Kamp melting point apparatus. The infrared spectra were registered as KBr disc on FTIR 8300

Transcription

1 EXPERIMENTAL All melting points are uncorrected and determined by the open capillary method using Gallen Kamp melting point apparatus. The infrared spectra were registered as KBr disc on FTIR 8300 Shimadzu Spectrophotometer and the results are expressed in wave number (cm-1). 1H NMR and 13CNMR spectra were recorded with Bruker AC 300 spectrometer (Fällanden, Switzerland) operating at 300 MHz for 1H and 75 MHz for 13 C, using deuterochloroform (CDCl3) as a solvent. Chemical shifts are expressed in δ (ppm) using TMS as the internal standard. Elemental microanalysis was carried out using CHNS elemental analyzer model EA3000 EURO VECTOR instruments. Surface active properties measurements of the prepared surfactants (γ) were made at 25 C with Du Nouy tensiometer (Kruss Type 8451) and biological activity are carried out at. Microbiology Department Faculty of Applied Science, Umm Al-Qura University, Kingdom of Saudi Arabia. Synthesis of 5-pentadecyl-1,3,4-thiadiazol-2-amine (2). A mixture of palmitic acid 1 (2.56g, 0.01 mol) and thiosemicarbazide (091g, 0.01 mol) in (20 ml) POCl 3 was refluxed for 8 hr. The reaction mixture was concentrated, cooled, and then poured onto ice while stirring. The produced solid was filtered off and recrystallized from ethanol. Pale yellow powder, yield, 1.89 g (74%), m.p o C. IR (ν/cm -1 ): 3363, 3192 (NH 2 ), 2849, 2916 (CH aliphatic), 1587 (C=N); 1 H NMR (δ, ppm): 0.88 (t, 3H, terminal CH 3 ), (m, 28H, 14 CH 2 of alkyl chain), 6.55 (brs, 2H, NH2). Anal. Calc. (%) for C 17 H 33 N 3 S (311.53): C, 65.54; H, 10.68; N, 13.49; S, Found: C, 65.76; H, 10.80; N, 13.62; S, Synthesis of 2-cyano-N-(5-pentadecyl-1,3,4-thiadiazol-2-yl)acetamide (3) To a solution of compound 2 (3.11 g, 0.01 mol) in dimethylformamide (30 ml), ethyl cyanoacetate (1.13 g, 0.01 mol) was added. The reaction mixture was heated under reflux for 5 h. The solid product formed upon pouring onto ice/water mixture was collected by filtration and

2 crystallized from 1,4-dioxane. White crystals, m.p C, yield, 2.33g (75%). IR (ν/cm -1 ): 3243 (NH), 2848, 2915 (CH aliphatic), 2199 (C N), 1688 (C=O), 1579 (C=N); 1 H NMR (δ, ppm): 0.89 (t, 3H, terminal CH 3 ), (m, 28H, 14CH 2 of alkyl chain), 2.99 (s, 2H, CH 2 ), 8.19 (s, 1H, NH) exchangeable by D 2 O. Anal. Calc. (%) for C 20 H 34 N 4 OS: (378.58): C, 63.45; H, 9.05; N, 14.80; S, Found: C, 63.68; H, 9.26; N, 14.99; S, Synthesis of 2-oxo-N-(5-pentadecyl-1,3,4-thiadiazol-2-yl)-2H-chromene-3-carboxamide (4). Procedure [31] Dissolved compound 3 (3.78 g, 0.01 mol) in 1,4-dioxane (25 ml) with piperidine (1.00 ml), and salicylaldehyde (1.22 g, 0.01 mol) was added. The reaction mixture was allowed to reflux for 5 hr. The solid products formed upon pouring onto ice-water mixture containing few drops of hydrochloric acid was collected by filtration and crystallized from 1,4-dioxane.Yellow crystals, m.p C, yield: 2.57 g (68%). IR (ν/cm -1 ): 3327 (NH), 3055 (CH aromatic), 2916, 2849 (CH2), 1690, 1664 (2C=O), 1601 (C=C), 1559 (C=N); 1 H NMR (δ, ppm): 0.86 (t, 3H, terminal CH 3, (m, 28H, 14 CH 2 of alkyl chain), 5.57 (s, 1H, CH of coumarin ring), (m, 4H, ArH), 8.68 (s, 1H, NH). Anal. Calc. (%) for C 27 H 37 N 3 O 3 S: (483.67): C, 67.05; H, 7.71; N, 8.69; S, Found: C, 67.31; H, 7.94; N, 8.86; S, Synthesis of (E)-2-cyano-N-(5-pentadecyl-1,3,4-thiadiazol-2-yl)-3-phenylacrylamide (5). Procedure [32] To a mixture of compound 3 (3.78 g, 0.01 mol) in 1,4-dioxane (25 ml) with piperidine (1.00 ml), benzaldehyde (1.06 g, 0.01 mol) was added. The reaction mixture was heated under reflux for 5 hr. The solid products formed upon pouring onto ice-water mixture containing few drops of hydrochloric acid was collected by filtration and crystallized from 1,4-dioxane. White yellow crystals, m.p C, yield: 2.94 g (78%). IR (ν/cm -1 ): 3192 (NH), 3057 (CH aromatic), 2848, 2916 (CH aliphatic, CH2), 2203 (C N), 1669 (C=O), 1622 (CH oliphenic, 1593 (C=N); 1 H NMR (δ, ppm): 0.86 (t, 3H, terminal CH 3 ), (m, 28H, 14 CH 2 of alkyl chain), (m, 5H,

