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J. Adamek et al. / Tetrahedron 70 (2014) 5725e5729
4.89 (ddd, J¼6.4, 1.4, 1.4 Hz, 1H), 3.32 (s, 3H), 2.57e2.46 (m, 1H),
2.35e2.19 (m, 2H), 2.12e2.02 (m, 1H); 13C NMR (100 MHz, CDCl3)
4.3.3.2. N-[1-(Benzotriazol-1-yl)ethyl]acetamide (3b). Colorless
crystals (173.6 mg, 85% yield or 175.6 mg, 86% yield, see Table 1),
d
179.5, 87.1, 54.4, 28.3, 27.9; IR (ATR) 3178 (nNH), 1671 (nC]O), 1283,
mp 122.0e124.0 ꢀC. 1H NMR (400 MHz, CDCl3)
d 8.04e7.98 (m, 1H),
1251, 1098, 1056, 1043 cmꢁ1
.
7.89e7.81 (m, 1H), 7.54e7.47 (m, 1H), 7.40e7.34 (m, 1H), 7.15 (d,
J¼10.0 Hz, 1H), 6.89 (dq, J¼9.2, 6.8 Hz, 1H), 2.03 (d, J¼6.8 Hz, 3H),
4.2.2.3. 7-Methoxyazepan-2-one (6i).31 Colorless crystals (pro-
cedure B; 916.5 mg, 80% yield), mp 62.0e63.0 ꢀC. 1H NMR
2.00 (s, 3H); 13C NMR (100 MHz, CDCl3)
d 169.7, 145.7, 132.5, 127.7,
124.3, 119.5, 110.4, 58.3, 23.0, 20.6; IR (ATR) 3202 (nNH), 3045, 1676
(400 MHz, CDCl3)
d
6.52 (br s, 1H), 4.31 (ddd, J¼5.6, 5.6, 2.0 Hz, 1H),
(
nC]O), 1549, 1373, 1272, 1157, 1077 cmꢁ1. HRMS (TOF-ESI) calcd for
3.36 (s, 3H), 2.67e2.59 (m, 1H), 2.46e2.39 (m, 1H), 2.15e2.05 (m,
C
10H12N4ONa [MþNa]þ 227.0909, found 227.0908.
1H), 2.03e1.89 (m, 1H), 1.86e1.65 (m, 3H), 1.62e1.49 (m, 1H); 13C
NMR (100 MHz, CDCl3)
(ATR) 3197 (nNH), 2934, 2918, 1663 (nC]O), 1625, 1433, 1356, 1079,
1068 cmꢁ1
d
178.5, 83.6, 55.3, 37.3, 34.2, 23.7, 23.2; IR
4 . 3 . 3 . 3 . N - [ 1 - ( B e n z o t r i a z o l - 1 - yl ) e t hyl ] b e n z a m i d e
(3c).34 Colorless crystals (186.4 mg, 70% yield), mp 151.5e152.5 ꢀC.
.
1H NMR (400 MHz, CDCl3)
d 8.03e7.97 (m, 1H), 7.95e7.90 (m, 1H),
The analytical and spectral data for the other N-(1-
7.82e7.78 (m, 2H), 7.62 (d, J¼9.2 Hz, 1H), 7.54e7.45 (m, 2H),
methoxyalkyl)amides 6 were reported in our previous paper.27
7.42e7.31 (m, 3H), 7.13 (dq, J¼9.2, 6.8 Hz, 1H), 2.14 (d, J¼6.8 Hz, 3H);
13C NMR (100 MHz, CDCl3)
d 166.8, 145.7, 132.8, 132.6, 132.2, 128.6,
127.8, 127.3, 124.3, 119.5, 110.5, 58.9, 20.7; IR (ATR) 3259 (nNH), 1659
4.3. Transformation of N-(1-methoxyalkyl)amides 6 to N-[1-
(
nC]O), 1530, 1329, 1274, 1151, 1070 cmꢁ1
.
