SYNTHESIS & ANTIFUNGAL ACTIVITY OF BIOACTIVE MOLECULE FLURO SUBSTITUTED BENZOTHIAZOLE COMPRISING QUINAZOLINE DERIVATIVES

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1 SYNTHESIS & ANTIFUNGAL ACTIVITY OF BIOACTIVE MOLECULE FLURO SUBSTITUTED BENZOTHIAZOLE COMPRISING QUINAZOLINE DERIVATIVES Niladry Sekhar Ghosh, Isan Verma, Ekta Paey* 1 School of Pharmaceutical Sciences, Bahra University, Shimla Hills HP, INDIA 2 Buelkha Institute of Eng. & Tech.Jhansi-(UP)-2848, INDIA ARTICLE INFO: Article history: Received: 2 October 2 Received in revised form: 23 October 2 Accepted: 1 November 2 Available online: 1 November 2 Correspoing Author: Ekta Paey Buelkha Institute of Eng. & Tech.Jhansi-(UP)-2848, INDIA ektakush@rediffmail.com Phone: Abstract In present work, fluorochloro aniline was treated with KSCN in presence of bromine in glacial acetic acid a ammonia to get 2- amino-6-fluro-7-chloro (1,3)- benzothiazole, which was coensed with anthranilic acid in presence of dry pyridine to get 2-amino-N-(2'-benzothiazolyl 6'-fluoro-7'-chloro) benzamides. To the above coensed product treated with carboisulphide in presence of alcoholic potassium hydroxide to get 2-thione-3-(2'- benzothiazolyl-6'-fluoro-7'-chloro)4-(3h) quinazolines (Cyclo addition reaction). To the above product different aromatic aniline, PABA, piperzino, diphenylamine, N-Methyl piperzino, O-toludine in presence of DMF were treated to get newly th synthesised compou through replacing at 7 position chlorine.the identity of compous were confirmed on the basis of their spectral (UV, IR, 1 H NMR a MASS) data. Further, they have been screened for their antimicrobial activities. Key words Fluorine, Benzothiazole, quinazoline. Antifungal. INTRODUCTION [1,2] The chemistry a pharmacology of quinazoline have been of great interest because, of its various biological activities, so that the biological a pharmacological activity of quinazoline with fluorobenzothiazoles may be taken into account for synergism. It is well known that the introduction of fluorine atom into an organic molecule causes dramatic changes in its biological profile, mainly due to high electro negativity of fluorine, the strong carbon-fluorine bo a increased solubility in lipids. Therefore it was thought worthwhile to synthesize better kis of drugs by incorporating quinazoline a fluorine atom in benzothiazole moiety. The rapid progress of organic Fluorine chemistry since 195 has been translated as a pathfier to invent useful biodynamic agents in Medicinal a Biochemistry. The new generation antibiotics like Norfloxacin, Ciproflaxacin, Flufloxacin, which were incorporated with fluorobenzene moiety proved their efficacy as potent bio active molecules. Nowadays vast number of compous with Fluorobenzene moiety features in diverse areas like antibacterial, antifungal, anti-inflammatory, psychoactive agents, pesticides, herbicides etc. The reasons forever increasing importance of Fluorine incorporated bio active molecules may be listed below. a) Fluorine being the seco smallest substituent next to Hydrogen, closely mimics Hydrogen in Enzyme-receptor interactions. b) The substitution of fluorine by hydrogen increases lipid solubility which in turn increases the transport a absorption of drug in-vivo.

2 can be accommodating for control of TB in Pakistan c) The strong electron withdrawing, iuctive effect (-I effect) of Fluorine influences stability a reactivity of functional groups which may in turn influence the reactivity of neighbouring reaction centers. d) The replacement of 'Hydrogen' by 'Fluorine' at or near reactive sites causes inhibition of metabolism due to high C-F bo energy. Based on the above observations we have synthesized some Fluoro-Benzothiazolequinazolinone derivatives starting with fluorochloroaniline, in hope of getting pharmacological agents with broad spectrum of clinical activity. In search for new bioactive potent molecule, it was thought worthwhile to incorporate some additional heterocyclic moieties in the quinazoline nucleus a study their biological a pharmacological activity, the review of literature reveal prompted us to synthesis substituted Fluoro-benzothiazolyl quinazoline compous a those will be screened for antifungal activity to get potent bioactive molecule. MATERIAL & METHODS Melting point was determined by open capillary tube method a are uncorrected T. L. C was run on silica gel G plates using butanol, ethyl acetate a chloroform (1 : 2 : 1) as developing solvent for testing the purity of the compous. I. R. Spectra w e r e r e c o r d e d o n S h i m a d z u F T I R Spectrophotometer by using nujol mull technique All the compous synthesized was screened for antifungal activities at two different concentrations (5ìg/ml, 1ìg/ml) against Caida albicans, Aspergillus niger by diffusion method using Griseoflavin as staards. Activity calculated which are shown in the table-3. First Step General synthesis of 2-amino-6-fluoro-7-chlorobenzothiazole [3, 4, 5] To glacial acetic acid (2ml) cooled below room temperature were added 8gm (.8mol) of potassium thiocyanate a 1.45g (.1 mol) of fluorochloro aniline. The mixture was placed in freezing mixture of ice a salt a mechanically stirred while 1.6ml of bromine in 6ml of glacial acetic acid was added from a dropping funnel at such a rate that the temperature never rose beyo room temperature. After all the bromine was added (min), the solution was stirred for 2 hours below room temperature a at room temperature for 1 hours, it was then allowed to sta overnight, during which period an orange precipitate settle at the bottom, water (6ml) was added quickly a slurry was heated at 85 c on a steam bath a filtered hot. The orange residue was placed in a reaction flask a treated with 1ml of glacial acetic acid heated again to 85 c a filtered hot. The combined filtrate was cooled a neutralized with concentrated ammonia solution to ph 6 A dark yellow precipitate was collected. Recrystallized from benzene, ethanol of (1:1) after treatment with animal charcoal gave yellow plates of 2-amino-6- fluoro-7-chloro-(1,3)-benzothiazole. After drying in a oven at 8 C, the dry material (1gm 51.2%) melted at 21-2 c. Seco Step General synthesis of 2-amino-N-(2'-benzothiazolyl 6'-fluoro-7'-chloro) benzamides [6, 7] Anthranilic acid (4. g,.29 mol) a 2-aminobenzothiazole (5.22 g,.26 mol), were dissolved in dry pyridine (2 ml,.25 mol). The solution was refluxed for 8 hr. The solution was cooled a pured in water. The separated mass was filtered, washed with water a dried. The product was recrystallized using ethanol. Third Step General synthesis of 2-thione-3-(2'-benzothiazolyl 6'-fluoro-7'-chloro)-4-(3H)-quinazolinones [4, 5] To an ice cold solution of potassium hydroxide (.1 g,.2 mol) in dry ethanol (5 ml), 2-amino-N-(2'- benzothiazolyl 6'-fluoro-7'-chloro) benzamide (2.6 g,.8 mol) a carbon disulphide (6. ml,.78 mol) was added with stirring. The solution was refluxed for 1 hr a cooled. The quantity of solvents was reduced by distillation. The separated solid was filtered, washed with dry ether a dried. The product was recrystallized using ethanol.

