (TFA 239) ferf-butyl ester deprotection was achieved using a residence time of 5 min at 34 °C and employing DCM as the reaction solvent to afford (E)-3-(ethoxycarbonyl)-4-phenylbut-3-enoic acid 246 in 82% yield. The deprotection was subsequently followed by a Friedel-Crafts acylation, using triethylamine 14 and acetic anhydride 37, to afford 4-acetoxy-naphthalene-2-carboxylic acid ethyl ester 241 in quantitative yield when conducted at 130 °C (residence time = 47 min). 

Methyl ethyl acetic acid may be prepared from methyl ethyl malonic ester by hydrolysis and subsequent heating of the methyl ethyl malonic acid.1 The yield by this method, in the preparation of large quantities, is about 61 per cent of the theoretical amount based on the malonic ester used. The acid was first prepared by Saur2 from methyl ethyl acetoacetic ester. It has also been made by oxidation of the corresponding aldehyde with chromic acid.3... 

Preparation of 2-[(2-ethyl-l-benzyl-l,6,7,8-tetrahydrocyclopent[g]indol-4-yl)-oxy]acetic acid methyl ester... 

The procedure for the elimination of HBr from the dibromo ester is a modification of the method of Lawton and co-workers for sui generis generation of the methyl or ethyl ester during a reaction. Methyl a-(bromomethyl)acrylate has also been prepared by bromination of methyl methacrylate in 700°C steam and by dehydrohalogenation with sodium acetate in acetic acid. Ethyl a-(bromomethyl)acrylate has been prepared by dehydrohalogenation with the monosodium salt of ethylene glycoP and ethyl diisopropylamine." The latter reaction was reported by Ohler et al. with no experimental details for the elimination reaction. The use of triethylamine as reported in this procedure appears to be the most efficient and convenient method for dehydrobromination to these acrylate esters. 

Reactions of Acetic Acid.—Acetic acid shows the properties which are characteristic of acids. It decomposes carbonates, forms salts with metallic hydroxides, and reacts v/ith iron, zinc, and other metals. Acetic acid forms esters with alcohols. In order to increase the yield of the ester and the rate of the reaction, a dehydrating agent is usually added to the mixture of alcohol and acid. Ethyl acetate is prepared by warming a mixture of glacial acetic acid, alcohol, and sulphuric acid —... 

Turchi and Cullen described the first examples of pyrazoles prepared from oxazoles (Scheme 1.231). Treatment of 5-ethoxy-p-oxo-2-phenyl-4-oxazolepropa-noic acid ethyl ester 857 with hydrazine did not afford the expected pyrazolone 858. Instead, the authors isolated ethyl-4-(benzoylamino)-5-ethoxy-l//-pyrazole-3-acet-ate 860 (R = H) in good yield. Similarly, reaction of 857 with methyUiydrazine produced 860 (R = CH3) in comparable yield. 

Names of esters are derived from the names of the alcohol and the acid used to prepare the ester. The alkyl group from the alcohol is named first followed by the name of the acid changed to end in -ate. For example, ethyl acetate is the name of the ester prepared from the reaction of ethanol and acetic acid. Ethyl acetate is a common solvent for lacquers and plastics and is often used as fingernail polish remover. 

The detection system employed, a pulsed amperometric detector, permits remarkable sensitivity (100 ppb), and provides the most sensitive workable commercially available detector yet developed for HPLC of under vatized carbohydrates. The drawback is that it requires strongly alkaline conditions for optimum carbohydrate oxidation (and detection). Eluants therefore contain high concentrations of non-volatile salts (typically sodium acetate and sodium hydroxide) and further structural elucidation or identification by e.g. mass spectroscopy and/or NMR requires prior desalting. The use of an anionic micromembrane suppressor downstream of the detector, thus converting the sodium hydroxide and sodium acetate to water and acetic acid, respectively, has been found satisfactory for NMR at 500 MHZ (86). However, with the inherent insensitivity of NMR and the low capacity of pellicular HPAEC columns, preparation for more sensitive analytical methods, e.g. MS, is desirable. Derivatization of fractionated oligosaccharides (either by methylation techniques or reductive coupling of 4-amino-ben oic acid ethyl ester, ABBE) and subsequent... 

In the present preparation, ethyl acetoacetate is treated with sufficient nitrous acid to convert half into the a-nitroso (or a-oximino) ester, which is reduced by zinc and acetic acid to the a-amino ester (I). The latter then condenses with... 

This is an alternative experiment to the actual preparation of the ester and will give the student practice in conducting a distillation under diminished pressure. Commercial ethyl acetoacetate generally contains inter alia some ethyl acetate and acetic acid these are removed in the following procedure. 

The hydrolysis of ethyl acetate, prepared by the reaction of ethylene with acetic acid under pressure (154), and the hydrolysis of the ethyl ester of chlorosulfonic acid (155) have been considered and found to be of Httie industrial importance. 

A modification of the K-R reaction was introduced by Mozingo. This method involved reacting an o-hydroxyacetophenone with an ester in the presence of metallic sodium to form a 1,3-diketone. Treatment of the diketone with an acid then delivered the chromone via an intramolecular cyclization reaction. This method was applied to the preparation of 2-ethylchromone (21). 0-hydroxyarylketone 22 was allowed to react with ethyl propionate (23) in the presence of sodium metal.The resulting sodium enolate was then quenched with acetic acid to deliver the 1,3-diketone 24. Upon heating 24 in glacial acetic acid and hydrochloric acid, 2-ethylchromone (21) was delivered in 70-75% overall yield. 

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