A SIAN J OURNAL OF C HEMISTRY A SIAN J OURNAL OF C HEMISTRY Synthesis of Some Substituted Pyrimidines Derived from 3-Acetyl Coumarin Asian of Chemistry; Vol. 27, No. 10 (2015),

The research work conducted during this study targets mainly the synthesis of a number of derivatives of coumarin containing ring pyrimidin-2-one substitutes different aromatic rings, taking advantage of the Biginelli reaction which includes the reaction of (3-acetyl coumarin) with suitable aromatic aldehydes and urea at the presence of AlCl 3 and ethanol absolute as a solvent. It has been indicated various scientific journals that have been referenced to the presence of biological activity is important and diverse to these kinds of compounds, which is the preparation of compound 3-acetyl coumarin ( 7 ) to be used as a compound base. The compounds created heterocyclic are expected to have various important biological and therapeutic applications. This proves structural formulas for each of new synthetic compounds on the basis of chemical reactions, rigorous analysis of the elements, the spectra infrared (FT-IR) and nuclear magnetic resonance of the ( 1 H NMR and 13 C NMR), in addition to various physical available means means.


INTRODUCTION
Coumarin derivatives received considerable attention by researchers as one of the compounds that possess medical and biological activities as well as industrial uses, where many of the products that contain coumarin units showed a various of pharmacological activities [1][2][3][4] . It is also found that compounds containing pyrimidine ring play an important role in many biological systems such as vitamins, enzymes assistance and many antibiotics as well as its presence in the nucleic acids 5 , which attracted multiple biological activities of compounds pyrimidine much attention in the past few years, so the researchers worked hard in the preparation of these compounds because of its great diversity in the effectiveness of biological and pharmaceutical critria 6 . The pyrimidine derivatives are major elements of a large number of pharmaceutical manufactured which show a group of derivatives pyrimidine activity as antimicrobial 8 , analgesic, antiviral, anti-inflammatory 9 , also anti-HIV 10 , anti-tubercular 11 , anti-tumor 12 , anti-malarial 13 and diuretic 14 , in addition to the pyrimidine compounds are also used as hypnotic drugs for the nervous system 15 . It can also prepare this type of compounds through a various of ways and Biginelli reaction 16 of the most important ways used for the preparation of this type of compounds, which includes this reaction blending ethyl acetoacetate (1) or its derivatives with benzaldehyde (2) or its derivatives, urea (3) and that the process occurs, the reaction is heating mixture of the three The research work conducted during this study targets mainly the synthesis of a number of derivatives of coumarin containing ring pyrimidin-2-one substitutes different aromatic rings, taking advantage of the Biginelli reaction which includes the reaction of (3-acetyl coumarin) with suitable aromatic aldehydes and urea at the presence of AlCl3 and ethanol absolute as a solvent. It has been indicated various scientific journals that have been referenced to the presence of biological activity is important and diverse to these kinds of compounds, which is the preparation of compound 3-acetyl coumarin (7) to be used as a compound base. The compounds created heterocyclic are expected to have various important biological and therapeutic applications. This proves structural formulas for each of new synthetic compounds on the basis of chemical reactions, rigorous analysis of the elements, the spectra infrared (FT-IR) and nuclear magnetic resonance of the ( 1 H NMR and 13 C NMR), in addition to various physical available means means.

Keywords: Coumarin derivatives, Pyrimidines substituted, 4,3-Dihydro-(4-aryl-6-coumarin)pyrimidin-2-one.
Asian Journal of Chemistry; Vol. 27, No. 10 (2015), 0000-0000 components dissolved in the solvent particularly with the availability of acidic conditions to produce through this method new derivatives pyrimidine known as 4,3-dihydro-pyrimidin-2-one (4) as shown in the following equation: Uracil is a very important class of pyrimidine derivatives 17a , where exhibit various pharmacological and biological activity 17b , for example, fluorouracil (5) is used widely as an anti-cancer 18 . While the compound 5-nitrouracil (6) used to inhibition of the enzyme thymidine phosphorylase 19 and also its derivative showed antibacterial activity 20 . Also 5-cinnamoyl-6-aminouracil (7) derivatives are used as agents inhibition against the growth of cancer cells 21 . While 6-aminouracils (8) find wide application as starting materials for the preparation of many of the active compounds and biologically important as well as, its derivatives can be used as a coupling component in dye chemistry 22 . In addition to the above mentioned properties, it was prepared a series of coumarin derivatives containing on pyrimidine ring (Scheme-I) and so by taking advantage of Biginelli condensing 23

General experimental procedures:
The chemicals used in the synthesis of all compounds were purchased from Aldrich, Merck and BDH Chemical Companies and used without further purification. The melting points were measured on an Electrothermal Melting point/SMP (Gallenkamp) and are uncorrected.
Either devices used in the spectral measurements are: (1) Infrared spectroscopy of type FT-IR spectrophotometer (Shimadzu), where KBr tablet used as a reference for those measurements. (2) Nuclear magnetic resonance spectroscopy of the proton and carbon-type Biospin Auance III and 400 MHz (Germany) 600 MHz using (DMSO-d6) as solvent and TMS as a reference.

Preparation of a series of compounds 3,4-dihydro(4aryl-6-coumarin)pyrimidin-2-one 23 (8-13):
A solution of 3acetylcoumarin (5mmol) in ethanol absolute (20 mL) contains AlCl3 (10 mol %) was refluxed with the appropriate substituted benzaldehyde (5 mmol) and urea (4 mmol) for about 8-12 h. The progress of reaction was monitored by TLC. After the completion of reaction, the reaction mixture was allowed to reach ambient temperature and then the precipitate formed was filtered, washed with water, dried and recrystallized from ethanol to get pure powder.
Coumarin derivatives (8)(9)(10)(11)(12)(13) were synthesized through of condensation 3-acetyl coumarin (7)  The mechanism proposed for this reaction includes two steps 26 : The first aldol condensation between benzaldeyde and methyl group to form a stabilized carbenium ion. A second step is the nucleophilic addition of urea gives the intermediate, which quickly dehydrates to give the desired product (Scheme-II).
The melting point was uncorrected which determined by open capillary tube and was listed in the Table-1 as well as other Physical properties. The synthesized compounds were characterized by their elemental analysis, IR, 1 H NMR, 13 C NMR. The IR spectra of the compounds 8-13 showed characteristic absorption bands at 3440-3172 cm -1 (OH; NH) stretching, 1751-1712 cm -1 due to (lactone C=O) and1697-1643 cm -1 attributed to the (amid C=O) stretching vibration. The absorption band seen at a 1596-1565 cm -1 could be attributed to the (C=C) stretching and other absorption bands was listed in Table-2. The 1 H NMR spectra of the compounds 8-13 showed singlet in the range 11.18-9.81 ppm, which is characteristic for N-H and singlet in the range 9.01-8.22 ppm due to H-4 for coumarin, as well as aromatic protons which is showed at range 7.98-7.00 ppm and other singles were listed in the Table-3. The 13 C NMR spectra of the compounds 8-13 showed singlet