About author :
Dept. of Pharmaceutical Chemistry
The process of establishing a new drug is exceedingly complexioned involves the talents of people from a variety of disciplines including Pharmaceutical chemistry, biochemistry, physiology, pharmacology, pharmaceutics and medicine. Heterocyclic chemistry is the branch of chemistry dealing with the synthesis, properties, and applications of heterocyclics. Heterocyclic chemistry comprises at least half of all organic chemistry research worldwide. In particular, heterocyclic structures form the basis of many pharmaceutical, agrochemical and veterinary products. Quinazolinone has been considered as a magic moiety possessing myriad spectrum of medicinal activities. Diversity of biological response profile has attracted considerable interest of several researchers across the globe to explore this skeleton for its assorted therapeutic significance. By using different synthetic methods new quinazolinone derivatives were synthesized and characterized by physic-chemical analysis. Quinazolinone is a lead nucleus for future developments to get effective compounds.
Key words: Quinazolinone, Anthranilic acid, Quinazoline, Aniline, 4-Hydroxy benzaldehyde, Ethanol, 2-phenyl-1, 3-benzoxazin-4-one.
Medicinal chemistry is concerned mainly with the organic, analytical and biological aspects of this process, but its people must interact productively with those in the other disciplines. It occupies a strategic position at the interface of chemistry and biology. There is considerable overlap with other disciplines for e.g. Medicinal chemistry and pharmacology both are concerned with mode of action and SAR of drugs. However, this kind of overlap facilities productive interactions in research. Any of a class of organic compounds whose molecules contain one or more rings of atoms with at least one atom being an element other than carbon, most frequently oxygen, nitrogen, or sulfur is called heterocyclic compounds. Heterocyclic chemistry is the branch of chemistry dealing with the synthesis, properties, and applications of heterocyclics. Heterocyclic chemistry comprises at least half of all organic chemistry research worldwide. In particular, heterocyclic structures form the basis of many pharmaceutical, agrochemical and veterinary products.
The word hetero means “different from carbon and hydrogen”. Many heterocyclic compounds are biosynthesized by plants & animals are biologically active. Some heterocyclic compounds are fundamentals of life, like haeme derivatives in blood & chlorophyll essential for photosynthesis in plants. Also the DNA & RNA are containing heterocyclic. Dyestuffs of plant origins include indigo blue used to dye jeans. Several heterocycles are the basic structure nucleus for nicotine, pyridoxine, cocaine, morphine etc. Quinazolinone has been considered as a magic moiety possessing myriad spectrum of medicinal activities. Diversity of biological response profile has attracted considerable interest of several researchers across the globe to explore this skeleton for its assorted therapeutic significance.
MATERIALS AND METHODS :
1. Synthesis of Anthranilic acid
Prepare a solution of 30 gm of sodium hydroxide in 120 ml of water. Cool to 00c.add 0.16 ml of bromine and shake until all the bromine gets reacted. Cool to 00c. Prepare a solution of 22 gms of NaOH in 80 ml of water. Add finely powdered phthalimide(0.163 mol) in one portion to the cold sodium hypobromite solution in the form of a thin paste. Shake vigorously until a clear yellow solution is obtained. Add the prepared NaOH rapidly, heat to 800c for 2 minutes. Cool in ice and add concentrated hydrochloric acid slowly with stirring until the solution is just neutral. Precipitate anthranilic acid completely by gradual addition of glacial acetic acid. Filter and recrystallise from hot water.
2. Synthesis of 2-phenyl-1, 3-benzoxazin-4-one
Anthranilic acid (0.1mol) was dissolved in 50 ml of pyridine. To this benzoyl chloride (0.2 mol) was added drop wise with constant stirring at low temperature. When the addition of benzoyl chloride was completed, mixture was treated with 10% sodium bicarbonate solution (15 ml). After the effervescence ceased, mixture was filtered and washed repeatedly with water to remove inorganic materials. The crude drug thus obtained was recrystallised from ethanol.
3.Synthesis-of 3-amino-2-phenyl quinazolin-4-(3H)-one
An equimolar (0.01 mol) mixture of benzoxazine and hydrazine hydrate was refluxed for 6hrs with 10ml of ethanol. The mixture was cooled to room temperature and poured into crushed ice, filter and then washed with water. The solid thus obtained was recrystallised from ethanol.
4. 2-Phenyl-3-(phenyl amino) methyl-amino)- 3H-quinazolin-4-one
An equimolar (0.01 mol) mixture of quinazoline, aniline (aromatic primary amine) and aldehyde was refluxed for 6hrs with 10ml of ethanol in acidic condition. The mixture was cooled to room temperature and poured into crushed ice, filter and then washed with water. The solid thus obtained was recrystallised from ethanol
Determination of Melting Point
The normal melting point of a solid is defined as the temperature at which the solid and liquid are in equilibrium at a total pressure of 1 atmosphere. There are several methods by which melting points can be determined, and the choice of method depends mainly upon how much material is available.
Capillary Melting Points
Capillary melting points, either in an oil bath or a melting-point apparatus, are most often used for the determination of the melting point of a solid. A few crystals of the compound are placed in a thin walled capillary tube 10-15 cm long, about 1 mm in inside diameter, and closed at one end. The capillary, which contains the sample, and a thermometer are then suspended so they can be heated slowly and evenly. The temperature range over which the sample is observed to melt is taken as the melting point.
Thin Layer Chromatography
Thin layer chromatography was carried out over plates (20cm×5cm) coated with silica gel – G 13 % containing calcium sulphate as binder.
When a mixture of compounds is spotted on a TLC plate and development with a suitable solvent system the compound which are not strongly adsorbed move up along with a solvent. Those which are more strongly adsorbed more or less rapidly get separated due to different rates of migration on the layer.
Preparation of Thin layer chromatographic plates
50gms of silica gel-G was weighed out and shaken to a homogenous suspension with 100 ml of distilled water for 90 seconds. This suspension was poured in to a TLC applicator which was adjusted to 0.25mm thickness. Twenty carrier plates (20cm×5mm) were laid together in a row on a template and coated with a silica gel-G by drawing the applicator. The plates were allowed to dry at room temperature and then dried at 1100c for 30min, in hot air oven for activation. The dry plates were stored in desiccators and used whenever required.
RESULTS & DISCUSSION:
The present study explains the synthesis and characterization of new quinazolinone derivative i.e., 2-Phenyl-3-(phenylamino methyl-amino)-3H-quinazolin-4-one. To study the structural activity relationship and to optimize the structure. The purity of the synthesized quinqzoline derivative was checked by thin layer chromatography (TLC) and Rf value was recorded.
By this study concluded that to find the structure-activity relationship and to optimize the structure of the synthesized quinazolinone derivative i.e., 2-Phenyl-3-(phenyl amino methyl-amino)-3H-quinazolin-4-one. The compound was characterized by physicochemical analysis, the purity of the compound was checked by TLC and it produces good yield.