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stirring at 808C for 24 h, the autoclave was cooled, degassed, and
opened. The crude reaction mixture was transferred to a round-
bottomed flask, and Et2O (5 mL) was added. The mixture was
stirred for 15 min, the ethereal phase was decanted, and the IL res-
idue was re-extracted with Et2O (55 mL). The collected ethereal
phases were evaporated to remove ꢀ80% of the solvent, and the
distilled Et2O was recovered to be reused. The residual ethereal so-
lution was kept at 08C for 15 h. Crystals of the pure product were
separated and collected by decantation (first crop). The decanted
solution was evaporated to remove ꢀ50% of the solvent, and the
distilled Et2O was recovered to be reused again. The residual ethe-
real solution was kept at 08C for 15 h. Additional crystals of the
pure product were separated and collected by decantation
(second crop). The collected crystals (first crop+second crop) were
dried in vacuo. N,N’-Dibutyloxalamide (3 f): 91 mg yield (82% from
1 f; Table 2, entry 6, run 1); N,N’-dibenzyloxalamide (3h): 128 mg
yield (86% from 1h; Table 2, entry 7, run 1).
zol-2(3H)-one (7b): 153 mg yield (92% from 6b; Table 3, entry 5,
run 1); oxazolo[4,5-b]pyridin-2(3H)-one (7c): 136 mg yield (90%
from 6c; Table 3, entry 6, run 1).
With 2-aminophenol (6a), the oxidative carbonylation reaction was
also performed using only 0.2 mol% of catalyst (Table 3, entry 4).
The general procedure described above was followed, starting
from 606 mg of 6a (5.55 mmol) in [bmim][BF4] (11.1 mL). The reac-
tion mixture was extracted with Et2O (610 mL), and the product
was separated by crystallization as described above. Yield: 710 mg,
95% from 6a (Table 3, entry 4, run 1).
Recycling procedure
The IL residue obtained as described above, which still contained
the catalytic system dissolved in it, was dried in vacuo for 15 h to
remove traces of Et2O and moisture. The dried IL residue was then
used as such for the next run. Thus, it was transferred into the
100 mL stainless-steel autoclave, the substrate was added, and the
same procedure described above was followed.
Recycling procedure
The IL residue obtained as described above, which still contained
the catalytic system dissolved in it, was dried in vacuo for 15 h to
remove traces of Et2O, CH2Cl2, and moisture. The dried IL residue
was then used as such for the next run. Thus, it was transferred
into the 100 mL stainless-steel autoclave, the amine substrate was
added, and the same procedure described above was followed.
Recyclable synthesis of tetrasubstituted oxamides 9a–f
(Table 4)
The general procedure for the recyclable catalyzed oxidative car-
bonylation of secondary amines 8a–f is as follows. A 100 mL stain-
less-steel autoclave was charged in air with PdI2 (4.0 mg, 1.11
10À2 mmol), KI (18.4 mg, 1.1110À1 mmol), and a solution of 8
[1.11 mmol; 8a, 97 mg (Table 4, entry 1); 8b, 95 mg (Table 4,
entry 3); 8c, 176 mg (Table 4, entry 4); 8d, 75 mg (Table 4, entry 5);
8e, 81 mg (Table 4, entry 6), 8 f, 112 mg (Table 4, entry 7)] in
[bmim][BF4] (2.2 mL). The autoclave was sealed and pressurized
with CO (16 bar) and air (4 bar) with stirring. After stirring at 1008C
for 24 h, the autoclave was cooled, degassed, and opened. The
crude reaction mixture was transferred to a round-bottomed flask,
and Et2O (5 mL) was added. The mixture was stirred for 15 min, the
ethereal phase was decanted, and the IL residue was re-extracted
with Et2O (55 mL).
