Benzyl p-toluenesulfonate

The specific rates of solvolysis of benzyl p-toluenesulfonate and nine benzylic-ring-substituted derivatives (324) have been satisfactorily correlated using Aij and Tots scales within the extended Grunwald-Winstein equation. The reactions of Z-phenylethyl X-benzenesulfonates (325) with Y-pyridines (326) in acetonitrile at 60 °C have been studied at high pressures. The results indicated that the mechanism of the reaction moves from a dissociative 5)vr2 to an early-type concerted 5)vr2 with increasing pressure. 

Another example, using an acetic acid-acetic anhydride solution with sodium nitrite, is the preparation of iV-nitroso-JV-benzyl-p-toluenesulfon-amide [60]. This nitrosoamide (Preparation 9-1) is said to be quite stable at room temperature. 

A pronounced rate-retardation of 1.65 x 104-fold by an a-McsSi group relative to Me in the solvolysis of benzylic p-toluenesulfonates is due to a steric effect66. The rate increment in ethanol decreases with increasing steric size of the a-silyl group attached to the benzylic position and follow the order listed in entry 54 of Table 1. 

Benzyl p-toluenesulfonate (8) is a highly O-selective benzylating agent22. Reaction of 9 with 8 gives the dibenzyl ether 10 in high yield (equation 8), whereas the yield of the ether is only 18% when benzyl chloride is used as a benzylating agent. Thus, the sulfonate 8 serves as an efficient benzyl synthon. 

Initially, we designed /7-(terr-butoxycarbonyloxy)benzyl p-toluenesulfonate (1) under anticipation that the addolytic deprotection of p-(te/t-butoxycarbonyloxy) (t-B(X ) residue would give an add-labile p-hydroxybei l sulfonate to liberate a sulfonic acid quite readily (Scheme 1). It was revealed that 1 does not meet the third... 

Microwave-assisted CROP of two monomers, EtOZO and PhOZO, was kinetically studied in acetonitrile with four initiators, benzyl chloride (BnCl), benzyl bromide (BnBr), benzyl iodide (Bnl), and benzyl p-toluenesulfonate (BnOTs), to examine the effect on the reaction rate of the four different... 

Related Reagents. Benzyl Chloride Benzyl Iodide Benzyl p-Toluenesulfonate Benzyl 2,2,2-Triehloroacetimidate Benzyl Trifluoromethanesulfonate 3,4-Dimethoxybenzyl Bromide p-Methoxybenzyl Chloride 4-Methoxybenzyl 2,2,2-Triehloroacetimidate. 

An ice- cooled suspension of p-toluenesul-fonic acid in moist ether treated with benzaldazine monoxide, and stored 12 hrs. with cooling -> benzyl p-toluenesulfonate (Y 81%) and benzaldehyde (Y 73%). 

Aqueous caprolactam is polymerized alone and in the presence of sebacic acid (S) or hexamethylenediamine (H).t After a 24-hr reaction time, the polymer is isolated and the end groups are analyzed by titrating the carboxyl groups with KOH in benzyl alcohol and the amino groups with p-toluenesulfonic acid in trifluoroethanol. The number of milliequivalents of carboxyl group per mole caprolactam converted to polymer, [A ], and the number of milliequivalents of amino groups per mole caprolactam converted to polymer, [B ], are given below for three different runs ... 

A solution was made of N-benzyl-L-tyrosine (5.7 g, 20 mmols) and N-methylmorphollne (2,04 g, 20 mmols) In 60 ml of THF, at -15°C, and to it was added ethyl chloroformate (2,08 g, 20 mmols), After 12 minutes, p-aminobenzoic acid (2.74 g, 20 mmols) dissolved in 25 ml of THF and 0.38 g of p-toluenesulfonic acid (2 mmols) were added, and the temperature allowed to rise to 5°C. After 2 hours and forty minutes, the mixture was poured into 1 liter of 0,1 N cold HCI, stirred one-half hour, filtered and dried, to give 8,7 g, MP 192°-223°C. The product was recrystallized from 90 ml methanol and 40 ml water, to give 6 g (74%) of product, N-benzoyl-L-tyrosyl-p-amlnobenzoic acid, MP 240°-242°C. 

Benzyl alcohol (8) Benzenemethanol (9) (100-51-6) p-Toluenesulfonic acid monohydrate (8) Benzenesulfonic acid,... 

L-(+)-Tartaric acid, benzyl alcohol, and p-toluenesulfon.io acid monohydrate were purchased from Wako Pure Chemical Industries, Ltd. (Japan). Guaranteed-grade toluene was dried and stored over sodium metal. 

Ordinarily, p-toluenesulfonic acid has been used as the catalyst. Although p-toluenesulfonic acid has high activity, its use results in the formation of by-products such as methylbenzyl-p-toluenesulfonates, high molecular weight condensates, and esters. We found that formic acid is a better catalyst for this reaction and gives almost quantitatively the mixture of HexMeDPM in a pure state without any contamination due to undesirable by-products. Formic acid also serves as a solvent. From this study, it was found that benzyl alcohols react easily with arenes to form asym DAMs, and formic acid is the most favorable catalyst for the benzylation reaction. 

In most cases, the reaction was carried out with formic acid. However, p-toluenesulfonic acid was used for the condensation of 4-methylbenzyl alcohol with benzene, benzyl alcohol with isodurene, and 2-methylbenzyl alcohol with p-xylene because formic acid was too weak an acid in these cases. 

Condensation of benzyl glycinate -toluenesulfonate salt with 4,5-diphenyl-1,3-dioxol-2-one affords 154, which can be converted to the 4,5-diphenyl-3-substituted-2(3//)-oxazolones 155 by sequential treatment with an aldehyde/LiHMDS followed by diaminosulfur trifluoride (DAST). Hydrogenolysis then affords the p-fluoro-a-amino acids 156 in excellent yields without any concomitant cleavage of the... 

Carbamates have been prepared by heating ethyl carbamate with a higherboiling alcohol in the presence or absence of catalysts [31-33], Aluminum iso-propoxide has been reported [34] to be an excellent catalyst for the interchange reaction between ethyl carbamate and benzyl alcohol. The interchange reaction is also effective for /V-alkyl carbamates as well as unsubstituted carbamates [35]. This catalyst is effective in preparing mono- and dicarbamates in excellent yields from primary and secondary alcohols and diols. Other effective catalysts are dibutyltin dilaurate [36], dibutyltin oxide [37], sulfuric acid or p-toluenesulfonic acid [31], and sodium metal (reacts with alcohols to give the alkoxide catalyst) [33]. 

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