3360
C. J. Perry, K. Holding, and E. Tyrrell
Impact 404 FT-IR, or neat on a Mattson Genesis II Reflectance FT-IR
instrument. Melting-points were recorded using a capillary melting-point
apparatus with mercury thermometer and are uncorrected. All CHN
analysis was undertaken by Warwick Analytical Service, University of
Warwick Science Park, UK.
N(2-Aminophenyl)urea (1a)
1,2-Diaminobenzene (0.1 mol, 10.8 g) was dissolved in glacial acetic acid
(10 mL) and diluted to 100 mL with distilled water. Separately, potassium
cyanate (0.1 mol, 8.1 g) was dissolved in 100 mL of distilled water and
then added to the first solution, with stirring, at room temperature. After
1 h, the mixture was cooled in an ice bath for 30 min or left overnight in a
refrigerator. The product was isolated by vacuum filtration, washed with
ice-cold distilled water, dried at 100 ꢄC, and recrystallized from ꢄmethanol
1
or ethanol if required. Off-white needles (78%); mp 166–168 C[14]; H
NMR: d 7.76 (s, 1H), 7.25 (m, 1H), 6.78 (m, 1H), 6.68 (m, 1H), 6.52 (m,
1H), 5.88 (s, 2H), 4.75 (br s, 2H); 13C NMR d 156.59, 140.64, 125.46,
123.89, 123.49, 116.64, 115.72: DEPT-135 confirms the three 4ry C environ-
ments expected. MS m=z 151 (Mþ), 134, 108 (100%). Anal. calcd. for
C7H9N3O: C, 55.62; H, 6.00; N, 27.88%. Found: C, 54.76; H, 5.90; N,
27.77%. IR (neat) 3417, 3333, 3288, 1646, 1620, 1525, 1355, 747 cmꢂ1.
N-(2-Aminophenyl)-N0-phenylurea (1c)
1,2-Diaminobenzene (0.1 mol, 10.8 g) was dissolved in sodium-dried Et2O
(300 mL) with stirring. Phenylisocyanate (0.1 mol, 11.9 g) was added
dropwise, and the solution was stirred for a further 1 h, then cooled in
an ice bath, whereupon 1c precipitated. It was recrystallized from ethanol
ꢄ
1
if required. White solid (90%); mp 189–191 C, H NMR: d 8.77 (s, 1H),
7.73 (s, 1H), 7.45 (m, 2H), 7.35 (m, 1H), 7.25 (m, 2H), 6.94 (m, 1H), 6.84
(m, 1H), 6.74 (m, 1H), 6.58 (m, 1H), 4.80 (br s, 2H); 13C NMR d 153.1,
140.9, 140.1, 128.8, 124.7, 124.4, 123.8, 121.5, 117.9, 116.8, 115.9: DEPT-
135 confirms the four 4ry C environments expected. MS m=z 227 (Mþ),
134 (100%), 119, 108, 93. Anal. calcd. for C13H13N3O: C, 68.71; H,
5.77; N, 18.49%. Found: C, 68.54; H, 5.71; N, 18.34%. IR (neat) 3424,
3278, 1646 (shoulder), 1610, 1593, 1549, 743 cmꢂ1.
N-(2-Aminophenyl)-N0-phenylthiourea (1d)
1,2-Diaminobenzene (0.1 mol, 10.8 g) was dissolved in boiling CHCl3
(200 mL) with stirring. Phenyl isothiocyanate (0.1 mol, 13.5 g) was added