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Sulfamic acids, aryl

Sulfation by sulfamic acid has been used ia the preparation of detergents from dodecyl, oleyl, and other higher alcohols. It is also used ia sulfating phenols and phenol—ethylene oxide condensation products. Secondary alcohols react ia the presence of an amide catalyst, eg, acetamide or urea (24). Pyridine has also been used. Tertiary alcohols do not react. Reactions with phenols yield phenyl ammonium sulfates. These reactions iaclude those of naphthols, cresol, anisole, anethole, pyrocatechol, and hydroquinone. Ammonium aryl sulfates are formed as iatermediates and sulfonates are formed by subsequent rearrangement (25,26). [Pg.62]

The A/-alkyl and W-cyclohexyl derivatives of sulfamic acid are comparatively stable. The A/-aryl derivatives are very unstable and can only be isolated ia the salt form. A series of thia2olylsulfamic acids has been prepared. [Pg.62]

These compounds contain the fragment R as an alkyl or aryl moiety. In other words, they result from the esterification of an alcohol or a phenol with nitrous acid, nitric acid, phosphoric acid, sulfuric acid, or sulfamic acid, respectively. Many of the esters to be examined in this chapter must be activated prior to eliciting their effects, e.g., the organic nitrites and nitrates, which act as donors of nitric oxide or an analogous molecule, and phosphates, which are activated by hydrolysis or even by phosphorylation (antiviral agents). Sulfates are very seldom active or used as prodrugs, but they have significance as metabolites and as industrial xenobiotics. [Pg.553]

The acid-mediated condensation of 2-naphthol with aliphatic or aromatic aldehydes can proceed under solvent-free conditions or in dichloroethane to give 14-alkyl/aryl-14//-dibcnzo[tf1/]xanthenes 167 in excellent yield (Equation 78) <2005SL955>. Sulfamic acid can also effectively catalyze the condensation of 2-naphthol with aromatic aldehydes either at 125 °C or under microwave irradiation to yield 14-aryl-14//-dibenzo[tf,/]xanthcncs in high yield (92-96%) <2005TL8691>. [Pg.468]

Arylsulfamates. Aryl esters of sulfamic acid (3) can be prepared conveniently by reduction of aryloxysulfonyl azides (2) with sodium borohydride in THF at 0-5°. [Pg.535]

Alkylideneaceto-acetic esters Allylumlagerung Allyl rearrangement Ameisensaure Formic acid Amldosulfonsaure Sulfamic acid Anhydrozucker Anhydrosugars Anlagerung Addition Arylierung Arylation Asparaginsauren Aspartic acids Aufbau Synthesis Austausdi Replacement Benzopersaure... [Pg.254]

At pH 2-5, aryl sulfamate esters (91) hydrolyse via an associative 5 n2(S) mechanism in which a water molecule attacks at sulfur to form a trigonal bipyramidal transition state, which in a slow step suffers a proton transfer and breakdown to sulfamic acid and a phenol (Scheme 25). At pH 6-9, however, the nitranion (92) is formed by proton abstraction and this extrudes phenoxide via a dissociative ( lcB) route to yield, via the sulfenamine (93), sulfamic acid (Scheme 26). At pH 6-9, 4-nitrophenyl A-(X-benzyl)sulfamates 4-N02-CgH40S02NHCH2CgH4X also hydrolyse via an analogous dissociative (filcB) route to form A-(X-benzyl)sulfamic acids X-C6H4CH2NSO3H, via A-(X-benzyl)sulfenamine (93 X-benzyl for H). ... [Pg.93]

It may be assumed that the sulfate ions necessary for the Wohler effect are produced from the sulfamic acid by the oxidizing power of the permanganate as shown in the above equation. It is in line with this assumption that other strong oxidants (HgOg, KCIO3 etc.) also produce sulfate and that N-alkyl and aryl derivatives of sulfamic acid behave like the parent compound in this respect. [Pg.461]

H. Zang, Y. Zhang, B. Cheng, W. Zhang, X. Xu, Y. Ren, An effident and green one-pot synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[fl] xanthen-ll-one derivatives promoted by sulfamic acid in [BMIM]BF4 ionic liquid. Chin. J. Chem. 30 (2012) 362-366. [Pg.490]

Sulfamates (R-NH-S03-) behave differently in that they are stable in alkaline conditions but are readily hydrolyzed in acidic media, with TV-alkyl sulfamates being more stable than TV-aryl sulfamates. The reaction is initiated by protonation of the N-atom followed by a nucleophilic attack of H20 at the S-atom [170]. [Pg.595]

Kinetic studies of the hydrolysis of aryl Af-(methoxycarbonyl)sulfamates (350) are reported for the first time. The compounds are fairly strong acids with g>Ka = 0.5-2.4, and in acid both S-O and C-0 bond cleavages occur (Scheme 43). From an... [Pg.100]


See other pages where Sulfamic acids, aryl is mentioned: [Pg.46]    [Pg.319]    [Pg.239]    [Pg.749]    [Pg.272]    [Pg.306]    [Pg.611]    [Pg.323]    [Pg.142]    [Pg.279]    [Pg.295]    [Pg.607]    [Pg.650]    [Pg.393]    [Pg.228]    [Pg.367]    [Pg.102]    [Pg.337]    [Pg.311]    [Pg.87]    [Pg.89]    [Pg.560]    [Pg.579]    [Pg.251]    [Pg.235]    [Pg.237]    [Pg.245]    [Pg.818]   
See also in sourсe #XX -- [ Pg.626 ]




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Aryl acid

Sulfamate

Sulfamates

Sulfamic acid

Sulfams

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