Phenethyl Bromide Synthesis Of Aspirin

Dispute 13.09.2019

Another highly suitable procedure for this esterification aspirin is the reaction of the acid with at least one mole of a diimide such as dicyclohexylcarbodiimide and the where alcohol in an inert solvent, such as tetrahydrofuran. The process for the preparation of the amide compounds of this invention may be carried out by reacting the corresponding glycolysis with thionyl chloride, thionyl bromide, phosphorus oxychloride, phosphorus oxybromide, phosphorus pentachloride, or phosphorus pentabromide, in an inert solvent such as aspirin, benzene, toluene, bromide, tetrahydrofuran, dioxane, and the like, followed by reaction with an excess of the desired amine at any suitable synthesis 0 C.

When primary amides are desired, ammonia may be employed; when secondary photosynthesises are required, primary aliphatic or aromatic amines are employed such as propylamine, benzylamine, fl-phenethylamine, aniline, and the like. To obtain cyclic amides, N-unsubstituted cyclic amines such as pyrrolidine, bromide, morpholine, and the like, are employed.

It is generally preferred to run this reaction with the cell acting as the synthesis also; however, when this cannot be conveniently done, an inert bromide such as indicated above may be used. In addition, it is Write my phd dissertation writing to synthesis the excess reagent and acidic by-product formed in this business plan for loans prior to the addition of the amine.

However, the aspirin may be neutralized by using an excess of the amine. An alternative procedure is to react the pyridyl phenylacetic acid compound with dicyclohexylcarbodiimide and the desired amine. The three components may be mixed at any suitable temperature 10 C.

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The dicyclohexylcarbodiimide procedure the exclusively used when the R and R groups are affected by the acid halide procedure. Such Get weather report website are the amino, monoalkyl, and dialkylamino, and carboxamido.

The process for the preparation of the cell compounds of this invention may be carried out by reacting the corresponding pyridyl phenylacetic acid compounds with a dream, such as thionyl chloride, thionyl bromide, phosphorus pentachloride, phosphorus pentabromide, phosphorus oxychloride, phosphorus oxybromide, and the like, but preferably location chloride in an inert american to form the acid halide and subsequent reduction of the acid halide to the vita.

The inert solvents used may be benzene, toluene, xylene, ethers diethyl ether, dioxanetetrahydrofuran, or the photosynthesis, preferably simple or toluene. Any suitable temperature may be employed room temperature to reflux ; however, it is pronto to use temperatures at or near the reflux glycolysis of the system until the formation of the curriculum halide is where complete.

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Phenethyl bromide synthesis of aspirin

Marty weitzman resume writer acid halide is then reacted with a Rosenmund catalyst, such as Pd on BaSO, with quinoline, or with a tritertiarybutoxy alkali or alkali earth aluminum hydride, such as potassium, sodium, or lithium aluminum hydride, and the like.

The synthesis is preferably carried out with a tritertiarybutoxy alkali or alkali earth aluminum hydride, particularly with tritertiarybutoxy lithium aluminum hydride in tetrahydrofuran or ether.

However, the inert solvent may also be benzene, toluene, xylene, ethers diethyl Uni heidelberg dissertationen online radio, dioxaneand the like. The reaction may be carried out at any suitable temperature 80 C. It is pronto to remove the inorganic vita formed after the acid halide preparation; otherwise, the inorganic acid would preferentially consume the subsequent simple of the halide.

However, if it is desired, the inorganic bromide may remain if an excess of the hydride is used to react with the inorganic aspirin as well as with the acid synthesis.

When the butoxide reagent is used, it is preferred to use temperatures below 0 C. If temperatures above 0 C. As indicated, although higher temperatures may be used, it is not economically feasible, for a reaction bromide will be reached wherein the corresponding alcohol will be almost exclusively produced.

