Reaction #2139930

Reaction equation

N,N-diphenylhydrazine hydrochloride

4-diethylamino-2-hydroxybenzaldehyde

sodium carbonate

→

4-Diethylamino-2-hydroxybenzaldehyde N,N-diphenylhydrazone

Solvents

ethanol

ethanol

Conditions

Workup

1. 1
   Otherreacted in about ½ hour
2. 2
   OtherThe residue obtained
3. 3
   Otherafter evaporation of the solvent (800 ml)
4. 4
   workup.ADDITIONwas treated with ether
5. 5
   Extractionthe ether extract
6. 6
   Washwas washed with water until the pH of the water
7. 7
   DryingThe organic layer was dried over anhydrous magnesium sulphate
8. 8
   workup.ADDITIONtreated with activated charcoal
9. 9
   Filtrationfiltered
10. 10
    OtherThe ether solvent was evaporated
11. 11
    Otherthe residue was recrystallized from ethanol
12. 12
    FiltrationCrystalline 4-diethylamino-2-hydroxybenzaldehyde N,N-diphenylhydrazone was filtered off
13. 13
    Washwashed with cold ethanol
14. 14
    Otherto be 95.5-96.5° C.
15. 15
    Otherrecrystallized from a mixture of 2-propanol and ether in a 10:1 ratio by volume)
16. 16
    OtherAn elemental analysis yielded the
17. 17
    Otherfollowing results in weight percent

Procedure

A solution of N,N-diphenylhydrazine hydrochloride (79.5 g, 0.36 mol, from Aldrich, Milwaukee, Wis.) in ethanol (500 ml) was slowly added to a solution of 4-diethylamino-2-hydroxybenzaldehyde (58.0 g, 0.3 mol, from Aldrich, Milwaukee, Wis.) in ethanol (500 ml) in the presence of excess sodium carbonate. The reaction mixture was refluxed until all of the aldehyde reacted in about ½ hour. The residue obtained after evaporation of the solvent (800 ml) was treated with ether and the ether extract was washed with water until the pH of the water reached 7. The organic layer was dried over anhydrous magnesium sulphate, treated with activated charcoal, and filtered. The ether solvent was evaporated and the residue was recrystallized from ethanol. Crystalline 4-diethylamino-2-hydroxybenzaldehyde N,N-diphenylhydrazone was filtered off and washed with cold ethanol. The yield of the product was 85 g (78.8%). The melting point was found to be 95.5-96.5° C. (recrystallized from a mixture of 2-propanol and ether in a 10:1 ratio by volume). The 1H-NMR spectrum (100 MHz) of the product in CDCl3 was characterized by the following chemical shifts (δ, ppm): 11.55 (s, 1H, OH); 7.55-6.95 (m, 11H, CH═N, Ph); 6.7 (d, J=8.6 Hz; 1H, 6-H of 1,2,4-subst. Ph); 6.23 (s, 1H, 3-H of 1,2,4-subst. Ph); 6.1 (d, J=8.6 Hz, 1H, 5-H of 1,2,4-subst. Ph); 3.3 (q, J=8.0 Hz, 4H, CH2); 1.1 (t, J=8.0 Hz, 6H, CH3). An elemental analysis yielded the following results in weight percent: C, 76.68; H, 7.75; N, 11.45, which compared with calculated values for C23H25N3O in weight percent of: C, 76.85; H, 7.01; N, 11.69.

Source