In
organic chemistry
Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic matter, organic materials, i.e., matter in its various forms that contain ...
, a semicarbazone is a
derivative
In mathematics, the derivative is a fundamental tool that quantifies the sensitivity to change of a function's output with respect to its input. The derivative of a function of a single variable at a chosen input value, when it exists, is t ...
of
imines formed by a
condensation reaction
In organic chemistry, a condensation reaction is a type of chemical reaction in which two molecules are combined to form a single molecule, usually with the loss of a small molecule such as water. If water is lost, the reaction is also known as a ...
between a
ketone
In organic chemistry, a ketone is an organic compound with the structure , where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group (a carbon-oxygen double bond C=O). The simplest ketone is acetone ( ...
or
aldehyde and
semicarbazide. They are classified as imine derivatives because they are formed from the reaction of an aldehyde or ketone with the terminal -NH
2 group of semicarbazide, which behaves very similarly to primary
amines.
Formation
;For ketones
:H
2NNHC(=O)NH
2 + RC(=O)R → R
2C=NNHC(=O)NH
2
;For aldehydes
:H
2NNHC(=O)NH
2 + RCHO → RCH=NNHC(=O)NH
2
For example, the semicarbazone of
acetone
Acetone (2-propanone or dimethyl ketone) is an organic compound with the chemical formula, formula . It is the simplest and smallest ketone (). It is a colorless, highly Volatile organic compound, volatile, and flammable liquid with a charact ...
would have the structure (CH
3)
2C=NNHC(=O)NH
2.
Properties and uses
Some semicarbazones, such as
nitrofurazone, and
thiosemicarbazones are known to have
anti-viral and
anti-cancer activity, usually mediated through binding to
copper
Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orang ...
or
iron
Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...
in cells. Many semicarbazones are crystalline solids, useful for the identification of the parent aldehydes/ketones by
melting point
The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state of matter, state from solid to liquid. At the melting point the solid and liquid phase (matter), phase exist in Thermodynamic equilib ...
analysis.
A ''thiosemicarbazone'' is an analog of a semicarbazone which contains a
sulfur
Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...
atom in place of the oxygen atom.
See also
*
Carbazone
*
Carbazide
*
Thiosemicarbazone
References
External links
Compounds Containing a N-CO-N-N or More Complex Group
{{Authority control
Functional groups
Semicarbazones