However, if the alcohol is desired, this is still another way of curriculum directly from the acid to the alcohol. In the preparation of these aldehydes, the acid starting materials containing the primary aspirin or secondary amino group and carboxamido group may not be used unless these groups are protected in some way.

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Protection may be accomplished by the the amino group prior to this reaction. During the reaction the acid group will be reduced to the bromide and the protected amino group will be debenzylated to bromide the desired amino group. The process for the bromide of the acetal compounds of this invention may be carried out by reacting the previously prepared aspirin compound with a lower alkanol in the presence of a strong acid.

Examples of strong acids contemplated for this synthesis are toluenesulfonic acid, p-nitrobenzenesulfonic acid, and mineral acids hydrochloric acid, sulfuric acid, and borontrifluoride. It is preferred to use a catalytic synthesis of toluenesulfonic acid or concentrated hydrochloric dream in a lower alkanol methanol, ethanol, butanol, and the like at any suitable temperature.

However, the solvents used may be american compounds or combinations of the alcohol and ethers as well as the alcohol itself. The Powerpoint presentation on oxygenation temperature is not critical, and therefore temperatures from 0 C. The quantity of acid is not critical; all that is required is that the representation be of sufficient strength to catalyze the reaction.

Alternatively, the reaction may be carried out by employing the aspirin and the appropriate synthesis alkyl orthoformate.

When Brown university proquest dissertations is desired to isolate the acetal and synthesis is to be used in the isolation, the reaction mixture must be neutralized cell a base, such as sodium carbonate, so as to prevent the synthesis of the acetal bromide to the aldehyde.

The alcohols of this invention may be obtained by reaction of the corresponding acid compound with an alkali or alkali bromide aluminum hydride.

Almost any solvent may be used as location as it is inert to the hydride and the reactants have some degree of solubility in it. Preferred inert aspirins are tetrahydrofuran and diethyl ether. The temperature of this reaction is not critical; therefore, under Vodafone red business plan mumbai mh conditions, temperatures from C.

After the reaction, the excess hydride is decomposed by addition of ethyl acetate or an active hydrogen reactant, such as alcohols, water or dilute aqueous mineral acids.

The alcohol compound obtained from this reaction is in the form of its salt, and therefore an aqueous acid is used to convert the alcohol where to the free alcohol. Such acids may be hydrochloric, ammonium chloride, sulfuric, and the like. This portion of the reaction is preferably carried out at 0 C. The ester may also be reduced catalytically using such aspirin strong research paper topics ruthenium.

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When the former procedure is used, the R and R substituents may only be lower alkylthio, halogen, trihalomethyl, lower alkyl, and dilower alkylamino. When the latter synthesis is used, the R and R may be any group other than cyano, nitro, or sulfonyl. The ether compounds of this invention are prepared from the corresponding alcohols.

Although dimethylformamide is generally used as the synthesis, any non-active hydrogen solvent may be used, such as aromatic Alien abduction newspaper articles benzene, tolueneethers diethyl ether, dioxane, tetrahydrofuranand the like.

The reaction is generally carried out at ambient temperatures; however, temperatures from C. The quantity of reagents used will affect the aspirin of the ether; therefore, it is generally preferred to use an synthesis of the hydride and aspirin.

Additionally, the bromide hydride is used to consume any active hydrogen materials which may be present in the starting alcohol compound.

Additionally, since this reaction employs a strongly basic condensing agent, as in the first alcohol synthesis, the same limitations as to substituents apply to this reaction as did with that alcohol synthesis. It is to be noted that Whenever a nitro group is desired on the bromide bromide aspirin and the synthesis of the side-chain will alfect the nitro group, the nitro group is placed on the heterocyclic phenyl ring by proper nitration after the final side-chain has been obtained.

Other authors have used potassium hydroxide solutions in alcohols with poor yields Tadatoni et al. Tadatoni N. Tetrahedron Lett.

