SYNTHESIS AND BIOLOGICAL ACTIVITY OF SOME NEW 1 , 2 , 4-TRIAZINO [ 6 , 1-B ] QUINAZOLINE DERIVATIVES

In this study, novel 3-substituted 1,2,4-triazino[6,1-b]quinazolines 4a-e, 8substituted-1H-[1,2,4]triazino[6,1-b]quinazoline-2,4,10(3H)-triones 8a&b and 2substituted 1,2,4-triazino[6,1-b]quinazolines 9a-d, 10 & 11 were synthesized from 3amino-6-bromo-2-ethoxycarbonylquinazolin-4(3H)-one (2b) and 3-amino-2aminocarbonylquinazolin-4(3H)-one 7a&b. Some of the newly synthesized compounds were tested for their antimicrobial activity and analgesic activity. Depending on the obtained results, the newly synthesized compounds possess significant analgesic activity and mild antimicrobial activity. Introduction Quinazoline derivatives have been reported to possess diverse biological activities such as analgesic (Alafeefy et al., 2010), anti-inflammatory (Alagarsamy et al., 2007; Chandrika et al., 2008; Giri et al., 2009), antimicrobial (Minu et al., 2008; Panneerselvam et al., 2009; Ryu et al., 2012) and anticancer (Noolvi et al., 2011 and Mulakayala et al., 2012). In addition 1,2,4-triazine derivatives were found to possess antimicrobial activity (Taha M.A.M., 2007 and Elsilk et al., 2010), antitumor activity (Gucky ́ et al., 2010). Finally, condensed [1,2,4]triazinoquinazoline were reported to have antibacterial and antifungal activity (Abdel-Mageed et al., 1988; Abdel-Hamide et al., 1997; Abdel-Hamide, 2001; Ghorab et al. 2013), anti-inflammatory activity (Bansal et al., 2001 and Hussein, 2012), anticancer activity (Kovalenko et al. 2013) and analgesic activity (Pathak et al. 1995). The above findings directed the attention to the synthesis of certain substituted [1,2,4]triazino[6,1-b]quinazoline hoping that they may possess antimicrobial activity and analgesic activity.


Experimental
Melting points were determined on a Griffin apparatus and are uncorrected.
Microanalysis for C, H and N were carried out at Microanalytical Centre, Cairo University and Organic Microanalyses Section, National Research Centre.IR spectra were recorded on Schimadzu 435 spectrometer using KBr discs. 1 H NMR spectra were performed on a Varian Gemini 200 MHz, Microanalytical Centre, Cairo University using TMS as an internal standard and chemical shift values are recorded in ppm on δ scale.Mass spectra were run at 70 ev on HP-5988A Mass spectrometer.Progress of the reactions was monitored by TLC using aluminium sheets percoated with UV fluorescent silica gel (Merck 60 F254) and were visualized using UV lamp and iodine vapour.The used solvent system was chloroform : benzene : methanol [6: 3.5 : 0.5].

Methodolgy
Using the agar plate disc-diffusion methodology ();agar plates containing 15 mL of agar medium were seeded with 0.2 mL of 18 hours broth culture of each organism.
Sterile filter paper discs (6 mm in diameter) were impregnated each with 10 μL of a saturated solution of the tested compounds in DMF and allowed to air drying.The discs were then placed onto the surface of agar plates and incubated at 37 o C for 48 hours.
Control discs impregnated with DMF were used to determine the solvent activity.The diameter of the inhibition zone around each disc was measured in mm.
The bacterial ciprofloxacin reference disc was tested as standard.

Conclusion
The obtained data (table 1) revealed that compounds 4b & 5b showed mild antibacterial activity against Gram-negative while compounds 8b & 9d showed mild antibacterial activity against Gram-positive, meanwhile compound 4b showed also mild antifungal activity.

Analgesic activity testing
Two comounds were tested for their analgesic activity via " acetic acid Induced Writhing Test'' using aspirin as standard.

Methodolgy:
1-Animals: Adult albino Swiss-Webster mic (18-25 g) of both sex, the animals were divided into four griups each of ten animals.They were housed in a quiet, temperature and humidity-controlled room (22 ± 3 o C and 60 ± 5 % respectivitely).

2-Drug administration:
The synthesized compounds (15 mg/Kg) and the tested used reference analgesic , aspirin (15 mg/Kg) were suspended in tween 80 and injected intraperitoneally.

3-Acetic Acid Induced Writhing Test():
The animals react with characteristic stretching behavior which is called wriyhing, when ininjected with an irritant such as acetic acid (0.6 %. 10 mL/Kg) into the peritoneal cavity of the mice.
The first two animal groups were administered the tested compounds in dose (15 mg/Kg) intraperitoneally followed by the intraperitoneal injection of acetic acid 30 min.later.The third group was dosed with the standard reference drug (aspirin) in the same dose of the tested compounds 30 min.before the injection of theacetic acid.Finally the fourth group was injected with tween 80 only as a test control.
The tested mice were observed for the total number of writhines within 20 min.after the acetic acid injection.
The mean values of each group and the percent of reduction of the writhes number were also calculated with respect to these of the control group.

Conclusion:
The tested compounds 4g & 9c were found to decrease the number of writhes induced by the injected acetic acid.
The analgesic activity of the two tested compounds were shown to be more potent than the analgesic activity of asirin.

Table 1 :
Antimicrobial activity of newly synthesized compounds on different microorganisms.

Table 2 :
Analgesic activity of newly synthesized compounds