Reaction #81996

Reaction equation

3-fluoro-1,2-diaminobenzene

4-fluoro-1,2-diaminobenzene

NaOH

4-amino-3-nitrobenzonitrile

CaCl2

→

3,4-Diaminobenzonitrile

Solvents

H2O

EtOH

HCl

EtOH

Conditions

Workup

1. 1
   Temperatureto reflux
2. 2
   OtherA precipitate separated as fine tan needles which
3. 3
   Filtrationwere collected by vacuum filtration
4. 4
   Washrinsed with cold H2O
5. 5
   Dryingdried in a vacuum desiccator (0.5 torr, 25° C.) over CaSO4

Procedure

3,4-Diaminobenzonitrile was prepared using an adaptation of the method of Tsuji et al. (Tsuji, Y. et al., J. Org. Chem. 55: 580 (1990)). Zn powder (2.51 g, 38.3 mmol), CaCl2 (251 mg), H2O (3.0 mL) and 9.0 mL EtOH were combined and brought to reflux as described for 4-fluoro-1,2-diaminobenzene (Example 10) and to this mixture was added slowly dropwise a solution of 4-amino-3-nitrobenzonitrile (500 mg, 3.06 mmol) in 20 mL EtOH. Analysis and workup were described for 3-fluoro-1,2-diaminobenzene except that the reaction residue was dissolved in 20 mL 1N HCl. This solution was then made basic by the addition of 20 mL 1.5M NaOH. A precipitate separated as fine tan needles which were collected by vacuum filtration, rinsed with cold H2O and dried in a vacuum desiccator (0.5 torr, 25° C.) over CaSO4 to yield 275 mg (67%) of tan crystals. 1H NMR (CDCl3) δ 3.42 (br s, 2H, NH2), 3.86 (br s, 2H, NH2), 6.70 (d, J=8, 1H, ArH), 6.96 (d, J=1, 1H, ArH), 7.06 (dd, J=8, J=1, 1H, ArH).

Source