3 ArH), 8.16 (s, 1H, benzylidine CH), 9.42 (s, 1H, NH). Anal. Calc. (%) for C 27 H 38 N 4 OS: (466.68): C, 69.49; H, 8.21; N, 12.01; S, Found: C, 69.26; H, 8.01; N, 11.84; S, Synthesis of 3-amino-N-(5-pentadecyl-1,3,4-thiadiazol-2-yl)-5-phenyl-1H-pyrazole-4-carboxamide (6a). Procedure [32] To a solution of compound 5 (4.66 g, 0.01 mol) in 1,4-dioxane (25 ml) and dimethylformamide (10 ml), hydrazine hydrate (0.50 g, 0.01 mol) was added. The reaction mixture, was heated under reflux for 5 h. The solid products formed, in each case, upon pouring onto ice/water mixture containing few drops of hydrochloric acid were collected by filtration, and crystallized from 1,4-dioxane/ dimethylformamide mixture. Pale yellow crystals, m.p C, yield: 3.26 g (70%). IR (ν/cm -1 ): 3363, 3269, 3199 (2NH, NH 2 ), 3058 (CH aromatic), 2849, 2915 (CH aliphatic, CH 2 ), 1685 (C=O), 1632 (C=C), 1593 (C=N); 1 H NMR (δ, ppm): 0.86 (t, 3H, terminal CH 3 ), (m, 28H, 14CH 2 of alkyl chain), 3.15 (s, 2H, NH 2 ), (m, 5H, ArH), 9.44 (s, 1H, NH-CO), (s, 1H, NH of pyrazole ring); 13 C NMR (δ, ppm): 14.72, 28.96, 29.22, 29.29, 29.32, 29.37, 29.47, 29.55, 29.61, 29.66, 29.69, 29.71, 30.35, 31.93, , , , , , , ,157.10, , Anal. Calc. (%) C 27 H 40 N 6 OS: (496.71): C, 65.29; H, 8.12; N, 16.92; S, Found: C, 65.04; H, 7.88; N, 16.69; S, Synthesis of 3-amino-N-(5-pentadecyl-1,3,4-thiadiazol-2-yl)-5-phenylisoxazole-4-carbox-amide (6b). Procedure [32] An equimolar amount of compound 5 (4.66 g, 0.01 mol) and hydroxyl amine hydrochloride (0.51 g, 0.01 mol) in 1,4-dioxane (25 ml) and dimethylformamide (10 ml) was refluxed for 5 hr. The solid products formed, upon pouring onto ice/water mixture containing few drops of hydrochloric acid were collected by filtration, and crystallized from 1,4-dioxane. Pale orange crystals, m.p C, yield: 3.44 g (74%). IR (ν/cm -1 ): 3364, 3198 (NH, NH 2 ), 3058 (CH

