Toluenesulfonyl residue

Methyl 3,4-isopropylidene-a-L-fucopyranoside was converted into the 2-tosyl derivative (LXXXII). After removing the isopropylidene residue with methanolic hydrogen chloride, methyl 3,4-dimethyl-2-tosyl-a-L-fucopyranoside (LXXXIII) was obtained by methylation with methyl iodide and silver oxide. Reductive fission of the p-toluenesulfonyl residue with sodium amalgam, followed by hydrolysis, gave 3,4-dimethyl-L-fucose83 (LXXXIV). 

The cleavage reagent known the longest, a mixture of hydroidodic acid and phosphonium iodide, discovered in E. Fischer s laboratory for the removal of the p-toluenesulfonyl residue (with the formation of thiocresol) and then systematically applied in peptide synthesis by R. Schonheimerin 1926, proved itself effective... 

After the autoclave was allowed to cool to room temperature, excess hydrogen was released carefully. The resulting mixture was evaporated, and the residue was purified by flash column chromatography over silica gel (eluent ethyl acetate/hexane= 1/20-1/5) to give (5)-3-methyl-A-(p-toluenesulfonyl)indoline... 

The step 2 product (3.49 mmol) was dissolved in 40 ml of CH2CI2 and then cooled in an ice bath and treated with triethylamine (5.23 mmol) followed by the dropwise addition of p-toluenesulfonyl chloride (3.84 mmol) dissolved in 5 ml of CH2CI2. The reaction mixture was stirred for 90 minutes at 0°C and then poured into ice water and extracted with CH2CI2. The organic phase was washed with 1 M HC1 and water, dried over MgSOzt, and concentrated. The residue was purified by recrystallization from 2-propanol and 1.91 g product isolated as a beige solid having an mp = 138-140°C. 

The filtrate, obtained after the crystals of bis-(4-iminopentane-2-ono) copper (II) were filtered off, was evaporated under reduced pressure. The residue was extracted with water, the extracts were filtered, and the filtrate was treated with sodium hydroxide and p-toluenesulfonyl chloride (18). In this way, about 30% of the 1,3-propanediamine was accounted for as the crude ditosylate (identity confirmed by lack of freezing-point depression with authentic sample), but only a trace of diamine could be detected in the distillate. 

B. Cyalobutyl toaylate. A 500-mL, three-necked, round-bottomed flask fitted with a stirrer and a thermometer is charged with 200 mL of pyridine (Note 5) and 32.3 g (0.448 mol) of cyclobutanol. The solution is stirred and chilled to 0°C, and then 89.8 g (0.471 mol) of p-toluenesulfonyl chloride (Note 5) is added in portions over a 20-min period. The reaction mixture is allowed to warm to room temperature and is stirred for 16 hr. The mixture is recooled to 0°C, and poured into 260 mL of concentrated hydrochloric acid in 800 mL of ice water. The mixture is extracted with three 300-mL portions of ether and the combined ethereal extracts are dried over anhydrous magnesium sulfate. The drying agent is removed by filtration and the filtrate is concentrated on a rotary evaporator. The residue 1s held under high vacuum (0.03 mm) at room temperature for 3 hr to give 93.3 g (92%) of cyclobutyl tosylate as a pale yellow oil (Note 7). 

The method was used in studies of a fungal heterogalactan.150 The polysaccharide was subjected to successive tritylation, methylation, detritylation, p-toluenesulfonylation, reaction with sodium iodide, and, finally, reaction with sodium p-toluenesulfinate. The product was then treated with sodium methylsulfinyl carbanion in dimethyl sulfoxide, the product remethylated, and the polysaccharide material recovered by gel chromatography. The polymer was hydrolyzed, and the sugars in the hydrolyzate were analyzed, as the alditol acetates, by g.l.c.-m.s.1 The analysis revealed that —60% of the hexose residues that were unsubstituted at C-6 had been eliminated. As the product was still polymeric, it was concluded that these residues had constituted a part of side chains linked to a main chain of (1 — 6)-linked D-galactose residues. 

To a solution of (S)-0-p-toluenesulfonyl-3-butyn-2-ol (11.2 g, 50.0 mmol), prepared by addition of p-toluenesulfonyl chloride and triethylamine to (S)-3-butyn-2-ol, in methanol (100 ml), was added 55% aqueous hydroxylamine (30 ml, 0.50 mol) and the reaction mixture was stirred at room temperature for 40 h. The reaction mixture was cooled to 10°C and concentrated HCI (50 ml) was added dropwise. The reaction mixture was concentrated in vacuum and the residue was partitioned between H20 (50 ml) and ethyl acetate (200 ml). The 2-phase mixture was cooled to 10°C and taken to pH 8 with 50% aqueous NaOH solution (60 ml). After stirring for 15 min the layers were separated and the aqueous phase was extracted twice with 200 ml of ethyl acetate. The combined ethyl acetate extracts were cooled to 10°C and a solution of KOCN (8.1 g, 0.10 mmol) in H20 (30 ml) was added, followed by dropwise addition of 11 ml of concentrated HCI, and the reaction mixture was... 

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