Toluenesulfonyl group

Treatment of this last with sulfuric acid in ethanol serves both to esterify the acid and to remove the toluenesulfonyl group to yield the secondary amine (81). ... 

Despite the effectiveness of chloramine-T in this new method, removal of the toluenesulfonyl group from the newly introduced nitrogen substituent requires harsh conditions. The finding that the N-chloramine salt of tert-butylsulfonamide is also an efficient nitrogen source and the terminal oxidant for aziridination of... 

In a variation of these reactions, Grieco and Masaki used p-toluenesulfonyl groups to direct alkylation reactions in the formation of carbon chains and then cleaved the sulphones with lithium in ethylamine. This type of synthetic construction involving the use of sulphur-containing molecules has become a typical sequence in organic syntheses. In this case, the reactions formed part of successful syntheses of squalene and sesquifenchene and were carried out without any migration or loss of stereochemical integrity of the double bonds. Similar sequences have been reported by Trost (prenylation reactions) and Marshall (synthesis of a cembranoid precursor). 

Methanesulfonyl group is called a mesyl group and /7-toluenesulfonyl group is... 

On occasion such reductive deprotection processes can be quite selective. Electrochemical reduction of A,A -di-p-toluenesulfonyl-A-t-butoxycarbonyl derivatives of aliphatic and aromatic diamines selectively removed the p-toluenesulfonyl group attached to a primary amine site63. Yields on the mono-protected products are fair to high selective deprotection of the corresponding A,A -dibenzoyl derivatives occurred in yields >92%. 

The present transformation seems to be accelerated by the presence of electron-donating substituents on the amino nitrogen of 44 (Tab. 6.4), while the p-toluenesulfonyl group and methoxycarbonyl groups suppress the formation of 45 under similar conditions. 

Also, in order to obtain a nitrogen protecting group that would be easier to remove than thep-toluenesulfonyl group (Ts), the ferf-butoxycarbamate (BocNR2) derivative 71 (Scheme 5.31) was also engaged in the same reaction to efficiently yield the desired dienyl product 72. 

The treatment of bis(phenyliodonium)diyne triflates, 19 (n = 5,6,8), with sodium p-toluenesulfinate provides access to disulfones possessing spiroannulated or tethered cyclopentene rings (equation 57)86. However, because migration of the / -toluenesulfonyl group in the intermediate carbenes is competitive with insertion, the yields of the bis-cyclopentene compounds are relatively low, and disulfones of general structures 20 and 21 are also obtained. 

The toluenesulfonyl group in these reactions is also a protecting group for nitrogen, for example in 3, but it must be removed subsequently to liberate the free secondary amine. There are various methods for achieving this deprotection step which are compatible with ether linkages. The two most useful involve either the use of hydrogen bromide in acetic acid in the... 

The related p-methoxybenzenesulfonyl group is a useful alternative to the toluenesulfonyl group and may be removed under milder acidic conditions, e.g. HBr-AcOH-PhOH at 50 °C.9... 

At lower temperatures, a tosylate is formed from the reaction of p-toluenesulfonyl chloride and an alcohol. The new bond is formed between the toluenesulfonyl group and the oxygen of the alcohol. At higher temperatures, the chloride anion can displace the -OTos group, which is an excellent leaving group, to form an organochloride. 

One gram of the sulfonic acid from the hydrosulfite reduction is boiled under reflux with 20 cc. 10 per cent hydrochloric acid. After a short time, the solution can be oxidized by air or an oxidizing agent to produce the characteristic red color obtained from 7-amino derivatives of l-amino-8-naphtholsulfonic acids. Since it is known that the Polar dyes contain the toluenesulfonyl group, it may be assumed that the acyl residue connected to the N is the p-toluenesulfonyl group. 

Sodium 4-toluenesulfonamide is a very useful nitrogen nucleophile for 71-allylpalladium complexes which permits a controlled sequential diallylation. Since the 4-toluenesulfonyl group is easily removed34, sodium 4-toluenesulfonamide can serve as an equivalent for ammonia, as well as for primary amines. 

The y-lactam 110 is prepared by the reaction of the lithium silyl-substituted ynolate 105 with the aziridine 108 activated by a p-toluenesulfonyl group. The initial product is the enolate 109, which can be acidified to yield the a-silyl-y-lactam 110. Intermediate 109 can be trapped by aldehydes to afford the a-alkylidene-y-lactams 111 via a Peterson reaction (equation 45) . These reactions may be considered to be formal [3 + 2] cycloadditions as well as tandem reactions involving nucleophilic ring opening and cyclization. 

Partial esterification of cellulose with p-toluenesulfonyl chloride may be accomplished in the presence of pyridine, or by reaction with alkali cellulose. The tosyl (p-toluenesulfonyl) group has been shown to react quite readily with the primary hydroxyl group of cellulose but much more slowly with the secondary groups. The reaction in the presence of pyridine must be carried out at low temperatures to prevent the introduction of nitrogen and halogen from side reactions. ... 

From this problem on, "Ts" will refer to the "tosyl" or "p-toluenesulfonyl" group ... 

Takahashi and co-workers [264] constructed two 48-member p-strand mimetic libraries on solid phase using a [2 -i- 3]-cycloaddition between two different Rink-amide resin-linked vinylsulfones (161) and azomethine imines. The latter were generated in situ from cyclic hydrazides (162) and various aliphatic and aromatic aldehydes (Scheme 34). The cycloaddition took place on refluxing 1,2-dichloro-ethane in a sealed tube for 48 h, followed by elimination of the p-toluenesulfonyl group with DBU. The reaction afforded a single regioisomer (164) in moderate to good yields. 

Phenylmethanesulfonyl fluoride was chosen for the first step because the phenylmethanesulfonyl group is a better leaving group in the SN2 displacement of the second step than the p-toluenesulfonyl group,... 

---