Tarikul Islam at Department of Chemistry, Khulna University of Engineering and Technology, Khulna, Bangladesh. I am also grateful to all the students and staff of the Department of Chemistry, Khulna University of Engineering and Technology for their cooperation.
Conclusion and Recommendations
LIST OF TABLES
IR spectrum of the compound (I) as KBr pellets 70
IR spectrum of the compound (IH) as KBr pellets 77
Antibacterial activity of compounds 1,2, 3 against Citobacter 80 freundi
Antifungal activity of compounds 1,2, 3 against Tricodarma 81 harzianu
General
- Requirements
- Types of Claisen condensation
At least one of the reactants must be enolizable (have an α-proton and can undergo deprotonation to form the enolate anion). Then the carbonyl carbon of the (other) ester nucleophile is attacked by the enolate anion. The alkoxy group is then eliminated, resulting in regeneration of the alkoxide), and the alkoxide removes the newly formed double α-proton to form a new, highly resonance-stabilized enolate anion.
Michel Reaction
- Donor compound
The acceptor compounds are usually a compound, esters, aldehydes, ketones and unsaturated nitriles, 13, in which the carbon-carbon and carbon-oxygen double bonds are doubled and separated by only one carbon-carbon single bond, i.e. The compound containing a -CH2 group and —CH group surrounded by two electrons with suppressing groups (_CN, -00C2H5,>CO) which can increase the activity of hydrogen and stabilize the conjugate base and called active hydrogen compound.
Chalcone
In fact, the pharmacological properties of the chalcones are due to the presence of both a, I-unsaturation. This is due to some specific advantages of the reaction of chalcone synthesis, which are as follows [23].
Chromene
Khellin (Figure 1.6), extracted from the seeds of the plant Ammi visnaga, was the first chromone in clinical practice and it has been used for centuries in the Mediterranean area as a diuretic to relieve renal colic [35]. The resulting chalcone can then be cyclized by the Algar-Flynn-Oyamada (AFO) reaction using alkaline hydrogen peroxide solution to a flavone (e.g. in the presence of iodine) or to the corresponding 3-hydroxyflavone [37].
Rivew of Chromene
- Acid as catalyst in chromone ring closure
- Hydrochloric acid as a catalyst
- Trillic anhydride as a catalyst
- Phosphorus oxychioride as a catalyst
- Base as catalyst in chromone ring closure
- Sodium formate as a catalyst
- Py.ldine as a catalyst
- Chronione ring closure under the microwave irradiation
- Chromone ring closure via solid-support
- Via solid-support catalysts
- Chromone ring closure through other methods
- Through base-induced elimination
- Recent Synthetic methods of chromones
In 2003, Boumendjel and co-workers obtained chromonc 24 in three steps starting from 2,6-dihydroxyacetophenone (Scheme 2.10); they used concentrated hydrochloric acid as a ring-closing catalyst [54]. In 2004, Sabui and Venkateswaran synthesized 6-methoxy-7-rnetyl chromone 27 using paratoluene sulfonic acid (PTS) as a ring-closing catalyst (Scheme 2.11). In 2001, Wallace and co-workers reported the synthesis of enantiomerically pure (S)-2-inethy1chroman-4-one 39 based on the following procedure (Scheme 2.14).
In 2007, Wu and co-workers prepared the chromone ring 46 using potassium tert -butoxide in the ring closure during the total synthesis of 6-dcmctoxycapillarisin (Scheme 2.16). In 2005, Kabalka and Mereddy reported a facile microwave synthesis of functionalized flavones and chronions via cyclization of 1-(2-hydroxyyl)-3-aryl-1,3-propanediones (Scheme 2.20). In 2009, Rizzacasa and co-workers described the synthesis of chromone 73 through the iodination of naringenin, followed by base-induced elimination (Scheme 2.26) [74].
