Ethanesulfenyl chloride

The reactions of 5,6-dihydro-2-methoxy-2H-pyran (101) with 1,3-dibromo-5,5-dimethylhydantoin in ether-methanol,137 and with ethanesulfenyl chloride,138 have been described by Baldwin and Brown. The former reaction gave a 2 1 mixture of the isomers 3/3-bromotetrahydro-2a ,4a-dimethoxypyran (102) and 3a-bromotetrahy-dro-2a,4/3-dimethoxypyran (103), respectively the structures and favored conformations of the isomers are shown. The reaction of ethanesulfenyl chloride with 5,6-dihydro-2-methoxy-2H-pyran (101)... 

The elimination of HC1 from the corresponding sulfenyl chlorides has been used in the synthesis of thioacetaldehyde182. The removal of HC1 was accomplished by photolysis of ethanesulfenyl chloride in an argon matrix at 12 K (equation 70). 

Ethyl phenyl disulfide 256a Ethanesulfenyl chloride (9.6 g) is dropped into a stirred solution of thiophenol (11 g) in ether (50 ml) at 0°. The mixture is warmed gently on the water-bath, the solvent is removed, and the residue is distilled in a vacuum. The product boils at 126°/ 15 mm. 

An elegant synthesis of -hydroxy acids from the next-lower (non-hydr-oxylated) carboxylic acids has been described by Weygand and Bestmann.43 They converted the acid chloride into the diazo ketone by means of diazomethane, treated the diazo ketone with ethanesulfenyl chloride, and decomposed the resulting ketone with aqueous alkali, e.g. ... 

Ethanesulfenyl chloride (7.9 g) is added slowly to a solution of diazoacetophenone (12 g) in anhydrous ether (75 ml) at 0-5°. Nitrogen is evolved vigorously. After 2 h at room temperature the ether is removed in a vacuum. The co-chloro-co-(ethylthio)acetophenone that is produced almost quantitatively must be at once used for further reaction. The crude product (3 g) is shaken with N-potassium hydroxide solution for 2 h, then warmed for 1 h on a water-bath. After cooling, by-products are removed by extraction with ether finally mandelic acid (formed in 65 % yield) is liberated by acidification and is isolated by means of ether. 

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