Cyclopropanone is an
organic compoundAn organic compound is any member of a large class of chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of compounds such as carbonates, simple oxides of carbon and cyanides, as well as the allotropes of carbon, are considered inorganic...
with molecular formula C
3H
4O consisting of a
cyclopropaneCyclopropane is a cycloalkane molecule with the molecular formula C
3H
6, consisting of three carbon atoms linked to each other to form a ring, with each carbon atom bearing two hydrogen atoms....
carbon framework with a
ketoneIn organic chemistry, a ketone is a type of compound that features a carbonyl group bonded to two other carbon atoms, i.e., R3CCO-CR3 where R can be a variety of atoms and groups of atoms...
functional groupIn organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part...
. The parent compound is labile with
melting pointThe melting point of a solid is the temperature range at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. When considered as the temperature of the reverse change from liquid to solid, it is referred to as the freezing point...
−90 °C and has been prepared by reaction of
keteneA ketene is an organic compound of the form R'RC=C=O where R',R are arbitrary radicals. The term is also used specifically to mean ethenone, the simplest ketene, where R' and R are hydrogens....
with
diazomethaneDiazomethane is the chemical compound CH
2N
2. It is one of the more common diazo compounds. In the pure form at room temperature, it is a famously explosive yellow gas, but it is almost universally used as a solution in diethyl ether...
at −145 °C. Derivatives of cyclopropanone are of some interest to
organic chemistryOrganic chemistry is a discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation of chemical compounds that contain carbon...
.
In
organic synthesisOrganic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic molecules can often contain a higher level of complexity compared to purely inorganic compounds, so the synthesis of organic compounds has...
the use of cyclopropanone itself is substituted by that of
synthonA synthon is a concept in retrosynthetic analysis. It is defined as a structural unit within a molecule which is related to a possible synthetic operation. The term was coined by E.J. Corey...
s like
acetalAn acetal is a molecule with two single bonded oxygens attached to the same carbon atom.Traditional usages distinguish ketal from acetal...
s
cyclopropanone ethyl hemiacetal or
cyclopropanone ethyl trimethylsilyl acetal.
Cyclopropanones are intermediates in the
Favorskii rearrangementThe Favorskii rearrangement , named for the Russian chemist Alexei Yevgrafovich Favorskii, is most principally a rearrangement of cyclopropanones and α-halo ketones which leads to carboxylic acid derivatives. In the case of cyclic α-halo ketones, the Favorski rearrangement constitutes a ring...
with cyclic ketones where
carboxylic acidCarboxylic acids are organic acids characterized by the presence of a carboxyl group, which has the formula -COH, usually written -COOH or -CO2H. Carboxylic acids are Brønsted-Lowry acids — they are proton donors. Salts and anions of carboxylic acids are called...
formation is accompanied by ring-contraction.
An interesting feature of cyclopropanones is that they react as
1,3-dipoleA 1,3-dipole is a type of organic compound with a three-atom pi-electron system containing 4 electrons delocalized over three atoms. They are reactants in 1,3-dipolar cycloadditions.Known 1,3-dipoles:* Azides* Ozone* Nitro compounds* Diazo compounds...
s in
cycloadditionA cycloaddition is a pericyclic chemical reaction, in which "two or more unsaturated molecules combine with the formation of a cyclic adduct in which there is a net reduction of the bond multiplicity." The resulting reaction is a cyclization reaction.Cycloadditions are usually described by the...
s for instance with cyclic dienes such as
furanFuran, also known as furane and furfuran, is a heterocyclic organic compound. It is typically derived by the thermal decomposition of pentose-containing materials, cellulosic solids especially pine-wood. Furan is a colorless, flammable, highly volatile liquid with a boiling point close to room...
.
Cyclopropanone is an
organic compoundAn organic compound is any member of a large class of chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of compounds such as carbonates, simple oxides of carbon and cyanides, as well as the allotropes of carbon, are considered inorganic...
with molecular formula C
3H
4O consisting of a
cyclopropaneCyclopropane is a cycloalkane molecule with the molecular formula C
3H
6, consisting of three carbon atoms linked to each other to form a ring, with each carbon atom bearing two hydrogen atoms....
carbon framework with a
ketoneIn organic chemistry, a ketone is a type of compound that features a carbonyl group bonded to two other carbon atoms, i.e., R3CCO-CR3 where R can be a variety of atoms and groups of atoms...
functional groupIn organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part...
. The parent compound is labile with
melting pointThe melting point of a solid is the temperature range at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. When considered as the temperature of the reverse change from liquid to solid, it is referred to as the freezing point...
−90 °C and has been prepared by reaction of
keteneA ketene is an organic compound of the form R'RC=C=O where R',R are arbitrary radicals. The term is also used specifically to mean ethenone, the simplest ketene, where R' and R are hydrogens....
with
diazomethaneDiazomethane is the chemical compound CH
2N
2. It is one of the more common diazo compounds. In the pure form at room temperature, it is a famously explosive yellow gas, but it is almost universally used as a solution in diethyl ether...
at −145 °C. Derivatives of cyclopropanone are of some interest to
organic chemistryOrganic chemistry is a discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation of chemical compounds that contain carbon...
.
