Hydrolysis with hydrochloric acid

In this case the ylide was not isolated but allowed to react with ben2ophenone to give, after hydrolysis with hydrochloric acid, 1,1-diphenylethylene, diphenylacetaldehyde, and triphenylarsine (160). An excellent method for preparing arsonium ylides involves the reaction between a stable dia2o compound and triphenylarsine in the presence of a copper catalyst such as bis(acetylacetonato)copper(II) (161). Rather than a dia2o compound, an iodonium yhde can be used again a copper catalyst is necessary for an optimum yield of product. An example of the use of a dia2o compound is shown in the formulation of triphenyl arsonium 2,3,4-triphenylcyclopentadienyLide [29629-32-17, C H As ... 

Upon carefully controlled hydrolysis with hydrochloric acid at room temperature, the corresponding serine methyl esters 4 are obtained in reasonable yields. Higher yields of 4 arc obtained by hydrolyzing with dilute trifluoroacetic acid5. In some cases, the diastereomeric ratio of 4 does not exactly correspond to the d.r. of the adduct 3, which is attributed to different kinetics in the hydrolysis of the diastereomers 4. Subsequent treatment of the methyl ester with excess 5 N hydrochloric acid and methyloxirane as an acid scavenger results in the free amino acid 54,7. 

The first constitutional studies were made by Schmiedeberg97 who gave a general idea of the type of structure in chondroitin. Levene considered that the molecule was a tetrasaccharide composed of two glucuronic acid residues conjugated with two units of chondrosamine, esterified with sulfuric acid. On hydrolysis with hydrochloric acid the... 

Aldehydes are obtained in 86% and 75% yields, respectively, from benzoic acid on refluxing for 6 hours and from nicotinic acid on standing at room temperature for 24 hours with bis(N-methylpiperazino)alane in tetrahydro-furan [963]. Reduction of 3-fluorosalicylic acid with 2% sodium amalgam in aqueous solution containing sodium chloride, boric acid and p-toluidine gave, at 13-15°, a Schiff base which on hydrolysis with hydrochloric acid and steam distillation afforded 3-fluorosalicylaldehyde in 57% yield [136. The purpose of p-toluidine is to react with the aldehyde as it is formed and protect it from further reduction. 

The separation of cystine and tyrosine as they are obtained by hydrolysis with hydrochloric acid was described by Morner in I901. The protein—hair, keratin from horn, eggshells, etc.—was boiled with five times its quantity of 13 per cent hydrochloric acid under a reflux condenser on a water bath for six to seven days. The solution was then decolorised with charcoal and evaporated in vacuo, and the residue dissolved in 60 to 70 per cent, alcohol. The two acids then crystallised out on neutralising with soda, and were separated by fractional crystallisation from ammonia if much tyrosine was present it separated out first, but if cystine exceeded tyrosine in quantity this compound crystallised out first the remainder was only separated with difficulty. Embden separated the mixture of the two acids by means of very dilute nitric acid, in which tyrosine is very easily soluble, but cystine with difficulty. Their separation may also be effected by precipitation with mercuric sulphate in 5 per cent, sulphuric acid solution in which the mercury compound of tyrosine is soluble (Hopkins and Cole). 

Benzoylserine was heated with phosphorus pentasulphide, and the product after hydrolysis with hydrochloric acid, gave cysteine which was converted by oxidation into cystine —... 

However, product 155 could well have structure 158, which is expected to be red, and this on hydrolysis with hydrochloric acid could give 156 and thence 157, via 159 and 160, as is observed. 

Reports of the presence of methionine sulfoxide are less frequent with respect to protein hydrolyzates than to free amino acid extracts. This is at least partially due to the fact that reduction and other changes occur upon hydrolysis with hydrochloric acid (16). The extent of decomposition depends on the conditions of hydrolysis and may approach 100%. One occasionally finds a published report of an amino acid analysis of protein in which data for methionine sulfoxide but not methio-... 

Simple enamines cannot be deprotonated directly at the a-position due to their low acidity, but starting from a-chloroenamines 685, a-lithioenamines 686991 have been prepared by chlorine-lithium exchange using an arene-catalyzed lithiation992. The treatment of compounds 685 with an excess of lithium and a catalytic amount of 4,4 -di-tert-butylbiphenyl (DTBB) in THF at —90 °C allowed the preparation of intermediates 686, which were trapped with a variety of electrophiles (Scheme 177). For aldol reactions, the arene-catalyzed lithiation has to be performed in the presence of aldehydes (Barbier conditions) at —40 °C. These adducts were transformed into a-hydroxy ketones after acid hydrolysis with hydrochloric acid or silica gel. 

Udic-Rheinau A process for making sugars from wood by hydrolysis with hydrochloric acid. Operated in Germany. See also Bergius (2). 

By using the p-methoxy-substituted enamide (192), Ninomiya et al. (54) succeeded in a simple synthesis of alloyohimbone (196) via the unconjugated lactam 194, which has an enol ether structure. Lithium aluminum hydride reduction of the lactam 194, followed by hydrolysis with hydrochloric acid and subsequent catalytic hydrogenation over platinum dioxide, yielded alloyohimbone (196) stereoselectively in an overall yield of 59% from harmalane (54) this was the most convenient synthesis of alloyohimbone (196) so far reported (Scheme 75). 