4 aromatic), 2848, 2916 CH aliphatic), 1686 (C=O), 1641 (C=C), 1632, 1593 (C=N); 1 H NMR (δ, ppm): 0.87 (t, 3H, terminal CH 3 ), (m, 28H, 14CH 2 of alkyl chain), 2.84 (s, 2H, NH 2 ), (m, 5H, ArH), 9.15 (s, 1H, NH). Anal. Calc. (%) C 27 H 39 N 5 O 2 S: (497.70): C, 65.16; H, 7.90; N, 14.07; S, Found: C, 64.88; H, 7.69; N, 13.81; S, Synthesis of 6-amino-2-oxo-1-(5-pentadecyl-1,3,4-thiadiazol-2-yl)-4-phenyl-1,2-dihydropyridine-3,5-dicarbonitrile (7). Procedure [33] To a solution of compound 5 (4.66 g, 0.01 mol) in 1,4-dioxane (25 ml) and dimethylformamide (5 ml) containing triethylamine (1.00 ml), malononitrile (0.66 g, 0.01 mol) was added. The reaction mixture, was heated under reflux for 5 hr, then cooled and neutralized by pouring onto ice/water mixture containing few drops of hydrochloric acid. The solid products formed, was filtered off and crystallized from 1,4-dioxane/dimethylformamide mixture. Pale yellow crystals, m.p C, yield: 3.35 g (72 %). IR (ν, cm 1 ): 3353, 3203 (NH2), 2849, 2917 (CH aliphatic), 2217, 2176 (2 C N), 1669 (C=O), 1622 (C=C), 1590 (C=N); 1 H NMR (δ, ppm): 0.89 (t, 3H, terminal CH 3 ), (m, 28H, 14CH 2 of alkyl chain), (m, 5H, ArH), 5.69 (s, 2H, NH 2 ); 13 C NMR (δ, ppm): 14.14, 22.70, 28.97, 29.23, 29.37, 29.47, 29.60, , 29.70, 30.38, 31.92, , , , , , , , , , , , , , ,166.48, Anal. Calc. (%) C 30 H 38 N 6 OS: (530.73): C, 67.89; H, 7.22; N, 15.83; S, Found: C, 67.66; H, 7.00; N, 15.61; S, Synthesis of 4,6-diamino-2-oxo-1-(5-pentadecyl-1,3,4-thiadiazol-2-yl)-1,2-dihydropyridine-3- carbonitrile (8). Procedure [33] A mixture of compound 3 (3.78 g, 0.01 mol), and malononitrile (0.66 g, 0.01 mol) in 1,4- dioxane (25 ml) and dimethylformamide (5 ml) containing triethylamine (1.00 ml) was heated under reflux for 5 hr, then cooled and neutralized by pouring onto ice/water mixture containing few

5 drops of hydrochloric acid. The solid products formed, was filtered off and crystallized from etanol. Pale orange crystals, m.p C, yield: 2.87 g (76%); IR (ν, cm 1 ): (2NH2), 2848, 2916 (CH aliphatic), 2210 (C N), 1684 (C=O), 1641, 1632 (C=C), 1593, 1568 (C=N); 1 H NMR (δ, ppm): 0.85 (t, 3H, terminal CH 3 ), (m, 28H, 14CH 2 of alkyl chain), 3.7, 3.67 (2s, 4H, 2 NH 2 ), 6.37 (s, 1H, CH of pyridine ring).anal. Calc. (%) C 23 H 36 N 6 OS: (444.64): C, 62.13; H, 8.16; N, 18.90; S, Found: C, 62.34; H, 8.36; N, 19.08; S, Synthesis of 3,5-diamino-4-cyano-N-(5-pentadecyl-1,3,4-thiadiazol-2-yl)thiophene-2-carboxamide (9). Procedure [31] To a solution of compound 3 (3.78 g, 0.01 mol) in 1,4-dioxane (25 ml) containing triethylamine (1.00 ml), malononitrile (0.66 g, 0.01 mol) was added followed by the addition of an equimolar amount of elemental sulfur (0.32 g, 0.01 mol). The reaction mixture was heated under reflux for 5 hr, then cooled and neutralized by pouring onto ice/water mixture containing few drops of hydrochloric acid. The solid product formed was collected by filtration and crystallized from dimethyl formamide. Brown crystals, m.p C, yield: 2.38 g (63%). IR (ν,cm 1 ): (NH, 2NH 2 ), 2848, 2919 (CH aliphatic), 2199 (C N), 1683 (C=O), 1587 (C=C), 1490 (C=N); 1 H NMR (δ, ppm): 0.88 (t, 3H, terminal CH 3 ), (m, 28H, 14CH 2 of alkyl chain), 3.73, 3.92 (2s, 4H, 2NH 2 ), 6.83 (s, 1H, NH). Anal. Calc. (%) C 23 H 36 N 6 OS 2 : (476.70): C, 57.95; H, 7.61; N, 17.63; S, Found: C, 57.67; H, 7.40; N, 17.37; S, Synthesis of 4-dmino-N-(5-pentadecyl-1,3,4-thiadiazol-2-yl)-3-phenyl-2-thioxo-2,3-dihydrothiazole-5-carboxamide (10). Procedure [34] To a mixture of compound 3 (3.78 g, 0.01 mol) in 1,4-dioxane (25 ml) containing triethylamine (1.00 ml), phenyl isothiocyanate (1.35 g, 0.01 mol) was added followed by the addition of an equimolar amount of elemental sulfur (0.32 g, 0.01 mol). The reaction mixture was

