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Usage

Uses

Used in Organic Synthesis:
Cyclopenta-2,4-dien-1-one is used as a key intermediate in the synthesis of various organic compounds due to its reactive diene and ketone groups. Its ability to participate in a range of chemical reactions, such as Diels-Alder reactions, makes it a versatile building block in the preparation of complex molecules.
Used in Polymer Chemistry:
In the field of polymer chemistry, cyclopenta-2,4-dien-1-one is used as a monomer for the production of polymers with unique properties. Its conjugated structure allows for the formation of polymers with enhanced thermal stability and other desirable characteristics, making it a valuable component in the development of advanced materials.
Used in Material Science:
Cyclopenta-2,4-dien-1-one is employed as a component in the development of new materials with improved properties. Its chemical stability and heat resistance contribute to the creation of materials with enhanced performance in various applications, such as in the aerospace, automotive, and electronics industries.
Used in Pharmaceutical Research:
Although still under investigation, cyclopenta-2,4-dien-1-one shows potential bioactivity, which makes it a candidate for further research in the pharmaceutical industry. Its aromatic nature and conjugated structure may lead to the discovery of new drugs with novel mechanisms of action and therapeutic applications.

Upstream product

• 1192-27-4 5-diazo-1,3-cyclopentadiene 
• 31519-30-9 tricyclo<2.1.0.0^2,5>pentan-3-one 
• 94923-08-7 2-diazo-1-(2-cyclopropen-1-yl)ethanone 
• 945657-34-1 4-(1-oxoethyl)-cyclopent-2-enone 
• 106-51-4 p-benzoquinone 
• 10374-07-9 3-oxabicyclo<3.2.0>hept-6-ene-2,4-dione 
• 583-63-1 ortoquinone 
• 42827-31-6 4-methylene-2-cyclobuten-1-one 
• 150-76-5 4-methoxy-phenol 
• 80156-16-7 5-hydroxy-1,3-cyclopentadiene 
• 150-78-7 1,4-dimethoxybezene 
• 90-05-1 2-methoxy-phenol 
• 84820-09-7 Bicyclobutandicarbonsaeureanhydrid 
• 88766-67-0 cyclopentadienone O-oxide 

Relevant academic research and scientific papers

The Photo-isomerization of Cyclopentadienone O-Oxide Isolated in Low Temperature Matrices

Discrepancies in recent reports from different laboratories on the i.r. spectrum of matrix-isolated cyclopentadienone O-oxide have now been reconciled by showing that two distinct isomers may be formed from cyclopentadienylidene and O2, and that one, a carbonyl oxide, may be converted photolytically into the other, a dioxirane.

Binuclear ruthenium(III) bis(thiosemicarbazone) complexes: Synthesis, spectral, electrochemical studies and catalytic oxidation of alcohol

(Chemical Equation Presented).A new series of binuclear ruthenium(III) thiosemicarbazone complexes of general formula [(EPh3)2 (X)2Ru-L-Ru(X)2(EPh3)2] (where E = P or As; X = Cl or Br; L = NS chelating bis(thiosemicarbazone ligands) has been synthesized and characterized by analytical and spectral (FT-IR, UV-Vis and EPR). IR spectra show that the thiosemicarbazones behave as monoanionic bidentate ligands coordinating through the azomethine nitrogen and thiolate sulphur. The electronic spectra of the complexes indicate that the presence of d-d and intense LMCT transitions in the visible region. The complexes are paramagnetic (low spin d5) in nature and all the complexes show rhombic distortion around the ruthenium ion with three different 'g' values (gx ≠ gy ≠ gz) at 77 K. All the complexes are redox active and exhibit an irreversible metal centered redox processes (RuIII-RuIII/RuIV-RuIV; RuIII-RuIII/RuII-RuII) within the potential range of 0.38- 0.86 V and -0.39 to -0.66 V respectively, versus Ag/AgCl. Further, the catalytic efficiency of one of the complexes [Ru2Cl2(AsPh3)4(L1)] (4) has been investigated in the case of oxidation of primary and secondary alcohols into their corresponding aldehydes and ketones in the presence of N-methylmorpholine- N-oxide(NMO) as co-oxidant. The formation of high valent RuV@O species is proposed as catalytic intermediate for the catalytic cycle.

