Jafar N. N, Al-Dahmoshi H. O. M, JeburAlmamoori A. M, Al-Khafajii N. S. K, Al-Masoudi N. Synthesis and Biological Activity of New Derivatives of 6-chloro-5-((4-chlorophenyl)diazenyl)pyrimidine-2,4-diamine and 4-chloro-6-methoxy-N,N-dimethylpyrimidin-2-amine. Biomed Pharmacol J 2013;6(2)

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Nadhir Najimabdullah Jafar¹*, Hussein Oleiwi Muttaleb Al-Dahmoshi², Ayad Mohammed JeburAlmamoori², Noor Salman Kadhim Al-Khafajii³ and NajimAbod Al-Masoudi³

¹Deparment of Chemistry, Babylon University, College of science, Babylonl, Iraq. ²Deparment of Biology, Babylon University, College of Science, Babylon, Iraq. ³Department of chemistry, Basrah university, College of Science, Basrah, Iraq.

DOI : https://dx.doi.org/10.13005/bpj/442

Abstract

6-chloro-5-((4-chlorophenyl)diazenyl)pyrimidine-2,4-diamine and 4-chloro-6-methoxy-N,N-dimethylpyrimidin-2-aminehas been used as precursors for the synthesis of new pyrimidine derivatives, employing Suzuki cross-coupling reaction. Thus, treatment of pyrimidine derivativewith various arylboronic acids in the presence of palladium tetraacetate, PhP3 and Na2CO3 in refluxing n-propanol afforded the target compounds. The synthesis was supported by spectroanalytical techniques. The synthesized compounds have been screened for their inhibitory activity against some microbial, the results were showed that among gram positive isolates only (1/10) isolates of S. aureus and (3/10) isolates of S. saprophyticaus were sensitive for compound 13, while (1/10) isolates of S. aureus and (1/10) isolates of S.saprophyticaus were sensitive for compound 4. All isolates of S. pyogenes were resisting to all compounds, among gram negative bacterial isolates only (2/10) isolates of E. coli and (1/10) isolates of K. pneumoniae were sensitive to compound 4. Concerning the antifungal effects of compounds3, 4, 5, 13, 14, 15 the results revealed that, all C. albicans and C. glabrata isolate were resist these compounds.

Keywords

Pyrimidine; arylboronic acid; synthesis; Suzuki; gram positive

Introduction

Pyrimidine is a prominent member of the diazine family of heterocyclics. It is found throughout nature as a component of nucleic acids, nucleotides and corresponding nucleosides. Pyrimidine was first isolated by Gabriel and Colman in 1899 [1]. Pyrimidine represents one of the most active class of compounds possessing wide  spectrum of biological activity viz. significant in vitroactivity against unrelated DNA and RNA, viruses including polio herpes viruses, diuretic, antitumor, anti HIV, cardiovascular [2]. Methoprim, 5-(3,4,5-trimethoxybenzyl)pyrimidine-2,4-diamine (1) [3], is a potent and interesting pyrimidine analogue was used, since 1980, in combination with sulfamethoxazole as a bacteriostaticantibiotic (Co-trimoxazole) and mainly prescribed in the treatment of urinary tract infections and Pneumocystis jirovecii pneumonia, the most prevalent opportunistic microorganisms afflicting individuals with HIV positive patients.

Here cited compounds 

The biodynamic property of the pyrimidine ring system prompted us to account for their pharmacological properties as antimicrobials acting against microorganisms [4]. In addition to this, pyrimidines ring is also found in vitamin B1, barbituric acid (2,4,6-trihydroxy pyrimidine) and its several derivatives e.g. Veranal2, which are used as hypnotics [5]. In 1957, Heidelberger and Duschinsky [6] had discovered 5-fluorouracil (5FU) 3 as a potential drug for tumor inhibition in mice and till update; this drug is used for treatment of cancer, in general.

Result and Discussion

Chemistry

Synthesis of 5-azoaryl-4-thioalkyl- and 4-benzylhydrazinyl-pyrimidines.

