Study On The Synthesis, Characterization And Antibacterial Property Of Sofalcone With Anti-ulcer Activity

The target molecule sofalcone was synthesized from p-hydroxybenzaldehyde, 2,4-dihydroxyacetophenone, prenyl bromide, and ethyl bromoacetate via aldol condensation reaction, prenylation, ester methylation and hydrolysis reaction. For all the synthesis, a series of analytical systems of thin-layer chromatography were developed, and some synthetic methods and reaction conditions were investigated and optimised. Three single crystals of the intermediates of sofalcone were cultivated. The molecular structures of sofalcone and it's intermediates were characterized by UV-Vis, FT-IR, ¹H-NMR, ¹³C-NMR, MS, elemental analysis and m.p. testing, and the crystal structures of the three intermediates were determined by X-ray diffraction on a Bruker SMART APEX area-detector diffractometer. The properties of sofalcone to resist Bacillus subtilis, Escherichia coli and Staphyloccocus aureus Rosenbach were tested. The mechanism of 2,4-dihydroxyacetophenone condensation with p-hydroxybenz- aldehyde was preliminarily surveyed. This work mainly includes following aspects:An analytical system of thin-layer chromatography was developed for the synthesis of 2',4',4-trihydroxychalcone( i.e. the intermediate?of sofalcone) from p-hydroxybenzaldehyde and 2,4-dihydroxyacetophenone in an alkaline medium. In this system, FeCl₃-K₃Fe(CN)₆ was used as the visualizing reagent. The developing solvent was an ethyl acetate/benzene mixture with a ratio of V (ethyl acetate) :V(benzene) = 1:2. After development, the Rf values of 2, 4-dihydroxyacetophenone, p-hydroxybenzaldehyde, and 2',4',4-trihydroxychalcone were 0.67, 0.58, and 0.38 respectively. The three compounds could be effectively separated, and the visualizing color was appeared on TLC sensitively and clearly. Monitored by this TLC, the synthesis of 2',4',4-trihydroxychalcone was researched according to the grind method without solvent, ultrasonic oscillation method, classical method in homogeneous phase and microwave assisted method. The results showed that the product 2',4',4-trihydroxychalcone wasn't obtained based on the grind method without solvent, a large amount of tar emerged following the ultrasonic oscillation method, and adopted the classical method in homogeneous phase, the yield of 2',4',4-trihydroxychalcone reached 82%, which was increased by 52 % comparing with document, by using diethylene glycol as solvent and KOH as catalyst, with the molar ratio(p-hydroxybenzaldehyde to 2,4-dihydroxyacetophenone) of 1.4 : 1 and the catalyst concentration of 50 %, at a temperature of 100?for the backing material and a temperature of 100?for the feeding of KOH, reaction for 4 h. On the basis of the classical method in homogeneous phase, 2',4',4-trihydroxychalcone was synthesized rapidly, smoothly and conveniently at a yield of 82.6 %, which was increased by 52.6 % comparing with document, by applying the microwave assisted method under the condition of a radiation power of 300W, a temperature of 120?, and a reaction time of 10 min. The molecular structure of 2',4',4-trihydroxychalcone was characterized by UV-Vis, FT-IR, ¹H-NMR, ¹³C-NMR, MS, elemental analysis and m.p. testing. By slowly volatilizing solvent, a well-shaped single crystal of 2',4',4-trihydroxychalcone was cultivated. The well-shaped single crystal of 2',4',4-trihydroxychalcone with the crystal size of 0.12 mm×0.10 mm×0.10 mm was selected for X-ray diffraction study on a Bruker SMART APEX area-detector diffractometer using a graphite-monochromatic MoK?(?= 0.71073 (?)) radiation. The single-crystal X-ray diffraction has revealed that one 2',4',4-trihydroxychalcone molecule bears one crystalline water molecule, and the crystal belongs to a monoclinic system, space group P2(1)/c with a = 11.489 (2) (?),b = 9.5903 (17) (?),c = 12.498 (2) (?),?= 90°,?= 103.649 (3)°,?= 90°, V = 1338.2 (4) ^-3, Z = 4, Dx = 1.361 Mg·m^-3,?= 0.10 mm^-1, S = 1.09 and F(000) = 576. As a result of the formation of a large conjugated system in the molecule, the bond lengths tend to average. But the oxygen atom and the carbon atoms in the skeleton of?,?(?)unsaturated ketone aren't completely coplanar, and the two benzene rings are not coplanar, making a dihedral angle of 7.24°. In the crystal, intermolecular O—H···O hydrogen bonds occur except an intramolecular O—H···O hydrogen bond. The intermolecular O—H···O hydrogen bonds lead to the formation of a three-dimensional network. Further, the intermolecular O—H···O hydrogen bonds and the obvious?-?packing between the benzene rings in neighboring molecules form a stabilized three-dimensional stereo structure and enhance the stability of the supramolecular structure. The mechanism of condensation reaction was preliminarily discussed by using the theory of resonance and the theory of conjugation effect.For the synthesis of the intermediate?of sofalcone ( i.e. (E)-1-(2-hydroxy-4-(3-methylbut- 2-enyloxy)phenyl)-3-(4-(3-methylbut-2-enyloxy)phenyl)prop-2-en-1-one), an analytical system of thin-layer chromatography was developed. In this system, the developing solvent was an acetone/ petroleum ether mixture with a ratio of V( acetone ) :V(petroleum ether) = 1:2. With the self-color of the crude material and the product as visualizing indication, no visualizing reagent was needed. After development, the Rf values of the intermediate?of sofalcone and 