S-Methylisothiosemicarbazide hydroiodide

N sodium hydroxide solution (5 ml) is added to a stirred suspension of S-methylisothiosemicarbazide hydroiodide (2.33 g) and hydroxylamine hydrochloride (0.70 g) in water (6 ml) and stirred for 48 hours. The solution is evaporated in vacuo to provide l-amino-3-hydroxyguanidine. One-third of the residue is dissolved in 16 ml of ethanol and 2,6-dichlorobenzaldehyde (0.6 g) is added to this solution. The reaction mixture is then stirred for 48 hours. 

The resultant mixture is evaporated in vacuo and the residue triturated with methylene chloride to afford a crude product. Recrystallization from ethanol-ether (1 3) provides 1 -(2.6-di-chlorobenzylideneamino)-3-hydroxyguanidine hydrochioride MP 173°Cto 175°C. When the above process is carried out and S-benzyiisothiosemicarbazide hydroiodide is used in piece of S-methylisothiosemicarbazide hydroiodide, the identical product is again obtained. 

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