Synthesis

The triazoles possess wide spectrum of biological activities like including antibacterial, antifungal, antiviral, anti-inflammatory, anticonvulsant, antidepressant, antihypertensive, analgesic, and hypoglycemic properties. The present reviews attempted to gather the basic developments in synthesis and biological activities of triazole derivatives. The novel chemical moiety used in medicinal active substance either (R) or (L) hence Dextro or Levo rotatory form. The broad spectrum of activity is due nitrogen hence nitrogen containing loan pair of electron transfer to another substance and formation of covalent bond.

Pyrazolines, the eminent five-membered nitrogen-containing heterocyclic compounds, have received significant interest in the fields of therapeutic and agricultural chemistry because of their broad spectrum of biological activities. The Pyrazoline ring is relatively stable and has inspired chemists to carry out various research activities. Pyrazolines, a class of electron-rich nitrogen heterocyclic compounds, possess a broad range of pharmacological functions such as anticancer, antitubercular, antimalarial, antibacterial, antifungal, anti-inflammatory, analgesic, anticonvulsant, and antioxidant activities. This review provides an outline on the recent grade of pyrazoline derivatives in terms of synthesis and various applications to realize their full potential as drugs.

9,10-Bicyclo-3-substituted-pyrazine-2-(1H)-one was prepared by mixing substituted  aromatic diamine and 2-oxo-2-substituteted acetic  acid in aq. HCl and then stirred at 400Cfor 4 hrs. Progress of the reaction by the formation of thick solid & it was monitored  by TLC ( ethyl acetate /Hexane ,1:1) After the completion of the reaction, the solid product was filtered, washed with the water and dried .The crude product was purified by dissolving in hot aqueous NaOH followed by neutralization with acetic acid. The isolated product was recrystalised from  methyl isobutyl ketone. The compounds thus synthesized have been characterized by physical and spectral data. All of these titled synthesized compounds have been screened for antimicrobial study and  are found to possesses excellent antimicrobial activities.

1-(4- chloro -1-hydroxynaphthalen-2-yl)-ethanone were prepared by refluxing 4- chloro -naphthalen-1-ol with  glacial acetic acid in presence of fused ZnCl2 then 1-(4- chloro -1-hydroxynaphthalen-2yl)-2-aryl-prop-2-en-1-one were synthesized  from  1-(4- chloro -1-hydroxynaphthalen-2-yl)-ethanones by condensing it with aromatic aldehydes. 1-(4- chloro -1-hydroxy-naphthalen-2-yl)-3-aryl-prop-2-en-1-ones, urea and concentrated HCl in DMF were added and refluxed. Cool & pour in crushed ice, it was then treated with cold NH4OH solution to get titled compounds. The structure assignment of the new compounds is based on chemical and spectroscopic evidence. All of these titled synthesized compounds are found to posses excellent antimicrobial activities.

Formamidines, Thiazoles, dithiazolidines, thiadiazines and other ring system derivatives have a long history of applications in pharmaceutical and agrochemical industries. Our interest in the chemistry of the formamidine  nucleus and its derivatives prompted us to explore the synthesis of 1-hepta-O-acetyl- β-D-lactopyranosyl-3-H/Aryl formamidines, N-hepta-O-acetyl- β-D-lactopyranosyl-N’-benzothiozolyl formamidines and N-hepta-O-acetyl-β-D–lactopyranosyl formimidic acid alkyl esters by reductive desulphurization of 1-hepta-O-acetyl- β-D–lactopyranosyl–H / aryl thiocarbamides, 1-hepta-O-acetyl-β-D-lactopyranosyl-3-[2-N-substituted benzothiazolyl] thiocarbamides and 1-hepta-O-acetyl-β-D–lactopyranosyl-O-alkyl thiocarbamates respectively using Raney Nickel. The identities of these newly synthesized derivatives have been established on the basis of chemical transformations and IR, 1H NMR and Mass spectral studies. The title compounds have been assayed for their biological activity against gram-positive as well as gram negative microorganisms. These compounds show most promising activity towards these micro-organisms.