6 heated under reflux for 5 hr, then cooled and neutralized by pouring onto ice/water mixture containing few drops of hydrochloric acid. The solid product formed collected by filtration and crystallized from dimethyl formamide. Dark brown crystals, m.p C, yield: 2.60 g (69 %). IR (ν, cm 1 ): 3318, 3141 (NH, NH 2 ), 2848, 2916 (CH aliphatic), 1678 (C=O), 1618 (C=C), 1570 (C=N), 1291 (C=S); 1 H NMR (δ, ppm): 0.79 (t, 3H, terminal CH 3 ), (m, 28H, 14CH 2 of alkyl chain), 4.68 (s, 2H, NH 2 ), (m, 5H, ArH), (s, 1H, NH). Anal. Calc. (%) C 27 H 39 N 5 OS 3 (545.83): C, 59.41; H, 7.20; N, 12.83; S, Found: C, 59.65; H, 7.51; N, 13.07; S, Syntheses of 6-amino-3-(5-pentadecyl-1,3,4-thiadiazol-2-yl)-1-phenyl-2-thioxo-2,3-dihydropyrimidin-4(1H)-one (11) Procedure [33] Equimolar amounts of compound 3 (3.78 g, 0.01 mol) and phenyl isothiocyanate (1.35 g, 0.01 mol) in 1,4-dioxane (20 ml) containing triethylamine (1.0 ml) were heated under reflux for 5hr. After cooling, the reaction mixture was acidified by hydrochloric acid and the crude product was precipitated, collected by filtration and crystallized from dimethylformamide. Pale yellow crystals, C, yield: 3.02 g (80%); IR (ν, cm 1 ): 3327, 3206 (NH 2 ), 2849, 2916 (CH aliphatic), 1689 (C=O), 1601 (C=C); 1559 (C=N), 1268 (C=S); 1 H NMR (δ, ppm): 0.86 (t, 3H, terminal CH 3 ), (m, 28H, 14CH 2 of alkyl chain), 3.09 (s, 1H, pyrimidine C3-H), (m, 5H, ArH), 7.82 (s, 2H, NH 2 ). 13 C NMR (δ, ppm): 14.12, 29.29, 29.37, 29.40, 29.45, 29.47, 29.64, 29.67, 29.71, 29.77, 29.85, 30.30, 31.93, 34.24, 36.26, 45.82, , , , , , , , , , , Anal. Calc. (%) C 27 H 39 N 5 OS 2 : (513.76): C, 63.12; H, 7.65; N, 13.63; S, Found: C, 63.38; H, 7.83; N, 13.90; S, Synthesis of (E)-2-oxo-2-((5-pentadecyl-1,3,4-thiadiazol-2-yl)amino)-N'-phenylacetohydrazonoyl cyanide (12). Procedure [33]

