Benzaldehyde method

Fischer and Armstrong17 suggested the application of the benzaldehyde method for the decomposition of D-xylose phenylosazone, and a slight modification of this method180 was later employed in obtaining D-xylosone for the synthesis of D-isoascorbic acid,12-181-182 and L-xylosone182 for the... 

The benzaldehyde method has advantages, however, where high purity of the osone is desirable.98 When the reagent is employed, the purity of the osazone is of prime importance,90 and recrystallization from absolute ethanol may be usefully carried out for the xylose phenylosazones104 as well as for the arabinose phenylosazones.183... 

Lactosone was first prepared by the hydrochloric acid decomposition of the phenylosazone,1 although it had been noted that, in acid solutions, lactose phenylosazone forms an anhydride.197 Since its discovery,17 the benzaldehyde method has usually been employed,6-10-28 because it avoids the risks of osone hydrolysis and of alteration to the osazone. Lactosone is hydrolyzed by hot, dilute, mineral acid to D-glucosone and D-galactose.1-6 It reacts with cyanide to form an analog of iminoascorbic acid which, on acid treatment, is converted into a mixture of D-glucoascorbic acid and D-galactose.10... 

SCHEME 5.14 The 2-(2-bromoethyl)benzaldehyde method for forming dihydroisoquinolinium salts. 

METHOD 9 -This is a little, oddball method that will transforms piperonal or benzaldehyde into a quasi-cydic intermediate that will lead directly to MD-P2P or P2P [25],... 

METHOD 1 This section is going to be as thoroughly helpful to those interested in X production as it will be to those interested in amphetamine production. The process is known as the Knoeve-nagel-Walter condensation which can turn a substituted benzal-dehyde such as piperonal (X) or plain old benzaldehyde (speed) into an intermediate called a p-nitropropene. This intermediate can then be transformed into MDA (Benzedrine for speed) or MD-P2P (P2P for speed) depending on the capabilities of the chemist. 

METHOD 2 [89]--1M MDA or benzedrine and 1M benzaldehyde is dissolved in 95% ethanol (Everclear), stirred, the solvent removed by distillation then the oil vacuum distilled to give 95% yellow oil which is a Schiff base intermediate. 1M of this intermediate, plus 1M iodomethane, is sealed in a pipe bomb that s dumped in boiling water for 5 hours giving an orangy-red heavy oil. The oil is taken up in methanol, 1/8 its volume of dH20 is added and the solution refluxed for 30 minutes. Next, an equal volume of water is added and the whole solution boiled openly until no more odor of benzaldehyde is detected (smells like almond extract). The solution is acidified with acetic acid, washed with ether (discard ether), the MDMA or meth freebase liberated with NaOH and extracted with ether to afford a yield of 90% for meth and 65% for MDMA. That s not a bad conversion but what s with having to use benzaldehyde (a List chemical) Strike wonders if another aldehyde can substitute. 

This will work just as well in converting benzaldehyde to pro-penylbenzene as it will in converting piperonal. This is like the millionth method Strike has pulled from the reference 19. This was the most street-applicable article Strike has ever come across, but the greatest thing about this article s recipes is that THEY WORK Strike means to say they work big time A lot of this has to do, no doubt, with the fact that the most accomplished amphetamine chemists co-authored the work Drs. Shulgin and Nichols. 

An assay method for benzaldehyde involves condensing benzaldehyde with hydroxyl amine hydrochloride to form an oxime. The released hydrochloric acid is then titrated. 

Benzaldehyde is sold as technical grade or as meeting the specifications of the NationalVormulary (NF) (7), the Vood Chemicals Codex (FCC) (8), or the British Pharmacopeia (BP) (9) (Tables 4 and 5). The test methods used for the analysis of benzaldehyde are standard methods, with the exception of the assay method. 

The assay method involves the reaction of benzaldehyde with hydroxylamine hydrochloride in an alcohoHc solution. Benzaldehyde oxime, water, and hydrochloric acid are the products of the reaction. The hydrochloric acid formed is then titrated with standard caustic solution to determine the benzaldehyde assay. 