Synthesis

The azo-pyrimidine derivative 2 have been prepared previously by Al-Masoudiet al. [7] from the commercially available 2,6-diamino-4-chloropyrimidine 1, and selected in our synthetic targets as a starting material for the synthesis of various pyrimidine analogs. Thus, treatment of 1 with p-chlorophenyldiazonium salt, prepared from reaction of p-chloroaniline with NaNO₂ and HCl at 0-5^oC, afforded 2,6-diamino-4-(p-chlorophenyl-azo)-4-chloropyrimidine 2. Nucleophilic substitution with primary and secondary aliphatic amines, as well as O- and S-nucleophiles (phenoxide and thiophenoxide ions), which are formed in situ in the reactions of phenols and thiophenols with bases, has been reported to be successful to some extent and well known [1-5]. Therefore, the presence of azo group at position 5 of compound 2 would facilitate the nucleophilic replacement of chloro group at position 4 by S-nucleophiles and amines. Treatment of 2 with NaSPh or NaSEt in DMF afforded, vianucleophilic displacements of the chlorine group, 3 and 4 in 89 and 90% yield, respectively. Similary, reaction of 2 with benzylhydrazine afforded compound 5 in 88% yields as shown in Scheme 1.

Here cited scheme

Scheme 1: Synthesis of compounds 3-5.

¹H and ¹³C NMR study

Structures of compounds 3-5 were assigned by the ¹H and ¹³C NMR spectra. The ¹H NMR spectra showed rather similar patterns for the phenyl and ethyl protons, while the singlets at d= 4.31-3.84 ppm was attributed to methylene of the benzylhydrazine group. The methylene protons (SCH₂) of compound 4 appeared at d 3.26 (J = 7.1 Hz) as a quartet, while methyl protons (SCH₃) appeared as a triplet at d = 1.29 ppm (J = 7.1 Hz). The aromatic protons H-3 and H-5 of 3 resonated at d = 7.78 ppm as a doublet (J = 7.0 Hz), while H-2 and H-6 appeared as a doublet at δ = 7.54 ppm (J = 7.0 Hz). C₆-NH₂ and C₂-NH₂ protons resonated at d = 9.25 and 8.10 ppm as two doublets (J = 5.0 and 5.1 Hz), respectively. The aromatic protons of 4 resonated in the range d = 7.90-7.80 ppm as a multiplet, while C₆-NH₂ and C₂-NH₂ protons appeared at δ = 9.25 and 6.88 ppm as two broad singlets, respectively. In¹³C NMR spectra of 3 and 4, C-4 of the pyrimidine ring resonated at d= 182.1 and d = 164.7 ppm, respectively, while C-2, C-5 and C-6 resonated at the regions (δ 164.6, 160.5 ppm), (δ = 118.5, 118.7 ppm) and (δ = 155.4, 155.9 ppm), respectively. The resonances at the regions δ= 166.9-161.0 ppm were attributed to C-4 and C-2 of 5, while, the resonances at δ = 104.7 and 105.5 ppm were assigned to C-5. The S-ethyl group of compound 4 were resonated at d = 14.5 ppm (CH₂ carbon atom) and d  = 23.0 ppm (CH₃ carbon atom).

ests. Structural modification of these compounds might optimize their biological activity by introducing diverse and potent functional group at pyrimidine back bone.

Experimental Section

Chemistry

General remarks

Melting points are uncorrected and were measured on a Stuart melting point apparatus (SMP30, England). The nuclear magnetic resonance data were obtained 400 and 600 MHz (¹H) and 150.91 MHz (¹³C) spectrometers (Avance III, Bruker, Germany), Tetramethylsilane TMS used as internal reference. The spectral data were reported in delta (δ) scale in ppm units relative to TMS reference line. Multiplicities (s = singlet, d = doublet, t = triplet, q = quartet and m = multiples).Heteronuclear assignments were verified by ¹H-¹³C HSQC experiments. Microanalytical data were obtained with a Vario, Elemental apparatus (Shimadzu, Japan). Thin layer chromatography (TLC) was carried out using TLC-silica plates GOF254 (0.2 mm) of the Merck Company. The detection was followed by UV-Lamp at 254 nm or through coloring with iodine. The chromatographic separations were carried out using silica gel (60-230 mesh). The ratio of the solvent and mixed mobile phases was given in volume ratio.

