Synthesis, screening and quantitative structure-activity relationship (QSAR) studies of some glutamine analogues for possible anticancer activity

We described the syntheses, biological activities and QSAR studies of 36 new 5-n-substituted-2-(substituted benzenesulphonyl) glutamines 6-41 with different substitutions. These compounds were designed as structural analogues of most reactive amino acid, 'glutamine' (GLN), especially in the tumor cells. They present the new basic lateral chains at R(5) position as well as different substitutions at 2', 3', 4', and 5' positions on the benzene ring. The synthesized compounds have been tested for antitumor activity against Ehrlich ascites carcinoma (EAC) in Swiss albino mice using percentage inhibition of tumor weight as inhibitory parameter. In order to elucidate the structural requirements for antitumor activity, quantitative structure-activity relationship (QSAR) studies have been performed using extra thermodynamic model of Hansch. QSAR equations showed that the electronic parameter (sigma) on the aromatic ring system, steric parameter (Es) and to some extent Sterimol length of the substituent (L) on the aliphatic side chain correlate significantly with the antitumor activity. Resonance factor occupies the major electronic contribution on the aromatic ring system to the activity.