Cyclopentadienone O-Oxide: A Highly Labile Intermediate in the Matrix Reaction between Cyclopentadienylidene and Oxygen

Cyclopentadienylidene reacts with oxygen in low-temperature matrices, giving a photolabile intermediate, the i.r. spectrum of which suggests that it is the carbonyl oxide, cyclopentadienone O-oxide.

Oxygen-Carbon bond dissociation enthalpies of benzyl phenyl ethers and anisoles. An example of temperature dependent substituent effects

For some time it has been assumed that the direction and magnitude of the effects of Y-substituents on the Z-X bond dissociation enthalpies (BDE's) in compounds of the general formula 4-YC6H4Z-X could be correlated with the polarity of the Z-X bond undergoing homolysis. Recently we have shown by DFT calculations on 4-YC6H4CH2-X (X = H, F, Cl, Br) that the effects of Y on CH2-X BDE's are small and roughly equal for each X, despite large changes in C-X bond polarity. We then proposed that when Y have significant effects on Z-X BDE's it is due to their stabilization or destabilization of the radical. This proposal has been examined by studying 4-YC6H4O-X BDE's for X = H, CH3, and CH2C6H5 both by theory and experiment. The magnitudes of the effects of Y on O-X BDE's were quantified by Hammett type plots of ΔBDE's vs σ+ (Y). Calculations reveal that changes in O-X BDE's induced by changing Y are large and essentially identical (ρ+ = 6.7-6.9 kcal mol-1) for these three classes of compounds. The calculated ρ+ values are close to those obtained experimentally for X = H at ca. 300 K and for X = CH2C6H5 at ca. 550 K. However, early literature reports of the effects of Y on O-X BDE's for X = CH3 with measurements made at ca. 1000 K gave ρ+ ≈ 3 kcal mol-1. We have confirmed some of these earlier, high-temperature O-CH3 BDE's and propose that at 1000 K, conjugating groups such as -OCH3 are essentially free rotors, and no longer lie mainly in the plane of the aromatic ring. As a consequence, the 298 K DFT-calculated ΔBDE for 4-OCH3-anisole of -6.1 kcal mol-1 decreases to -3.8 kcal mol-1 for free rotation, in agreement with the ca. 1000 K experimental value. In contrast, high-temperature O-CH3 ΔBDE's for three anisoles with strongly hindered substituent rotation are essentially identical to those that would be observed at ambient temperatures. We conclude that substituent effects measured at elevated temperatures may differ substantially from those appropriate for 298 K.

Parabenzoquinone pyrolysis and oxidation in a flow reactor

An experimental and theoretical study of the pyrolysis and oxidation of parabenzoquinone has been performed. The experiments were conducted in an isothermal quartz flow reactor at atmospheric pressure in the temperature range 600-1500 K. The main variables considered are temperature, oxygen concentration, and presence of CO. A detailed reaction mechanism for the pyrolysis and oxidation chemistry of parabenzoquinone is proposed, which provides a good description of the experimental results. Both the experimental work and the kinetic mechanism proposed for the pyrolysis and oxidation of parabenzoquinone represent the first systematic study carried out for this important aromatic compound. Our pyrolysis results confirm that the primary dissociation channel for p-benzoquinone leads to CO and a C5H4O isomer, presumably cyclopentadienone. However, significant formation of CO2 during the pyrolysis may indicate the existence of a secondary dissociation channel leading to CO2 and a C5H4 isomer. Under oxidizing conditions, consumption of p-benzoquinone occurs mainly by dissociation at lower temperatures. As the temperature increases interaction of OC6H4O with the radical pool becomes more significant, occurring primarily through hydrogen abstraction reactions followed by ring opening reactions of the OC6H3O radical.

Small Rings, 54. Cyclopentadienone

Cyclopentadienone (1) can be generated by photolysis or pyrolysis of several precursors and isolated in an argon matrix.It dimerizes even on thawing of the matrix (38 K).The IR and UV spectroscopic properties of 1 are discussed.

NEUE WEGE ZUM CYCLOBUTADIEN UND METHYLENCYCLOPROPEN

New routes to cyclobutadiene (2) and methylenecyclopropene (4) are described.Matrix irradiation of cyclopropenylketene (9) gives cyclobutadiene.Flash pyrolysis of 8, 11, 16, 17 and 18 also generates cyclobutadiene, which can be deposited from the gas phase onto a window cooled to 10 K.Methylenecyclopropene is one of he products in the thermal fragmentation of 8 or 14.