Iodine → (4-Iodo-pyridin-3-YL)-carbamic acid tert-butyl ester

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Reaction Conditions

Reaction Steps

In heat-dried argon purged 4-neck flask was placed a solution of pyridin-3-yl-carbamic acid tert-butyl ester (10 g, 51.5 mmol, CAS RN 56700-70-0) in THF (100 mL). After cooling down to −75° C., tert-butyllithium (1.7M solution in n-pentane, 66.6 mL, 113 mmol) was added dropwise over 15 min keeping the temperature below −60° C. The resulting light brown suspension was stirred at −75° C. for 3.75 h. A solution of iodine (28.7 g, 113 mmol) in THF (50 mL) was added dropwise over 20 min. below −63° C. The reaction mixture was stirred at −75° C. for 1.5 h and then poured on saturated aqueous NH4Cl solution (1000 mL) and EtOAc (500 mL). The layers were separated. The organic layer was washed once with 10% aqueous Na2S2O3 solution (300 mL) and once with brine (250 mL), dried over MgSO4, filtered, treated with silica gel and evaporated. The compound was purified by silica gel chromatography on a 120 g column using a MPLC system eluting with a gradient of n-heptane:EtOAc (100:0 to 0:100). Yellow solid (11.7 g; 71%). MS (ESI): m/z=321.1 [M+H]+.

Provenance & Evidence