Solvents

Solvents were dried and purified by conventional methods prior to use. Acetone was dried and distilled prior to use from phosphorus pentaoxide (P₂O₅). Chloroform and dichloromethane were dried and distilled over dry Calcium chloride, collected over magnesium sulphate then filtered over magnesium sulphate. All of these solvent obtained from Scharalau. But Hexane, Ethanol, Methanol, Propanol, DMF obtained from Thomas Baker (chemicals) limited. Whereas THF and ethyl acetate were obtained from a BDH Chemical Ltd (pode England).

Chemicals

6-chloro-5-((4-chlorophenyl)diazenyl)pyrimidine-2,4-diamine were given from Prof. Najim Al-Masoudi prepared by same procedure puplished in .J.Med.Chem [7].

6-chloro-1,3-dimethyl-5-nitropyrimidine-2,4(1H,3H)-dione,2,6-Diamino-4-chloro-pyrimidine and all arylboronic acids listed below were purchased from Sigma-Aldrich.

synthesis

Preparation of 2,6-diamono-4-chloro-5-p-chlorophenylazopyrimidine

The compound was prepared by method described in reference [7] from the commercially available 2,6-diamino-4-chloropyrimidine 2 (2.55 g, 20 mmol) in 6N HCl (10 mL) and p-chlorophenyldiazonium salt [from NaNO₂ (1.38 g, 20 mmol) in water (6 mL) at 0 ^oC]. Yield: 78%, m.p. 267 ^oC, Lit. 268 ^oC.

Diamino-6-phenylthio-5-p-chlorophenylazopyrimidine

A solution of 2 (250 mg, 0.89 mmol) in benzene (20 mL) containing NaSPh (110 mg, 0.89 mmol) was heated under reflux. After for 8 h, the color of solution was changed into an yellow color, where the completion of reaction was monitored by TLC. After cooling, the solution was concentrated and left overnight at low temperature. The yellow crystals werecollected and recrystallized from EOH to give 3 (281 mg, 89%), m.p. 237-238 ^oC.¹H NMR (DMSO-d₆): δ = 9.25 (br s., 2H, C₆-NH₂); 7.90-7.30 (m, 9H, H_arom), 6.88 (br s., 2H, C₂-NH₂). ¹³C NMR (DMSO-d₆): δ = 182.1 (C-4); 164.6 (C-2); 155.4 (C-6); 139.8 (C_arom-Cl); 133.4 (C^1”_arom-S); 129.4, 129.3, 128.7, 128.3, 127.5, 125.4, 124.1, 122.9 (C_arom); 118.5 (C-5). Anal. calcd. For C₁₆H₁₃ClN₆S (356.83): C, 53.85; H, 3.67; N, 23.55. Found; C, 53.53; H, 3.54; N, 23.72.

Diamino-4-ethylthio-5-p-chlorophenylazapyrimidine

Method was analogues to the proceeding procedure, using instead 2 (250 mg, 0.87 mmol) and NaSEt (74 mg, 0.887 mmol). Yield: 235 mg (90%), m.p. 267-268 ^oC.¹H NMR (DMSO-d₆): δ = 9.25 (d, 2H, J = 5.0 Hz, C₆-NH₂); 8.10 (d, 2H, J = 5.1 Hz, C₂-NH₂); 7.78 (d, 2H, J = 7.0 Hz, H_arom-3 + H_arom-5); 7.54 (d, 2H, J = 7.0 Hz, H_arom-2 + H_arom-6). ¹³C NMR (DMSO-d₆): δ =164.7 (C-4); 161.2 (C-2); 155.9 (C-6); 133.5 (C_arom-Cl); 129.3, 123.3 (C_arom); 118.7 (C-5). Anal. calcd. For C₁₂H₁₃ClN₆S (308.79): C, 46.68; H, 4.24; N, 27.22. Found; C, 46.38; H, 4.18; N, 27.39.

