Diethyl cyanophosphonate → 6-(Azetidin-1-yl)pyridin-3-amine

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Reaction Steps

Add, dropwise, 4.26 g (24.83 mmol) of diethyl cyanophosphonate to a solution, stirred at 20° C. under a nitrogen atmosphere, of 7 g (20.69 mmol) of 5-trifluoromethyl-1-[(3-fluorophenyl)methyl]-1H-pyrrolo[2,3-b]pyridine-2-carboxylic acid as obtained in Stage 1.3 and 3.7 g (24.83 mmol) of 3-amino-6-(azetidin-1-yl)-pyridine prepared in the preceding stage in 140 mL of dimethylformamide. Then add, dropwise, 4.6 mL (45.53 mmol) of triethylamine, then stir the reaction mixture for 70 hours at 20° C. After this time, the mixture is concentrated at reduced pressure and then taken up in 700 mL of ethyl acetate and 300 mL of water. The aqueous phase is separated and then extracted with 200 mL of ethyl acetate. The organic phases are combined, washed three times with 200 mL of a saturated sodium bicarbonate solution, then dried over sodium sulfate and concentrated at reduced pressure. The product thus obtained is purified in a silica column, eluting with a mixture of dichloromethane and ethyl acetate, then recrystallized from a mixture of ethanol and methanol. In this way we isolate 5.7 g of the expected product in the form of white crystals.

Provenance & Evidence