Schiff Bases Derived from 1-Aminoanthraquinone: A New Class of Analgesic Compounds

Schiff Bases from 1-Aminoanthraquinone

Abstract

A series of Schiff bases 1-17 were synthesised by way of a facile condensation between 1-amino-
anthraquinone with a variety of carbonyl compounds in the presence of a catalytic amount of dodeca-
tungstosilicic acid/P2O5 under solvent free conditions at room temperature. These were charachterised by
1H- and 13C-NMR, LCMS, FTIR and elemental analyses. All the compounds were screened for their
analgesic activity using hot plate thermal stimuli method at dose of 10 and 30 mg/kg. Diclofenac sodium
was used as a reference drug. All the compounds at dose of 10 and 30 mg/kg body weight showed the
significant (p<0.05) increase in latency time as compared to control (normal saline). Compound 5 showed
excellent activity after 120 min of drug administration (10 mg/kg) of body weight. Compound 10 was
found to be potent (10.48±1.19s, 11.27±1.2s and 10.24±1.9s) at dose of 30 mg/kg at 30, 60 and 120 min,
respectively when compared to the standard drug. Compound 6 (10.13±0.4s) was also found to be an
excellent analgesic compound at a dose of 30 mg/kg at 120 min. However, the studies on analgesic activity
revealed that some of the target compounds may be strong candidates as an analgesic drug.