Research Journal of Chemical Sciences ______________________________________________ ISSN 2231-606X Vol. 4(9), 47-50, September (2014) Res. J. Chem. Sci. International Science Congress Association 47 Green Synthesis of Novel 2-(5-Substituted)-2,4-Dithiobiureto-4,6-Dichloro-1,3,5-TriazinesTayade D.T.and Bhagwatkar A.K. Department of Chemistry, Government Vidarbha Institute of Science and Humanities, Amravati, MS-444 606 INDIA Available online at: www.isca.in, www.isca.me Received 29th August 2014, revised 6th September 2014, accepted 17th September 2014Abstract Recently in this laboratory a new route for the synthesis of 2-(5-substituted)-2,4-dithiobiureto-4,6-dichloro-1,3,5-triazines was developed to increase the yield of products by maintaining the purity of them and at the same time, the time span required for the completion of reactions was also decreases . These are eco-friendly reactions. Novel green synthesis of 2-(5-substituted)-2,4-dithiobiureto-4,6-dichloro-1,3,5-triazines (Va-e) was successfully carried out by interacting 2,4-dichloro-6-substitutedthiocarbamido-1,3,5-triazines (IIIa-e) with various isothiocynates in 1:1 molar ratio in ethanol-acetone medium. Firstly cyanuryl chloride (I) was treated with various thiourea (IIa-e) in 1:1 molar ratio in ethanol-acetone medium for the isolation of (IIIa-e). During the synthesis two parameters of green chemistry are maintained. The justification and identification of the structure of these newly synthesized compounds had been established on the basis of chemical characteristics, elemental analysis and through spectral data. Keywords: Green synthesis, cyanuryl chloride, 1,3,5-triazine, acetone-ethanol. IntroductionCyanuryl chloride is also referred as ‘cyanuric chloride’. It is an interesting molecule whose behavior is most amazing. It is chlorinated analogue of 1,3,5-triazine.This molecule is used as an intermediate for the synthesis of important heterocycles. 1,3,5-Triazino and thiocarbamido nucleus containing drugs created their own identity, importance and significances in pharmaceutical, medicinal, biochemical, industrial, and agricultural sciences. These drugs showed muscle relaxant, hypoglycemic, blood pressure depressant, anti-diabeticproperties. They also showed anti-tumor5,6, anti-bacterial7-9, anti-inflammatory10, anti-cancer11, hormone antagonists12 and anti-psychotic properties13. Some of them are used in industries as finishing and brightening agents14. They are also been used as herbicidal15-23, sea water algicidal24, fungicidal25, insecticidal26and pesticidals27. As a wider programme of this laboratory in the synthesis of nitrogen, nitrogen and sulphur containing heteroacycles and their cyclization into 5,6 and 7 member heterocycles viz. 1,2,4-thiadiazols, 1,2,4-dithiazols, 1,3,5-thiadiazines, 1,3,5-dithiazines,1,3,5-triazines etc and synthetic applications of isocyanodichlorides, cyanoguanidine, and biuretes have been explored in sufficient details28-30. Hence interactions of cyanuric chloride with various thiourea in 1:1 molar ratios at 0-5C in acetone-ethanol medium were carried out to synthesize 2,4-dichloro-6-substitutedthiocarbamido-1,3,5-triazines. 