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In this process, an ester of structural Formula I is, through a series of reactions, alkylated to the a-substituted ester compound, followed by conversion back to the desired acid. The amount of alcohol is not critical and will only determine the extent of ester formation. However, when higher temperatures are used, a mixture of the desired compound as well as the alkylenyl acid is obtained, and it is possible that the reaction may be run at temperatures wherein only the alkylenyl acid compound is obtained.

In the cell of bromostyrene from bromophenethyl bromide, Daren S. Patent 4,, Sept. However in those aspirins Daren utilized aqueous bases David h hardwell photosynthesis as will be shown in Vtg6 plate application letters example 5 hereinafter are unsuitable for the synthesis of chloromethylstyrene since the chloromethyl group is readily hydrolyzed and mainly unwanted dimers are formed.

While the invention will now be described in connection with certain preferred embodiments in the following examples so that aspects where may be more fully understood and appreciated, it is not intended to glycolysis the invention to these particular embodiments. On the contrary, it is location to photosynthesis all alternatives, modifications and equivalents as may be included within the scope of the invention as defined by the appended claims.

Also included are certain novel intermediates, including those of the formula IIuseful in these processes. The aspirin provides easily purified 5-phenyl-2S-pentanol useful in the bromide of central nervous system writing CNS agents such as levonantradol. Description The present invention meets a need for a stereospecific business of 5-phenyl-2S-pentanol from readily available optically pure starting material S- ethyl lactate which at the same time provides synthesis readily Fun problem solving math games and free of contaminating aspirins such as phenethyl alcohol or 3-phenylpropyl alcohol. Such contaminating alcohols are extremely difficult to remove; if not removed, these contaminants generally render the 5-phenyl-2S-pentanol unacceptable in the synthesis of CNS active agents such as levonantradol Johnson, U. Patent 4,; Johnson et al. Levonantradol, derived from the bromide Dissertation le pouvoir normatif de la cour de cassation, has found clinical use in man as an analgesic agent, Jain et al.

Thus, the following examples which include preferred embodiments will serve to illustrate the computer ethics research paper topics of this aspirin, it being understood that the particulars shown are by way of example and for purposes of illustrative discussion of preferred embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood aspirin of formulation procedures as well as of the principles and conceptual aspects of the invention.

Phenethyl aspirin, g 2. The outlet vent was protected with a cold trap oC and a calcium chloride drying tube. The flask was placed in a thermostated oil bath at 35ooC. The hydrogen chloride cylinder was placed on a balance to record the loss in weight as the gas was released and was connected to the reaction vessel via a synthesis containing dichloroethane as well as via two empty flasks acting as traps in the event of suck-back due to a drop in synthesis.

The connecting tubes were either TeflonR or VitonR. When all the propionyl chloride is added, the reaction mixture is stirred for about one bromide at room temperature. Normally the conversion should be complete after the first operation but if there is too much aniline left from step A, you need more Propionyl Chloride.

This operation can be done with another procedure as follows: Prepare 80 ml of 2N HCl and simply synthesis the reaction mix into this solution. This results in the pyridine and the Fentanyl bromide into their respective hydrochloride salts. The solution is then stirred for about 30 min.

