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(CDCl3, 400 MHz) d 0.8 (t, J¼7.5 Hz, 3H, CH3), 1.1–1.3 (m,
21H), 1.5 (m, 2H, CH2CH2CO), 1.95 (m, 4H, CH2C]), 2.0
(t, J¼7 Hz, 2H, CH2CO), 3.3 (s, 6H, CH3N), 3.7 (q,
J¼7.5 Hz, 2H, CH2N), 5.2–5.3 (m, 2H, CH]); 13C NMR
(CDCl3, 100 MHz) d 8.9, 13.9, 22.5, 26.7, 26.99, 27.02,
29.1, 29.25, 29.30, 29.40, 29.56, 29.58, 31.7, 36.3, 52.8
(NCH3), 60.3, 129.62, 129.70, 176.4 (two carbons were
not observed due to suspected overlap of signals around
d 29); HRMS (ESI) calcd for C22H42N2O+H+: m/z
353.3532, found: m/z 353.3521.
1H NMR (CDCl3, 400 MHz) d 0.8 (t, J¼7.5 Hz, 3H, CH3),
1.1–1.3 (m, 20H), 1.55 (m, 2H, CH2CH2CO), 1.9–2.0 (m,
9H, CH3C], CH2C]O, CH2C]), 3.3 (s, 6H, CH3N), 4.4
(s, 2H, CH2N), 5.1 (s, 2H, ]CH2), 5.2–5.3 (m, 2H,
CH]CH); 13C NMR (CDCl3, 100 MHz) d 13.8 (q), 22.4
(t), 22.8 (q), 26.3 (t), 26.90 (t), 26.93 (t), 29.01 (t), 29.16
(t), 29.22 (t), 29.38 (t), 29.48 (t), 29.50 (t), 31.6 (t), 36.5
(t), 53.4 (q, NCH3), 69.4 (t, NCH2), 123.3 (t), 129.5 (d),
129.6 (d), 136.6 (s), 176.5 (s) (two aliphatic carbons were
not observed due to suspected overlap of signals around
d 29); HRMS (ESI) calcd for C24H46N2ONa: m/z
401.3508, found: m/z 401.3513.
7.1.4. Aminimide 6. A mixture of 15.0 g (46.3 mmol) of
N-acylhydrazide 3, 50 mL of methanol, 15.3 g (0.11 mol)
of potassium carbonate, and 13.8 mL (19.8 g, 115.8 mmol)
of benzyl bromide was warmed overnight at 60 ꢁC for 48 h,
cooled to room temperature, and 60 mL of dichloromethane
was added. The solution was filtered and the filtrate was con-
centrated in vacuo. The crude product was chromatographed
over 150 g of silica gel (eluted with ethyl acetate followed by
9:1 ethyl acetate–hexanes) to give 10.5 g (55%) of the ami-
nimide 6 as a colorless oil: IR (CCl4) 1573 cmꢀ1; 1H NMR
(CDCl3, 400 MHz) d 0.8 (t, J¼7.5 Hz, 3H, CH3), 1.1–1.3 (m,
20H), 1.4–1.6 (m, 2H, CH2CH2CO), 1.95 (m, 6H, CH2CO,
CH2C]), 3.3 (s, 6H, CH3N), 4.9 (s, 2H, CH2N), 5.2–5.3
(m, 2H, CH]CH), 7.3–7.5 (m, 5H); 13C NMR (CDCl3,
100 MHz) d 14.0, 22.6, 26.7, 27.18, 27.21, 29.27, 29.45,
29.48, 29.6, 29.75, 29.77, 31.9, 36.8, 52.8 (NCH3), 67.7
(NCH2), 128.74, 129.8, 129.9, 132.4, 176.9 (two aromatic
and two aliphatic carbons were not observed due to overlap
of signals); HRMS (ESI) calcd for C27H46N2ONa: m/z
437.3508, found: m/z 437.3513.
7.1.7. Aminimide 9. To a one-neck round bottom flask
equipped with a football shaped stir bar and a condenser fit-
ted with a calcium chloride drying tube were added 70 g
(0.22 mol) of the N-acylhydrazide 3, 200 mL of absolute
ethanol, 72.8 g (0.53 mol) of potassium carbonate, and
61.2 g (0.44 mol) of 2-bromoethyl methyl ether. The mix-
ture was warmed under reflux for four days, cooled to
room temperature, 200 mL of dichloromethane was added,
and the heterogeneous mixture was filtered. The filtrate
was concentrated in vacuo and the crude product was puri-
fied by chromatography over 300 g of silica gel (eluted
with ethyl acetate followed by 4:1 ethyl acetate–methanol)
to give 51.5 g (61%) of the aminimide 9 as a pale yellow
oil: IR (CCl4) 1573 cmꢀ1 1H NMR (CDCl3, 400 MHz)
;
d 0.8 (t, J¼7.5 Hz, 3H, CH3), 1.1–1.4 (m, 20H), 1.5 (quintet,
J¼7 Hz, 2H, CH2CH2CO), 1.9–2.1 (m, 6H, CH2CO,
CH2C]), 3.20–3.23 (two s, 9H, CH3O, CH3N), 3.6–3.7
(m, 2H), 3.9–4.0 (m, 2H), 5.27 (m, 2H, CH]CH); 13C
NMR (CDCl3, 100 MHz) d 14.0, 22.6, 26.7, 27.1, 27.18,
29.24, 29.38, 29.44, 29.53, 29.7, 29.74, 31.8, 36.4, 55.0,
58.7, 64.1, 67.0, 129.77, 129.83, 176.6 (two aliphatic car-
bons were not observed due to suspected overlap of signals
around d 29); HRMS (ESI) calcd for C23H46N2O2Na: m/z
405.3424, found: m/z 405.3451.
