Abstract An efficient and rapid parallel liquid-phase synthesis of pyrazolines has been developed. The one-pot three-components reaction of polyethylene glycol (PEG)-supported acrylate 1, aldehyde 2 and aryl hydrazine 3 in the presence of chloramine-T in methanol gave the corresponding PEG-supported pyrazolines 5. Cleavage from the support under mild conditions afforded pyrazolines 6 in good yields (69-91%) and high purities (91-100 ...