Triethylamine → L-(-)-Ornithine

Participants

Reaction Steps

DOTA (1,4,7,10-tetraazacyclododecan-1,4,7,10-tetraacetic acid) 0.5 mmol and 1.5 mmol of triethylamine were dissolved in 10 ml DCM. 0.6 mmol of DCC was dissolved in 5 ml DCM and added to the mixture. The reaction was carried out for 1 hour at room temperature. The white crystals that appeared in the mixture were filtered out. 0.5 mmol of solid BOC-Orn-OtBu was added to the reaction. The reaction was carried out for 20 hours at room temperature. The mixture was filtered and the DCM was evaporated. The product was washed several times with ethanol and air-dried. Cleavage of the protecting groups (BOC, OtBu) was carried out in 1 ml TFA+5% water for 3 hours. The acid was evaporated in a vacuum over a KOH pellet. The final product, L-Orn(DOTA), was washed several times with diethyl ether and dried. The product was dissolved in water and lyophilized.

Provenance & Evidence