3 Fourth Step General synthesis of 2-(2'-thione-4'(3H) quinazolinonyl)-6-fluoro 7 substituted benzothiazole [1,3] The.75 mol (2.7 gm) of 2-thione-3-(2'- benzohiazolyl 6'-fluoro-7'-chloro)-4-(3H) quinazolinone was treated with.8 mol of various substituted aromatic aniline, PABA, morpholine, piperazine, diphenylamine O- toluidine, N-Methyl piperazine a refluxed for 2 hrs in presence of DMF (dimethyl formamide) then the mixture was cooled a poured into crushed ice. The solid separated was filter off, dried a recrystallize with super dry alcohol. SCHEME RESULT AND DISCUSSION The synthesized compous are screened against two selected fungal strains Caida albicans a Aspergillus niger by using diffusion method. Sythesised compous of 2(2'-thione-4'(3'H)- quinazolinonyl) -6-fluoro-7-substituted (1,3) benzothiazole was tested for antifungal activity [8, 9,1] against Caida albicans a Aspergillus niger. Among the compous tested; VA5, VA9, showed good activity against Caida albicans at both concentration compare to staard Griseoflavin. VA4, VA5, VA1 & VA showed significant activity against Aspergillus niger compared to staard Griseoflavin. R = o, m, p- nitro aniline (A 1 - A 3) R' = morpholine, piperazine = o, m, p- chloro aniline (A 4 A 6) = N-methyl piperazine = N- phenyl (A 9) = ( A 7, A 8, A 1 2 ) = o-ethyl, p-carboxyl (A 1 A )

4 ANALYTICAL DATA TABLE-1 Sl. No Comp. Code M.P/ B.P C % Yield 1 V A V A 2 V A 3 V A 4 V A 5 V A 6 V A 7 V A 8 V A 9 V A 1 V A V A MOL. FORM M.Wt. gm. C% H% N% C H O S N lf NMR Spectral Data of Compous VA, VA, VA, VA Sl. Spectra Compou Code 1 32 VA VA 6 -Ar 3 34 VA VA 9 TABLE-2 Hydrogen ä (ppm) Multiplity Solvent

5 Antifungal activity Sl Name of the compous Griseoflavin V A 1 V A 2 V A 3 V A 4 V A 5 V A 6 V A 7 V A 8 V A 9 V A 1 V A V A TABLE-3 Mean zone of inhibition (in mm) Caida albicans Aspergillus niger 5µg 1µg 5µg 1µg CONCLUSION The lead compous of scheme I was characterized by melting point, TLC, calculated elemental analysis, UV, IR a 1HNMR spectral studies. The compous were tested for antifungal studies. The antifungal studies of synthesized compous VA 4, VA 5, VA 9, a VA 1 showed significant activity at low a high concentrations compared to staard; still further studies are requested. REFERENCES 1. FILLER RJ. Fluorine Chem 1986; 33: Greco Micheal N, Hangman William E.ChemAbstr 1992; 7; Abdel-Hamide SG. Iian J Heterocyclic Chem 2; 1: VarshaJatav, Jain SK, Kashaw SK, Mishra P. Iian J Pharmaceutical Sci 26; Amar R Desai, Kishor R Desai. ARKIVOC 25, (AKRAT USA, Inc) Chakole RD, Amenkar ND, Khedekar PB, Bhusarik P. Iian J Heterocyclic Chem25; : Chakole RD, Amenkar ND, Khedekar PB, Bhusarik P. Iian J Heterocyclic Chem 26; 1: Gangwal NA, Kothwade UR, Galae AD, Pharae DS, Dhake AS. I J Heterocyclic Chem 21; 1: VarshaJatav, Jain SK, Kashaw SK, Mishra P. Iian J Pharmaceutical Sci 26; Amar R Desai, Kishor R Desai. ARKIVOC 25, (AKRAT USA, Inc)