In
organic synthesisOrganic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic molecules can often contain a higher level of complexity compared to purely inorganic compounds, so the synthesis of organic compounds has...
the use of cyclopropanone itself is substituted by that of
synthonA synthon is a concept in retrosynthetic analysis. It is defined as a structural unit within a molecule which is related to a possible synthetic operation. The term was coined by E.J. Corey...
s like
acetalAn acetal is a molecule with two single bonded oxygens attached to the same carbon atom.Traditional usages distinguish ketal from acetal...
s
cyclopropanone ethyl hemiacetal or
cyclopropanone ethyl trimethylsilyl acetal.
Derivatives
Cyclopropanones are intermediates in the
Favorskii rearrangementThe Favorskii rearrangement , named for the Russian chemist Alexei Yevgrafovich Favorskii, is most principally a rearrangement of cyclopropanones and α-halo ketones which leads to carboxylic acid derivatives. In the case of cyclic α-halo ketones, the Favorski rearrangement constitutes a ring...
with cyclic ketones where
carboxylic acidCarboxylic acids are organic acids characterized by the presence of a carboxyl group, which has the formula -COH, usually written -COOH or -CO2H. Carboxylic acids are Brønsted-Lowry acids — they are proton donors. Salts and anions of carboxylic acids are called...
formation is accompanied by ring-contraction.
An interesting feature of cyclopropanones is that they react as
1,3-dipoleA 1,3-dipole is a type of organic compound with a three-atom pi-electron system containing 4 electrons delocalized over three atoms. They are reactants in 1,3-dipolar cycloadditions.Known 1,3-dipoles:* Azides* Ozone* Nitro compounds* Diazo compounds...
s in
cycloadditionA cycloaddition is a pericyclic chemical reaction, in which "two or more unsaturated molecules combine with the formation of a cyclic adduct in which there is a net reduction of the bond multiplicity." The resulting reaction is a cyclization reaction.Cycloadditions are usually described by the...
s for instance with cyclic dienes such as
furanFuran, also known as furane and furfuran, is a heterocyclic organic compound. It is typically derived by the thermal decomposition of pentose-containing materials, cellulosic solids especially pine-wood. Furan is a colorless, flammable, highly volatile liquid with a boiling point close to room...
. An oxyallyl intermediate or valence tautomer (formed by cleavage of the C2-C3 bond) is suggested as the active intermediate or even a biradical structure (compare to the related trimethylenemethane).
Experimental evidence is not conclusive. Other reactions of cyclopropanones take place through this intermediate. For instance enantiopure (+)-
trans-2,3-di-tert-butylcyclopropanone
racemizesIn chemistry racemization refers to partial conversion of one enantiomer into another.- Stereochemistry :Chiral molecules have two forms which differ in their optical characteristics: the levorotatory form will rotate the plane of polarization of a beam of light to the left, while the...
when heated to 80 °C.
An oxyallyl intermediate is also proposed in the
photochemicalIn the area of photochemistry, a photochemical reaction is a chemical reaction that is induced by light. Photochemical reactions are valuable in organic and inorganic chemistry because they proceed differently than thermal reactions. Photochemical reactions are not only very useful but also can be...
conversion of a 3,5-dihydro-4H-pyrazole-4-one with expulsion of nitrogen to an
indaneIndane is a hydrocarbon petrochemical compound.-Derivatives:Derivatives include compounds such as 1-methyl-indane and 2-methyl-indane , 4-methyl-indane and 5-methyl-indane , various dimethyl-indanes, and various pharmaceutical derivatives.Other derivatives can be...
:
In this reaction oxyallyl intermediate
A, in
chemical equilibriumIn a chemical process, chemical equilibrium is the state in which the chemical activities or concentrations of the reactants and products have no net change over time. Usually, this would be the state that results when the forward chemical process proceeds at the same rate as their reverse reaction...
with cyclopropanone
B attacks the phenyl ring through its
carbocationA carbocation is an ion with a positively-charged carbon atom. The charged carbon atom in a carbocation is a "sextet", i.e. it has only six electrons in its outer valence shell instead of the eight valence electrons that ensures maximum stability . Therefore carbocations are often reactive,...
forming a transient
cyclohexadiene C (with UV trace similar to
isotolueneThe Isotoluenes in organic chemistry are the non-aromatic toluene isomers with an exocyclic double bond. They are of some academic interest in relation to aromaticity and isomerization mechanisms...
) followed by rearomatization. The energy difference between A and B is 5 to 7
kcalThe calorie is a pre-SI metric unit of energy. The unit was first defined by Professor Nicolas Clément in 1824 as a unit of heat. This definition entered French and English dictionaries between 1841 and 1867. In most fields its use is archaic, having been replaced by the SI unit of energy, the joule...
/
molThe mole is a unit of amount of substance: it is an SI base unit, and one of the few units used to measure this physical quantity. The name "mole" was coined in German by Wilhelm Ostwald in 1893, although the related concept of equivalent mass had been in use at least a century earlier...
(21 to 29 kJ/mol).
See also
- Other cyclic ketones: cyclobutanone, cyclopentanone
Cyclopentanone is a colorless liquid organic compound with a peppermint-like odor. It is a cyclic ketone, structurally similar to cyclopentane, consisting of a five-membered ring containing a ketone functional group.-Safety:...
, cyclohexanoneCyclohexanone is the organic compound with the formula
5CO. The molecule consists of six-carbon cyclic molecule with a ketone functional group. This colorless oil has an odor reminiscent of peardrop sweets as well as acetone. Over time, samples assume a yellow color due to oxidation...
- Other cyclopropane derivatives: cyclopropene
Cyclopropene is an organic compound with the formula
34. It is the simplest isolable cycloalkene. It has a triangular structure...
, cyclopropenone