ChemicalBook CAS DataBase List 1-(3,4-DICHLOROPHENYL)-2-THIOUREA

1-(3,4-DICHLOROPHENYL)-2-THIOUREA synthesis

6synthesis methods

Product Name:1-(3,4-DICHLOROPHENYL)-2-THIOUREA
CAS Number:19250-09-0
Molecular formula:C7H6Cl2N2S
Molecular Weight:221.11

Ethanamine, N-[(3,5-dichlorophenyl)methylene]-2,2-diethoxy-

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95-76-1 Synthesis

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Yield: 29.4%

Reaction Conditions:

Stage #1:ammonium thiocyanate;m,p-dichloroaniline with hydrogenchloride in water for 1 h;Heating;
Stage #2:Heating;

Steps:

General procedure for the synthesis of aryl thiourea(1a-i)
General procedure: To a suspension of (0.30 mol) of aryl amine in 100 mL ofwarm water, concentrated hydrochloric acid (HCl) (0.33mol, 9.16 mL) was added with stirring. The resulting solutionwas placed in a large porcelain evaporating dish,ammonium thiocyanate (0.3 mol, 8.33 g) was added and themixture was heated on a steam bath for 1 h. The liquid, fromwhich a mass of large needles of aryl amine thiocyanateseparated, was allowed to cool, set aside at room temperaturefor 1 h and then evaporated slowly to dryness over aperiod of 2-3 hrs. The crystalline residue was crushedfinely, 100 mL water was added, and again the mixture wasevaporated slowly. The dry grayish white residual powderwas heated finally on a steam bath for 4-5 hrs. The resultingmixture of crude substituted phenylthiourea and ammoniumchloride was powdered finely and suspended in 100 mL ofwater. The mixture was warmed slowly to 70 °C with stirring,and then allowed to cool to 35 °C and the solid wasfiltered with suction. The crude material was dissolved inabsolute ethanol, the solution boiled with decolourizingcarbon for a few minutes and then filtered. The whitecrystalline mass of substituted phenylthiourea, whichseparated on cooling and standing, was separated by filtration,was washed with light petroleum ether and dried.Thin layer chromatography was carried out on precoatedsilica plates, using the solvent system methanol: chloroform (1:9). Physical and spectral analysis confirmed the formationof the corresponding thiourea (Rabjohn, 2005).(3,4-Dichloro-phenyl)-thiourea (1a)White crystalline solid; Yield: 29.40 %; Melting range:180-182 °C; IR (KBr, cm-1) 3419 (N-H), 1465 (C=C),1064 (C-N), 810(C=S); ESI-MS m/z = 221.0 [M+].

References:

Diwakar, Kirti;Sonar, Pankaj Kumar;Mishra, Mudita;Tripathi, Avinash C.;Saraf, Shailendra K. [Medicinal Chemistry Research,2016,vol. 25,# 11,p. 2631 - 2642]