Biological Activity
- Antioxidant
- Anticancer Activity
Pongaglabol showed activity against the bacteria Shigella dysenteriae, Streptococcus 13-hacmolyticus and Staphylococcus aurcus; the lowest concentration for inhibition of the first two types of bacteria is 64 ig/ml [90] Methanol and ethyl acetate extracts of Pongamia pinnata plants mixed with carangin 79 [91] showed antibacterial activity. An extract of flavonoids from Lonchocarpus montanus plants in dichloromethane. containing 19% pongamol and 8% lanceolatin B, showed activity against Staphylococcus aureus, whereas pongamol itself was active against Bacillus subtilis and Cladosporium cladosporioide [92]. Some of the chromanone analogues showed good insecticidal activity against Mythima separately at a dose of 500 mg/l [96].
The methyl ether of pongol 86 isolated from the plant Millettia erythrocalyx showed activity against both types of herpes virus HSV-1 and HSV-2138. Activity against human immunodeficiency virus (HIV) and herpes virus has been found in alkaloids of the Schumanniophyton plants. The presence of the piperidine ring and unsubstituted hydroxy groups in their molecules is responsible for the activity against HIV [97-98].
General
- Anhydrous Zinc chloride
Drying of alcohol: One liter of commercial grade ethanol was placed in two 500 ml Erlenmeyer flasks containing freshly ignited calcium oxide (CaO) and allowed to stand overnight. A dry round bottom flask followed by 40-60 ml of ethanol (which was left overnight). The mixture was treated until the iodine disappeared. Then, the remaining amount of ethanol (950 mL) was poured into the round-bottom flask and refluxed for 40 minutes.
Then the mixture was distilled and ethanol was collected (bp 78°C) and stored in well stopper bottle. Commercial grade anhydrous zinc chloride was placed in a porcelain sink and heated over a small flame. The fused salt was allowed to solidify in desiccators and added to the reaction mixture.
Experimental Techniques Employed
- Chromatographic Technique (Thin layer chromatography)
A smooth sheet of filter paper is inserted into the reservoir and allowed to soak in the solvent. The tank is then sealed airtight and left for a few minutes to saturate the internal atmosphere with solvent vapors. A small spot of the solution is applied to the activated silicon plate with a capillary tube just 1 cm above the bottom edge of the plate.
The spot is dried with a hot air blower and a straight line is drawn 2 cm below the upper edge of the activated plate marking the upper limit of the solvent flow. The stained plate is then placed in the tank in such a way that the applied stain is held above the surface of the solvent system and the cap/lid is placed again. When the solvent front reaches the given mark, the plate is removed and air dried.
Solvent treatment
Application of sample on the plate
Development of plates
Location of Spots
Iodine chamber
The R1 value
Spectroscopic Techniques Ultraviolet and visible spectra
Rotary evaporator
Abbreviation Used
Melting point apparatus
Melting point (m.p.) was determined using an electrothermal melting point apparatus (Mel-temp. OGAWA SEIKICO, and Japan).
Preparation of substituted chalcones
The 'H NMR spectrum (Fig 3.1.1) of the compound in CDCl3 gave the following signals (value) using TMS as an internal standard. Based on physical properties, chemical behavior and spectral properties, the following figure (3.1.1) has been assigned to this product.
Preparation of 1,3 diphenyl-propanone Procedure
The dye product was white in color and the melting point of the pure product was 42°-430C. The course of the reaction and the formation of the product will be monitored by TLC on silica gel plates (eluted solvent, ethyl acetate:hexane, 60:40). When both reactants disappeared, the reaction mixture was neutralized with 0.01 M HCl where precipitation occurred.
The structure determination of the product was 1 -(4-amino-phenyl)-3-phenyl-propenone given Fig 3.1.3. The product of the color was yellow color and the melting point of the pure product was 142°-143° C. The progress of the reaction and formation of the product will be monitored by TLC on silica gel plates (eluting solvents, ethyl acetate: hexane, 60: 40). The 'H NMR spectrum (Fig 4.2) of the compound in CDC13 gave the following signals (1 value) using TMS as an internal standard.