Several 1-Tetra-O-acetyl-β-D-glucopyranosyl-5-aryl-isothiobiurets were synthesized by the interaction of tetra-O-acetyl-β-D-glucopyranosylthiocarbamides with various aryl isocyanatesand were evaluated for their antibacterial and antifungal activities. The identities of these new N-glucosides have been established on the basis of elemental analysis, IR, 1HNMR, 13CNMR and MS spectral studies.

A facile synthesis of 1,4-bis-(6-arylimino-[1,2,4]-triazolo-(3,4-b)-[1,3,4]-thiadiazol-3-yl)-benzenes have been carried out by reacting 1,4-bis-(4-amino-3-mercapto-4H-[1,2,4]-triazol-5-yl-benzene with N-aryl isocyanodichlorides followed by the basification with dilute ammonium hydroxide solution. 1,4-bis-(4-amino-3-mercapto-4H-[1,2,4]-triazol-5-yl-benzene was synthesized by the interaction of terephthalic acid dihydrazide with carbondisulphide and potassium hydroxide followed by the addition of hydrazine hydrate. The acetylation of bis-triazolo-dithiadiazines afforded di-acetyl derivatives. The structures of synthesized compounds have been established on the basis of chemical transformation, elemental analysis, equivalent weight determination and IR, 1H-NMR, mass spectral studies. The title compounds have been assayed for their antimicrobial activity against gram-positive as well as gram-negative micro-organisms.

A number of resins (2,4DHAPDF) were synthesized by condensation of 2,4 dihydroxyacetophenone (2,4-DHA) and p-phenylenediamine (p-PD )with formaldehyde (F) in the presence of 2 M HCl as a catalyst with three different molar ratios of reacting monomers (1:1:2, 2:1:3, 3:1:4) at 1300C ±20C. Resins have been characterized by elemental analysis, infrared (IR) spectroscopy and nuclear magnetic resonance (1HNMR) spectroscopy and the morphology of the resin was examined by SEM technique. The number average molecular weight of the resin was determined by non –aqueous conductometric titration. The antimicrobial activities of the terpolymer were screened on various bacteria and fungi. All the synthetic terpolymer showed excellent antimicrobial activities with increasing molar ratios of reacting monomers.

2 (H/substituted)-4-aryl-5H,6H, 7-arylimino-1,2,3,5,6-thiatetraazepines (6) have been obtained by basification of 2-(H/substituted)-4-aryl-5H,6H-7-arylmino-1,2,3,5,6-thiatetraazepine monohydrochloride (5).  The latter were synthesized by the interaction of N-aryl-S-chloro isothiocarbamoyl chloride (4) and 1-(H / substituted)-3-aryl-dihydroformazan (3), which were prepared initially by the condensation of aryl acid hydrazide (1) and hydrazine hydrate or substituted hydrazine (2). Compound (6) on benzoylation with benzoyl chloride and excess 10 % sodium hydroxide solution afforded benzoyl derivatives (7) and on boiling with aqueous ethanolic sodium hydroxide solution isomerizes into corresponding 1, 2, 3, 5, 6-pentaazepines (8).  The structures of all the synthesized compounds were established on the basis of elemental analysis, equivalent weight determination, spectral analysis like IR, 1H-NMR and Mass.  These newly synthesized compounds (6) were screened for their antifungal and antibacterial activity.

4-(4′-chlorophenyl)-thiazol-2-carbohydrazide(2) obtained from Ethyl-4-(4′-chloro phenyl)-thiazol-2-carboxylate(1) by the treatment with hydrazine hydrate. The synthesis of Potassium-[4-(4′-chlorophenyl)-thiazol]-2-dithiocarbazinate(3) was performed from reaction of 2 with alcoholic potassium hydroxide and carbon disulphide. Moreover 4-amino-5-(4′-(4′′-chlorophenyl)thiazol-2′-yl)-3-mercapto-4H-1,2,4-triazole(4) were obtained by refluxed in the presence of compound 3 and hydrazine hydrate with water. The condensation of 4 with substituted aromatic aldehydes generated the corresponding different triazole Derivatives (5a-m). The structures of the compounds were confirmed by elemental analysis and spectral analysis. Antibacterial activity of the synthesized compounds was evaluated by tube dilution method against two gram positive and two gram negative bacteria using ciprofloxacin as standard.