(benzotriazol-1-yl)alkyl]amides 3; general procedures
4.3.3.4. Benzyl N-[1-(benzotriazol-1-yl)phenylmethyl]carbamate
(3d).26,35 Colorless crystals (308.2 mg, 86% yield), mp
131.5e132.5 ꢀC. 1H NMR (400 MHz, CDCl3)
8.12e8.06 (m, 1H), 7.66
4.3.1. Reactions with benzotriazole and organic bases (Procedure
C). To a solution of N-(1-methoxyalkyl)amide 6 (1 mmol) in chlo-
roform (2 cm3) were added triphenylphosphonium tetra-
fluoroborate (350.1 mg, 1 mmol), benzotriazole (119.1 mg, 1 mmol),
d
(d, J¼9.6 Hz, 1H), 7.60e7.52 (m, 1H), 7.51e7.42 (m, 1H), 7.41e7.23
(m, 10H), 7.20e7.12 (m, 1H), 6.36 (d, J¼8.0 Hz, 1H), 5.17 (d,
J¼12.0 Hz, 1H), 5.07 (d, J¼12.0 Hz, 1H); 13C NMR (100 MHz, CDCl3)
€
and Hunig’s base (0.174 ml, 129.2 mg, 1 mmol). After the mixture
was stirred for 2 h at 20 ꢀC, the solvent was evaporated under re-
duced pressure and the residue was extracted with toluene
(3ꢃ1 cm3) at 50 ꢀC. The solvent was evaporated under reduced
pressure and the crude product was recrystallized from toluene to
yield N-[1-(benzotriazol-1-yl)alkyl]amides 3 as colorless crystals.
d 155.2, 146.0, 136.0, 135.5, 132.6, 129.4, 129.1, 128.6, 128.4, 128.2,
127.9, 126.3, 124.3, 120.1, 109.7, 67.8, 67.3; IR (ATR) 3276 (nNH), 1717
(
nC]O), 1527, 1451, 1241, 1226, 1211, 1140, 1042 cmꢁ1
.
4.3.3.5. Benzyl N-[1-(benzotriazol-1-yl)-2-methylpropyl]carba-
mate (3e).8,26 Colorless crystals (262.8 mg, 81% yield or 269.3 mg,
4.3.2. Reactions with benzotriazole and solid-state-supported bases
83% yield, see Table 1), mp 165.0e167.0 ꢀC. 1H NMR (400 MHz,
(Procedure D). To
a
solution of N-(1-methoxyalkyl)amide
6
CDCl3)
d
8.09e8.03 (m,1H), 7.74 (d, J¼8.4 Hz,1H), 7.55e7.47 (m,1H),
(1 mmol) in chloroform (2 cm3) was added triphenylphosphonium
tetrafluoroborate (350.1 mg, 1 mmol). After a homogeneous solu-
tion was obtained, the solvent was evaporated to dryness. The
residue was again dissolved in chloroform (2 cm3) and benzo-
triazole (119.1 mg,1 mmol) and solid-state-supported base SiO2-Pip
(920 mg) or weak base anion exchanger Amberlite IRA-67 (720 mg)
were added. After the mixture was stirred for 2 h (Amberlite IRA-
67) or 4 h (SiO2-Pip) at 20 ꢀC, the base was filtered off and the
solvent was evaporated under reduced pressure. The crude product
was recrystallized from toluene to give N-[1-(benzotriazol-1-yl)
alkyl]amides 3 as colorless crystals.
7.42e7.34 (m, 1H), 7.34e7.27 (m, 4H), 7.20e7.14 (m, 1H), 6.10 (dd,
J¼9.6, 9.6 Hz,1H), 5.94 (d, J¼9.2 Hz,1H), 5.12 (d, J¼12.4 Hz,1H), 4.98
(d, J¼12.0 Hz, 1H), 2.82e2.69 (m, 1H), 1.20 (d, J¼6.8 Hz, 3H), 0.79 (d,
J¼6.8 Hz, 3H); 13C NMR (100 MHz, CDCl3)
d 155.7,145.5,135.6,133.3,
128.5, 128.3, 128.1, 127.7, 124.1, 119.8, 109.8, 70.3, 67.5, 33.3, 19.0,
18.7; IR (ATR) 3196 (nNH), 3027, 1719 (nC]O), 1545, 1287, 1239, 1154,
1042, 1027 cmꢁ1
.
