Synthesis , Spectroscopic and Antibacterial Investigation of New Molecular hybridized 4-Aminoantipyrine Derivatives of pharmaceutical Interest.

A new series of a hybridized 4-(N-substituted) aminoantipyrine derivatives with amide linkage backbone aminoantipyrine, series (A),compounds [13a-g] and secondary amine linkage, series(B), compounds [l4a-20a] were prepared through systematic sequence coupling reaction of 4-aminoantipyrine (4-AA) and well established active nitrogen bases moieties of phthalimide,piperidine and substituted aniline derivatives with chloroacetylchloride of actively different chlorine functions. . The antibacterial activity of some selected products was reported.


Introduction
Organic molecules owe their biological activities to verity of structural features; some activities are associated with the structural backbone of parent molecule others associated with the type and orientation of additives modification.However, many compounds containing the pyrazolone ring moiety have been prepared and reported to posses varied pharmacological activities (1-5).They used in the treatment of arthritis , musculoskeletal and joint disorders (6).Also, the term pyrazolone some time refer to the non steroidal anti-inflammatory drug (NSAID).e.g Phenylbutazone [1], Oxyphenbutazone [2].and Morazone (7) , [3].Additionally, analgesic and anti-pyretic activities were found to be associated with the pyazolone derivative, antipyrine [4].
The pyrazolone derivative 4-Aminoantipl.ren(4-AA),[5] have been used as intermediate for the Synthesis of pharmaceutically active ingredients e.g..Aminopyrine [6] and Dipyrone (DP), [7].Recent study reported that (4-AA) was as a metabolite of dipyrone(DP) , scheme I ,which was found to be associated with a property of delaying the gastric emptying (GE) of liquid meal in rats (8-9).
On the basis of the above finding ,encouraged us to prepare new modified antipyrine derivatives, compounds series (A )and (B ) as shown in scheme 2 and 3, hoping that such companion affect the pyrazolone ring bassist, hydrophilicity hexing a new biologically active pharmacophore.

Experimantal
Melting point were determined on digital electro thermal apparatus and are uncorrected.The IR spectra were recorded by FT-IR-8400s Shimadzu as KBr disc.U:V spectra were recorded by using CECIC-CE3021 spectrophotometers' I NMR spectra were recorded on Bruker AC-250 using TMS as internal stander .Elemental analysis were done by the analytical service unit, Faculat for chemi.Konstans University.

General procdure for the preparation of the new 4-( N-substituted ) aminoantipyrin. dervatives, compounds [13a-13g1 and [14a-20a].
Equimolar mixture of 0.02 mol. of nitrogen amine base and 0.02 mol.Of freshly distilled chloroacetylchloride in 40 ml of cold dry benzene and in the presence of 0.9 g,0.00lmol.Of potassium carbonate was stirred at room temperature for l-3 hrs .The solution mixture was filtered , evaporated and residue was collected and recrystalized from ethanol afforded the pure intermediates of 4-N-(chloroacetyl) amine base derivatives.Equimolar of the prepared.4-N-(chloroacetyl) arrine base 0.001 mol, .anddesired nitrogen amine base 0.001mol.in4o ml of dry benzene and the presence of 0.9 g, 0.001 mol.K2CO3 was stirred under refluxes for 4-8 hrs .The solution then filtered , evaporated and the precipitate collected and recrystalized from ethanol.

Results and Discussion
The new antipyrine derivatives compounds of series (A) ,and series (B) were prepared through a multistep reaction as outlined in scheme 2 and 3. Due to the highly active acetoyl chlorine the reaction of the chloroacetylchloride with the required amine in dry benzene and the presence of potassium carbonate at room temperature afford the N-(chloroacetyl) derivatives [13][14][15][16][17][18][19] '.In case of aniline derivatives was observed to be greatly affected by the substituent .Generally, substituent, electron withdrawing substituent showed the slower reaction time and that agree with the expected variation of aniline bassist and nucleophilicity .In case of the phthalimide derivative [20] was prepared by using sodium salt due to the slow and poor yield . ).The bathochromic shift in compounds of series (A) comparing to the parent aminoantipyrine may be due to formation of less stable conjugation chromophore consisted of rhe C3-C4 double bond,nitrogen lone pair and the carbonyl group in a extended resonance in the pyrazolone ring ,structure [12].by the inductive effect of amide carbonyl group .
The IR spectra (KBr disc) of both series showed a common carbonyl absorption as sharp strong band in the region 1650-1700) cm -l and 1600-1650 cm -1 assigned for amide and ring carbonyl stretching respectably.The spectra also exhibited.two broad band at 33 6l-3362cm -1 and3481-3482 cam assayed for the NH of amide and secondary amine stretching respectively.The l H NMR spectra of the prepared compounds showed pattern almost in good agreement with the required structure.Peaks of each proton was assigned according to their Environment (shieldeddesheilded) and comparison with that obtained for starting material and some intermediate.The spectra showed correct aliphatic/aromatic protons ratio supporting the stichiometry and the purity of the prepared compounds.However, the I H NMR spectrum of compound [13f] showed a remarkable up field shift signal at δ 2.88 ppm for the methylene protons compare to that observed for tire intermediate [19] which showed signal for the same protons at δ 4.22ppm supporting the replacement of the cblorine by piperidyl group, δ the spectrum a.tso showed three signal as multiple are δ 1.66,1.89andδ 3.12 ppm assigned for ring methylene protons.Also,the presence of aromatic protons signal as two multiple at δ 7.13-7 .42ppm supporting the right structure.

Preliminary antibacterial screening
Four of the synthesized new 4-AA derivatives , compounds ( 13f,13g) and (19ap0a) were selected for comparison in preliminary antibacterial screening ( Table l).The agar diffusion technique(l3'ra) was applied The organism tested were a Staphylococcus aureus.Escherichia coli and,Klebsiella sp.The agar media were incubated with the tested organisms and a solution of testedcompound in sterile water and ethanol (lmg/ml) was placed separately in discks (8mm.diameter)in the agar medium.The resulting inhibition zones were measured after 24 hrs incubation.A0.l% solution .Ciprofloxacin was used as reference., as shown in Table l.It could be concluded, that there were no effect of tested compounds 13f,13gr19a and 20a on the different bacterial strains, compared to the reference antibiotic.Other pharmacological evaluation is under investigation.

Table (l):
-The inhibition zones in mm.of compounds 13f,13g,19a and 20a and the antibiotics control against S. aureus, E.coli and klebsiella sp.
reaction with the free phthalimide base Coupling of the prepared Nchloroaetyl derivatives with the corresponding amine in refluxing dry benzene and the presence of potassium carbonate afforded the required compounds of series (A),[13a-g] and [l4a-20a), seies(B).The prepared compounds were characterized by UV , IR , I H NMRand elemental analysis.The UV spectral were carried out in ethanol and the.λmax for the pyrazolone ring were determined according to the comparison with that observed of series (A) of amide link aminoantipyrine showed λ max at range of (223 -229 nm ),while compounds of series (B ) of amine link antipl,rine showd λ max at range of (231-245nm