Tributylphosphine → 5-(1-Isopropyl-piperidin-4-yloxy)-pyrrolo[2,3-b]pyridine-1,2-dicarboxylic Acid 1-tert-butyl Ester 2-ethyl Ester

Participants

Reaction Conditions

Reaction Steps

To the turbid solution of 0.2 g (0.65 mmol) 5-hydroxy-pyrrolo[2,3-b]pyridine-1,2-dicarboxylic acid 1-tert-butyl ester 2-ethyl ester (as prepared in WO 05/000849) and 1-isopropyl-piperidin-4-ol (commercially available) in 6 ml tetrahydrofuran, 0.26 g (1.3 mmol) tributylphosphine were added and the mixture was cooled to 0° C. Within 60 min. 32.9 mg (1.3 mmol) 1,1′-(azodicarbonyl)dipiperidine were added under stirring and the reaction was allowed to reach room temperature. After 19 hours the brown suspension was filtered and evaporated. The residue was stirred in tert butyl methyl ether, filtered and the clear filtrate was evaporated and flash-chromatographed on silica gel with dichloromethane:methanol:ammonia (9:1:0.1 v/v) to give 60 mg (21%) of the product as a yellow oil.

Provenance & Evidence