, a derivative is a compound
that is derived
from a similar compound by a chemical reaction
In the past, derivative also meant a compound that ''can be imagined to'' arise from another compound, if one atom
or group of atoms
is replaced with another atom or group of atoms,
but modern chemical language now uses the term structural analog
for this meaning, thus eliminating ambiguity. The term "structural analogue" is common in organic chemistry
, the word is used for compounds that at least theoretically can be formed from the precursor
Chemical derivatives may be used to facilitate analysis. For example, melting point
(MP) analysis can assist in identification of many organic compounds. A crystalline derivative may be prepared, such as a semicarbazone
(derived from aldehyde
s or ketone
s), as a simple way of verifying the identity of the original compound, assuming that a table of derivative MP values is available.
Prior to the advent of spectroscopic analysis
, such methods were widely used.