1-[3-(Hydroxymethyl)phenyl]-3-phenylurea

In the title compound, C14H14N2O2, the dihedral angle between the benzene rings is 23.6 (1)°. The H atoms of the urea NH groups are positioned syn to each other. In the crystal, intermolecular N—H⋯O and O—H⋯O hydrogen bonds link the molecules into a three-dimensional network.


Comment
Melanin plays a major role in human skin protection as well as in undesirable browning of fruits and vegetables (Kubo et al., 2000). Tyrosinase is a key enzyme involved in the first stage of melanin synthesis. Tyrosinase catalyses two distinct reactions involving molecular oxygen, the hydroxylation of tyrosine to L-DOPA as a monophenolase and the oxidation of L-DOPA to dopaquinone as a diphenolase. Dopaquinone is non-enzymatically converted into dopachrome and dihydroxyindols, which induce the production of melanin pigments (Claus & Decker, 2006). Tyrosinase inhibitors have become increasingly important in both agriculture cosmetic industry and medication due to decreasing the excessive accumulation of pigmentation resulting from the enzyme action . Numerous potential tyrosinase inhibitors have been discovered from natural and synthetic sources, such as ascorbic acid (Kojima et al., 1995), kojic acid (Cabanes et al., 1994), arbutin (Casañola-Martin et al., 2006) and tropolone (Son et al., 2000). They contain aromatic, methoxy, hydroxyl (Hong et al., 2008;Lee et al., 2007), aldehyde (Yi et al., 2010), and amide (Choi et al., 2010) groups in their structure. Nevertheless, some of their individual activities are either not potent enough to be considered of practical use or not compatible with safety regulations for food and cosmetic additives. Therefore, it is still necessary to search and develop novel tyrosinase inhibitors with potent activities and lower side effects. In our continuing search for tyrosinase inhibitors, we have synthesized the title compound, (I), from the reaction of 3-aminobenzyl alcohol and phenyl isocyanate under ambient condition. Here, the crystal sturucture of (I) is described (Fig.1).
The 3-hydroxymethylphenyl moiety is essentially planar with a mean deviation of 0.010 Å from the corresponding least-squares plane defined by the eight constituent atoms. The dihedral angle between the benzene rings is 23.6 (1) °. The presence of intermolecular N-H···O and O-H···O hydrogen bonds link the molecules into a three-dimensional network Table 1). The H atoms of the NH groups of urea are positioned syn to each other.
Experimental 3-Aminobenzyl alcohol and phenyl isocyanate were purchased from Sigma Chemical Co. Solvents used for organic synthesis were redistilled before use. All other chemicals and solvents were of analytical grade and used without further purification.
The title compound was prepared from the reaction of 3-aminobenzyl alcohol (0.2 g, 1.0 mmol) with phenyl isocyanate (0.23 g, 1.2 mmol) in acetonitrile (6 ml) with stirring. The reaction was completed within 30 min at room temperature under 1 atm of N 2 gas. The solvents were removed under reduced pressure. The solids collected and washed with dichloromethane.
Removal of the solvent gave a white solid (73%, m.p. 446 K). Single crystals were obtained from an ethanolic solution by slow evaporation of the solvent at room temperature.