Chemical Papers
HCONH2) δ 100.6. HR-MS: calcd for [C36H34O6N4]
618.2473; found m/z 618.2477. Calc. (%): C, 69.93; H, 5.54;
N, 9.06 Found (%): C, 69.92; H, 5.52; N, 8.98.
Synthetic procedures
N,N′‑Dinitrourea (DNU) (4)
2,6‑Dibenzylglycoluril (7)
DNU was prepared from urea by the reported procedure
To water (30 mL) was added benzylurea (0.067 mol),
40% aqueous glyoxal (0.027 mol) and concentrated HCl
(0.027 mol). The whole was brought to a boil and held for
20 min. The reaction mixture was then cooled to room tem-
perature, and the precipitated crystals were collected by fl-
tration, washed with 2-propanol and water, and dried under
atmospheric pressure. Yield: 3.40 g (40%). Mp: 298–300 °C.
IR (cm−1): 3222, 3121, 3030, 2938, 1708, 1694, 1460, 1454,
1356, 1247, 1132, 1076, 887, 821, 704. 1H NMR (400 MHz,
DMSO-d6) δ 4.04, 4.56 (d, J=15.6 Hz, 2H, CH2-Ph); 5.04
Benzylurea
Benzylurea was prepared by the reported procedure (Yagod-
1,3‑Dibenzylurea (DBU) (5)
A weighed portion of DNU (5 g, 0.033 mol) was added to
distilled water (30 mL), and benzylamine (11 mL, 0.1 mol)
prediluted with water to a total volume of 60 mL was then
poured with stirring at a temperature not above 5 °C. The
reaction mixture was gradually heated to 90 °C and held for
4 h. The precipitate was collected by fltration and washed
with cold water. Yield: 5.76 g (72% of the theoretical). Mp:
166–168 °C. IR (cm−1): 3353, 3321, 3063, 3031, 3086,
2924, 2876, 1626, 1572, 1453, 1493, 1262, 1081, 753,
(s, 2H, CH); 7.26–7.33 (m, 10H, Ph); 7.81 (s, 2H, NH). 13
C
NMR δ 43.16 (CH2); 64.88 (CH); 127.19 (p-Ph); 127.74 (o-
Ph); 128.49 (m-Ph); 137.37 (i-Ph); 158.86 (C=O).
2,4,6,8‑Tetrabenzylglycoluril (1a)
Into a flask was added 2,6-dibenzylglycoluril (1.61 g,
0.005 mol), acetonitrile (30 mL), benzyl chloride (2.3 mL,
0.02 mol) and KOH (1.12 g, 0.06 mol). The whole was
heated to 80 °C for 3 h. After the holding time was com-
plete, the reaction mixture was fltered of and the mother
solution was evaporated. The resultant crystals were washed
with diethyl ether, water, and diethyl ether again, and
dried under atmospheric pressure. Yield: 1.36 g (63% of
the theoretical). Mp: 100–102 °C. IR (cm−1): 3062, 3030,
2931, 1708, 1604, 1468, 1452, 1359, 1328, 1232, 1145,
1
729, 695. H NMR (400 MHz, DMSO-d6) δ 4.23 (s, 2H,
CH2), 4.24(d, 2H, J=5.9 Hz, CH2), 6.43–6.44 (s, 2H, 2NH),
7.22–7.31 (m, 10H, 2Ph).
3,3′‑Bi(6,8‑dibenzyl‑2,4‑dioxa‑9,8‑diazabicyclo[3.3.0]
octan‑7‑one (6b)
A mixture (suspension) composed of water (9 mL),
1,3-dibenzylurea (0.02 mol), 40% aqueous glyoxal
(0.01 mol) and 2 mL concentrated HCl was stirred at
23−25 °C for 5 days. Afterwards, the suspension was fl-
tered. The flter cake (initial unreacted compound) was dis-
carded, and the fltrate was evaporated in vacuo. The white
crystals resulting from the evaporation of the fltrate were
washed with water and dried under atmospheric pressure.
Yield: 1.46 g (24% of the theoretical). Mp: 200–202 °C.
IR (cm−1): 3063, 3030, 2924, 1716, 1604, 1496, 1464,
1
1074, 1029, 951, 735, 701. H NMR (500 MHz, CD2Cl2)
δ 4.11 and 4.83 (d, 4H, J = 15.7 Hz, CH2-Ph), 4.84 (s,
2H, N–CH–N), 7.08–7.15 (m, 8H, o-Ph), 7.27–7.36 (m,
12H, m, p-Ph). 13C NMR (126 MHz, CD2Cl2) δ 47.23
1
3
(tt, JCH = 139 Hz, JCH = 4.4 Hz, CH21-Ph), 67.71 (dm,
1JCH = 164 Hz, N–CH–N), 127.97 (dm, JCH = 155 Hz, o-
Ph), 128.08 (dt, 1JCH =157 Hz, 4JCH =7.2 Hz, p-Ph), 129.17
(dd, 1JCH =160.5 Hz, 4JCH =7.8 Hz, m-Ph), 136.24 (m, i-Ph),
159.54 (br s, C=O). 15N NMR (51 MHz, HCONH2) δ 100.3.
HR-MS: calcd for [C32H30N4O2] [M]+.502.2363; found m/z
502.2369. Calc. (%):C, 76.52; H, 6.03; N, 11.15 Found (%):
C, 76.51; H, 6.05; N, 10.87.
1
1435, 1349, 1237, 1093, 965, 930, 731 698. H NMR
(500 MHz, CDCl3) δ 4.20 and 4.90 (d, 4H, J = 15.1 Hz,
CH2-Ph), 4.95 (s, 2H, O–CH–O), 5.37 (s, 4H, N–CH–O),
7.20–7.50 (m, 20H, Ph). 13C NMR (126 MHz, CDCl3) δ
45.02 (tt, 1JCH =139 Hz, 3JCH =4 Hz, CH2-Ph), 85.42 (ddt,
1JCH =180 Hz, 3JC-CH =4.6 Hz, 3JC-CH2 =2.3 Hz, N–CH–O),
Results and discussion
1
2
3
99.18 (ddt, JCH = 173 Hz, JCH = 3.5 Hz, JCH = 2.6 Hz,
O–CH–O), 127.87 (dt, 1JCH =160 Hz, 3JCH =7.3 Hz, p-Ph),
128.47 (d quint, 1JCH =157 Hz, 3JCH =5.5 Hz, o-Ph), 128.83
(dd, 1JCH =161 Hz, 3JCH =6.0 Hz, m-Ph), 136.47 (m, i-Ph),
Tetrabenzylglycoluril 1a was supposed to be synthesized in
this study by standard procedures (Scheme 3) (Kravchenko
et al. 2018) via the condensation reaction between urea
method was elaborated for the synthesis of 1,3-dibenzylurea
157.45 (sept, JCH = 3.3 Hz, C=O); 15N NMR (51 MHz,
3
1 3