Acetals hydroxyacetals

The formation of RDX cluster ions in LC/MS and the origin of the clustering agents have been studied in order to determine whether the clustering anions originate from self-decomposition of RDX in the source or from impurities in the mobile phase [19], IsotopicaUy labeled RDX ( C3-RDX and Ng-RDX) were used in order to estabhsh the composition and formation route of RDX adduct ions produced in ESI and APCI sources. Results showed that in ESI, RDX clusters with formate, acetate, hydroxyacetate and chloride anions, present in the mobile phase as impurities at ppm levels. In APCI, part of the RDX molecules decompose, yielding NO2 species, which in turn cluster with a second RDX molecule, producing abundant [M- -N02] cluster ions. 

Contaminants and by-products which are usually present in 2- and 4-aminophenol made by catalytic reduction can be reduced or even removed completely by a variety of procedures. These include treatment with 2-propanol (74), with aUphatic, cycloaUphatic, or aromatic ketones (75), with aromatic amines (76), with toluene or low mass alkyl acetates (77), or with phosphoric acid, hydroxyacetic acid, hydroxypropionic acid, or citric acid (78). In addition, purity may be enhanced by extraction with methylene chloride, chloroform (79), or nitrobenzene (80). 

The opening of the epoxide in the cij-decalin 24 by acetic acid leads exclusively to the hydroxyacetate 25 (through a kinetically controlled rrani-diaxial opening) rather than to the wanted diastereomer 26 (c/ the stereochemistry of the "southern" part of reserpine). To obtain the correct diastereomer the epoxy-lactone 22 is first formed (Scheme 8.6). Thus the conformation of the cij-decalin system, and therefore that of the substituents, is reversed. The kinetic tran -diaxial opening of the epoxide occurs in a regio- and stereoselective manner to afford compound 28 in which the substituents have the correct position and configuration (a-OH, P-OAc),... 

Glycolic acid (or hydroxyacetic acid C2H403 MW = 76.05) is the smallest a-hy-droxy acid (Fig. 3.5.2). In its pure form, glycolic acid is a colorless, crystalline solid. It is very soluble in water (0.1 g/ml), alcohols, acetone, and ethyl acetate. Glycolic acid is isolated from sugarcane, sugar beets, and unripe grapes. 

Pyrolysis of the ethylene acetal of bicyclo[4.2.0]octa-4,7-diene-2,3-dione yields a-(2-hydroxyphenyl)-y-butyrolactonc 11 a mechanism involving a phenyl ketene acetal is proposed. Tartrate reacts with methanediol (formaldehyde hydrate) in alkaline solution to give an acetal-type species (9) 12 the formation constant was measured as ca 0.15 by H-NMR. Hydroxyacetal (10a) exists mainly in a boat-chair conformation (boat cycloheptanol ling), whereas the methyl derivative (10b) is chair-boat,13 as shown by 1 H-NMR, supported by molecular mechanics calculations. 

Af-Methylguanidine acetic acid, c277 4-Methylhexahydrophthalic anhydride, ml 96 Methyl hydroxyacetate, m259... 

Ketones and aldehydes have been economically a-hydroxylated (to give a-hydroxy-acetals), using iodine in basic methanol.327 Enolate formation and iodination to give cY-iodocarbonyl is then followed by transformation into the hydroxyacetal, a dimethyl acetal under the MeO /MeOH conditions employed. 

Smaller organic anions Amino acids, alkane caiiwxylic acids (formate, acetate, propionate, butyrate), chloro carboxylic acids (chloroacetate, dichloroacetate), hydroxy acids (hydroxyacetate, lactate, tartrate, citrate), glycolate, gluconate, pyruvate, dicarboxylic acids (oxalate, malonate, succinate, glutarate, fumarate, maleate), alkanesulfonic acids (methanesulfonate, ethanesulfonate). 

To a stirred mixture of indole (35 mg, 0.3 mmol) and aniline (42 pL, 0.45 mmol) ethyl glyoxylate (freshly distilled 50 mg, 0.45 mmol) was added at ambient temperature. The reaction mixture was stirred for 1 min. The crude product was purified by flash chromatography on silica gel (petroleum ether-EtOAc, 4 1) to give ethyl 2-(l//-indol-3-yl)-2-(phenylamino)acetate as a colorless oil (66 mg, 75%) and ethyl 2-(l//-indol-3-yl)-2-hydroxyacetate (12 mg, 19%). 

Formic and acetic acids are most attractive, but would probably be volatile under scrubber conditions (8). Succinic and lactic acids would not be cost-effective if purchased at market price. Fumaric acid is more subject to oxidative degradation. Phthalic and Benzoic acids may give undesirable aromatic degradation products. Therefore, the most useful buffers appear to be hydroxypropionic, sulfosuccinic, fumaric, sulfopropionic, adipic, and hydroxyacetic. 

The hydroxy acids did not degrade as fast as the dicarboxylic and sulfocarboxylic acids. The maximum degradation constant observed with these acids was 0.2 M"1 with hydroxypropionic acid at pH 4.5 with no Mn. Run AA2 with 10 mM adipic, 10 mlj[ hydroxy-acetic, and 1 mM Mn at pH 5.5 gave k,j values of 0.5 M" for adipic and less than 0.1 for hydroxyacetic. 

Aluminum Diacetate- Bisiaceto-0)hydroxyalumi-num hydroxybis(acetato)aluminum basic aluminum acetate aluminum subacetate aluminum hydroxyacetate Lenicet Casil. C4H7A Os mol wt 162.08. C 29.64%, H 4.36%. Al 16.64%, O 49.36%. AKOHXCHjCO j. Prepd from aluminum hydroxide and acetic acid or from sodium acetate and aluminum chloride hexahydrate Hood, Hide. J. Am. Cheat. Soc. 72, 2094 (1950). Other methods of prepn Gmelin s Aluminum (8th ed.) 35B, p 296 (1934). Also prepd in eq solution, see Aluminum Subacetate Solution. 

Numerous organic acids have been identified in tobacco. These volatile, nonvolatile, and amino acids have been discussed in-depth by Tso [see Chapter 24 in (3973)]. The major nonvolatile acids are 2-hydroxy-l,2,3-propanetricarboxylic (citric), hydroxybutanedioic (malic), and ethanedioic (oxalic). The minor nonvolatile acids are hydroxyacetic (glycolic), butanedioic (succinic), propanedioic acid (malonic), butene-dioic (E) (fumaric acid), and 2-oxopropanoic (pyruvic). The major volatile acids in tobacco are acetic and formic acid minor volatile acids are propanoic, 2-furancarboxylic acid (2-furoic), benzoic, a-methylbutyric, P-methylvaleric, and numerous others. Over forty amino acids and related compounds have been identified in tobacco [Leffingwell (2337)]. 

Acetylsalicylic acid (uh-SEE-till-sal-in-SILL-ik As-id, or uh-se-TEEL-sal-ih-SEEL-ik AS-id), more commonly known as aspirin, is the world s most commonly used therapeutic drug. By one estimate, about 137 million aspirin tablets are taken every day throughout the world. The drug is also known by other names including o-acetoxybenzoic acid 2-(acetyloxy)-benzoic acid 2-carboxyphenyl acetate and benzoic acid, 2-hydroxyacetate, in addition to about ten other systematic names and many common names. 

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