1,3-Cyclobutanedione is an organic compound with the formula . It is an isomer of
1,2-cyclobutanedione. The compound would be of little interest except that its tautomer is a subunit in some commercial dyes.
In solution, 1,3-cyclobutanedione exists in equilibrium with a less stable
tautomer
In chemistry, tautomers () are structural isomers (constitutional isomers) of chemical compounds that readily interconvert.
The chemical reaction interconverting the two is called tautomerization. This conversion commonly results from the reloca ...
, called squaraine, 3-hydroxycyclobut-2-enone.
Squaraine dye
Squaraine dyes are a class of organic dyes showing intense fluorescence, typically in the red and near infrared region (absorption maxima are found between 630 and 670 nm and their emission maxima are between 650 and 700 nm). They are c ...
s are, formally at least, derivatives of squaraine. In such dyes, the ene-one tautomer predominates.
The mixture of tautomers can be prepared by hydrolysis of 1-ethoxycyclobutene-3-one, which is prepared from the cycloaddition of ethoxyacetylene to
ketene
In organic chemistry, a ketene is an organic compound of the form , where R and R' are two arbitrary valence (chemistry), monovalent functional group, chemical groups (or two separate Substituent, substitution sites in the same molecule). The na ...
.
Substituted derivatives
A variety of substituted 1,3-Cyclobutanediones form upon spontaneous dimerization of disubstituted
ketene
In organic chemistry, a ketene is an organic compound of the form , where R and R' are two arbitrary valence (chemistry), monovalent functional group, chemical groups (or two separate Substituent, substitution sites in the same molecule). The na ...
s.
2,2,4,4-Tetramethylcyclobutanedione
2,2,4,4-Tetramethylcyclobutanedione is the organic compound with the formula (CH3)4C4O2. The compound is a diketone of cyclobutane, bearing four methyl groups. It is a white solid that is used as a precursor to diverse industrial products.
Synth ...
is thus formed by
dehydrochlorination
In chemistry, dehydrohalogenation is an elimination reaction which removes a hydrogen halide from a substrate. The reaction is usually associated with the synthesis of alkenes, but it has wider applications.
Dehydrohalogenation from alkyl halide ...
of
isobutyryl chloride
Isobutyryl chloride (2-methylpropanoyl chloride) is the organic compound with the formula . A colorless liquid, it the simplest branched-chain acyl chloride. It is prepared by chlorination of isobutyric acid.
Reactions
As an ordinary acid chlor ...
:
:
:
Ketene itself dimerizes mainly to give the lactone called
diketene
Diketene is an organic compound with the molecular formula , and which is sometimes written as . It is formed by dimerization of ketene, . Diketene is a member of the oxetane family. It is used as a reagent in organic chemistry. It is a colorle ...
as well as a small amount of 1,3-cyclobutanedione.
Related compounds
*
Moniliformin
Moniliformin is the organic compound with the formula (M+ = K+ or Na+). Both the sodium and potassium salts are generally hydrated, e.g. . In terms of its structure, it is the alkali metal salt of the conjugate base of 3-hydroxy-1,2-cyclobutene ...
, a naturally occurring derivative of 3-hydroxycyclobut-2-enone
References
{{DEFAULTSORT:Cyclobutanedione, 1,3-
Cyclobutanes
Cycloalkanones
Diketones