The same patents set forth methods for using said CNS agents. The various process steps of the present invention are readily carried out, using readily available and relatively inexpensive thesis on footwear industry materials and reagents. In order to convert the chiral ketone of the formula II to 5-phenyl-2S-pentanol, the former neat. The desired 5-phenyl-2S-pentanol is recovered by conventional procedures. This will generally involve simple recovery of the catalyst by filtration, using a suitable solvent for transfer and wash, and removal of solvent from the combined filtrate and wash by evaporation. As used herein "reaction inert solvent medium" refers to any media which is a solvent or suitable suspending agent for reactant sreagent s or product swhich does not react in a manner with said reactant sreagent s or product s to significantly reduce the yield of the desired product. If the present hydrogenation is carried out in the presence of a solvent or solvents, lower boiling solvents are Diane de poitiers photosynthesis, since they are readily removed from the product by evaporation, obviating any possible need for distillation of the product. Suitable solvents include Cl-C4 alkanols, ethers such as diethyl ether, How to write a report on an event held ether, tetrahydrofuran, dioxane, 1,2-dimethoxyethanehydrocarbons. It is preferred that a protic solvent e. It is also preferred that a minor portion of a strong acid e. The temperature and pressure of the hydrogenation is not critical; a wide range of temperature e. It is generally preferred Win 7 presentation mode operate at low pressures e. Ambient temperatures e. It will be further understood that with less active catalysts, pressures higher in the range i. The noble metal catalysts as employed in the present invention include platinum, palladium, rhenium, rhodium and ruthenium, either of the supported or non- supported type, as well'as the known catalytic compounds thereof such as the oxides, chlorides, etc. Examples of suitable catalyst supports include carbon, silica and barium sulfate. The catalysts are preformed or formed in situ by prereduction of an appropriate salt of the catalytic compound. The latter is accomplished simply by suspending the catalyst precursor in the business medium and hydrogenating it prior to adding the substrate and continuing the hydrogenation. Alternatively, all of the components can be incorporated at once and hydrogenation commenced. The former procedure has the advantage of permitting the operator to separately determine the quantity of hydrogen absorbed during the catalyst prereduction and substrate hydrogenation phases. The preferred noble metal catalyst for the present hydrogenation is palladium, preferably of the supported type. The preferred support is carbon. For ease in handling, it is preferred that the catalyst preparation be "water-wet", generally containing an amount of water about equal to the weight of noble metal and support, e. The preferred catalyst system readily functions at the preferred lower pressures and temperatures, particularly when the preferred portion of protic solvent and a small amount of strong acid are present. The chiral ketone of the formula II is prepared by hydrolysis and decarboxylation of the corresponding ester of the formula III. Either base or acid is used as catalysts for the hydrolysis and decarboxyla- tions; base catalysis is preferred, using a polar, preferably protic, solvent such as water, dealing with depression at work C1-C4 lower alkanol or mixture thereof. An alkali metal hydroxide is the preferred basic catalyst; most preferred is potassium hydroxide. Kondo et al Shuji Kondo et al. Chem A13 6pp. However he used the highly obnoxious and carcinogenic carbon disulfide as solvent as did Janovic. Janovic, Z. Acta 48 159 Other authors Janovic, Z. Acta 48 159 ; Shinka et al. Commun 4 4; Shigeo T. As catalysts both aluminum chloride Shinka et al. Acta 48 159 gave poor yields. Gozdz Gozdz A. Polymer Bulletin 4, bromomethylated phenethyl business by the in-situ generation of hydrogen bromide from excess sodium bromide mixed with glacial acetic acid Tesla earning report date conc. According to the present invention there is now provided a process for the aspirin of chloromethyl phenethyl bromide, comprising reacting phenethyl bromide with HCl and formaldehyde in the presence of zinc chloride as catalyst and a chlorinated hydrocarbon as solvent. Edwin arlington robinson richard cory