P-Toluenesulfonate esters

Benzenesulfomc acid, 4-methyl, 2,2 dimeth ylpropyl ester [1-Propanol, 2,2-di-methyh, p-toluenesulfonate], 55, 112 Benzenesulfomc acid, 4-methyl-, esters [p-Toluenesulfonates], reaction with organocuprates, 55, 112 Benzenesultonic acid, 4-methyl-, ( )-4-hexen-l-yl ester ]( )-4-Hexen-l-yl p-toluenesulfonate], 55, 57 Benzenesulfomc acid, 4-methyl-, 1-methyl-heptyl ester [2-Octanol, p-toluenesulfonate], 55,112... 

Cesium fluoride, 68 Sulfonic acids and esters p-Toluenesulfonate esters p-Toluenesulfonyl chloride, 313 Trifluoromethanesulfonate esters N-Phenyltrifluoromethanesulfonimide, 142... 

Boric acid esters/p-toluenesulfonic acid Carboxylic acid amides from carboxylic acids... 

Peptides. Benzenesulfonyl chloride added at -10° to a soln. of L-2-(carbo-benzoxyamino) butyric acid in pyridine, after 10 min. glycine p-nitrobenzyl ester p-toluenesulfonate added, stirring continued 30 min. at -10° and 2 hrs. without cooling p-nitrobenzyl N- [l-2- (carbobenzoxyamino) butyryl] -glycinate. 

Typical procedure. Urea ester 1021 (R = Me) [753] A solution of CDI (1.25 g, 7.70 mmol, 1.10 equiv.) in dichloromethane was stirred at room temperature, and then a solution of alanine benzyl ester p-toluenesulfonate 1020 (2.45 g, 7.00 mmol) and N-methylmorpholine (NMM) (3.0 mL, 2.50 mmol) in dichloromethane was added via a cannula. The reaction mixture was stirred for 5 min, and then a second solution of phenylalanine methyl ester hydrochloride (1.50 g, 7.00 mmol) and NMM (3.0 mL, 2.50 mmol) in dichloromethane was added. The entire sequence of events was performed under a positive pressure of N2. The resultant reaction mixture was poured into a separatory funnel containing dilute aqueous NaHCOa solution. The organic layer was washed several times with water and dried over Na2S04. Filtration and evaporation of the solvent in vacuo left a viscous oil, which was kept under vacuum for 2 h to remove all traces of NMM. The residue was further purified by column chromatography (EtOAc/hexane, 3 1) to give 2 g of the urea ester 1021 as a viscous oil. 

L-Phenylalanine, 5 moles of dimethyl sulfite, and 1.1 moles of anhydrous p-toluenesulfonic acid heated 4.5 hrs. on a steam bath L-phenylalanine methyl ester p-toluenesulfonate. Y 99%.—This method is of advantage if the p-toluenesulfonates are more readily purified than the hydrochlorides (best prepn. of the latter with SOGlg, s. Synth. Meth. 9, 344). F. e., also benzyl esters, s. J. M. Theobald, M. W. Williams, and G. T. Young, Soc. 1963, 1927. 

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