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Amino hydroxy compounds, formation

Wang P.S. and Odell G.V. (1973) Formation of pyrazines from thermal treatment of some amino-hydroxy compounds. J. Agric. Food Chem. 21, 868-70. [Pg.391]

The diazotization of amino derivatives of six-membered heteroaromatic ring systems, particularly that of aminopyridines and aminopyridine oxides, was studied in detail by Kalatzis and coworkers. Diazotization of 3-aminopyridine and its derivatives is similar to that of aromatic amines because of the formation of rather stable diazonium ions. 2- and 4-aminopyridines were considered to resist diazotization or to form mainly the corresponding hydroxy compounds. However, Kalatzis (1967 a) showed that true diazotization of these compounds proceeds in a similar way to that of the aromatic amines in 0,5-4.0 m hydrochloric, sulfuric, or perchloric acid, by mixing the solutions with aqueous sodium nitrite at 0 °C. However, the rapidly formed diazonium ion is hydrolyzed very easily within a few minutes (hydroxy-de-diazonia-tion). The diazonium ion must be used immediately after formation, e. g., for a diazo coupling reaction, or must be stabilized as the diazoate by prompt neutralization (after 45 s) to pH 10-11 with sodium hydroxide-borax buffer. All isomeric aminopyridine-1-oxides can be diazotized in the usual way (Kalatzis and Mastrokalos, 1977). The diazotization of 5-aminopyrimidines results in a complex ring opening and conversion into other heterocyclic systems (see Nemeryuk et al., 1985). [Pg.20]

Reduction of the nitro group in 70 with zinc in hot sodium hydroxide results in formation of pyrrolo[2,l-(f][l,2,5]benzotriazepine 71 by intramolecular coupling of the amino group with the newly formed nitroso group (Scheme 16). If the reduction is carried out under the less rigorous conditions of zinc in aqueous ammonium chloride the intermediate hydroxy compound is formed <96T10751>. [Pg.330]

A review entitled a-heteroatom-substituted 1-alkenyllithium regents carbanions and carbenoids for C-C bond formation has addressed the methods of generation of such species, illustrated the carbenoid reactivity of a-lithiated vinyl halides and vinyl ethers, and emphasized the synthetic potential of the carbanion species in asymmetric synthesis of a-hydroxy- and a-amino-carbonyl compounds. ... [Pg.368]

A number of general methods for the synthesis of meso-ionic 1,2,4-triazol-3-ones are available. Sodium ethoxide-catalyzed cyclization of 1-benzoyl-l,4-diphenylsemicarbazide (201, R = R = R = Ph, X = O) yielded anhydro-3-hydroxy-1,4,5-triphenyl-1,2,4-triazolium hydroxide (200, R = R = R = Ph). A general route to meso-ionic 1,2,4-triazol-3-ones (200) is exemplified by the formation of the 1,4,5-triphenyl derivative (200, R = R = R = Ph) from A-amino-MA -diphenylbenzamidine (202, R = R = R = Ph) and phosgene. In contrast with this ready meso-ionic compound formation, the corresponding reaction of the iV-methylbenzamidine (202, R = Me, R = R = Ph) did not yield the meso-ionic 1,2,4-triazol-3-one (200, R = Me, R = R = Ph). The product was in fact 3,4-diphenyl-2-methyl-l,2,4-triazol-5-onium chloride (203), which on heating gave 3,4-diphenyl-1,2,4-triazol-5-one (204, R = Ph). The formation of the A-methyl derivative (200, R = Me, R = R = Ph, yield 79%) by heating the 7V-thiobenzoyl semicarbazide (201, R = Me, R = R = Ph, X = S) with potassium carbonate in methyl cyanide has been reported. Another synthesis of A-methyl derivatives (200, R = Me) involves methylation of 3-methyl-4-phenyl-l,2,4-triazol-5-one (204,... [Pg.43]

These compounds can be synthesized from amidoximes reacting with the anhydride of trichloracetic acid. In contrast to the 3-trichloro-methyl derivatives, the CCI3 group in this class is reactive. Under formation of chloroform the 5-amino, 5-hydrazino, or 5-hydroxy-compounds can be obtained under mild conditions (compare p. 841,843). [Pg.195]

Formation mechanisms of imidazoles in the Maillard reaction are not as well understood as those of other heterocyclic compounds. The role of a-amino carbonyl fragments as intermediates in imidazole formation was suggested in the reaction of sucrose and ammonia (43). In a study of a L-rhamnose/ammonia model system, which produced fifty-two imidazoles, it was proposed that an amino-hydroxy fragment was responsible for imidazole... [Pg.139]

Coupling carbonyl compounds with aromatic amines bearing amino, hydroxy, or thiol groups in o -positions is known to be a general method for the synthesis of 1,3-benzazoles, with the intermediate formation of the respective 2,3-dihydro derivatives. No heterocyclization occurs, however, in the reaction of o-phenylene-diamines or o-aminophenols with /i-quinones. In these cases, the reaction stops at the stage of formation of the deeply colored quinoneimine 105 which is similar to that obtained by the previously studied reaction of a variety of / -substituted anilines with derivatives of p -bcn/oquinonc.6 Compounds 10 do not undergo cyclization under heating or irradiation of its solution (Scheme 4). [Pg.317]

Some a-hydroxy carbonyl compounds when heated with ammonia, ammonium acetate or formate, or formamide have been shown to give pyrazines the reaction presumably proceeds through the a-amino carbonyl compound. [Pg.18]