Recyclable synthesis of 2-oxazolidinones 5a and 5b and
benzoxazolones 7a–c (Table 3)
The general procedure for the recyclable catalyzed oxidative car-
bonylation of b-amino alcohols 4a and 4b and 2-aminophenols
6a–c is as follows. A 100 mL stainless-steel autoclave was charged
in air with PdI2 (4.0 mg, 1.1110À2 mmol), KI (18.4 mg, 1.11
10À1 mmol), and a solution of 4 [1.11 mmol; 4a, 83 mg (Table 3,
entry 1); 4b, 152 mg (Table 3, entry 2)] or 6 [1.11 mmol; 6a,
121 mg (Table 3, entry 3); 6b, 137 mg (Table 3, entry 5); 6c, 122 mg
(Table 2, entry 6)] in [bmim][BF4] (2.2 mL). The autoclave was sealed
and pressurized with CO (16 bar) and air (4 bar) with stirring. After
stirring at 1008C for 24 h, the autoclave was cooled, degassed, and
opened. The crude reaction mixture was transferred to a round-
bottomed flask, and Et2O (5 mL) was added. The mixture was
stirred for 15 min, the ethereal phase was decanted, and the IL res-
idue was re-extracted with Et2O (55 mL).
In the case of the reactions of 8a–e, the collected ethereal phases
were evaporated to remove ꢀ80% of the solvent, and the distilled
Et2O was recovered to be reused. The residual ethereal solution
was kept at 08C for 15 h. Crystals of the pure product were sepa-
rated and collected by decantation (first crop). The decanted solu-
tion was evaporated to remove ꢀ50% of the solvent, and the dis-
tilled Et2O was recovered to be reused. The residual ethereal solu-
tion was kept at 08C for 15 h. Additional crystals of the pure prod-
uct were separated and collected by decantation (second crop).
The collected crystals (first crop+second crop) were dried in vacuo.
1,2-Dimorpholinoethane-1,2-dione (9a): 108 mg yield (85% from
8a; Table 4, entry 1, run 1); 1,2-di(piperidin-1-yl)ethane-1,2-dione
(9b): 113 mg yield (91% from 8b; Table 4, entry 3, run 1); 1,2-di-(4-
ethoxycarbonyl)piperazinoethane-1,2-dione (9c): 200 mg yield
(97% from 8c; Table 4, entry 4, run 1); 1,2-di(pyrrolidin-1-yl)ethane-
1,2-dione (9d): 98 mg yield (90% from 8d; Table 4, entry 5, run 1);
tetraethyloxalamide (9e): 102 mg yield (92% from 8e; Table 4,
entry 6, run 1).
In the case of the reaction of 4a, the collected ethereal phases
were evaporated, and the residue purified by column chromato-
graphy on silica gel using 95:5 hexane/AcOEt to give pure 4-meth-
yloxazolidin-2-one (5a; 105 mg yield; 94% from 4a; Table 3,
entry 1, run 1).
In the case of the reactions of 4b and 6a–c, the collected ethereal
phases were evaporated to remove ꢀ80% of the solvent, and the
distilled Et2O was recovered to be reused. The residual ethereal so-
lution was kept at 08C for 15 h. Crystals of the pure product were
separated and collected by decantation (first crop). The decanted
solution was evaporated to remove ꢀ50% of the solvent, and the
distilled Et2O was recovered to be reused. The residual ethereal so-
lution was kept at 08C for 15 h. Additional crystals of the pure
product were separated and collected by decantation (second
crop). The collected crystals (first crop+second crop) were dried in
vacuo. (R)-4-Phenyloxazolidin-2-one (5b): 144 mg yield (80% from
4b; Table 3, entry 2, run 1); benzo[d]oxazol-2(3H)-one (7a): 147 mg
yield (98% from 6a; Table 3, entry 3, run 1); 6-methylbenzo[d]oxa-
In the case of the reaction of 8 f, the collected ethereal phases
were evaporated, and the residue was purified by column chroma-
tography on silica gel using 8:2 hexane/AcOEt to give pure tetrai-
sopropyloxalamide (9 f). Yield: 154 mg; 89% from 8 f (Table 4,
entry 7, run 1).
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