7 To a cold solution (0 5 C) of compound 3 (3.78 g, 0.01 mol), in ethanol (20 ml) containing sodium hydroxide (1.00 g) an equimolar amount of diazotized aniline was gradually added while stirring. The solid product formed upon cooling in an ice-bath was collected by filtration, washed with water and crystallized from 1,4-dioxane. Pale yellow crystals, m.p C, yield: 2.34 g (62%); IR (ν,cm 1 ): 3352, 3205 (2NH), 2849, 2917 (CH aliphatic), 2217 (C N), 1669 (C=O), 1598 (C=N); 1 H NMR (δ, ppm): 0.86 (t, 3H, terminal CH 3 ), (m, 28H, 14CH 2 of alkyl chain), (m, 5H, ArH), 9.56,11.62 (2s, 2H, 2NH). 13 C NMR (δ, ppm): 14.10, 29.23, 29.37, 29.44, 29.54, 29.60, 29.65, 29.66, 29.67, 29.70, 29.74, 29.88, 29.91, 30.39, 31.92, , , , , , , , , , , Anal. Calc. (%) C 26 H 38 N 6 OS: (482.68): C, 64.70; H, 7.94; N, 17.41; S, Found: C, 64.48; H, 7.75; N, 17.23; S, Synthesis of 2,4-diamino-6-oxo-1-(5-pentadecyl-1,3,4-thiadiazol-2-yl)-5-(phenyldiazenyl) -1,6- dihydropyridine-3-carbonitrile (13). Procedure [35] To a solution of compound 12 (4.82 g, 0.01 mol) in ethanol (25 ml) and dimethylformamide (5 ml) containing triethylamine (1.00 ml), malononitrile (0.66 g, 0.01 mol) was added. The reaction mixture, was heated under reflux for 5 hr, then cooled and neutralized by pouring onto ice/water mixture containing few drops of hydrochloric acid. The solid products formed, was filtered off and crystallized from ethanol/dimethylformamide mixture. Dark yellow crystals, m.p C, yield: 3.76 g (78%); IR (ν,cm 1 ): (2NH 2 ), 3057 (CH aromatic), 2848, 2916 (CH alipatic), 2207 (C N), 1685 (C=O), 1632 (C=C), 1593 (C=N); 1 H NMR (δ, ppm): 0.86 (t, 3H, terminal CH 3 ), (m, 28H, 14CH 2 of alkyl chain), 3.02, 3.70 (2s, 4H, 2NH 2 ), (m, 5H, ArH),. Anal. Calc. (%) C 29 H 40 N 8 OS (548.75): C, 63.47; H, 7.35; N, 20.42; S, Found: C, 63.65; H, 7.56; N, 20.67; S, Synthesis of 2-(4-oxo-4,5-dihydrothiazol-2-yl)-N-(5-pentadecyl-1,3,4-thiadiazol-2-yl)acetamide (14).

8 Procedure [36] To a stirred solution of compound 3 (3.78g, 0.01 mol) in glacial acetic acid (30 ml), thioglycollic acid (0.92g, 0.01 mol) was added. The reaction mixture was refluxed for 10 hr, evaporated under reduced pressure. The residue was solidified with petroleum ether, the obtained solid was filtered off, dried and crystallized from ethanol, m.p o C, yield: 2.43 g (65%); IR (ν/cm -1 ): 3376 (NH), 2849, 2916 (CH aliphatic), 1688, 1667 (C=O), 1579 (C=N). 1 H NMR (CDCl 3 ): δ 0.86 (t, 3H, terminal CH 3 ), (m, 28H, 14 CH 2 in alkyl chain), 1.74 (s, 2H, COCH 2 ), 2.93 (s, 2H, CH 2 of thiazole ring), 7.92 (s, 1H, NH). Anal. Calc. (%) C 22 H 36 N 4 O 2 S 2 (452.68): C, 58.37; H, 8.02; N, 12.38; S, Found: C, 58.37; H, 8.02; N, 12.38; S, Preparation of nonionic surface active agents (Propoxylation) Following Morgos procedure [37], 0.5 wt % KOH solution containing 0.01 mol of the synthesized compound was stirred and heated to 70 o C while passing a slow stream of nitrogen through the system to flush out oxygen. The nitrogen stream was stopped and propylene oxide (5 moles) was added drop-wise with continuous stirring and heating under an efficient reflux system to retain the propylene oxide. The reaction was conducted for different intervals of time ranging from 1 10 h. The apparatus was then filled with nitrogen and cooled. The reaction vessel was weighed. The amount of reacted propylene oxide and the average degree of propoxylation were determined from the increment in the mass of the reaction mixture [38]. Antimicrobial activity The cap-assay method containing (g/l): peptone 6, yeast extract 3, meat extract 1.5, glucose 1 and agar 20 were used. The medium was sterilized and divided while hot (50 60 C) in 15 ml portions among sterile petri-dishes of 9 cm diameter. One ml of the spore suspension of each microorganism was spread all over the surface of the cold solid medium placed in the petri-dish. Each of the tested compounds (0.5 g) was dissolved in 5 ml of dimethylformamide. An amount of 0.1 ml of test solution was placed on watman paper disc of 9 mm diameter and the solvent was left