Preparation of chromenes derivative
- Reaction of 3-(4-Hydroxy-phenyl)-1-phenyl-propen one with dimedone in presence of zinc chloride catalyst
The mixture was microwaved at 350w for several minutes and the progress of the reactions was followed by TLC on a silica gel plate (eluent ethyl acetate: n-hexane; 40:60). The reaction mixture was cooled and the solid was filtered off and recrystallized from n-hexane and ethyl acetate. The colored product was white, the melting point of the pure product was 162°-I 65°C.
The 1 H NMR spectrum of the compound in DMSO gave the following signals (value 8) using TMS as an internal standard. Based on chemical behavior and spectral properties, the following structure was assigned to this product.
Antimicrobial Activity
- Introduction
- Principle of Disc Diffusion Method
- Test materials of Sample
- Test Organisms
- Methods
- Determination of antimicrobial activity by the zone of inhibition
- Disc diffusion methods
Based on the diameter of the inhibition zone, the results are then assigned to three categories: susceptible, intermediate or resistant. The larger the diameter of the inhibition zone, the more sensitive the microorganism is to the antimicrobial agent [99]. After incubation, the antimicrobial activities of the test materials were determined by measuring the diameter of the inhibition zones in millimeters with a transparent scale.
The broth culture was incubated at 37°C until it reached or exceeded the turbidity of the 0.5 McFarland standard (usually 2 to 6 hours). Application of chips on inoculated agar plates.. a) The predetermined battery of antimicrobial chips was dispensed on the surface of the inoculated agar plate. Each disc's was marked by a marker as a small symbol so that each of the discs could be easily identified.
1JffiLi 'ij
Reaction of 4- Hydroxy benzaldehyde and acetophenone
The reaction of 4-hydroxybenzaldehyde with acetophenone in the presence of ethanol at room temperature gave a crystalline solid, m.p.184-185°C. The IR spectrum (Fig 4.1) of the product carried out as KBr pellet showed the following stretching bands, Vnjax in cm 1. The 'H NMR spectrum (Fig 4.2) of the compound in CDC13 showed the following signals ( ö value) by TMS as an internal standard.
Structure (1) was assigned to the obtained product based on the spectral properties (NMR, IR) and chemical behavior. The 'FT NMR spectrum (Fig. 4.3) of the compound in DMSO gave the following signals (S value) using TMS as internal standard. Based on the spectral properties (NMR, TR) and chemical behavior, structure (II) was assigned to the product obtained.
Reaction of 3-(4-Hydroxy-phenyl)-1-phenyl-propenone with Dimedone Catalyst by anhydrous Zinc chloride
The IR spectrum (Fig. 4.4) of the product run as KBr pellet showed the following stretching bands, V.ax in crn. The 'HNlvfR spectrum (Fig. 4.5) of the compound in DMSO gave the following signals (S value) using TMS as an internal standard. 11 Based on the spectral properties (NMR, IR) and chemical behavior, structure (Ill) has been assigned to the product obtained.
Reading plates and interpreting results for bacteria
Reading plates and interpreting results for fungi
This chalcone showed antibacterial activity against Staphylococcus aureus and good antifungal activity against Trichoderma harzianum. The international journal for rapid publication of all preliminary communications in organic chemistry, Vol. 34; Modulation of P-Glycoprotein-Mediated Multidrug Resistance by Flavonoid Derivatives and Analogues". Journal of Medicinal Chemistry, Vol.
Martin, N., Richardson, C., Rigoreau, L., Stockley, M., and Smith, GCM Selective bcnzopyranonc and pyrimido[2,1-a]isoquinoline-4-one inhibitors of DNA-dependent protein kinase: synthesis, structure-activity studies and radiosensitization of a human tumor cell line in vitro". The International Journal for the Rapid Publication of All Preliminary Communications in Organic Chemistry, Vol.46, pp. 34; Trifluoromethanesulfonic acid supported on carbon used as catalysts in the synthesis of flavones and chromones".
