Ethyl -cinnamate

In a 2-1. two-neck flask fitted with a short reflux condenser and mechanical stirrer (Note 1) are placed 400 cc. of dry xylene (Note 2) and 29 g. (1.26 moles) of clean sodium (Note 3) cut in small pieces. The flask is surrounded by an oil-bath and heated until the sodium has melted. At this point the stirrer is started and the sodium is broken up into very small particles (Note 4). The oil-bath is removed but stirring is continued until the sodium has solidified as very fine particles. The xylene is then poured off, and to the sodium is added 455 cc. (4.7 moles) of absolute ethyl acetate (Note 5) containing 3-4 cc. of absolute ethyl alcohol (Note 6). The flask is quickly cooled to o° and 106 g. (1 mole) of pure benzaldehyde (Note 7) is added slowly from a separatory funnel while the mixture is stirred. The temperature is held between 0° and 50 (Note 8). The reaction starts as soon as the benzaldehyde is added, as is shown by the production of a reddish substance on the particles of the sodium. About one and a half to two hours are required for this addition. The stirring is continued until practically all of the sodium has reacted (one hour after all the aldehyde has been added). When most of the sodium (Note 9) has disappeared, 90-95 cc. of glacial acetic acid is added and the mixture is carefully diluted with 

The stirrer must be very efficient in-order to powder the sodium without splashing it onto the walls of the flask above the solvent. 

The use of sodium powdered under xylene allows the reaction to be carried out much more rapidly than is the case if the sodium is cut into small pieces with a knife. Toluene may be used in place of xylene. The sodium should be as free as possible from oxide. 

To obtain the maximum yield it is necessary to use slightly more than one equivalent of sodium. When exactly one equivalent is used the yield is about 60 per cent of the theoretical amount. 

The powdered sodium may also be prepared by melting the sodium under hot xylene and shaking in a tightly stoppered flask wrapped in a heavy cloth. 

Dissolve 50 g. of piperonal and 75 g. of malonic acid in a mixture of 160 ml. of pyridine and 2-5 ml. of piperidine contained in a 500 ml. round-bottomed flask, and heat under reflux for 1 hour on a water bath. A rapid evolution of carbon dioxide takes place. Complete the reaction by boiling the solution for 5 minutes. Cool, pour into excess of water containing enough hydrochloric acid to combine with the pyridine, filter ofiFthe piperonylacrylic acid, wash with a little water, and dry. The yield is almost quantitative and the acid is practically pure. It may be recrystallised from glacial acetic acid m.p. 238°. 

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For a further example of the Fischer-Speier method, see Ethyl cinnamate,... 

Ethyl Cinnamate. C H5CH CHCOOC2H5. Required Cinnamic acid, 20 g. rectified spirit, 20 ml. 

Ethyl cinnamate is a colourless liquid of b.p. 271° and 1-05 it possesses a pleasant and characteristic odour. 

As a general guide, however, it may be noted that the following have fairly easily recognisable odours methyl and ethyl formate methyl and ethyl acetate (apples) methyl and ethyl benzoate methyl salicylate (oil of winter-green) and ethyl salicylate methyl and ethyl cinnamate. (It is however usually impracticable to distinguish by odour alone between the methyl and ethyl esters of a particular acid.) Methyl and ethyl o. alate, and methyl and ethyl phthalate are almost odourless. Succinic and tartaric esters have faint odours. 

Successful results have been obtained (Renfrew and Chaney, 1946) with ethyl formate methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec.-butyl and iso-amyl acetat ethyleneglycol diacetate ethyl monochloro- and trichloro-acetates methyl, n-propyl, n-octyl and n-dodecyl propionates ethyl butyrate n-butyl and n-amyl valerates ethyl laurate ethyl lactate ethyl acetoacetate diethyl carbonate dimethyl and diethyl oxalates diethyl malonate diethyl adipate di-n-butyl tartrate ethyl phenylacetate methyl and ethyl benzoates methyl and ethyl salicylates diethyl and di-n-butyl phthalates. The method fails for vinyl acetate, ieri.-butyl acetate, n-octadecyl propionate, ethyl and >i-butyl stearate, phenyl, benzyl- and guaicol-acetate, methyl and ethyl cinnamate, diethyl sulphate and ethyl p-aminobenzoate. 

Ethyl cinnamate may also be prepared by the esterification of cinnamic acid. The pure compound boils at 127°/6 mm. 

Phenylpropiolic acid. This is an example of an aromatic acetylenic acid, and is made by adding bromine to the ethylenio linkage in ethyl cinnamate, and treating the resulting dibromide with alcohobc potassium hydroxide which eliminates two molecules of hydrogen bromide ... 

