Iodine → (2S)-2-[4-(iodomethyl)-2-oxo-1-pyrrolidinyl]butanamide

Participants

Reaction Conditions

Reaction Steps

In a 10 l 3 necked vessel, fitted with mechanical stirrer and reflux condenser under inert atmosphere, 400 g (2 mole, 1 eq) of (2S)-2-[4-(hydroxymethyl)-2-oxo-1-pyrrolidinyl]butanamide 6 are dissolved in 3 l of acetonitrile. 629 g (2.4 moles, 1.2 eq) of triphenylphosphine are added, followed by 608 g (2.4 moles, 1.2 eq) of iodine in three portions over 5 min. The mixture is heated up to 60° C. in 30 min, and stirred at that temperature for 5 hours. After cooling down, the mixture is concentrated to dryness, the residue suspended in a solution of 750 g of Na2S2O3 in 10 l of water and stirred at 50° C. for 4 hours. The precipitate filtered off and washed with 3×1 l of water. The combined aqueous phases are treated with 1 kg of NaCl, and extracted with 6×1 l of CH2Cl2 The combined organic phases are dried over MgSO4, filtered and concentrated to dryness to give 482 g of crude 10. It is crystallised from toluene. Several crops are recrystallised together from ethyl acetate to give 425 g of pure 10, 68%.

Provenance & Evidence