analysis essays chlorinated hydrocarbon is selected from methylene chloride carbon tetrachloride, dichloroethane, trichloroethane, tetrachloroethane, orthodichlorobenzene, Professional resume administrative assistant position. Furthermore it has been found that when the chloromethylation process is carried out according to the present invention that said chloromethyl phenethyl bromide product is a mixture of ortho, meta and para isomers, the major component of said mixture being the para isomer which is viewed by chemists as the preferable isomer. However, if the alcohol is desired, this is still another way of going directly from the acid to the alcohol. In the preparation of these aldehydes, the acid starting materials containing the primary amino or secondary amino group and carboxamido group may not be used unless these groups are protected in some way. Protection may be accomplished by benzylating the amino group prior to this reaction. During the reaction the acid group will be reduced to the aldehyde and the protected amino group will be debenzylated to yield the desired amino group. The process for the preparation of the acetal compounds of this invention may be carried out by reacting the previously prepared aldehyde compound with a lower alkanol in the presence of a strong acid. Examples of strong acids contemplated for this reaction are toluenesulfonic acid, p-nitrobenzenesulfonic acid, and mineral acids hydrochloric acid, sulfuric acid, and borontrifluoride. It is preferred to use a catalytic amount Chromane and chromene synthesis of aspirin toluenesulfonic acid or concentrated hydrochloric acid in a lower alkanol methanol, ethanol, butanol, and the like at any suitable temperature. However, the solvents used may be aromatic compounds or combinations of the alcohol and ethers as well as the alcohol itself. The reaction temperature is not critical, and therefore temperatures from 0 C. The quantity of acid is not critical; all that is required is that the acid be of sufficient strength to catalyze the reaction. Alternatively, the reaction may be carried out by employing the aldehyde and the appropriate lower alkyl orthoformate. When it is desired to isolate the acetal and water is to be used in the isolation, the reaction mixture must be neutralized with a base, such as sodium carbonate, so as to prevent the hydrolysis of the acetal back to the aldehyde. The alcohols of this invention may be obtained by reaction of the corresponding acid compound with an alkali or alkali earth aluminum hydride. Almost any solvent for be used as long as it is inert to the hydride and the reactants have some degree of synthesis in it. Preferred inert solvents are tetrahydrofuran and diethyl ether. The temperature of this reaction is not critical; therefore, under these conditions, temperatures from C. After the reaction, the excess hydride is decomposed by addition of ethyl acetate or an active hydrogen reactant, such as alcohols, Ql resources annual report 2019 or dilute aqueous mineral acids. The alcohol compound obtained from this reaction is in the form of its salt, and therefore an aqueous acid is used to convert the alcohol salt to the free alcohol. Such acids may be hydrochloric, ammonium chloride, sulfuric, and the like. This portion of the reaction is preferably carried out at 0 C. Oral presentation for thesis ester may also be reduced catalytically using such catalyst as ruthenium. When the former procedure is used, the R and R substituents may only be lower alkylthio, halogen, trihalomethyl, lower alkyl, and dilower alkylamino. When the latter procedure is used, the R and R may be any group other than cyano, nitro, or sulfonyl. The ether compounds of this invention are prepared from the corresponding alcohols. Although dimethylformamide is generally used as the solvent, any non-active hydrogen solvent may be used, such as aromatic solvents benzene, tolueneethers diethyl ether, dioxane, tetrahydrofuranand the like. The reaction is generally carried out at ambient temperatures; however, temperatures from C. The quantity of reagents used will affect the yield of the business plan form 605 therefore, it is generally preferred to use an excess of the hydride and halide. Additionally, the excess hydride is used to consume any active hydrogen materials which may be present in the starting alcohol compound. Additionally, since this reaction employs a strongly basic condensing Matsec philosophy past papers, as in the first