Synthesis and study of the biological activity of some new Thiohydantoin Derivatives

1-acetyl-3-[(5-bromo-2-acetoxy-phenylmethylene)-amino]-4-oxoimidazolidin-2-thione (2) and 5-acetyl-3-[(5-bromo-2-hydroxy-phenylmethylene)amino]-4-oxo-imidazolidin-2-thione(3)prepared by Acylation of 3-[(5-bromo-2hydroxy-phenylmethylene)-amino]-4-oxo-imidazolidin-2-thione(1) by different method. The reaction of 3-[(5-bromo-2-hydroxy-phenylmethylene)-amino]-4-oxoimidazolidin-2-thione (1) with bromine in presence of glacial acetic acid result the 5bromo3-[(5-bromo-2-hydroxy-phenylmethylene)-amino]-4-oxo -imidazolidin-2thione (4). The Acylation of compound (4) with acetic anhydride led to formation 5bromo-1,5-diacetyl-3-[(5-bromo-2-acetoxy-phenylmethylene)-amino]-4-oxoimidazolidin-2-thione (5). The hydrazinolysis of compound (1) with hydrazine hydrated led to formation of 2, 4-dihydrazino-3-[(5-bromo-2-hydroxy-phenylmethyl)amino]-imidazolidine (6). The condensation of compound (1) with different aldehyde led to formation of (7a-c). The action of acetic anhydride on compounds (7a-c) under reflux led to formation of (8a-c).


Introduction:
The chemistry and properties of hydantoins and their derivatives have been investigated for more than 140 years.The hydantoin moiety which is present in various biologically active compounds represents a pharmaceutical importance.
The 1-aminohydantion (1)(2) is an antimicrobial drug for the treatment of urinary tract infections, while its analog Dantrolene represents a well known skeletal muscle relaxant.Another 1-aminohydantoin, azmilide, is a promising drug candidate for the treatment of cardiac arrhythmia.Phenylhydantoin (3) , a 5,5-diphenyl-imidazolidin-2,4-dione is an anticonvulasant used for the treatment of epilepsy.Sulfahydantoin (4) acts as a serine protease inhibitor.
Among the known thiohydantoins, 2-thiohydantoins are most notably known due to their wide applications as hypolipidemic, anticarcinogenic, antimutagenic, antithyroidal, antiviral (e.g., against herpes simplex virus, HSV), human immunodeficiency virus (HIV) and tuberculosis), antimicrobial (antifungal and antibacterial), antiulcer and anti-inflammatory agents, as well as pesticides.Additionally, 2-thiohydantoins have been used as reference standards for the development of C-terminal protein sequencing, as reagents for the development of dyes and in textile printing, metal cation complexation and polymerization catalysis (5) .Also, 2-Thiohydantoin derivatives have been identified as molecules which may interact with a wide range of applications as theropeutics (6)(7)(8) as well as fungicides and herbicides (9).

Antimicrobial studies
Applying the agar plate diffusion technique (10) for some of the newly synthesized compounds was screened in Vitro for antimicrobial activity against: I)-Gram positive bacteria such as: 1-Bacillus Subtilis.

Procedure:
Nutrient agar medium had been utilized for growing test organisms.This medium was of the following composition (g/L) peptone (5.0 gm), beef extract (3.0 gm), sodium chloride (5.0 gm); agar (18.00 gm) and water (100 CC).Each compound was tested at the prementioned concentration dissolved in dimethyl formamide, while dimethyl formamide itself was used as control for comparison.
Bacterial suspensions from activity growing cultures were prepared using sterile distilled water.The media was prepared, poured into 9 cm diameter plates, allowed to solidify and then one mL/ plate of bacterial suspension was transferred aseptically to these plates incubated at 27 ْ ◌ C for 24 hours.The compounds were tested at 100 μg/mL concentration and the activity was determined by measuring the zone of inhibition.
The screening results given in the following tables indicated that all the compounds exhibited antimicrobial activities against one or the other type of bacteria and fungi.

Experimental Section
Melting points were measured on a MEL-TEMP II apparatus and uncorrected.Infrared spectra were measured with Perkin-Elmer FT IR 410 spectrometer in KBr pellets in the Micro-analytical Unit at the Faculty of Science, Cairo University, Egypt.The 1 H-NMR spectra were performed on a VARIAN MERCURY 300 MHz spectrometer in DMSO-d 6 or CDCl 3 using TMS as an internal standard in the Microanalytical Unit at the Faculty of Science, Cairo University, Egypt.Mass spectra were obtained on a Joel JMSD-300 spectrometer operating at 70 eV in the Micro-analytical Unit at the Faculty of Science, Cairo University, Egypt.The elemental analyses were conducted using an elemental analyzer Heneaas CHN-OSRAPID 1106 in the Elemental-analysis Unit at the Faculty of Science, Cairo University, Egypt.

1) By acetic anhydride:
A solution of (1) in acetic anhydride (25 ml) was heated under reflux for 2-3 hr, then cooled and poured into ice-water.The resulting product was filtered off, washed with water, dried and purified by re-crystallization with ethanol to give (2).