Diamino-4-(2-benzylhydrazinyl)-5-p-chlorophenylazopyrimidine

To a solution of 2 (1.0 g, 3.54 mmol) in EtOH (30 mL) was added benzylhydrazine hydrochloride (0.45 g, 2.84 mmol) and the mixture was heated under reflux for 2 h. After cooling, the orange solution was concentrated and left overnight at 0 ^oC. The orange crystals werre filtered, and recrystallized from EtOH to give 8 (1.14 g, 88%), m.p. 211-215 ^oC.¹H NMR (DMSO-d₆): δ = 9.31 (br s., 2H, C₆-NH₂), 9.00-8.96 (m, 2H, 2xNH); 8.26 (brs., 2H, C₄-NH₂); 7.99-7.35 (m, 9H, H_arom); 4.06 (s, 2H, CH₂). ¹³C NMR (DMSO-d₆): δ = 164.7 (C-4); 160.5 (C-2); 155.4 (C-6); 139.8 (C¹_{phenylhydraz.}); 133.4 (C_arom-Cl); 129.3, 129.2, 128.4, 128.1 (C_arom); 103.8 (C-5); 53.6 (CH₂). Anal. calcd. For C₁₇H₁₇ClN₈. (368.82): C, 55.36; H, 4.65; N, 30.38. Found C, 55.36; H, 4.50; N, 30.21.

General procedure of Suzuki reaction for preparation of 7 and 12- 15

Diamino-4-(2-benzylhydrazinyl)-5-(4′-fluoro-[1,1′-biphenyl]-4-yl)pyrimidine 

A mixture of halopyrimidine and arylboronic acid in n-propanol (15 mL) was stirred for 15 min. To this mixture was added Pd(OAc)₄ (650 mg, 0.19 mmol), triphenylphosphene (498 mg, 0.19 mmol) and 2M aq. solution of Na₂CO₃ (3.5 mL). The reaction mixture was refluxed under nitrogen for 4-6 h and completion ofreaction was monitored by TLC. After cooling, water was added (7 mL), followed by stirring for 5 min. The mixture was partitioned with ethyl acetate (3×10 mL) and the combined organic layers were washed subsequently with 5% Na₂CO₃ solution (2×10 mL), brine solution (2×10 mL) and finally with water (10 mL). The organic phase was decolorized with charcoal, filtered and the filtrate was dried (Na₂SO₄), filtered through celite and evaporated to dryness to give, after purification, the desired product.

From 5 (70 mg, 0.19 mmol) and p-fluorophenylboronic acid 6 (27 mg, 0.19 mmol). Yield: 63 mg (78%), as a brown crystals, m.p. 180-182 ^oC (dec), R_f = 0.67 (eluent: etheyl acetate/ hexane 3:2). ¹H NMR (DMSO-d₆): δ = 8.03 (br s., 2H, C₆-NH₂). 7.82-7.67 (m, 4H, C₂-NH₂+2xNH); 7.64-7.31 (m, 13H, H_arom); 4.31 (d, 2H, J = 5.5 Hz, CH₂). ¹³C NMR (DMSO-d₆): δ = 166.9 (C-4); 162.1 (C-2); 161.1 (d, J_C4”,F = 250 Hz, C_4”-F); 152.2 (C-6); 139.5 (C-4′ + C¹_{phenylhydraz.}); 139.2 (d, J_C-1”,F = 2.4 Hz, C-1”); 133.9, 133.1, 131.9, 131.4, 129.2, 128.7, 128.6, 127.2, 119.2 (C_arom); 104.7 (C-5); 55.4 (CH₂). Anal. calcd. For C₂₃H₂₁FN₈ (428.46): C, 64.47; H, 4.94; N, 26.15. Found: C, 64.24; H, 4.90; N, 25.94.

Diamino-4-(3,4-dimethoxyphenyl)-5-(3,4-dimethoxy[1,1′-biphenyl]-4-yl) pyrimidine 

From 5 (122 mg, 0.40 mmol) and 3,4-dimethoxyphenylboronic acid9 (155 mg, 0.85 mmol). Yield: 193 mg (92%), as a red crystals, m.p. 165-166 ^oC, R_f= 0.54 (eluent: etheyl acetate/ hexane 3:2). ¹H NMR (DMSO-d₆): δ = 9.00 (br s, 2H, C₆-NH₂); 7.73-7.65 (m, 10H, H_arom); 6.71 (br s, 2H, C₂-NH₂); 3.83, 3.76, 3.74 (m, 12H, 4×OMe). ¹³C NMR (DMSO-d₆): δ = 163.7 (C-2); 161.7 (C-4), 160.9 (C-6), 151.8, 147.0 (4×C-OMe); 141.0 (C-1′); 131.9, 131.4, 131.3, 129.2, 128.7, 128.5 (C_arom); 122.9 (C-5); 113.5, 112.1, 110.3 (C_arom); 55.1 (4×OMe). Anal. calcd. for C₂₆H₂₆N₆O₄ (486.52): C, 64.19; H, 5.39; N, 17.27. Found: C, 64.56; H, 5.31; N, 17.20.

