Sulphonate esters chromatographic

Metabolites formed during the decolourization of the azo dye Reactive red 22 by Pseudomonas luteola were separated and identified by HPLC-DAD and HPLC-MS. The chemical structures of Reactive red 22 (3-amino-4-methoxyphcnyl-/fhydroxyl-sulphonc sulphonic acid ester) and its decomposition products are shown in Fig. 3.92. RP-HPLC measurements were carried out in an ODS column using an isocratic elution of 50 per cent methanol, 0.4 per cent Na2HP04 and 49.6 per cent water. The flow rate was 0.5 ml/min, and intermediates were detected at 254 nm. The analytes of interest were collected and submitted to MS. RP-HPLC profiles of metabolites after various incubation periods are shown in Fig. 3.93. It was concluded from the chromatographic data that the decomposition process involves the breakdown of the azo bond resulting in two aromatic amines [154],... 

Stable esters coming formally from alkynols and carboxylic, sulphonic or dialkyl phosphoric acids were prepared for the first time via alkynyliodonium salts with the corresponding anion. Several alkynyl carboxylates were obtained by anion exchange of alkynyl iodonium tosylates the initially formed salts, PhI+C=CR RCO2, were converted spontaneously into the esters on elution through a chromatographic column packed with an anion-exchange resin (Pol+ArCOj) ... 

Baker and Boyce [122] determined isomers of toluenesulphonic acid as ethyl esters prepared by the reaction with triethyl orthoformate. About 0.1 ml of sulphonic acid was added to a known amount of toluene (12 ml) and the water produced was removed by azeotropic distillation with about 5 ml of toluene. o-Terphenyl (0.05 g in 3 ml of toluene) was added as an internal standard, followed by a 20-fold excess of triethyl orthoformate, and the solution was refluxed for 15 min. After this period the reaction proceeds quantitatively and the reaction mixture can be injected directly into the chromatograph. The separation was carried out on 3% of OV-101. 

Selective removal of bromine from 3/3,5,6/3-tribromo-5a-cholestane to give 3/3-bromocholest-5-ene was achieved by reaction with [T -C5H5Cr(N02)2]2. The reactions of 11/3-hydroxy-steroids with dialkylaminosulphur trifluorides depend on the substitution at C-9 and involve the formation of intermediate (11) (Scheme 1) (see ref. 232). Selective dehydration with FeCls adsorbed on silica gel allowed the conversion of 5a-cholestane-3/3,5-diol into cholesterol (80%) and 3i3-acetoxy-5a-cholestane-5,25-diol into 3/S-acetoxycholest-5-en-25-ol (72%). Other examples and additionally the hydrolysis of 5,6a-epoxy-5o -cholestan-3/3-ol to the 3/3,5a,6/8-triol (90%) were reported. Chromatographic alumina is reported to effect smooth elimination of sulphonic acids from the esters with less than normal rearrangement. Thus lanosteryl tosylate and cycloartenyl tosylate gave the respective A -compounds in yields of 90% and 45% respec-... 

---