8
50
V. D. Bobade et al.
3
mixture and extracted with DCM (60 cm 9 3). The
organic phase was washed with water and brine, dried over
anhydrous Na SO , filtered, and concentrated in vacuo.
ethyl acetate:petroleum ether (2:3) to obtain 0.37 g (50%)
a,b-unsaturated lactam 11 as a thick oil; 0.24 g compound
1
10 were recovered. H NMR (400 MHz, CDCl ): d = 0.94
2
4
3
The residue was purified by column chromatography,
(d, J = 6.6 Hz, 6H), 1.53 (s, 9H), 1.87 (m, 1H), 2.24 (d,
1
J = 7.1 Hz, 2H), 4.17 (s, 2H), 5.83 (s, 1H) ppm; C NMR
3
eluting with ethyl acetate:hexane (1:4) to afford 2.84 g
1
63%) acrylamide 9 as a colorless oil. H NMR (400 MHz,
(
(75 MHz, CDCl ): d = 22.25, 27.09, 27.88, 38.81, 53.23,
3
CDCl ): d = 0.87 (d, J = 6.6 Hz, 6H), 1.77 (m, 1H), 1.90
82.40, 122.48, 149.27, 161.42, 169.45 ppm; IR (CHCl3):
3
(
d, J = 7.2 Hz, 2H), 3.87 (d, J = 5.9 Hz, 2H), 4.82 (d,
J = 1.3 Hz, 1H), 4.89 (d, J = 1.3 Hz, 1H), 5.64 (dd,
J = 1.4, 10.2 Hz, 1H), 6.11 (dd, J = 10.2, 17.0 Hz, 1H),
v = 3,448, 3,093, 2,963, 2,874, 1,776, 1,736, 1,712, 1,636,
-
1
1,458, 1,329, 1,165, 1,087 cm ; LCMS: m/z = 240
(M ? 1).
1
.29 (dd, J = 1.4, 17.0 Hz, 1H) ppm; C NMR (75 MHz,
3
6
t-Butyl 4-(2-methylpropyl)-2-oxopyrrolidine-
1-carboxylate (12)
To a mixture of 0.120 g 11 (0.500 mmol) and 0.12 g
CDCl ): d = 22.65, 27.86, 41.33, 42.41, 111.42, 128.62,
1
3
3
30.52, 148.92, 169.18 ppm; IR (CHCl ): v = 3,286,
3
-
1
;
,081, 2,975, 2,920, 1,916, 1,721, 1,627, 1,550 cm
3
NiCl Á6H O (0.500 mmol) in 8 cm MeOH at 15 °C,
2
2
LCMS: m/z = 168 (M ? 1).
0
.041 g solid NaBH (1.100 mmol) were added [in
4
t-Butyl acryloyl(4-methyl-2-methylenepentyl)carbamate
(
portions (15 min), under stirring], and this mixture was
then stirred for another hour (TLC). The reaction mixture
was filtered over a Celite bed and washed with methanol;
the solvent was concentrated under reduced pressure and
the residue quenched in water. The aqueous layer was
10, C H NO )
15 25 3
To a stirred solution of 2.5 g 9 (0.015 mol) and 0.18 g
3
DMAP (0.015 mol) in 25 cm anhydrous CH CN, 3.7 g di-
3
3
tert-butyl dicarbonate (0.017 mol) in 40 cm anhydrous
3
CH CN were added, and the reaction mixture was allowed
3
extracted with DCM (10 cm 9 2). The combined organic
to stir for 5 h. After the completion of the reaction (TLC),
the solvent was removed on a rotary evaporator under
layers were washed with brine, dried over anhydrous
Na SO , and concentrated in vacuo to furnish 0.117 g
2
4
reduced pressure, and the residue was extracted with DCM
3
100 cm 9 3). The organic phase was washed with water
(96%) 12 as a yellow oil identical to the material described
in [40].
(
and brine, dried over anhydrous Na SO , filtered, and
4
2
concentrated in vacuo. The residue obtained was purified
by column chromatography using ethyl acetate:hexane
4-(2-Methylpropyl)pyrrolidin-2-one (13)
tert-Butyl 4-(2-methylpropyl)-2-oxopyrrolidine-1-carboxy-
3
(
1:6) to furnish 3.00 g (75%) carbamate 10 as a thick
1
late (12, 110 mg, 0.450 mmol) was treated with 3 cm
3
anhydrous TFA in 10 cm dichloromethane at 0 °C for
45 min, concentrated under reduced pressure, and triturated
colorless oil. H NMR (400 MHz, CDCl ): d = 0.89 (d,
3
J = 6.5 Hz, 6H), 1.45 (s, 9H), 1.70 (m, 1H), 1.90 (d,
J = 7.2 Hz, 2H), 4.22 (s, 2H), 4.68 (d, J = 1.2 Hz, 1H),
with dry ether several times to get the TFA salt in
3
quantitative yield. The TFA salt was treated with 0.14 cm
4
6
1
.76 (d, J = 1.2 Hz, 1H), 5.69 (dd, J = 1.6, 10.3 Hz, 1H),
.32 (dd, J = 1.6, 16.8 Hz, 1H), 7.03 (dd, J = 10.3,
N-methylmorpholine (1.250 mmol) to liberate free amide
13 (50 mg, 76%), which was identical to the material
described in [36].
1
3
6.8 Hz, 1H) ppm;
C NMR (75 MHz, CDCl3):
d = 22.18, 27.04, 27.83, 43.64, 45.81, 81.65, 115.11,
1
28.72, 132.53, 147.92, 153.86, 171.46 ppm; IR (CHCl ):
3
3
-(Aminomethyl)-5-methylhexanoic acid (1)
-
1
v = 3,366, 2,979, 2,937, 1,734, 1,687, 1,620, 1,404 cm
LCMS: m/z = 268 (M ? 1).
;
4
-(2-Methylpropyl)pyrrolidin-2-one (13, 0.141 g, 1.000 mmol)
3
was refluxed with 8 cm 4 N HCl for 24 h before the
3
reaction mass was cooled and extracted with DCM (3 cm
t-Butyl 4-(2-methylpropyl)-2-oxo-3-pyrrolin-1-carboxylate
(
9
2). The aqueous layer was concentrated, saturated with
11, C H NO )
13 21 3
3
sodium chloride, and extracted with isobutanol (5 cm 9
To
a stirred homogeneous solution of 0.83 g 10
3
3). The organic layer was concentrated and filtered hot
(
3.100 mmol) in 60 cm anhydrous toluene, 0.26 g
1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene]dichloro-
phenylmethylene)(tricyclohexylphosphine) ruthenium (Grubbs’
through a Celite bed, the filtrated was cooled and n-Bu N
3
[
was added to pH 4–5. The product was filtered and washed
(
with isobutanol to afford 0.114 g (72%) 1. M.p.:
second-generation catalyst, 0.306 mmol) were added, and
the solution was degassed with argon and heated at 80 °C
until the completion of the reaction (15 h, TLC). The
reaction mixture was concentrated in vacuo and the residue
obtained was purified by column chromatography using
1
80–181 °C, [41]: 182–183 °C.
Acknowledgments This work was supported by the University
Grants Commission, New Delhi. We thank Prof. D.D. Dhavale,
University of Pune, for useful discussions and help.
1
23