390
N. Allendörfer et al. / Tetrahedron Letters 53 (2012) 388–391
Table 3
Prepared CF3–Ketones 3
Supplementary data
Supplementary data (experimental procedures, yields, charac-
terization and crystallographic data CCDC-822153 (2d) and
CCDC-787285 (3d)), associated with this article can be found, in
the online version.
TMS-CF3
TBAF
N
O
NH2
1
O
6
O
CF3
2
3
R
R
DMSO, r.t.
Acknowledgment
5
4
2
3
We thank Bayer CropScience for the financial support.
References and notes
Entry
Benzoxazinone
Substituents Ra
Product
Yield (%)
1
2
3
4
5
6
7
2a
2b
2c
2d
2e
2f
4-Cl
6-Me
4,6-Cl
4-Cl, 6-Me
4-I, 6-Me
4-CN, 6-Me
4,5-OMe
3a
3b
3c
3d
3e
3f
13
53
17
57
43
32
23
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24. General procedure for the synthesis of benzoxazinones: The o-amino benzoic acid
1 (1.00 equiv) was dissolved in toluene (5 mL/mmol), then Ac2O (3.00 equiv)
and NEt3 (3.00 equiv) were added. The mixture was stirred for 15 h at 110 °C.
After complete consumption of starting material the solvent was removed
under reduced pressure. The residue was taken up with water and ethyl
acetate (3:1) and phases were separated. The organic layer was dried over
In conclusion, a new method for the preparation of ortho-amino-
substituted 2,2,2-trifluoroacetophenones was developed. Thus,
benzoxazinones were trifluoromethylated with Ruppert’s reagent
and the removal of the amino protecting group could be achieved
in situ.