THP-PEG5-alcohol

THP-PEG5-alcohol is a PEG-based linker building block containing a free terminal alcohol and a tetrahydropyranyl-protected alcohol at the opposite end. The PEG segment provides a flexible, ether-rich spacer that can be incorporated into PROTACs and other conjugates through sequential functionalization. The THP group temporarily masks one hydroxyl group, allowing the unprotected alcohol to be modified selectively before acid-mediated deprotection.

Structure: THP-PEG5-alcohol comprises an oligoethylene glycol chain bearing a free hydroxyl group at one terminus and a tetrahydropyranyl ether at the other. THP denotes a tetrahydropyranyl group, which is an oxygen-containing six-membered cyclic ether used for alcohol protection; it is not a sulfur-containing group. The PEG ether oxygen atoms and terminal hydroxyl group provide hydrogen-bond-accepting sites, while the hydroxyl group can also act as a hydrogen-bond donor.

Reactivity: The free terminal alcohol can be converted into esters, carbonates, ethers, sulfonates, or other activated derivatives selected for subsequent PROTAC assembly. Meanwhile, the THP ether protects the second alcohol from many neutral and basic reaction conditions. Treatment with a suitable dilute acid cleaves the acid-labile THP group to reveal the corresponding terminal hydroxyl group. Reaction conditions should be selected to avoid premature THP deprotection and to preserve acid-sensitive groups elsewhere in the molecule.