1-TERT-BUTYL 3-METHYL 5-NITRO-1H-INDOLE-1,3-DICARBOXYLATE synthesis

Yield:1058740-09-2 86%

Reaction Conditions:

with dmap in tetrahydrofuran;acetonitrile at 20 - 30;

Steps:

L

Example L; 1 -tert-butyl-3-methyl 5-nitro-indole-1 ,3-dicarboxylate; 5.9 g methyl 5-nitro-1 H-indole-3-carboxylate are dissolved in 100 ml acetonitrile, combined with 100 mg N,N-dimethylamino-pyhdine and a solution of 6.4 g di-tert.-butyl-dicarbonate in 20 ml of tetrahydrofuran is added dropwise thereto. The mixture is stirred overnight at ambient temperature, then heated to 30⁰C for 30 minutes and cooled to 0⁰C. The solid thus precipitated is suction filtered. The mother liquor is freed from the solvents in vacuo and the residue is extracted from petroleum ether/ethyl acetate. Yield: 7.4 g (86 % of theory) R_f value: 0.50 (silica gel: petroleum ether/ethyl acetate 3:1 )

References:

WO2008/113760,2008,A2 Location in patent:Page/Page column 136