The synthesis and spectral investigation of new thiosubstituted butadienes and butenynes

Poly(thio)substituted butadienes 3a and 4b-g were synthesized from 1,1,3,3,4,4-hexa-chloro-butene and aromatic thiols in dimethylformamide (DMF) within 2 hr at room temperature in the presence of triethylamine N(C 2 H 5 ) 3 . Thiosubstituted butenyne compounds 5e-g and the butadiene compound 6h were synthesized from 1,1,3,3,4,4-hexa-chloro-butene and aromatic thiols in EtOH/H 2 O solution of NaOH. The thiosubstituted butenyne 8e , 8g and the thiosubstituted butadiene 9h were obtained from the reactions of 1-bromo-1,2,4,4-tetrachloro-1,3-butadiene and aromatic thiols in EtOH/H 2 O solution of NaOH. Structures of the novel compounds were characterized by microanalysis, FT-IR, UV/Vis, 1 H-NMR, 13 C-NMR, MS and fluorescence spectroscopy.


Introduction
In recent years, synthesis of thiosubstituted, aliphatic and conjugated hyrdocarbons has been widely studied because of the high reactivity of butadiene moiety or framework. 14][5][6][7][8][9] It is known from the US-Patent 10 that some tetrakis(thio)substituted butadienes and some thiols 11 have biological activities such as fungicidal, insecticidal, herbicidal and nematocidal.Other sulfur containing molecules play an important role in redox mechanisms of biological systems. 12oumarins, an old class of compounds, which we used our investigations, are naturally occuring benzopyrene derivatives.Coumarins have attracted a great interest in recent years because of their diverse pharmacological proporties.4][15][16][17] The aim of this study is synthesis and characterization of novel thiosubstiuted butadiene and butenyne compounds.

Result and Discussion
The tris(thio)substituted compound 3a was prepared by the reaction between the halobutene compound 1 and p-fluorothiophenol 2a in the presence of DMF and triethylamine N(C 2 H 5 ) 3 . 18etrakis(thio) substituted compounds 4b-g were synthesized from the halobutene compound 1 and other aromatic thiols 2b-g in the presence of N(C 2 H 5 ) 3 .New butenyne compounds 5e-g and the thiosubstituted butadiene 6h were obtained from the reaction of halobutene compounds 1 and 2e-h in the presence of EtOH/H 2 O solution of NaOH.
In the possible reaction mechanism, it is thought that 2H-pentachlorobutadiene was formed from the HCl elimination of compound 1.And then perchlorobutenyne was constituted from it.The compounds 5e-g were constituted from the substitution of perchlorobutenyne compound.The new thiosubstituted butenyne compounds 8e, 8g and the new butadiene compound 9h were prepared by the reactions of 1-bromo-1,2,4,4-tetrachloro-1,3-butadiene 7 and 2e, 2g-h, respevtively (Scheme 1).The IR spectrum of the compound 3a showed a characteristic band at 1593 cm -1 for the (C=C) streching.The 1 H-NMR spectrum of the compound 3a exhibited the presence of vinyl protons at 6.20 ppm.The IR spectra of compounds 4b and 4d showed broad bands at 3152 and 3326 cm -1 for the -OH streching, respectively.In 1 H-NMR spectra of 4b and 4d, singlets at 7.9 and 4.9 ppm were assigned to hydroxyl groups of this compounds.The IR spectrum of the compound 4c showed a sharp peak at 1247 cm -1 indicating for the C-O streching.

Cl
The mass spectra of 9h in the positive ion mode for ESI confirmed the proposed structure; molecular peak was identified at m/z 401(Figure 1).The fragmantation of molecular peak gave fragments corresponding to the cleavage of a chlorine atom at m/z 366.All compounds's spectral characterization are reported in experimental section.The coumarins showed maximum absorption with a single band at 270-310 nm. 19UV-Vis spectra of compounds 4e, 5e and 8e in CHCl 3 showed broad bands at 277, 276 and 264 nm respectively (Table 1).Excitation and emission slit widths were set at 5 nm.General procedure 1 1,1,3,3,4,4-Hexa-choloro-butene (1.0 g, 3.8 mmol) and aromatic thiols (15.2 mmol) were stirred in a mixture of DMF (30 mL) and triethylamine (3mL) for 2h at room temperature.Chloroform was added to the reaction mixture to separate the organic layer.Then, the organic layer was washed with water (4x30mL) and dried with MgSO 4 .After filtering, the solvent was evaporated and the residue was purified by column choromatography on silica gel.

General procedure 2
Equimolar amounts of 1,1,3,3,4,4-Hexa-choloro-butene (1.0 g, 3.8 mmol) and thiols (3.8 mmol) were stirred in a mixture of EtOH (30 mL) and aqueous solution of NaOH (1.2 g NaOH and 8 ml water) for 2h at room temperature.Chloroform was added to the reaction mixture to separate the organic layer.Then the organic layer was washed with water(4x30mL) and dried with MgSO 4 .The solvent was evaporated and the residue was purified by column choromatography on silica gel.

Table 1 .
UV-Vis data for different solvents a CHCl 3 ; b DMF; c Hexane.
VarianUNITYINOVA spectrometer operating at 500 MHz.Mass spectra were obtained on a Thermo Finnigan LCQ Advantage MAX LC/MS/MS spectrometer using ion-trap mass analyzer for both APCI or ESI source.Products were isolated by column chromatography on silica gel (Fluka silica gel 60, particle size 63-200 µm).Thin-layer chromatgoraphy was performed on Merck silica gel plates (60F 254 ) and detection was carried out with ultraviolet light (254 nm).All reagents and solvents were of reagent-grade, obtained from commercial suppliers and used without further purification.Mass spectra were obtained on a Thermo Finnigan LCQ Advantage MAX LC/MS/MS spectrometer using ion-trap mass analyzer for both APCI or ESI source.Finnigan Xcalibur® 1.4 13neral Procedures.Melting points were measured using a Buchi B-540 melting point apparatus and are uncorrected.Microanalyses were performed on a Thermo Finnigan Flash EA 1112 series elemental analyser.Infrared (IR) spectra were recorded in KBr pellets in Nujol mulls on a Perkin Elmer Precisely Spectrum One FTIR spectrometer.UV spectra were recorded in Perkin Elmer Precisely Lambda 35 UV-VIS spectrometer.Fluorescence Spectra were run on a VARIAN Cary Eclipse Fluorescence Spectrophotometer. 1 H-NMR,13C-NMR spectra were recorded in CDCl 3 or DMSO-d 6 on a was used to collect and process data.Experimental details of the analyses were 214.10 °C for capillary temperature and 9.29 V for capillary voltage.Sheath Gas and Aux/Sweep Gas flow rate were 39.55 and19.50,respectively.