Reaction #55992

Reaction equation

2-Amino-5,7-dimethylbenzothiazole

sodium

Ethoxymethylenemalononitrile

3,5-dimethylaniline

ammonium thiocyanate

N-(3,5-dimethylphenyl) thiourea

bromine

→

desired product

Yield 72.7%

2-[(5,7-Dimethylbenzothiazol-2-ylimino)methylene]-propanedinitrile

Yield 72.7%

Solvents

ethanol

chloroform

Conditions

Workup

1. 1
   workup.ADDITION(34.5 millimoles), was added to the solution
2. 2
   Temperaturethe mixture was heated
3. 3
   Temperatureat reflux for about 2 hrs
4. 4
   FiltrationThe precipitated solid was collected by filtration
5. 5
   Washwashed with ethanol
6. 6
   Otherdried in vacuo at 100°
7. 7
   Otheryielding 6.93 g
8. 8
   OtherA small portion was recrystallized from 95% ethanol

Procedure

- 2-Amino-5,7-dimethylbenzothiazole was prepared by treatment of 3,5-dimethylaniline with ammonium thiocyanate and conversion of the resulting N-(3,5-dimethylphenyl) thiourea with bromine and chloroform (Barnikow and Bodeker Ber. 100(5), 1394), m.p. 142°-144°. 2-Amino-5,7-dimethylbenzothiazole, 6.16 g. (34.5 millimoles) was added to a solution of a pea-sized piece of sodium in 40 ml. of anhydrous ethanol. Ethoxymethylenemalononitrile, 4.22 g. (34.5 millimoles), was added to the solution and the mixture was heated at reflux for about 2 hrs. The precipitated solid was collected by filtration, washed with ethanol, and dried in vacuo at 100°, yielding 6.93 g. (72.7%) of the desired product which was a yellow solid, m.p. 239°-241°. A small portion was recrystallized from 95% ethanol and submitted for analysis, m.p. 241°-243°.

Source