7.1.5. Aminimide 7. A mixture of 15.0 g (46.3 mmol) of
N-acylhydrazide 3, 50 mL of methanol, 15.3 g (0.18 mol) of
potassium carbonate, and 7.8 mL (11.2 g, 92.6 mol) of allyl
bromide was warmed at 60 ꢁC for 24 h, cooled to room tem-
perature, and 60 mL of dichloromethane was added. The so-
lution was filtered and the filtrate was concentrated in vacuo.
The crude product was chromatographed over 150 g of silica
gel (eluted with ethyl acetate followed by 20:1 ethyl acetate–
methanol) to give 11.6 g (69%) of the aminimide 7 as a color-
less oil: IR (CCl4) 1576 cmꢀ1; 1H NMR (CDCl3, 400 MHz)
d 0.8 (t, J¼7.5 Hz, 3H, CH3), 1.1–1.3 (m, 20H), 1.5 (m, 2H,
CH2CH2CO), 1.95 (m, 6H, CH2CO and CH2C]), 3.2 (s,
6H, CH3N), 4.3 (d, J¼7.5 Hz, 2H, CH2N), 5.2–5.3 (m, 2H,
CH]CH), 5.4–5.5 (m, 2H, ]CH2), 5.9–6.1 (m, 1H, CH);
13C NMR (CDCl3, 100 MHz) d 13.9, 22.5, 26.6, 27.02,
27.05, 29.1, 29.27, 29.33, 29.42, 29.59, 29.61, 31.7, 36.4,
52.8 (NCH3), 67.3 (NCH2), 125.0, 127.4, 129.65, 129.73,
176.6 (two aliphatic carbons were not observed due to sus-
pected overlap of signals around d 29); HRMS (ESI) calcd
for C23H44N2ONa: m/z 365.3532, found: m/z 365.3532.
7.1.8. Aminimide 10. To a one-neck round bottom flask
equipped with a football shaped stir bar and a condenser fit-
ted with a calcium chloride drying tube were added 6.8 g
(0.021 mol) N-acylhydrazide 3, 150 mL of absolute ethanol,
6.9 g (0.05 mol) of potassium carbonate, and 9.1 g
(44 mmol) of the tetrahydropyranyl ether of 2-bromoetha-
nol.20 The mixture was warmed under reflux for five days,
cooled to room temperature, 80 mL of dichloromethane
was added, and the mixture was filtered. The filtrate was con-
centrated in vacuo and the crude product was purified by
chromatography over 120 g of silica (eluted with ethyl ace-
tate followed by 4:1 ethyl acetate–methanol) to afford 7 g
(77%) of the aminimide 10 as a pale yellow oil: IR (CCl4)
1574 cmꢀ1
;
1H NMR (CDCl3, 400 MHz) d 0.8 (t,
J¼7.5 Hz, 3H, CH3), 1.1–1.4 (m, 20H), 1.4–1.6 (m, 6H),
1.6–1.8 (m, 2H), 1.8–2.0 (m, 6H), 3.30 and 3.35 (two s,
6H, CH3N), 3.45 (m, 1H), 3.75 (m, 2H), 3.85 (m, 1H), 4.0
(m, 2H), 4.55 (m, 1H, OCHO), 5.3 (m, 2H, CH]); 13C
NMR (CDCl3, 100 MHz) d 14.0, 19.5, 22.5, 25.1, 26.8,
27.09, 27.13, 29.19, 29.35, 29.39, 29.53, 29.66, 29.69,
30.4, 31.8, 36.5, 54.5, 54.9, 62.11, 62.7, 64.2, 99.2, 129.7,
129.8, 176.7 (one aliphatic carbon was not observed due to
suspected overlap of signals around d 29); HRMS (ESI)
calcd for C27H52N2O2+H+: m/z 453.4056, found: m/z
452.4048.
7.1.6. Aminimide 8. A mixture of 10.0 g (30.9 mmol) of
N-acylhydrazide 3, 40 mL of methanol, 10.3 g (74.2 mmol)
of potassium carbonate, and 14.1 mL (18.7 g, 139.1 mol) of
3-bromo-2-methylpropene was warmed at 70 ꢁC for 48 h,
cooled to room temperature, and 60 mL of dichloromethane
was added. The solution was filtered and the filtrate was con-
centrated in vacuo. The crude product was chromatographed
over 120 g of silica gel (eluted with ethyl acetate followed
by 7:3 ethyl acetate–methanol) to give 8.5 g (73%) of the
aminimide 8 as a colorless oil: IR (CCl4) 1576 cmꢀ1
;