Diamino-4-(4-fluorophenyl)-5-(4-fluoro[1,1′-biphenyl]-4-yl) pyrimidine 

From 2 (86 mg, 0.30 mmol) and 4-Flurophenylboronic acid 6 (85 mg, 0.60 mmol) Yield: 93 mg (76%), as a red crystals, m.p. 179-180 ^oC, R_f = 0.70 (eluent: etheyl acetate/ hexane 2:1). ¹H NMR (DMSO-d₆): δ = 9.43 (br s, 2H, C₆-NH₂) 8.05-7.31 (m, 12H, H_arom); 7.06 (br s, 2H, C₂-NH₂). ¹³C NMR (DMSO-d₆): δ = 165.4 (C-2); 161.0 (m, C-4 + 2xC_4”-F); 155.9 (C-6); 139.7 (C-1′); 133.9, 133.1, 132.1, 131.45, 131.36, 130.67, 129.9, 127.2 (C_arom); 122.3 (C-5); 120.8, 116.2, 115.3 (C_arom-c+ C_arom-e+C-3”+C5”). Anal. calcd. For C₂₂H₁₆F₂N₆ (402.40): C, 65.66; H, 4.01; N, 20.88. Found: C, 65.42: H, 3.96; N, 20.65.

Diamino-4-(3,4-dimethoxyphenyl)-5-(3,4-dimethoxy[1,1′-biphenyl]-4-yl) pyrimidi

From 2 (122 mg, 0.40 mmol) and 3,4-dimethoxyphenylboronic acid 9 (155 mg, 0.85 mmol). Yield: 193 mg (92%), as a red crystals, m.p. 165-166 ^oC, R_f= 0.54 (eluent: etheyl acetate/ hexane 3:2). ¹H NMR (DMSO-d₆): δ = 9.00 (br s, 2H, C₆-NH₂); 7.73-7.65 (m, 10H, H_arom); 6.71 (br s, 2H, C₂-NH₂); 3.83, 3.76, 3.74 (m, 12H, 4×OMe). ¹³C NMR (DMSO-d₆): δ = 163.7 (C-2); 161.7 (C-4), 160.9 (C-6), 151.8, 147.0 (4×C-OMe); 141.0 (C-1′); 131.9, 131.4, 131.3, 129.2, 128.7, 128.5 (C_arom); 122.9 (C-5); 113.5, 112.1, 110.3 (C_arom); 55.1 (4×OMe). Anal. calcd. For C₂₆H₂₆N₆O₄ (486.52): C, 64.19; H, 5.39; N, 17.27. Found: C, 64.56; H, 5.31; N, 17.20.

Diamino-4-(2-benzylhydrazinyl)-5-(2′-fluoro-[1,1′-biphenyl]-4-yl)pyrimidine

From 5(70 mg, 0.19 mmol) and o-fluorophenylboronic acid (27 mg, 0.19 mmol). Yield: 63 mg (78%), as a brown crystals, m.p. 180-182 ^oC (dec), R_f = 0.67 (eluent: etheyl acetate/ hexane 3:2). ¹H NMR (DMSO-d₆): δ = 8.03 (br s., 2H, C₆-NH₂). 7.82-7.67 (m, 4H, C₂-NH₂+2xNH); 7.64-7.31 (m, 13H, H_arom); 4.31 (d, 2H, J = 5.5 Hz, CH₂). ¹³C NMR (DMSO-d₆): δ = 166.9 (C-4); 162.1 (C-2); 161.1 (d, J_C4”,F = 250 Hz, C_4”-F); 152.2 (C-6); 139.5 (C-4′ + C¹_{phenylhydraz.}); 139.2 (d, J_C-1”,F = 2.4 Hz, C-1”); 133.9, 133.1, 131.9, 131.4, 129.2, 128.7, 128.6, 127.2, 119.2 (C_arom); 104.7 (C-5); 55.4 (CH₂). Anal. calcd. for C₂₃H₂₁FN₈ (428.46): C, 64.47; H, 4.94; N, 26.15. Found: C, 64.24; H, 4.90; N, 25.94.

