Triisopropylamine

Disposable 5-mL polypropylene reactors fitted with a PTFE filter were acquired from Thermo Fisher Scientific (Hvidovre, Denmark). Tentagel S RAM resin, TFA, piperidine, and Fmoc-protected l- and d-amino acids were purchased from Iris-Biotech GmbH (Marktredwitz, Germany) Primary amines, bromoacetic acid, DIEA and Triisopropylamine were from Sigma-Aldrich (Søborg, Denmark). HOAt (1-Hydroxy-7-azabenzotriazole) and HATU (1-[Bis(dimethylamino)methylene]-1H-1,2,3-triazolo [4,5-b]pyridinium 3-oxid hexafluorophosphate, N-[(Dimethylamino)-1H-1,2,3-triazolo-[4,5-b]pyridin-1-ylmethylene]-N-methylmethanaminium hexa-fluorophosphate N-oxide) were from GL Biochem (Shanghai, China). DMF (dimethylformamide, synthesis grade), DCM (dichloromethane, optical grade), MeCN (acetonitrile, optical grade) were from VWR (Copenhagen, Denmark). All reagents and solvents were used without further purification.

Picloram (4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid) and picloram-oleyl (PO) were the gift of Nufarm Ltd. (Laverton, Vic, Australia), O-(6-chlorobenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate (HCTU), triisopropylamine, methoxypolyethylene glycol 350 (Me-EO₇–OH), 1-bromododecane, 18-crown-6, sodium hydroxide and potassium carbonate anhydrous were purchased from Sigma-Aldrich (St. Louis, MO, USA). p-Toluenesulfonyl chloride (Ots-Cl) and 3,5-dihydroxybenzyl alcohol were purchased from TCL Co. Ltd. (Chuo-ku, Tokyo, Japan). Diethyl ether, chloroform, methanol, acetonitrile and magnesium sulphate anhydrous were purchased from Merck Pty. Ltd. (Kilsyth, Vic, Australia).