4 - -4-sulfo

Calcon carboxylic acid [3-hydroxy-4-(2-hydroxy-4-sulfo-l-napbtbylazo)napbtbalene-2-carboxylic acid] [3737-95-9] M 428.4, m 300°, X,max 560nm, pKj 1.2, pK2 3.8, PK3 9.26, PK4 13.14. Purified through its p-toluidinium salt. The dye was dissolved in warm 20% aq MeOH and treated with p-toluidine to ppte the salt after cooling. Finally recrystd from hot water. [Itoh and Ueno Analyst (London) 95 583 1970.] Patton and Reeder (Anal Chem 28 1026 1956) indicator and complexes with Ca in presence of Mg and other metal ions. 

Common additives in food are sulfur S(IV) oxospecies. Quinoline Yellow and Tartrazine show excellent stability toward S(IV) oxospecies while erythrosine. Red 2G, and Green S show good stability. - All other colorants show fair stability, except indigotine, which fades. In the presence of metabisulflte. Sunset Yellow FCF is degraded to a lemon yellow compound identified as l-(4 -sulfo-l-phenylhydrazo)-keto-3,3,4-trihydronaphtalene-4,6-disulfonic acid by NMR and FAB-MS techniques. ... 

The hydrolytic stability of water soluble poly[N-(4-sulfo-phenyDdimethacrylamide] (PSPDM) was studied at 90 C in aqueous solutions at pH 7, pH 1.2 (0.1M HC1), and pH 12.3 (0.1M NaOH). PSPDM, which possesses predominantly 5-mem-bered ring imides, was prepared by the cyclopolymerization and subsequent sulfonation of N-phenyldimethacrylamide. No detectable PSPDM imide hydrolysis occurred after 30 days at pH 7 or pH 1.2. Under basic conditions, however, complete hydrolysis to amic acid occurred after one day. The resulting Nsubstituted amide was extremely stable to further basic hydrolysis. 

Turner, S.R., Walker, T.O. and Thaler, W.A. "Sodium Styrene Sulfonate Co-Sodium N-(4-Sulfo Phenyl) Maleimide An Improved Viscosity Control Additive," US Patent 4,478,727(1984). 

Among the methods described for the synthesis of the key intermediate 4-(chloromethyl)-L-phenylalaninej123-125 direct chloromethylation of a protected l-phenylalanine followed by deprotection represents the simplest procedure. 126 This intermediate is converted into the 4-sulfomethyl derivative which is then used to prepare the /V -/ert-butyloxycarbonyl-4-(sulfo-methyl)phenylalanine monosodium salt l2S and the related Fmoc derivative. 126 ... 

Auch Sulfbnsaure-Gruppen in der 4(5)-Position des Imidazol-Rings konnen unter diesen Be-dingungen abgespalten werden. So erhalt man aus 4(5)-Methyl-5(4)-sulfo- bzw. aus 2-Methyl-4(5)-sulfo-imidazol in konz. Salzsaure bei 170° 4(5)-Methyl- bzw. 2-Methyl-imidazol479. 

Carboxy-5-kydroxy- -(4-sulfo-phenyl)-4- (4-sulfo-phenylazo )-pyrrazol-Trinatrium-Salz... 

Carmoisine, azorubine 122 14720 A Disodium-4-hydroxy-3-(4-sulfo-l-naphthylazo)-naphthalene-1-sulfonate C2oH]2N2Na207S2 502.44 510... 

Amaranth, bordeaux S, FD C red 2 123 16185 A Trisodium-2-hydroxyl-l-(4-sulfo-l-naphthylazo)-naphthalene-3,6-disulfonate C2oHnN2Na3010S3 604.48 519- 525... 

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