Diamino-4-(4-nitrophenyl)-5-(4-nitro[1,1′-biphenyl]-4-yl)pyrimidine

From 2 (213 mg, 0.75 mmol) and 4-nitrophenylboronic acid 11 (250 mg, 1.50 mmol). Yield: 323 mg, (94%), as a red crystals, m.p. 185-187 ^oC, R_f = 0.70 (eluent: etheyl acetate/ hexane 2:1). ¹H NMR (DMSO-d₆): δ = 9.24 (s, 2H, C₆-NH₂); 8.16-6.96 (m, 12H, H_arom); 6.94 (s, 2H, C₂-NH₂). ¹³C NMR (DMSO-d₆): δ = 164.5 (C-2); 161.0 (C-4); 155.7 (C-6); 150.9 (C-1” + 2×C_4”-NO₂); 133.2, 131.8, 131.2, 129.1, 126.0, 122.6, 121.9 (C_arom); 118.5 (C-5). Anal. calcd. For C₂₂H₁₆N₈O₄ (456.41): C, 57.89; H, 3.53; N, 24.55. Found: C, 57.76; H, 3.48; N, 24.71.

General procedure for preparation of 6-amino-4-methoxy-N,N-dimethyl-6-arylpyrimidines 20-23 via Suzuki reaction.

A suspension of 2-amino-4-chloro-6-methoxy-N,N-dimethylpyrimidine 16 and arylboronic acid in n-propanol (15 mL), then it was stirring for 15 minute until the solid was dissolved. To this solution Pd(OAc)₄ (360 mg, 0.11 mmol), Ph₃P (128 mg, 0.49 mmol) and 2M aq. solution of Na₂CO₃ (4 mL)was added. The reaction mixture was refluxed under nitrogen for 4-8 h, and the reaction progress was monitored by TLC (eluent: etheyl acetate/ hexane 1:1). After cooling, the reaction mixture was filtered, and concentrated under vaccum. The solid product was filtered and washed with cold ether to give the desired product.

Amino-4-methoxy-N,N-dimethyl-6-(4-nitrophenyl)pyrimidine

From 16 (100 mg, 0.53 mmol) and p-nitrophenolboronic acid 11 (89 mg, 0.53 mmol). Yield: 100 mg (68%), as a green crystals, m.p. 137-139 ^oC, R_f= 0.40. ¹H NMR (DMSO-d₆): δ = 8.35-8.16 (m, 4H, H_arom); 6.72 (s, 1H, H-5), 3.92 (s, 3H, OMe), 3.21 (s, 6H, NMe₂). ¹³C NMR (DMSO-d₆): δ =171.2 (C-4); 162.2 (C-2 + C-6); 148.8 (C_4′-NO₂); 143.8 (C_arom-1′); 128.4 (C_arom-2’+ C_arom-6′); 124.1 (C_arom-3’+ C_arom-5′); 92.5 (C-5); 53.5 (OMe); 36.9 (NMe₂). Anal. calcd. For C₁₃H₁₄N₄O₃ (274.28): C, 56.93; H, 5.14; N, 20.43. Found: C, 56.71; H, 5.02; N, 20.21.

(N,N-Dimethylamino)-6-methoxypyrimidin-4-yl)benzoic acid 

From 16 (100 mg, 0.53 mmol), and 3-boronobenzoic acid 17 (88 mg, 0.53 mmol). Yield: 85 mg (59%), as a white powder, m.p. >300 ^oC (dec.), R_f= 0.60. ¹H NMR (DMSO-d₆): δ = 10.45 (s, 1H, CO₂H); 8.29-8.02 (m, 4H, H_arom); 6.62 (s, 1H, H-5); 3.90 (s, 3H, C₄-OMe); 3.20 (s, 6H, NMe₂). ¹³C NMR (DMSO-d₆): δ =173.4 (CO₂H); 170.5 (C-4); 162.7 (C-6); 161.7 (C-2); 132.2, 130.9, 129.6, 129.1, 128.7 (C_arom); 91.4 (C-5); 52.8 (OMe); 36.3 (NMe₂). Anal. calcd. For C₁₄H₁₅N₃O₃ (273.29): C, 61.53; H, 5.53; N, 15.38. Found: C, 61.32; H, 5.41; N, 15.17.

