Triethylamine → N-t-butoxycarbonyl-L-alanylglycine iodopropargyl ester

Participants

Reaction Steps

To a magnetically stirred, anhydrous dichloromethane (20 ml.) solution of glycine iodopropargyl ester trifluoroacetate (Compound #7) (2.00 g., 5.66 mmole) held at 0° C. with an ice-bath was added triethylamine (0.79 ml., 5.67 mmole), followed by N-t-butoxycarbonyl-L-alanine (1.07 g., 5.66 mmole), 1-hydroxybenzotriazole hydrate (0.77 g., 5.70 mmole) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (1.30 g., 6.78 mmole). The reaction mixture was held at 5° C. for 17 hours. The resultant solution was transferred to a separatory funnel and diluted to an approximate volume of 100 ml. with dichloromethane, then washed successively with water, 10% aqueous potassium hydrogen sulfate, water, saturated aqueous sodium bicarbonate, water and a final wash with saturated aqueous sodium chloride. The organic layer was dried with magnesium sulfate, filtered and concentrated in vacuo with a rotary evaporator to give 2.09 g. (90% yield) of the desired N-t-butoxycarbonyl-L-alanylglycine iodopropargyl ester as a dry white foam. 1H-NMR (200 MHz, CDCl3) δ=1.40, d, 3H; 1.47, 1.77, two s, 9H; 4.08, d, 2H; 4.24, m, 1H; 4.90, s, 2H; 5.06, d, 1H; 6.81, s, 1H. IR (CHCl3) 1160, 1375, 1495, 1690, 1755, 2200, 2985, 3440 cm-1.

Provenance & Evidence