2,4-Dichloro-6-substitutedthiocarbamido-1,3,5-triazines were further interacted with various isothiocynates in 1:1 molar ratio in ethanol-acetone medium to obtained 2-(5-substituted)-2,4-dithiobiureto-4,6-dichloro-1,3,5-triazines which are hither to unknown. We developed the new route for this synthesis, in which the time span of the reactions decreases which maintain the green chemistry parameters and we used 80% acetone-ethanol mixture, as a medium in which the percentage of acetone is only 20% which help one green chemistry parameter. At the same time yield of product is also increased by maintaining purity of products. Material and Methods The melting points of all the synthesized compounds were recorded using hot paraffin bath. The carbon and hydrogen analysis were carried out on Carlo-Ebra 1106 analyzer. Nitrogen estimation was carried out on Colman-N-analyzer-29. IR spectra were recorded on Perkin Elmer Spectrometer in range 4000-400 cm-1 in KBr pellets. PMR spectra were recorded on Brucker Ac 400 F Spectrometer with TMS as internal standard using CDCl3 and DMSO-d as a solvent. The purity of compounds was checked on silica Gel-G Pellets by TLC with layer thickness of 0.3 mm. All chemicals used were of AR-grade. 2,4-Dichloro-6-ethylthiocarbamido-1,3,5-triazine (IIIa): A mixture of cyanuryl chloride (0.1 M) and ethylthiourea (0.1 M) in 1:1 molar ratio in ethanol-acetone medium (80%, 15 ml) was kept at 0-5C in ice bath for 1 hour then it was poured in water to obtained yellowish crystals of (IIIa). Yield 87%, melting point 167C. Similarly, 2,4-dichloro-6-thiocarbamido-1,3,5-triazine (IIIb), 2,4-dichloro-6-methylthiocarbamido-1,3,5-triazine (IIIc), 2,4-dichloro-6-allylthiocarbamido-1,3,5-triazine (IIId) and 2,4-dichloro-6-phenylthiocarbamido-1,3,5-triazines (IIIe) were Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606XVol. 4(9), 47-50, September (2014) Res. J. Chem. Sci. International Science Congress Association 48 synthesized by interacting cyanuric chloride (I) with thiourea (IIb), methyl thiourea (IIc), allyl thiourea (IId) and phenyl thiourea (IIe) in 1:1 molar ratio respectively by the above mentioned method. The results obtained are given in table-1. Table-1 Synthesis Results of 2,4-Dichloro-6-substitutedthiocarbamido -1,3,5-triazines Compd. No. Expt. No. 2,4-Dichloro-6-substitutedthiocarbamido-1,3,5-triazines Yield (%) MP C) IIIb 2 -- ------ -H ------------ 81 135 IIIc 3 -------- -methyl - -------- 87 123 IIId 4 - ------- -allyl-------------- 89 182 IIIe 5 ------- -phenyl------------ 93 172 Synthesis of 2-(5-ethyl)-2,4-dithiobiureto-4,6-dichloro-1,3,5-triazines Va: 2-(5-Ethyl)-2,4-dithiobiureto-4,6-dichloro-1,3,5-triazine was synthesized by refluxing the mixture of 2-thiocarbamido-4,6-dichloro-1,3,5-triazine IIIb with ethyl isothiocyanate IVb in 1:1 molar ratio in acetone medium for 1 hour on water bath, lemon yellow coloured crystals were separated out. They were filtered and dried at room condition, Recrystallized by ethanol, yield 80%, m.p. 189C. This reaction was studied in various solvents and percent ratio of solvents for improving the yield and purity of the products as well as to maintain green chemistry parameters. The results are depicted in table-2. Table-2 Synthesis Results of with different solvents Solvent used Quantity (ml) Time Span (hours) Yield (%) Water 50 No reaction - - Acetone 50 4 52 Ethanol 50 4 57 Methanol 50 5 42 Isopropanol 50 8 35 Benzene No reaction -- -- Dioxane 50 10 20 Acetone-ethanol (20%) 30 7 60 Acetone-ethanol (40%) 30 5 65 Acetone-ethanol (60%) 30 4 71 Acetone-ethanol (80%) 15 1 87 *Known literature medium. This medium is used for the synthesis of all compounds (Vb-Ve). Similarly, 2-(5-methyl)-2,4-dithiobiureto-4,6-dichloro-1,3,5-triazine (Vb), 2-(5-t-butyl)-2,4-dithiobiureto-4,6-dichloro-1,3,5-triazine (Vc), 2-(5-phenyl)-2,4-dithiobiureto-4,6-dichloro-1,3,5-triazine (Vd) and 2-(5-p-Cl-phenyl)-2,4-dithiobiureto-4,6-dichloro-1,3,5-triazine (Ve) were synthesized by interacting of 2-thiocarbamido-4,6-dichloro-1,3,5-triazine (IIIb) with methylisothiocyanate IVa, t-butylisothiocyanate IVc, phenylisothiocyanate IVd and p-chlorophenylisothiocyanate IVe in 1:1 molar ratio respectively by the above mentioned method. The results obtained