Amino-4-(2-fluorophenyl)-6-methoxy-N,N-dimethylpyrimidine  

From 16(100 mg, 0.53 mmol) and 2-(fluoro)phenylboronic acid 18 (75 mg, 0.53 mmol). Yield: 96 mg, (73%), as a yellowish powder, m.p. 249-253 ^oC, R_f = 0.48. ¹H NMR (DMSO-d₆): δ = 7.81-7.43 (m, 4H, H_arom); 6.82 (s, 1H, H-5); 3.82 (s, 3H, C₄-OMe); 3.13 (s, 6H, NMe₂). ¹³C NMR (DMSO-d₆): δ = 171.8 (C-4); 164.4 (C-6); 161.1 (C-2); 156.6 (d, J_C2′,F = 251 Hz, C_2′-F); 129.2, 129.1, 128.8, 127.5, 125.4, 122.9. 115.1 (m, J_C,F couplings, C_arom); 95.0 (C-5); 53.5 (OMe); 36.8 (NMe₂). Anal. calcd. For C₁₃H₁₄FN₃O (247.27): C, 63.15; H, 5.71; N, 16.99. Found: C, 62.90; H, 5.65; N, 15.82.

(Dimethylamino)-6-methoxypyrimidin-4-yl)furan-2-carbaldehyde

From 16 (200 mg, 1.07 mmol) and (5-formyl-2-yl)boronic acid 19 (150 mg, 1.07 mmol). Yield: 177 mg (67%), as a pale brown powder, m.p. 248-250 ^oC (dec.), R_f= 0.61. ¹H NMR (DMSO-d₆): δ = 10.54 (s,1H, CHO); 8.58 (d, 1H, J = 5.2 Hz, H_furan-4′); 7.96 (d, 1H, J = 5.2 Hz, H_furan-3′); 6.83 (s, 1H, H-5); 4.25 (s, 3H, OMe); 2.94 (s, 6H, NMe₂). ¹³C NMR (DMSO-d₆): δ = 178.5 (CHO); 170.3 (C-4); 167.4 (C-6); 163.1 (C-2); 161.1 (C_furan-1′); 152.3 (C-CHO); 124.6 (C_furan-3′); 111.8 (C_furan-2′); 102.3 (C-5); 53.8 (OMe); 38.1 (NMe₂). Anal. calcd. For C₁₂H₁₃N₃O₃ (274.25): C, 58.29; H, 5.30; N, 16.99. Found: C, 58.02; H, 5.22; N, 16.42.

Biology

Tested Microbes

The antimicrobial effects of the fourteen synthetic organic compounds (under test) were experimented on the different local pathogenic isolates of gram positive bacteria (10 isolates of Staphylococcus aureus, 10 isolates of Staphylococcus saprophyticus  and 10 isolates of Streptococcus pyogenes), gram negative bacteria (10 isolates of Escherichia coli, 10 isolates of Klebsiella pneumonia and 10 isolates of Pseudomonas aeruginosa) and some of the clinically important yeast (10 isolates of Candida albicans and 10 isolates of Candida glabrata). All these isolates were gathered from the advanced microbiology lab, Biology departments in faculty of science- Babylon University, Iraq.

Well Diffusion Method

The synthetic organic compounds were used for studying their antibacterial activity. A loop full of the experimented isolates of bacteria or fungus was inoculated in 30 mL of Nutrient broth in a conical flask and incubated for 72 hrs to get active strain by using agar well diffusion method. Muller Hinton Agar (or Potato dextrose agar for fungus) was poured into Petri dishes. After solidification 0.25 ml of test, strains were inoculated in the media separately. Care was taken to ensure proper homogenization. The experiment was performed under strict aseptic conditions. After the medium solidified, a well was made in the plates with sterile borer (5mm).The compound (50 μl) was introduced into the well and plates were incubated at 37°C for 72 hrs. All samples were tested in triplicates. Microbial growth was determined by measuring the diameter of zone of inhibition [20]

Acknowledgements

We thank Mr. U. Haunz and Miss A. Friemel of chemistry department, University of Konstanz, Germany for NMR experiments.

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