Klein et al. (978) first attempted the alkaline hydrolysis of 3-chloropyrazine 1 -oxide to 3-hydroxypyrazine 1 -oxide, and although spectroscopic evidence indicated the formation of the hydroxy compound, good quality homogeneous material could not be isolated. Later work by Berkowitz and Bardos (1034) has shown that 3-chloropyrazine 1-oxide was hydrolyzed by refluxing with two equivalents of aqueous sodium hydroxide, and treatment of the product with trimethylsilyl chloride and triethylamine gave 3-(trimethylsilyl)oxypyrazine 1-oxide. 3,6-Di-s-butyl-2-hydroxypyrazine 1-oxide has been prepared from the chloro analogue (no details given) (982). Hydrolysis of 2-amino-6-chloro-3-cyano-5-methylpyrazine... [Pg.151]

What now is the constitution of these diazo compounds The facts thus far considered and which must be explained by an accepted constitutional formula are, (i) Their formation by the action of nitrous acid on a primary- amine, (2) Their conversion into azo, amino azo, hydroxy azo and hydrazine compounds and (3) the basic character of the hydroxy compound, diazo benzene, and the true salt character of the compounds formed with strong acids. [Pg.588]

The second group of hydroxy compound derivatization reactions includes acylation of OH groups with the formation of esters. The most important are listed below (for the table of physicochemical and gas chromatographic constants of acylation reagents refer to the entry Derivatization of Amines, Amino Acids, Amides, and Imides for GC Analysis). [Pg.507]

The presence of hydroxyl ions from the dissociation of ammonium hydroxide, alkyl or arylammonium hydroxide, or water is responsible for the simultaneous formation of hydroxy compounds in certain reactions. Thus, in the amination of chlorobenzene and chloroanthraquinones by this unit process, phenol and hydroxyanthraquinones, respectively, are found accompanying the amino compounds in the reaction product ... [Pg.391]

The indan-based a-amino acid derivatives can be synthesized by PTC. Kotha and Brahmachary [11] indicated that solid-liquid PTC is an attractive method that offered an effective way of preparing optically active products by chiral PTC. They found that ethyl isocyanoacetate can be easily bisalkylated in the presence of K2CO3 as the base and tetrabutylammonium hydrogen sulfate as the catalyst. The advantage of isolating water from the reaction medium is to avoid the formation of unwanted hydroxy compounds in the nucleophilic substitution reaction. If liquid-liquid PTC is applied in the system with the strong base NaOH and dichloromethane as the organic solvent, the formation of dihydroxy or cyclic ether can be observed. [Pg.297]

Some special derivatization methods that lead to the formation of cyclic products were recommended for alcohols with more than two hydroxyl groups in the molecule (polyols including carbohydrates), amino alcohols, and polyfunctional aromatic hydroxy compounds. An appropriate arrangement of two functional groups [(OH)2, (OH) + (NH2) or (OH) + (CO2H)] in 1,2 (vie) 1,3 or ortho (in aromatic series) positions is necessary for their realization (Table 8). [Pg.1171]

Quaternary salts, 706 Quinolines, from the condensation of ethyl pyridyl-acetates with o-amino-aromatic aldehydes, 345 formation from, pyridineace-tic derivatives, 497, 498 pyridine hydroxy compounds, 368... [Pg.1246]

Pyridoxal Phosphate, Codecarboxylase. An independent approach to the nature of the amino acid decarboxylases was made by Gunsalus, Umbreit, and collaborators. They found that the production of tyrosine decarboxylase by Streptococcus faecalis depended on the vitamin, pyri-doxine. In the absence of pyridoxine the cells grew but had little decarboxylase. However, addition of the vitamin permitted deficient cells to decarboxylate tyrosine, and dried cells exhibited active enzyme in the presence of pyridoxal (a derivative of pyridoxine) and ATP, implying the formation of an active cofactor from these substances. Pyridoxal is a more active growth factor for a strain of Streptococcus faecalis than pyridoxine both synthetic pyridoxal and pyridoxamine exhibit 5000 to 9000 times the activity of the hydroxy compound. ... [Pg.279]

The formation of osazones from 2-methoxybutanone 225), 2-methoxy- 226) and 2-chlorocyclohexanone 2f, and 2-0-methyl and 2-amino sugars indicates the ready lability of the functional group alpha to the carbonyl function. In these cases, osazone formation may proceed by direct replacement of the alpha functional group by a phenylhydrazine molecule to give (III) without prior hydrolysis to give an alpha hydroxy compound. [Pg.458]

Amino)cinnamoyl compounds 79 can be regarded as primary products they may arise from an aldol condensation catalyzed by base, add, or (most frequently) by Lewis acids [173]. Alternatively, quinoline formation may result from primary cross aldol addition, subsequent cydocondensation to an imine(4-hydroxy-3,4-dihydroquinoHne), and aromatization by H2O elimination [174]). [Pg.397]


See other pages where Amino hydroxy compounds, formation is mentioned: [Pg.431]    [Pg.136]    [Pg.364]    [Pg.323]    [Pg.273]    [Pg.188]    [Pg.204]    [Pg.43]    [Pg.361]    [Pg.319]    [Pg.557]    [Pg.45]    [Pg.505]    [Pg.19]    [Pg.86]    [Pg.512]    [Pg.424]    [Pg.438]    [Pg.361]    [Pg.126]    [Pg.366]    [Pg.2315]    [Pg.1165]    [Pg.5027]    [Pg.433]    [Pg.307]    [Pg.307]   


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Amino compounds

Amino formation

Amino hydroxy

Hydroxy compounds

Hydroxy formation

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