9 to evaporate. These saturated discs were placed carefully on the surface of the inoculated solid medium; each petri-dish contains at least 3 discs. The petri-dishes were incubated at 5 C for an hour to permit good diffusion and then transferred to an incubator of 85 C overnight, then examined. The results were recorded by measuring the inhibition zone diameters [39] were tabled in Table 1. Surface active properties of surfactants Surface and interfacial tension. Surface and interfacial tension measurements on (15-28) were carried out according to Findlay [40] with a Kru ss tensiometer [41] (Kru ss GmbH, Hamburg, Instrument Nr. K 6 ) for different concentrations of the synthesized surfactants ( mol/l), using a platinumiridium ring at constant temperature (25 ± 1 o C). Paraffin oil was used for the interfacial tension measurements. The tensiometer was calibrated using the method described in ASTM Designation: D [42]. Cloud point. The cloud point is a measure of the inverse solubility of a nonionic surface active agent. In a temperature-controlled bath, a 1.0 wt% solution of the tested compound was gradually heated until the clear or nearly clear solution became definitely turbid [43]. The temperature was then recorded and the solution was allowed to cool down until it became clear again. The process was repeated to check the reproducibility of the recorded temperature. Wetting time. Wetting time was measured by immersing a cotton skein (1 g) in a 0.1 wt% solution of the prepared surfactants in distilled water at 25 o C according to the Draves technique [30]. The sinking time was measured in seconds. Foaming properties. Foam height was measured by the Ross Miles method [44]. In this procedure a given surfactant solution was allowed to fall from a set height into the same surfactant solution in a volumetric cylinder, hence creating foam. The height of the foam was visually assessed. In this procedure a 25 ml of the solution (1.0 wt %) was shaken vigorously for 10 seconds in a 100 ml graduated cylinder with glass stopper at 25 o C. The solution was allowed to stand for 30 seconds, and then, the foam height was measured.

10 Emulsification stability. The emulsifying property of the prepared surfactants was determined as follows: In a 100-mL graduated stoppered tube; an aqueous solution of the surfactant (10 ml, 20 mol) was mixed with light paraffin oil (6 ml). The mixture was shaken vigorously by magnetic stirring [Thermo scientific Cimarec TM stirring hot plate, model no: sp , estimated stirring speed (1,100 rpm)] for 2 min at 25 o C. The tube was placed upright and the separation of the formed emulsion was observed. The time taken for the separation of (9 ml) of the aqueous layer indicates the emulsion stability of the surfactant [45]. Biodegradability of the Synthesized Surfactants The biodegradation tests of the synthesized nonionic surfactantswere performed according to the River Water Die-Away method [46]. The river water for testingwas sampled from the River Nile. In this test, a stirred solution containing the tested surfactant (1,000 ppm)was incubated at 25 o C. Sampleswere withdrawn daily, filtered using Whatman filter paper and the surface tension was measured using a Du-Nouy tensiometer (Kruss type K 6 ). The process was repeated for 7 days. The biodegradation percentage D % was calculated in terms of the measured surface tension according to the following relation. D = [(γ t -γ o ) (γ bt -γ o )] x 100 where γ t = surface tension at time t γ o = surface tension at zero time γ bt = surface tension of blank experiment at time t (without samples)

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