Name: Tos-PEG4-COOtBu
Brand: BOC Sciences
Rating: 5 (1 reviews)

Size

Price

Stock

Quantity

$--

In stock

Purity

≥95%

Solubility

Soluble in DMSO

Storage

Store at 2-8°C for short term (days to weeks) or -20°C for long term (months to years)

Shipping

Room temperature in continental US; may vary elsewhere.

IUPACName

tert-butyl 3-[2-[2-[2-(4-methylphenyl)sulfonyloxyethoxy]ethoxy]ethoxy]propanoate

Synonyms

3-(2-{2-[2-(Toluene-4-sulfonyloxy)-ethoxy]-ethoxy}-ethoxy)-propionic acid tert-butyl ester; Tos-PEG4-Boc; 2-(2-(tert-butoxycarbonyl)ethoxy)ethyl 4-methylbenzenesulfonate; 2-(2-(tert-butoxycarbonyl)ethoxy)ethyl4-methylbenzenesulfonate; Tos-PEG4-t-butyl ester; tert-butyl 3-(2-(2-(2-(tosyloxy)ethoxy)ethoxy)ethoxy)propanoate

Boiling Point

528.5±45.0 °C at 760 mmHg

Density

1.2±0.1 g/cm3

InChI Key

AAQWIVKRAHBPDM-UHFFFAOYSA-N

InChI

InChI=1S/C20H32O8S/c1-17-5-7-18(8-6-17)29(22,23)27-16-15-26-14-13-25-12-11-24-10-9-19(21)28-20(2,3)4/h5-8H,9-16H2,1-4H3

SMILES

CC1=CC=C(C=C1)S(=O)(=O)OCCOCCOCCOCCC(=O)OC(C)(C)C

This Tos-PEG4-COOtBu linker is designed to support modular PROTAC assembly by providing a PEG-based spacer that can improve solubility and tune the effective distance between binding elements. The tosyl-activated terminus enables efficient nucleophilic substitution, while the protected carboxylate functionality supports controlled coupling strategies. Together, these features facilitate reliable synthesis of targeted protein degraders, with the detailed structural and reactivity considerations provided below.

Structure: The linker contains an oligo(ethylene glycol) segment that confers flexibility and enhanced polarity, flanked by a tosyl leaving group and a tert-butyl-protected carboxylate. It features aromatic sulfonate connectivity, ether linkages within the PEG chain, and an ester-like protected acid motif suitable for stepwise functionalization.

Reactivity: The tosyl group is suitable for substitution under nucleophilic conditions, enabling formation of new C–heteroatom or C–C connections depending on the nucleophile used during PROTAC synthesis. Coupling strategies commonly rely on base-mediated substitution, followed by deprotection of the tert-butyl ester under acidic conditions to reveal the carboxylate for subsequent amide or ester bond formation. Solvent systems compatible with PEG solubility and sulfonate displacement are typically selected to maintain reactivity and minimize side reactions.

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* Our calculator is based on the following equation:
Concentration (start) x Volume (start) = Concentration (final) x Volume (final)
It is commonly abbreviated as: C₁V₁ = C₂V₂