Performing the titration to a potentiometric end point, rather than to a colored end point, has been shown to be the more accurate method. Since other carbonyl containing compounds also react to form the oxime and release hydrochloric acid, this test is not specific for benzaldehyde. 

The levels of trace impurities in the product benzaldehyde are often more important than the product assay. Gas chromatographic methods for the deterrnination of those trace impurities are widely used. 

The other significant production method for natural benzaldehyde involves the steam distillation of bitter almond oil which has been derived from the kernels of fmit such as apricots, peaches, cherries, plums, or pmnes. The benzaldehyde product obtained in this fashion is claimed to have a superior flavor profile. The use of peach and apricot pits to produce the more profitable product laettile apparently affects the supply available to natural benzaldehyde producers. 

Pure PEA possesses an extremely mild roselike odor. Commercial grades of PEA which are >99% pure vary in odor because of the impurities present which depend on the method of manufacture. The common impurities are benzaldehyde [100-52-7], benzylacetone [2550-26-7],... 

Another potentially valuable method for the preparation of cinnamic acid involves treatment of benzaldehyde with ketene (12). The initially formed oligomer of P-hydroxy-P-phenylpropionic acid is thermally decomposed at 100—250°C in the presence of an acid or base catalyst. 

An important biological process is the basis for a general coupling method of aldehydes into symmetncal acyloins, such as BETYROIN. The key catalyst is 5-(2-hydroxyethyl)-4-methyl-l,3-thiazole, an analog of thiamin. Condensation of ketones and aldehydes with excess acetonitrile can be accomplished in a simple way to produce a,p-unsaturated nitriles Cyclohexanone leads to CY-CLOHEXYLIDENEACETONITRILE while benzaldehyde gives CINNA-MONITRILE. 

A method of fixing the position of the double bond involves first condensing the 20-ketopregnane with benzaldehyde at C-21, then reducing the ketone to hydroxyl and dehydrating.Alternatively, the 20-keto-21-benzylidene steroid can be converted to the A ° -enol chloride prior to ozonolysis. 

Benzaldehyde.—The aldehydes of the aromatic seiies may also be obtained by the oxidation of a methyl side-chain with chromium oxychloride. The solid brown product, C,H,.CH.)(CrO,CL)2, formed by adding C1O2CIJ to toluene, dissolved in carbon bisulphide, is decomposed with water, and benzaldehyde sepaiates out (Etard). Other methods for pie-paring aromatic aldehydes are (i) the Fiiedel-Crafts reaction, in which a mixture of carbon monoxide and hydrogen chloride aie passed into the hydrocaibon in presence of aluminium chloride and a little cuprous chloride,... 

The reactions of enamines with aldehydes (329,350) are noteworthy in that they provide a route to the monobenzylidene derivatives of five- to seven-membered eyclic ketones as well as a method for the formation of other a, 9-unsaturated carbonyl compounds, in fair to good yields. The condensation of benzaldehyde with enamines is also involved in the formation of 3,5-dibenzylpyridine from piperidine and benzaldehyde (191-193). 

Thus the structure of the oxazirane must formally involve elimination of water from one molecule each of the carbonyl compound and of an alkyl hydroxylamine. (In the synthesis of oxazirane from N-methylhydroxylamine-O-sulfonic acid and benzaldehyde, this method... 

In the case of natural bitter almond oil the method gave, uo useful results, presumably because the saponification of Ihn benzaldehyde-evanobydrin into mandilic acid was ineompleic... 

For the estimation of benzaldehyde, Eipper proposed a volumetric modification of the bisulphite process, the aldehyde being shaken with a measured volume of a standard solution of bisulphite, and the excess of bisulphite titrated back with iodine solution at a low tempe/atnrer Dodge found this give fairly accurate results, and recommends the iollowing method of carrying out the determination. About 0 15 gram... 

One problem with reductive amination as a method of amine synthesis is that by-products are sometimes obtained. For example, reductive amination of benzaldehyde with methylamine leads to a mixture of iV-methylbenzylamine and i -methyldibenzylarnine. How do you suppose the tertiary amine byproduct is formed Propose a mechanism. 

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