Novel Diazole / Triazole and Dibenzothiophene Dioxide Containing Pentacyclic Systems with Promising Biological Activities

The aim of the current work is to synthesize the new heterocyclic pentacyclic condensed systems that combine benzothiophen and benzimidazole/triazole into one molecule. The dibenzothiophene was taken as an initial compound and by consistent “extension” was annihilated the imidazole and triazole nucleuses. As a result two new pentacyclic systems were produced: 3H-, 7H-diimidazole[4,5-b][5,4-g] dibenzothiophene-5,5-dioxide and 3H-, 7H-ditriazole[4,5-b][5,4-g] dibenzothiophene-5,5-dioxide with the promising antimicrobial activity. Their spectral characteristics were studied.


Introduction
The world medical practice confirms that the microorganisms and viruses are becoming more and more dangerous to humans.It is impossible to create a vaccine against all infectious diseases.The pathogenic and conditionally pathogenic strains of bacteria causing the infection processes are characterized by a large number of genetic resistance as well as residence in adverse conditions.These genetic monsters represent the products of selection at those massively used antimicrobial and antiviral drugs.Therefore the antimicrobial drugs are periodically changing.
Therefore the synthesis of new compounds and their antimicrobial and antiviral activities study become very important.
The synthesis of the biologically active compounds on the base of heterocyclic compounds is one of the main directions in the search of new drugs.Substances containing heterocyclic fragments quantitatively rank the first in the arsenal of drugs (60%-over).Because the creation of new drug is very important chemical modification of a known physiologically active molecule, which also means combination of two or more pharmacologically active molecules in one molecule that can promote the increase of biological activity of the new molecule and expand the spectrum of its pharmacological action.This article involves the integration into a single molecule of biologically active fragments, such as benzimidazole/benzotriazole on the one hand and benzothiophene on the other hand.
Each of these compounds is characterized by a high biologically, especially antiviral and antifungal activity [1]

Results and Discussion
In our previous works were successfully synthesized tetracyclic systems on the base of benzimidazole/benzotriazole and benzothiophene [6] The synthesized compounds revealed high antimicrobial activity in the preliminary study.The current study aimed to create pentacyclic systems where two imidazole/triazole nucleuses would be annihilated with the tricycle system of thiophene.

Experiment
The electronic absorption spectrawere recorded on the device "Varian" Cary100 UV-Vis spectrophotometer.IR spectra were recorded on spectrum meter  "Thermo Nicolet" Avatar 370. 1 H NMR spectra were recorded on spectrometer "Bruker" WM-400 (400 MHz) in DMSO-d 6 , TMS internal standard.Elemental analysis was performed on the analyzer HP-165B CHN.Melting point was defined on the apparatus "Mel-Temp 3.0".Control of the reaction and purity of the products was carried out on the plates Dibenzothiophene-5,5-dioxide (2).18.4 g (0.1 mole) dibenzothiophene (1) was mixed in 100 ml glacial acetic acid and then heated.At the boiling and stirring conditions 30ml of hydrogen peroxide with drops was added and white colored crystals were precipitated.The reaction area was sustained under boiling and stirring processes for 1 hour and was added 10ml of hydrogen peroxide and boiled for 30 minutes again.The mixture was leaved for 24 hours and filtrated.Filter paper remains monoxide and dioxide precipitates out of the filtrate that was processed with water and dried in the neutral area and was crystallized with 96% ethanol.It was received 20.6 g dibenzothiophene-5,5-dioxide(2).M = 216; C 12 H 8 O 2 ; Yield: 95.3%.T m.p = 231˚C, Lit.T m.p = 232˚C -233˚C [11].White needle-like crystals; control-chloroform/ethyl acetate-3/1.
was added into 20 ml ethanol and 5g KOH dissolved in 20ml water.It was kept at stirring and boiling conditions for 30 minutes.Violet crystals were filtrated, washed until neutral reaction and dried.Then it is crystallized in ethyl acetate.Yields: 0.38 g.