[NH2:1][C:2]1[C:7]2[CH2:8][CH:9]([CH3:11])[O:10][C:6]=2[C:5]([Cl:12])=[CH:4][C:3]=1[Cl:13].[N:14]([O-])=O.[Na+].[Sn](Cl)Cl.[OH-].[Na+]>OS(O)(=O)=O.O.Cl>[Cl:13][C:3]1[CH:4]=[C:5]([Cl:12])[C:6]2[O:10][CH:9]([CH3:11])[CH2:8][C:7]=2[C:2]=1[NH:1][NH2:14]
2.19 g of 38A was suspended in 9 mL of concentrated H2SO4 and 9 mL of water at -5° C. A solution of 0.69 g of sodium nitrite in 4 mL of H2O was added slowly and the resulting solution was stirred at 0° C. for one hour. This solution was added slowly to a mixture of 4.51 g of tin (II) chloride in 15 mL of concentrated hydrochloric acid which was precooled to -10° C., so as to maintain -10° C. to -5° C. The mixture was slowly warmed to room temperature and stirred for 16 hours. With cooling, 50% sodium hydroxide solution was added to adjust the pH to 11. The mixture was extracted with ether. The extract was washed with water, brine, dried (MgSO4) and stripped of solvent to leave crude 5,7-dichloro-2,3-dihydro-4-hydrazino-2-methylbenzofuran (38B), as pale orange solid, m.p.: 59°-64° C.
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