2-Hydroxy-1,2,3-propanetricarboxylic acid hydrate (1:1) → 10-(3-Hydroxymethyl-azetidin-1-yl)-5,6,8,9-tetrahydro-1,4,7,10a-tetraaza-cyclohepta[f]indene-7-carboxylic acid tert-butyl ester

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Reaction Steps

A mixture of 2.57 g (13.75 mmol) 3-hydroxymethyl-azetidine-1-carboxylic acid tert-butyl ester and 2.62 g (13.75 mmol) para-toluenesulfonic acid monohydrate in 14 mL DCM was stirred at room temperature for 16 hours. After evaporation of the solvent, the residue was dissolved in 28 mL EtOH, then 4.8 mL (27.5 mmol) DIPEA followed by 4.03 g (12.5 mmol) 10-chloro-5,6,8,9-tetrahydro-1,4,7,10a-tetraaza-cyclohepta[f]indene-7-carboxylic acid tert-butyl ester were added and the reaction mixture was heated under reflux for 24 hours. The mixture was allowed to cool to room temperature and the solvent was evaporated. 300 mL DCM was added to the mixture, the organic layer was washed sequentially with 100 mL saturated solution of NaHCO3, a mixture of 1.94 g (9.23 mmol) citric acid monohydrate in 100 mL H2O and 100 mL saturated brine, then was dried over MgSO4. After filtration and evaporation of the solvent the product was purified by column chromatography (Biotage silica 40+M, heptane/EtOAc 1:1 to EtOAc).

Provenance & Evidence