1-(4-Acetylphenyl)-3-butyrylthiourea

The title compound, C13H16N2O2S, crystallizes in the thioamide form with an intramolecular hydrogen bond of type N—H⋯Obutyryl. Molecules are linked into chains parallel to [10] by a further hydrogen bond of type N—H⋯Oacetyl. C—H⋯O and C—H⋯S hydrogen bonds are also present.

The title compound, C 13 H 16 N 2 O 2 S, crystallizes in the thioamide form with an intramolecular hydrogen bond of type N-HÁ Á ÁO butyryl . Molecules are linked into chains parallel to [101] by a further hydrogen bond of type N-HÁ Á ÁO acetyl . C-HÁ Á ÁO and C-HÁ Á ÁS hydrogen bonds are also present.

Comment
Thiourea and its derivatives have found extensive applications in the fields of medicine, agriculture and analytical chemistry.
Molecules are connected in chains parallel to [101] by classical hydrogen bonds N1-H1···O2 and a weak bifurcated component C3-H3B···O2; the chains are further connected in an antiparallel sense by a bifurcated system of two C-H···S contacts (Table 2, Fig. 2).

Experimental
The title compound was synthesized by a slight modification of the published procedure (Douglas & Dains, 1934). A solution of butanoyl chloride (0.1 mol) in dry acetone (75 ml) was added dropwise to a suspension of ammonium thiocyanate (0.1 mol) in dry acetone (55 ml) and the reaction mixture was refluxed for 45 minutes. After cooling to room temperature, a solution of 4-aminoacetophenone (0.1 mol) in dry acetone (25 ml) was added and the resulting mixture refluxed for 1.5 hrs.
The reaction mixture was poured into five times its volume of cold water whereupon the thiourea precipitated as a solid. The product was recrystallized from ethyl acetate as colourless crystals (2.85 g, 79%). m.p.458 K.

Refinement
H atoms of NH groups were refined freely. Methyl H atoms were included on the basis of idealized rigid groups (C-H 0.98 Å, H-C-H 109.5°) allowed to rotate but not tip. Other hydrogen atoms were included using a riding model with C-H 0.95 (aromatic) or 0.99 (methylene) Å. U(H) values were fixed at 1.5U iso (C) of the parent C atom for methyl H, 1.2U iso (C) for other H. Fig. 1. The molecule of the title compound in the crystal. Ellipsoids represent 50% probability levels.