2',4',4-trihydroxychalcone were 0.82 and 0.30 respectively. The intermediate?of sofalcone was synthesized in a pot and the yield reached 96 % by using acetone as solvent and anhydrous K₂CO₃ as catalyst, with the molar ratio of 2',4',4-trihydroxychalcone to anhydrous K₂CO₃ of 1:2.6 and the molar ratio of 2',4',4-trihydroxychalcone to prenyl bromide of 1:2.6, at a temperature of 30?, reaction for 60 min. The molecular structure of the intermediate?of sofalcone was determined by UV-Vis, FT-IR, ¹H-NMR, ¹³C-NMR, MS, elemental analysis and m.p. testing. A well-shaped single crystal of the intermediate?of sofalcone was cultivated by using methanol as solvent and slowly volatilizing the solvent. The well-shaped single crystal of the intermediate?of sofalcone with the crystal size of 0.16 mm×0.12 mm×0.10 mm was selected for X-ray diffraction study on a Bruker SMART APEX area-detector diffractometer using a graphite-monochromatic MoK?(?= 0.71073 (?)) radiation. The single-crystal X-ray diffraction has exhibited a triclinic system, space group P-1 with a = 5.1117(9) (?), b = 11.1674(19) (?), c = 19.625(3) (?),?= 97.646(3)°,?= 92.026(3)°,?= 100.409(3)°, V = 1090.0(3) (?)3, Z = 2, Dx = 1.196 Mg·m^-3,?= 0.08 mm(?)1, and F(000) = 420. Because of the formation of a large conjugated system in the molecule, the bond lengths tend to average. The four atoms forming the skeleton of?,?(?)unsaturated ketone with a torsion angle of 1.0(6)°almost are coplanar. But the two benzene rings are not coplanar, making a dihedral angle of 9.04°. In the crystal, intermolecular C—H···O hydrogen bonds occur except an intermolecular O—H···O hydrogen bond. The intermolecular C—H···O hydrogen bonds lead to the formation of a bidimensional network and enhance the stability of the supramolecular structure.For the synthesis of the intermediate?of sofalcone( i.e. (E)-ethyl 2-(5-(3-methylbut- 2-enyloxy)-2-(3-(4-(3-methylbut-2-enyloxy) phenyl) Acryloyl)phenoxy)acetate), an analytical system of thin-layer chromatography was developed. In this system, the developing solvent was an acetone/ petroleum ether mixture with a ratio of V(ethyl acetate ) :V(petroleum ether) =1:4. With the self-color of the crude material and the product as visualizing indication, no visualizing reagent was needed. After development, the Rf values of the intermediate?of sofalcone and the intermediate?of sofalcone were 0.80 and 0.45 respectively. The intermediate?of sofalcone was synthesized and the yield reached 92 % by using acetone as solvent and KOH as catalyst, with the molar ratio of the intermediate?of sofalcone to KOH of 1:1.5 and the molar ratio of the intermediate?of sofalcone to ethyl bromoacetate of 1:1.25, at a temperature of 15?, reaction for 110 min. The molecular structure of the intermediate?of sofalcone was determined by UV-Vis, FT-IR, ¹H-NMR, ¹³C-NMR, MS, elemental analysis and m.p. testing. A well-shaped single crystal of the intermediate?of sofalcone was cultivated by using methanol as solvent and slowly volatilizing the solvent. The well-shaped single crystal of the intermediate?of sofalcone with the crystal size of 0.32 mm×0.29 mm×0.25 mm was selected for X-ray diffraction study on a Bruker SMART APEX area-detector diffractometer using a graphite-monochromatic MoK?(?= 0.71073 (?)) radiation. The single-crystal X-ray diffraction has indicated a monoclinic system, space group P21/n with a = 14.6832(14), b = 7.7581(7), c = 23.075(2) (?),?= 90°,?= 101.670(2)o,?= 90°, V = 2574.2(4) (?)3, Z = 4, Dc = 1.235 Mg·m^-3,?= 0.085 mm-1, and F(000) = 1024.An analytical system of thin-layer chromatography was developed for the synthesis of sofalcone. In this system, the developing solvent was an acetone/ petroleum ether mixture with a ratio of V (ethyl acetate ) :V(petroleum ether) =1:4. With the self-color of the crude material and the product as visualizing indication, no visualizing reagent was needed. After development, the Rf values of the sodium salt of sofalcone and the intermediate?of sofalcone were 0.00 and 0.45 respectively. Sofalcone was synthesized and the yield reached 92 % by using acetone as solvent and NaOH as hydrolytic alkali, with the molar ratio of the intermediate?of sofalcone to NaOH of 1:2.0, at a temperature of 25?, reaction for 30 min. By UV-Vis, FT-IR, 1H-NMR, ¹³C-NMR, MS, elemental analysis and m.p. testing, the molecular structure of sofalcone was determined. The total yield for the total synthesis of sofalcone was 71.5 % according to 2,4-dihydroxyacetophenone, which was increased by 15.3 % comparing with the highest yield 56.2 % in the document. Generally speak, the total synthesis of sofalcone was convenient to handle, the mixture was easy to separate, and the whole reaction time was sharply shorten.At last, the antibacterial property of sofalcone was investigated by using filter paper method and contrasted with the antibacterial property of chloramphenicol. The results indicated that sofalcone in ethyl acetate at concentration of 0.2-1.0 mg/mL didn't have antibacterial activity to Bacillus subtilis, the antibacterial activity to Escherichia coli of sofalcone in ethyl acetate at concentration of 0.2 mg/mL corresponded to the one of chloramphenicol in water at concentration of 0.1 mg/mL, and the antibacterial activity to Staphyloccocus aureus Rosenbach of sofalcone in ethyl acetate at concentration of 0.2 mg/mL was the same comparing with the one of chloramphenicol in water at concentration of 0.1 mg/mL.