OCH2CH3

OCH2CH3 denotes the ethoxy group, an alkoxy substituent widely used in organic chemistry. It consists of an oxygen atom bonded to an ethyl group, giving the formula C2H5O. In structural notation, it appears as -O-CH2-CH3 and can attach to a parent molecule to form an ether or, as the alkoxy component of an ester, contribute to an ethyl ester.

Nomenclature and context: When used as a substituent, the group is named ethoxy. For example, ethoxybenzene refers to a benzene ring bonded to an O-CH2CH3 unit (phenetol). The ethoxy fragment is also the alkoxy portion of esters such as ethyl acetate, where the linkage is R-CO-O-CH2CH3. In ethers, a common instance is diethyl ether, with the structure CH3CH2–O–CH2CH3, containing two ethoxy groups bonded to a central oxygen.

Synthesis and reactivity: The ethoxy group can be introduced via the Williamson ether synthesis, where an alkoxide (R-O−) reacts with an ethyl halide (EtX) to form R-O-CH2CH3. It also forms as the alkoxy portion of ethyl esters through reactions of carboxylic acids with ethanol under activating conditions. In general, alkoxy groups influence the polarity, solubility, and boiling points of the molecules they inhabit, and they can be cleaved or transformed under appropriate catalytic or acidic conditions.

Applications: The ethoxy motif appears in many ethers and esters used as solvents, intermediates in organic synthesis, and components of pharmaceuticals and fragrances.