hexanoyl

Hexanoyl is the acyl substituent derived from hexanoic acid (also known as caproic acid). The hexanoyl group has the structural formula CH3-(CH2)4-CO-, and it is attached to other molecules through the carbonyl carbon to form acyl linkages found in esters, amides, and anhydrides. The term is commonly used interchangeably with caproyl in many contexts.

As a building block in organic synthesis, hexanoyl is used to introduce a six-carbon, relatively hydrophobic aliphatic chain bearing a terminal carbonyl. The most practical derivative is hexanoyl chloride (caproyl chloride), the acid chloride of hexanoic acid, which is a reactive acylating agent. Reactions of hexanoyl chloride with alcohols give alkyl hexanoates (R-O-CO-CH2-CH2-CH2-CH2-CH3), while reactions with amines form hexanoyl amides. Hexanoyl groups can also be incorporated via various coupling methods to form mixed anhydrides and related derivatives.

In usage, hexanoyl groups appear in esters and amides where the hexanoyl fragment serves as the acyl portion of the molecule. The long aliphatic chain influences properties such as hydrophobicity and volatility, aiding in the design of compounds for flavors, fragrances, or pharmaceutical applications where a six-carbon acyl unit is desirable.

See also: hexanoic acid, caproic acid, caproyl, acyl group, acyl chloride.