The catalyst is inactive for the hydrogenation of the (isolated) benzene nucleus and so may bo used for the hydrogenation of aromatic compounds containing aldehyde, keto, carbalkoxy or amide groups to the corresponding alcohols, amines, etc., e.g., ethyl benzoate to benzyl alcohol methyl p-toluate to p-methylbenzyl alcohol ethyl cinnamate to 3 phenyl 1-propanol. 

Ethyl cinnamate (one of the constituents of the sex pheromone of the male onental fmit moth)... 

The addition of diazomethane to unsaturated esters (1), as ethyl acrylate, methyl crotonate and ethyl cinnamate, was investigated by Auwers who showed that the primary addition product is a A -pyrazoline (2) which rearranges spontaneously to the conjugated A -pyrazoline (3). 

Due to the high reactivity of sulfonium ylide 2 for a,P-unsaturated ketone substrates, it normally undergoes methylene transfer to the carbonyl to give the corresponding epoxides. However, cyclopropanation did take place when 1,1-diphenylethylene and ethyl cinnamate were treated with 2 to furnish cyclopropanes 53 and 54, respectively. 

In Corey and Chaykovsky s initial investigation, a cyclic ylide 79 was observed from the reaction of ethyl cinnamate with ylide 1 in addition to 32% of cyclopropane 53. In a similar fashion, an intermolecular cycloaddition between 2-acyl-3,3-bis(methylthio)acrylnitrile 80 and 1 furnished 1-methylthiabenzene 1-oxide 81. Similar cases are found in transformations of ynone 82 to 1-arylthiabenzene 1-oxide 83 and N-cyanoimidate 84 to adduct ylide 85, which was subsequently transformed to 1-methyl-lX -4-thiazin-l-oxide 86. ... 

The asymmetric epoxidation of electron-poor cinnamate ester derivatives was highlighted by Jacobsen in the synthesis of the Taxol side-chain. Asymmetric epoxidation of ethyl cinnamate provided the desired epoxide in 96% ee and in 56% yield. Epoxide ring opening with ammonia followed by saponification and protection provided the Taxol side-chain 46 (Scheme 1.4.12). 

To a solution of m-ethyl cinnamate (44, 352 mg, 85% pure, 1.70 mmol) and 4-phenylpyridine-A-oxide (85.5 mg, 29 mol%) in 1,2-dichloromethane (4.0 mL) was added catalyst 12 (38.0 mg, 3.5 mol%). The resulting brown solution was cooled to 4°C and then combined with 4.0 mL (8.9 mmol) of pre-cooled bleach solution. The two-phase mixture was stirred for 12 h at 4°C. The reaction mixture was diluted with methyl-t-butyl ether (40 mL) and the organic phase separated, washed with water (2 x 40 mL), brine (40 mL), and then dried over Na2S04. The drying agent was removed by filtration the mother liquors concentrated under reduce pressure. The resulting residue was purified by flash chromatography (silica gel, pet ether/ether = 87 13 v/v) to afford a fraction enriched in cis-epoxide (45, cis/trans . 96 4, 215 mg) and a fraction enriched in trans-epoxide cis/trans 13 87, 54 mg). The combined yield of pure epoxides was 83%. ee of the cis-epoxide was determined to be 92% and the trans-epoxide to be 65%. 

Ethylene oxide (2.5 ml, 0.05 mole) is condensed in a 50-ml round-bottom flask containing 5 ml of methylene chloride by introducing the gas via a tube into the ice-cooled flask. To the cooled flask are added triphenylphosphine (6.6 g, 0.025 mole), benzaldehyde (2.6 g, 0.025 mole), and ethyl bromoacetate (4.2 g, 0.025 mole). The flask is closed with a drying tube, brought to room temperature, and allowed to stand overnight. Fractional distillation of the solution then yields 2-bromoethanol, bp 55717 mm followed by the desired ethyl cinnamate, bp 142-144717 mm (27171 atm) in about 90% yield. The residue consists of triphenylphosphine oxide, mp 150°. 

Ethyl Cinnamate.—The cinnamic ester of ethyl alcohol is a natural constituent of a few essential oils, including camphor oil and storax. It is formed synthetically by condensing cinnamic acid and ethyl alcohol by dry hydrochloric acid gas. It has a soft and sweet odour, and is particularly suitable for blending in soap perfumes. It is an oil at ordinary temperatures, melting at 12°, and boiling at 271°. Its specific gravity is 1 0546, and its refractive index 1 5590. 

Ethyl rec.-hutylmalonate, 11, 22, 76, 77 Ethyl -butyrate, 13, 24 Ethyl carbonate, 11, 98 Ethyl chelidonate, 17, 40 Ethyl chloroacetate, 18, 10 Ethyl chloroformate, 12, 38 17, 49 Ethyl cinnamate, 12, 36 ETHYL a,0-DIBROMO-0-PHENYLPROFION-AIE, 12, 36, 60... 

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