A wide variety of A-benzoyl-l,2-dih droquinaldonitriles (7) and A-benzoyI-l,2-dihydroisoquinaldonitriles (8) with various ring substituents were subjected to hydrolysis with hydrochloric acid in the presence of 2,4-dinitrophenylhydrazine to give, with the exceptions... 

Symmetrical dimethylhydrazine has been obtained by heating the methiodide of i-methylpyrazole. It has usually been prepared by methylation of diformylhydrazine and subsequent hydrolysis with hydrochloric acid. The present method is based on the observation of Folpmers that dibenzoylhydrazine may be similarly employed. ... 

Alanine, a-amino- -butyric acid, and a-aminoisobutyric acid are prepared by permanganate oxidation of the N-benzoyl derivatives of the corresponding amino alcohols. The free amino acids are obtained from the benzoyl derivatives by hydrolysis with hydrochloric acid followed by treatment with aniline. Over-all yields for the four step process are 45-60%. 

Preparative Methods (i) preparation of racemic DPEN and its optical resolution Reaction of benzil and cyclohexanone in the presence of ammonium acetate and acetic acid at reflux temperature gives a cyclic bis-imine (1) (eq 1). Stereoselective reduction of the bis-imine with lithium in THF-liquid ammonia at —78 °C followed by addition of ethanol, then hydrolysis with hydrochloric acid and neutralization with sodium hydroxide produces the racemic diamine (2). Recrystallization of the l-tartaric acid salt from a 1 1 water-ethanol mixture followed by neutralization with sodium hydroxide, recrystallization from hexane results in (5,5)-DPEN (3) as colorless crystals. 

Gastaldi (286) first described this synthesis, in which an a-hydroxyimino ketone was treated with aqueous sodium bisulfite saturated with sulfur dioxide, and the bisulfite compound treated with potassium cyanide followed by hydrolysis with hydrochloric acid. By this procedure, Gastaldi prepared 2,5-dicyano-3,6-dimethyl-pyrazine from hydroxyiminoacetone, and 2,5-dicyano-3,6-diphenylpyrazine and some 3-cyano-2,5-diphenylpyrazine from hydroxyiminoacetophenone. He proposed a reaction mechanism involving the intermediate compounds (21) and (22). Sharp and Spring (287) used the same procedure to prepare 2,5-dicyano-3,6-diethyl-pyrazine from ethyl hydroxyiminomethyl ketone. 

In its various modifications, however, the most widely used method of N-terminal residue analysis is one introduced in 1950 by Pehr Edman (of the University of Lund, Sweden). This is based upon the reaction between an amino group and phenyl isothiocyanate to form a substituted thiourea (compare Sec. 32.7). Mild hydrolysis with hydrochloric acid selectively removes the N-terminal residue as the phenylthiohydantoin, which is then identified. The great advantage of this... 

High-purity fibrous cellulose, obtained by washing under very mild acidic conditions and, successively, with organic solvents, is also used in TLC. AVICEL is formed by dissolving the amorphous part of native cellulose by hydrolysis with hydrochloric acid. 

Before all these acetal-based protecting groups were introduced, the tetrahydropyranyl (THP) ether had found extensive use in organic synthesis. It can easily be synthesized from a variety of hydroxy-containing compounds like carbohydrates, amino acids, steroids and nucleotides by the acid-catalyzed reaction with dihydropyran. It is stable to bases, but the protection is removed through acidic hydrolysis with hydrochloric acid, toluenesulfonic acid or acidic ion-exchange resin (Scheme 27). In the case of acid sensitive substrates, e.g. containing an epoxide or a further acetal, pyridinium p-toluenesulfonate should be applied for particularly mild deprotection conditions. ... 

Tropine mixed with tropic acid can be obtained from atropine by hydrolysis with hydrochloric acid or a barium hydroxide solution. 

Hydrolysis of oximes. Brooks et al. (Glaxo Labs.) found difficulty in regenerating steroid 3,20-diketones from their 3,20-dioximes by usual methods. Thus hydrolysis with hydrochloric acid generally resulted in hydrolysis of only the C2o-function. A successful method was found in oxidative hydrolysis with persulfurie acid. Thus 0.25 g. of cortisol 3,20-dioxime (1) was dissolved in a warm solution of 0.16 g. of ammonium persulfate in 50 mi. of warm N sulfuric acid. 50 ml. of methylene chloride was added, and the mixture shaken for 8 days at room temperature. Isolation of the steroid yielded 0.191 g. of cortisol (2). The reagent Is successful because it oxidizes the liberated hydroxylamine however, ferrie salts uuuld no) he used in place of the persulfate. 

The top yellow layer is poured off into a sep funnel, and any water carried along is drained off. Then the yellow oil is poured into a 2000 ml round bottom flask. It is now ready for hydrolysis with hydrochloric acid solution to make amphetamine. The approximate volume of the crude amide is determined, and five times that volume of 15% hydrochloric acid solution is added to it. Fifteen (15) percent hydrochloric acid solution is easily made by starting with the 28% hardware store hydrochloric acid, and adding just about an equal volume of water to it. A wise move here is to rinse the inside of the sep funnel with acid. This rinses off the amide clinging to the glass insides of the sep funnel. 

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