4.3.3.6. Benzyl
N-[1-(benzotriazol-1-yl)-3-methylbutyl]carba-
mate (3f).8,35 Colorless crystals (264.0 mg, 78% yield or 253.8 mg,
75% yield, see Table 1), mp 129.5e130.5 ꢀC. 1H NMR (600 MHz,
CDCl3)
d
8.05 (d, J¼8.4 Hz, 1H), 7.82 (d, J¼8.4 Hz, 1H), 7.54e7.49
4.3.3. Reactions with benzotriazole sodium salt (Procedure E). To
a solution of N-(1-methoxyalkyl)amide 6 (1 mmol) in chloroform
(2 cm3) was added triphenylphosphonium tetrafluoroborate
(350.1 mg, 1 mmol). After a homogeneous solution was obtained,
the solvent was evaporated to dryness. The residue was again
dissolved in chloroform and benzotriazole sodium salt (141.1 mg,
1 mmol) was added. After the mixture was stirred for 2 h at 20 ꢀC,
sodium tetrafluoroborate was filtered off and the solvent was
evaporated under reduced pressure. The crude product was
recrystallized from toluene to yield N-[1-(benzotriazol-1-yl)alkyl]
amides 3 as colorless crystals.
(m, 1H), 7.40e7.35 (m, 1H), 7.34e7.25 (m, 5H), 6.56e6.49 (m, 1H),
5.89 (d, J¼9.6 Hz, 1H), 5.12 (d, J¼12.6 Hz, 1H), 4.97 (d, J¼12.0 Hz,
1H), 2.44e2.35 (m, 1H), 2.26e2.17 (m, 1H), 1.54e1.44 (m, 1H),
0.96 (d, J¼6.6 Hz, 3H), 0.95 (d, J¼4.8 Hz, 3H); 13C NMR
(150 MHz, CDCl3)
d 155.5, 145.6, 135.6, 132.8, 128.4, 128.2, 128.0,
127.6, 124.1, 119.7, 110.1, 67.3, 63.4, 42.9, 24.5, 22.1, 22.0; IR (ATR)
3199 (nNH), 2962, 1717 (nC]O), 1554, 1257, 1242, 1160, 1100, 1034,
1026 cmꢁ1
.
4.3.3.7. Benzyl N-[1-(benzotriazol-1-yl)-2-phenylethyl]carbamate
(3g).26,35 Colorless crystals (275.6 mg, 74% yield or 279.3 mg, 75%
yield, see Table 1), mp 125.5e127.0 ꢀC. 1H NMR (600 MHz, CDCl3)
4.3.3.1. N-[1-(Benzotriazol-1-yl)ethyl]pivaloylamide
(3a).34 Colorless crystals (192.1 mg, 78% yield or 214.3 mg, 87%
yield or 160.1 mg, 65% yield or 221.7 mg, 90% yield, see Table 1), mp
d
8.00e7.97 (m, 1H), 7.55 (d, J¼8.4 Hz, 1H), 7.42e7.35 (m, 1H),
7.32e7.25 (m, 4H), 7.24e7.19 (m, 2H), 7.18e7.10 (m, 3H),
7.09e7.04 (m, 2H), 6.68e6.62 (m, 1H), 6.27 (d, J¼9.6 Hz, 1H),
5.09 (d, J¼12.6 Hz, 1H), 4.95 (d, J¼12.0 Hz, 1H), 3.73 (dd, J¼13.5,
8.7 Hz, 1H), 3.64 (dd, J¼9.2, 6.6 Hz, 1H); 13C NMR (150 MHz,
139.5e140.5 ꢀC. 1H NMR (400 MHz, CDCl3)
d 8.06e8.00 (m, 1H),
7.85e7.79 (m, 1H), 7.53e7.47 (m, 1H), 7.41e7.33 (m, 1H), 6.88 (dq,
J¼9.0, 6.7 Hz, 1H), 6.79 (d, J¼8.8 Hz, 1H), 2.03 (d, J¼6.4 Hz, 3H), 1.16
CDCl3)
d 155.3, 145.5, 135.5, 134.7, 133.0, 129.0, 128.9, 128.5, 128.3,
(s, 9H); 13C NMR (100 MHz, CDCl3)
d
178.1, 145.7, 132.4, 127.7, 124.2,
128.0, 127.6, 127.3, 124.1, 119.6, 109.8, 67.4, 65.9, 40.9; IR (ATR)
119.6, 110.3, 58.5, 38.7, 27.2, 20.9; IR (ATR) 3346 (nNH), 2969, 1668
3176 (nNH), 3009, 1712 (nC]O), 1548, 1280, 1261, 1245, 1196,
(
nC]O), 1511, 1193, 1153, 1067 cmꢁ1
.
1022 cmꢁ1
.