NaN3, cold

A mixture of the arylsulfonyl chloride (5 mmol), benzene (2.56 mol), NaN3 (5 mmol), NaHCO, (20 mmol), and methyltrioctylammonium chloride (0.5 mmol), under N2 in an autoclave, was stirred al 40 C for 3 h. The mixture was then heated slowly to 125 C and maintained at this temperature for another 3 h, during which time the pressure in the vessel rose to 31 -54 atm. The mixture was allowed to cool and the autoclave was depressurized. The residual mass was filtered, and the residue washed thoroughly with cold H20. The benzene solution was separated from the aqueous filtrate, dried, and evaporated to give the crude product as a reddish yellow mass which was purified by column chromatography (neutral alumina, hexane/ benzene 3 2). The 1-(arylsulfonyl)-l//-azepines 16 were crystallized from light petroleum ether (bp 60-80 LC). 

Method A Mixed anhydride method To a stirred soln of For-D-Met-OH (1.77 g, 10 mmol) and NMM (l.llmL, lOmmol) in dry THF (20mL) cooled to —15°C, ClC02Et (0.96mL, lOmmol) was added. After the mixture had stirred for 15min, a soln of NaN3 (1.30g, 20mmol) in H20 (lOmL) was added. The mixture was placed in an ice bath and allowed to stir for 30 min. The mixture was extracted with cold EtOAc (50 mL) and the organic layer was washed successively with cooled solns of brine, sat. 

A mixture of 2-[4-(dimethylamino)phenyl]-l,3-benzodithiol-2-ium perchlorate (1.12 g, 3 mmol) and NaN3 (0.22 g, 3 mmol) in MeCN (50 mL) was refluxed overnight. The mixture was diluted with cold H20 and extracted with CH2C12. The extract was washed with H20, dried, and evaporated. Chromatography (silica gel, benzene) of the residue gave the product as yellow needles yield 0.44 g (51 %) mp 123 °C (cyclohexane). 

A solution of NaN3 is treated in the cold with a slight excess of AgNO 3 solution. The AgN3 precipitate is decanted, filtered, washed with water, alcohol and ether, and dried in vacuum over cone. H3SO4. 

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