2-(2-Methoxyethoxy)ethanamine

This substance is typically obtained as a clear, colorless to pale yellow liquid with a faint amine-like odor. Its molecular formula is C5H13NO2, corresponding to a molecular weight of 119.16. The boiling point is approximately 190–195 °C at atmospheric pressure, with a calculated density near 0.98 g/cm³ at 20 °C. It is completely miscible with water and common organic solvents including methanol, ethanol, acetone, and dichloromethane, reflecting its amphiphilic character imparted by the ether oxygens and primary amine. The compound contains both hydrogen bond donors and acceptors, contributing to its hydrophilic nature. It is stable under normal laboratory conditions but may slowly absorb carbon dioxide from air to form carbamate salts. Storage in tightly sealed containers under inert atmosphere at reduced temperature (2–8 °C) is recommended to maintain purity. Contact with strong oxidizing agents, acid chlorides, and isocyanates should be managed with appropriate laboratory precautions.

2-(2-Methoxyethoxy)ethanamine, also known as amino-PEG2-methyl ether, consists of a short polyethylene glycol chain terminated at one end by a primary amine and at the other by a methoxy group. The molecule features two ether linkages within a flexible ethylenoxy backbone, providing both hydrophilicity and conformational freedom. The primary amine serves as a nucleophilic handle for diverse chemical transformations including amide bond formation, reductive amination, and alkylation reactions. The terminal methoxy group is inert under most reaction conditions, serving as a permanent capping group that prevents further chain extension. This combination of a reactive amine with a hydrophilic, non-ionic spacer makes the compound a valuable intermediate for constructing molecules requiring improved aqueous solubility, reduced nonspecific binding, and defined spatial separation between functional elements.

PEGylation Reagent
This amine-terminated PEG derivative is widely employed for introducing hydrophilic polyethylene glycol chains into peptides, proteins, and small molecules. The flexible ether spacer enhances aqueous solubility, reduces immunogenicity, and extends plasma half-life of therapeutic conjugates. The primary amine enables facile coupling to carboxylic acids via amide formation or to aldehydes via reductive amination, making it a standard tool in bioconjugation chemistry for improving pharmacokinetic properties of drug candidates.

Pharmaceutical Intermediate
In medicinal chemistry, this compound serves as a building block for synthesizing prodrugs and targeted therapeutics. The PEG chain can improve solubility of hydrophobic drug cores while maintaining biological activity. It is incorporated into antibody-drug conjugate linkers where the hydrophilic spacer reduces aggregation and enhances stability during circulation. The amine handle allows attachment to various payloads including cytotoxic agents, imaging probes, and targeting ligands.

Surfactant and Emulsifier Precursor
The amphiphilic nature of this amino-PEG derivative makes it valuable for preparing non-ionic surfactants and emulsifiers. Reaction with fatty acids yields PEGylated amides or esters with balanced hydrophilic-lipophilic properties suitable for cosmetic formulations, pharmaceutical excipients, and industrial cleaning products. These surfactants exhibit low toxicity and biodegradability, aligning with green chemistry principles.

Organic Synthesis Building Block
As a versatile synthetic intermediate, 2-(2-methoxyethoxy)ethanamine participates in diverse transformations including amide coupling with activated carboxylic acids, reductive amination with aldehydes, and Michael addition to α,β-unsaturated carbonyl compounds. The ether chain remains stable under most reaction conditions, enabling its use as a solubilizing tether in solid-phase synthesis and combinatorial chemistry. Its utility extends to the preparation of functionalized PEGs for materials science applications including hydrogels, polymer brushes, and surface coatings.