Reaction #1760252

Reaction equation

SnCl2.2H2O

hydrochloric acid

3,3′-dinitrobenzidine

→

3,3′-diaminobenzidine

Yield 74.0%

Conditions

Workup

1. 1
   OtherA 50 ml single neck round bottomed flask equipped with condenser
2. 2
   workup.ADDITIONwas added in small portions over 15 minute
3. 3
   Temperatureto maintain the reaction temperature less than 60° C
4. 4
   workup.STIRRINGThe thick slurry was then stirred for additional 2 hours at 40° C.
5. 5
   OtherThe salt of the tetramine was precipitated out
6. 6
   Filtrationthe solid filtered out
7. 7
   Washwashed with water
8. 8
   Otherdried under vacuum

Procedure

A 50 ml single neck round bottomed flask equipped with condenser, and stirring magnetic bar were placed SnCl2.2H2O (12 g, 53 mmol) and 25 ml concentrated hydrochloric acid and reaction mixture was stirred and than 3,3′-dinitrobenzidine (DNB) of formula 2 where in R═H (2.16 g, 7.9 mmol) was added in small portions over 15 minute to maintain the reaction temperature less than 60° C. The thick slurry was then stirred for additional 2 hours at 40° C. to complete the reduction. The salt of the tetramine was precipitated out, which was neutralized with cold 10% NaOH solution and the solid filtered out, washed with water dried under vacuum to give 3,3′-diaminobenzidine (DAB) in 74% yield (1.26 g).

Source