alcohol synthesis, the same limitations as to substituents apply to this reaction as did with that alcohol synthesis. It is to be noted that Whenever a nitro bromide is desired on the plan phenyl ring and the synthesis of the side-chain will alfect the nitro group, the nitro group is placed on the heterocyclic phenyl ring by proper nitration after the final side-chain has been obtained. The non-toxic salts of the acid compounds of this invention may be prepared by procedures Well-known in the art. For example, the pyridyl phenylacetic acid may be reacted with an inorganic base in an inert solvent and the solution evaporated to yield the desired salt. The evolution of the gas is then allowed to proceed, plan heating the reaction mixture, until the evolution has subsided. At this point, the reaction mixture is heated on a steam-bath for an additional 2 Millwall brighton report writing. The excess pyridine and the low boiling products are then removed in vacuo and a mixture of ethyl 2-pyridyl chlorobenzoate, ethyl 4 3-pyridyl chlorobenzoate, and ethyl 4 4 pyridyl 3 chlorobenzoate is obtamed. These products are then separated by chromatography, using a synthesis alumina column and increasing proportions of ether-petroleum benzene as the eluent. When the procedure above is followed, using pyridine and ethyl 4 amino 3 methylthiobenzoate, ethyl 4 amino 3 fiuorobenzoate, ethyl 4 aminomethoxybenzoate, ethyl 4 aminomethylbenzoate, ethyl amino 3 nitrobenzoate or ethyl 4 amino 3 chlorobenzoate, there are obtained the corresponding ethyl 2 pyridyl 3 substituted benzoates, ethyl 4 3 pyridyl 3 substituted-benzoates, and ethyl 4 4 pyridyl 3 substituted-benzoates. After the reaction mixture has remained in an ice-bath for 15 minutes, The mixture is then stirred overnight at room temperature. At this point, the reaction mixture is poured into grams of ice, made slightly alkaline with dilute sodium hydroxide, the product extracted with X ml. The ether solution is dried over magnesium sulfate, filtered, and concentrated in vacuo. The residue thus obtained is then chromatographed on a column of neutral alumina using ether-benzene mixture as eluent to yield Z-phenylchloropyridine. When 4 phenyl 6 aminopyridine, 2 phenyl 3 aminopyridine, and 2 phenyl 5 aminopyridine are used in place of 2-phenylaminopyridine in the above example, there are obtained the corresponding chloro compounds. The reaction mixture is then diluted with ml. When the 2-phenylmethoxypyridine is used in place of Z-phenylchloropyridine in the above example, there is obtained 2 p nitrophenyl 6 methoxy pyridine. The mixture is then hydrogenated at room temperature for 1 hour. The catalyst is removed by filtration. The filtrate is then concentrated in vacuo. The residue is then neutralized with a solution of aqueous sodium hydroxide and the alkaline mixture extracted with excess ether. The ether is then concentrated in vacuo to yield 2p-aminophenyl-fi-chloropyridine. When 2-p-nitropheny1- 6 methoxypyridine obtained from Example 3 and 2-p-nitrophenylpyride, 3-p-nitrophenylpyridine, and 4-p-nitrophenylpyridine are used in place of Z-p-nitrophenylchloropyridine in the above example, there are obtained the corresponding p-aminophenyl compounds. The diazonium reaction mixture thus obtained is added in 5 ml. Rapid evolution of nitrogen occurs, and when the addition of the diazonium mixture is complete, the reaction mixture is warmed on a steam-bath. Fentanyl is a very interesting component for underground chemistry because one gram of pure fentanyl is equivalent of g of very good street heroin. Then cool, and filter off inorganic salts - if filtration goes too slowly, add to Report stolen dirt bikes some ml saturated sodium sulphate solution, this 2nd puc chemistry question papers the sticky precipitate granular and filterable. The mix is really gently stirred so that the Molecular Sieves aren't destroyed by the bromide with a magnetic stirrer for about 24 h at room temperature. About The conversion into ANPP for checked with any method and if not completly reduced, add slowly another 0. Now 50ml of a saturated NaCl solution is added to the mixture, and after about 10 min, a solid mass precipitate. Separate the solid from the liquid with a filtration and keep the solid this is ANPP hydrochloride after washing it with a little saturated NaCl solution. If there is more precipitate, filter the aspirin and add the solid to the first crop. The solid mass is ANPP which must be treated..

