2,3-DIHYDRO-INDOLE-1,6-DICARBOXYLIC ACID 1-TERT-BUTYL ESTER 6-METHYL ESTER synthesis
- Product Name:2,3-DIHYDRO-INDOLE-1,6-DICARBOXYLIC ACID 1-TERT-BUTYL ESTER 6-METHYL ESTER
- CAS Number:928771-49-7
- Molecular formula:C16H21NO5
- Molecular Weight:307.34
928771-48-6
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928771-49-7
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$357.00/250mg
Yield:928771-49-7 47%
Reaction Conditions:
with N-ethyl-N,N-diisopropylamine in tetrahydrofuran; for 16 h;Heating / reflux;
Steps:
14.2
Step 2: Di-tert-butyl carbonate (2.9 g, 13.5 mmol, 1 equiv.) was added to a stirred mixture of 4-methoxy-2,3-dihydro-1H-indole-6-carboxylic acid methyl ester (2.8 g 13.5 mmol, 1 equiv.) and diisopropyl ethyl amine (4.7 mL, 27 mmol, 2 equiv.) in tetrahydrofuran (30 mL) and the mixture was heated at reflux for 16 hours. The solvent was evaporated under vacuum and the residue purified by column chromatography (SiO2, 1:8 EtOAc:heptane). The fractions were combined to afford 4-methoxy-2,3-dihydro-indole-1,6-dicarboxylic acid 1-tert-butyl ester 6-methyl ester, 1.96 g (47% yield). δH (250 MHz; d6-DMSO) 7.80 (1H, s), 7.10 (1H, s), 3.96 (2H, t), 3.78 (6H, s), 3.03 (2H, t), 1.45 (9H, m).
References:
US2007/60567,2007,A1 Location in patent:Page/Page column 22