Preparation, Identification and study Antibacterial Activity of Some new 2,3-Dihydroquinazolin-4 (1H)-one Derivatives

I n this study some new compounds have been prepared including the reaction of diazoium salt of 1,4-phenylenediamine with 2-mercaptobenzaldehyde at (0-5) 0 C[F 1 ]. Then Schiff bases [F 2 -F 6 ] were then synthesized through the reaction of compound [F 1 ] with substituteds aniline in absolute ethanol, and Schiff bases were converted into 2,3 - dihyroquinazolin - 4(1H) - one derivatives [F 7 -F 11 ] by the reaction with 2-amino benzoic acid in ethanol. The prepared compounds were characterized by color and melting point, FT-IR, UV-Vis spectral analysis. Some of the prepared compounds were identified by 1 H-NMR spectra and C.H.N analysis. The antibacterial activities were studied against different kinds of bacteria, in addition, the stability of prepared dyes which proved to be of high stability and bright colors was studies, in addition the conformation of prepared compounds at the lower energy level were studied.


Introduction
Azo dyes contain at least one Nitrogen-Nitrogen double bond (N=N); however, many different structures are possible [1].Mono azo dyes have only( N=N) double bond, while diazo and triazo dyes contain two and three (N=N) double bonds, respectively.The azo groups are generally connected to benzene and naphthalene rings, but can also be attached to aromatic heterocyclic such as chloroquine [2].Schiff bases are one of the most prevalent and important mixed donor systems in the field of coordination chemistry.The first preparation of imines was reported in the 19 th century by Schiff (1864), which were prepared by condensing primary amines with an aldehyde or ketone under specific conditions.Because of the relative easiness of preparation, flexibility and special properties of C=N group, Schiff bases are considered as an excellent chelating agents.Schiff bases and its metal complexes have found to exhibit biological activities [3][4][5][6][7][8].Quinazolinones are among the most important classes of heterocyclic compounds, which possess versatile types of biological activities such as; anticancer [9,10], anti-tubercular [11], antibacterial [12], antifungal, anti-HIV activities [13].

Experimental
Materials: All chemicals have been used as supplied by (Merch, Fluka, BDH and Aldrich).Devices used: The melting points were determined by Electrothermal Melting Apparatus 9300 in open capillary tubes that were uncorrected.Thin layer chromatography ( TLC) was used for monitory the reaction and to check purity.The FT-IR spectra were recorded using FT-IR 8400S Shimadzu spectrophotometer Scale (4000-400)cm -1 .The UV-Vis.spectra was measured in ethanol using Shimadzu 800UV in rang (200-400) nm.H 1 -NMR Spectra was recorded on Varian operating at 400 MH 2 instrument using DMSO-d6 as a solvent.Quantitative analysis of the spectrophotometer elements determined using C.H.N analysis.

Results and Discussion
In this research many compounds were prepared including azo, Schiff bases and 2,3-dihydroquinazolin -4(1H)-one, as in the following Scheme:

Scheme: Represents preparation compound [F 1 -F 11 ]
Azo dye[F 1 ] was prepared by the reaction diazonium salt of 1,4-phenylenediamine with 2-mercapto benzaldehyde at (0-5) °C.The UV spectra showed the transions nπ* and ππ* which have confirmed the presence of the unbonded electrons pair on Nitrogen, Sulpher atoms and aromatic system (double bond).
The UV-Vis.spectra showed the transions nπ* and ππ* which have confirmed the presence of the unbonded electrons pair on Nitrogen, Sulpher, Oxygen atoms and aromatic system (double bond).

Dyeing process:
The resulting new dyes were highly colored and proven, as these dyes have thermal stability in which temperatures exceeded 100 °C, It was characterized by bright colors and showed clear consistency when washed with distilled water and dried, and then washed with sodium hypochlorite (NaOCl).This is due to the length of the double bonds sequence resulted from the large structural formulas of the prepared compounds, as shown in fig.(6,7).

Antibacterial activity
The effect of the prepared compounds on the growth of bacteria, namely: 1-Eschershia coli 2-Klebislla Pneumonia 3-Staphylococcus aureus 4-Staphylococcus epidermidis.Antibacterial activity of the prepared compounds were studied and the results showed that some of the prepared compounds possess good antibacterial activity [17].The results were shown in table (8), see Fig. (8)(9)(10)(11).

Table ( 2): Physical properties, yield and R f of 2,3-dihydroquinazolin-4(1H)-one [F 7 -F 11 ].
Dyeing was done for cotton and wool by dissolving prepared compounds [F 1 -F 11 ] in ethanol, then the cotton and wool were dried at (50°C) for one hour.Washing was done with distilled water, and dried again, washed with sodium hypochlorite (NaOCl) and then dried.The stability of prepared pigments and the dyes proved high stability and bright colors.