|
|
wt/vol
|
MW
|
moles
|
density
|
equivs.
|
yield
|
|
I
|
0.994 g
|
129.11
|
0.0077
|
|
1.0
|
|
|
II
|
1.488 g
|
189.21
|
0.0079
|
|
1.0
|
|
|
III
|
1.690 g
|
206.33
|
0.0082
|
|
1.1
|
|
|
IV
|
0.994 g
|
122.17
|
0.0081
|
|
1.1
|
|
|
V
|
50 mL
|
-
|
-
|
|
|
|
|
VI
|
1.885 g
|
300.31
|
0.0063
|
|
|
(82%)
|
Procedure: 100 mL
1-neck flask, stirbar, septum, N2 inlet
Dissolved
0.994 g of difluoroaniline (I) and
1.488 g of II in 50 mL of dry CH2Cl2. Stirred at rt. Added 1.690 g of DCC followed by 0.994
g of DMAP. After 4.5 h, a white
ppt had formed. TLC (30:70
EtOAc-hexanes, UV) showed product spot at Rf 0.35. The reaction mixture was filtered through Celite and
concentrated by rotary evaporation.
The product was isolated by flash chromatography on silica gel using
30:70 EtOAc-hexanes as eluant. The
product was a white solid.
1H NMR (CDCl3,
300 MHz) d 8.85 (br, NH), 7.10 (d, J = 7.1 Hz, ArH), 6.53 (m, ArH), 3.95 (s, COCH2),
3.01 (s, NCH3), 1.49 (s, C(CH3)3).
notes
The reaction follows one of two
possible pathways as illustrated below.