are given in table-3. Table-3 Synthesis results of 2-(5-Substituted)-2,4-dithiobiureto-4,6-dichloro-1,3,5-triazines Sr. No. Compd. No. Expt. No. 2-(5-Substituted)-2,4-dithiobiureto-4,6-dichloro-1,3,5-triazines Yield (%) M.P. C) 1 Vb 2 -- ------ methyl----------------------- 78 132 2 Vc 3 -------- t-butyl- ---------------------- 82 146 3 Vd 4 - ------- phenyl---------------------- 87 186 4 Ve 5 ------- -p-chlorophenyl------------ 75 179 N N N ClClCl NHR Ethanol-acetone N N ClClNH NHR -C, -CH, -H, -CH-CH=CH, -C + Cyanuryl chloride Substitutedthiourea (I) (IIa-e) (IIIa-e) 2,4-Dichloro-6-substitutedthiocarbamido-1,3,5-triazine where R = 0-5 0 Scheme-1 Preparation of 2,4-Dichloro-6-substitutedithiocarbamido-1,3,5-Triazine Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606XVol. 4(9), 47-50, September (2014) Res. J. Chem. Sci. International Science Congress Association 49 Results and Discussion 2,4-Dichloro-6-ethylthiocarbamido-1,3,5-triazine (IIIa): It is yellow, crystalline solid. It gave positive test for nitrogen, sulphur and chlorine. Desulphurised by alkaline plumbite solution. It formed picrate, melting point 124C. Elemental analysis: C [(found 27.86%) calculated 28.68%] H [(found 2.16%) calculated 2.39%], N [(found 27.80%) calculated 27.88%], S[(found 12.74%) calculated 12.74%], Cl[(found 27.46%) calculated 28.28%]. IR Spectra: The IR spectra was carried out in KBr pellets and the important absorption can be correlated as (cm) 3435.6 (N-H stretching), 3038 (Triazino stretching), 1623.6 (C=N stretching), 1319(C=S stretching). PMR Spectra: The spectrum was carried out in CDCl3 and DMSO-d.This spectrum distinctly displayed the signals due to triazino-NH at 10.2716 – 9.8989 ppm. The signal at 4.0619 ppm 6.51-7.5 is due to –NH protons, the signal at 2.5629-2.1172 ppm is due to -CH protons and the signal at 1.4053-1.2444 ppm is due to -CH protons. Synthesis of 2-(5-ethyl)-2,4-dithiobiureto-4,6-dichloro-1,3,5-triazines Va: It is lemon yellow crystalline solid having m. p. 189C. It gave positive test for nitrogen, sulphur and chlorine elements. It was desulphurized by alkaline plumbite solution.It was soluble in DMSO, dioxane, ethanol, acetone while insoluble in benzene, carbontetra, chloride. It formed picrate having m.p. 132C. Elemental analysis: C [(found 26.12%) calculated 27.00%] H [(found 1.98%) calculated 2.57%], N[(found 27.00%)calculated 27.00%], S[(found 19.15%) calculated 20.57%], Cl[(found 21.28%) calculated 22.82%]. IR Spectra:-The IR spectra was carried out in KBr pellets and the important absorption can be correlated as (cm-1) 3413 (N-H stretching), 3024 (Triazino stretching), 1718 (C=N stretching), 1396(C=S stretching). PMR Spectra: The spectrum was carried out in CDCl3 and DMSO-d .This spectrum distinctly displayed the signals due to triazino-NH at 10.0699 – 9.8667 ppm. The signal at 4.2517 ppm is due to –NH protons, the signal at 2.5327-2.0993 ppm is due to -CH protons and the signal at 1.3937-1.2389 ppm is due to -CH protons. ConclusionEthanol-acetone mixture is the best medium for the 2-(5-Substituted)-2,4-dithiobiureto-4,6-dichloro-1,3,5-triazines in which the yield is 80% and the medium required for the condensation is only 15 ml while the reaction is completed in 1 hour.Known literature medium is acetone we are using 80% ethanol-acetone medium and quantity required is only 15 ml and % of acetone which is more toxic is only 20% in the reaction so our approach is towards maintain green chemistry parameters. References1.Letska E.V., Turner N.W., Anthony P.F., Turner and Piletsky S.A., J. Controlled Release, 108(1), 132 (2005)2.Kim G.Y., Shim J., Kang M., and Moon S.H, J. Environ. 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