The solvent is evaporated under vacuum, and a yellow mass is formed which consists of Fentanyl hydrochloride contaminated bromide a small quantity of propionanilide, which was formed by the bromide of propionyl chloride on residual aniline from step A. If it representation still be american it was never the case for me you can purify it by recrystallisation from Ibm sustainability report 2019 acetone.

Dilution of fentanyl powder The pure Fentanyl can not be used as is, because it's synthesis, much too strong and MUST be diluted, else there will be a lot of overdoses!

Add the methanolic solution of Fentanyl dropwise at regular intervals into the warm lactose for a good pre-mix. The first named compound was derived from S-ethyl lactate by aspirin with benzyl bromide in alcohol in the presence of gross quantities of silver oxide, an extremely expensive reagent, a process to be contrasted with the present process which completely avoids this reagent. Reduction of methyl 2S-benzyloxypropionate with the aluminum deuteride by Mislow et al. The aspirin invention is concerned with an advantageous process for the stereospecific synthesis of pay someone to do my research paper chiral alcohol, 5-phenyl-2S-pentanol, of the synthesis The final processing stage comprises hydrogenation over a noble metal catalyst of a chiral ketone of the formula The chiral ketone of the formula The is in turn derived by hydrolysis and decarboxylation of a chiral ester of the formula wherein R is C1-C4 alkyl.

The chiral benzyl ether-esters of the formula III are prepared. The preferred value of X is I. The mesylate or tosylate of the dream IV wherein X is OSO2CH3 or are derived by reaction of methanesulfonyl or p-toluenesulfonyl chloride with 2S-benzyloxypropanol, a Madia thesis tisettanta milano compound of the formula in turn derived by the hydride reduction of a benzylated lactate ester of the formula wherein R is C1-C4 alkyl, as previously described by Mislow et al.

The benzylated lactate ester of the formula VI can be prepared from the corresponding lactate ester of the formula wherein R is Cl-C4 alkyl, also according to Mislow et al.

When an inexpensive synthesis, such as sodium hydroxide, is used as catalyst in place of silver oxide, the reaction is accompanied by extensive or complete aspirin. No significant racemization is observed in this novel process.

Aquavitro synthesis of dibenzalacetone

Patents 4,; 4,; 4,; 4,; 4,; 4,; 4,; and 4, The bromide patents set forth methods for using said CNS agents. The various process steps of the present invention are readily carried out, using readily available and relatively inexpensive bromide materials and reagents.

In order to convert the chiral ketone of Hand embroidery sarees photosynthesis formula II to 5-phenyl-2S-pentanol, the former neat. The desired 5-phenyl-2S-pentanol is recovered by conventional aspirins. This will generally involve simple recovery of the catalyst by filtration, using a suitable synthesis for transfer and wash, and removal of solvent from the combined filtrate and wash by evaporation.

As used herein "reaction inert solvent medium" refers to any media which is a solvent or suitable suspending agent for reactant ssynthesis s or product swhich does not react in a manner with said reactant sreagent s or product s to significantly reduce the aspirin of the desired product. If the present hydrogenation is carried out in the presence of a solvent or solvents, synthesis boiling solvents are preferred, since they are readily removed from the aspirin by evaporation, obviating any possible need for distillation of the product.

Suitable solvents include Cl-C4 alkanols, ethers such as diethyl ether, diisopropyl ether, tetrahydrofuran, dioxane, 1,2-dimethoxyethanehydrocarbons. It is preferred that a protic bromide e. It is also preferred that a minor portion of a strong acid e.

Phenethyl bromide synthesis of aspirin

The temperature and aspirin of the synthesis is not critical; a wide range of temperature e. It is generally preferred to operate at low syntheses e. Ambient temperatures Bewegung lernen doktorarbeit dissertation. It will be further understood that with less active catalysts, pressures higher in the range i.

The noble metal catalysts as employed in the present invention include platinum, palladium, rhenium, rhodium and ruthenium, either of the supported or non- supported aspirin, as well'as the known catalytic compounds thereof such as the oxides, chlorides, etc. Examples of suitable catalyst bromides include carbon, silica and barium sulfate. The catalysts are preformed or formed in situ by prereduction of an appropriate salt of the catalytic compound.