Ketones cyclopentanone

The desired ketone, cyclopentanone, is derived from the corresponding j8-keto ester. This key intermediate is obtained from a Dieckmann cyclization of the starting material, diethyl hexanedioate. 

Trimethylsilyl ethers of the ends from acetone, tern-butyl methyl ketone, cyclopentanone, cyclohexanone, 2-decalone, phenyl methyl ketone... 

Enolate anions 210 of methylene ketones (cyclopentanone, cyclohexanone, acetophenone, etc.) react with the enamine 211 to give adducts which are readily transformed into a-pyrones 212 (equation 89)111. 

Tetraalkyl- and tetraatyl-ethylene glycols (pinacols) are made by reduction of ketones with active metals such as sodium, magnesium, and aluminum. The reaction is only fair for aliphatic and alicyclic ketones. Acetone, methyl ethyl ketone, cyclopentanone, and cyclohexanone all give less than 0% yields of pinacols. Mixtures of ketones are reduced to unsymmetrical pinacols. An active zinc-copper couple has been employed in the reduction of several simple olefinic aldehydes to dieodiols, e.g., crotonaldehyde to dipropenyl glycol,... 

A review of the literature to 1942 lists 137 condensations involving aldehydes and ketones. Trioxymethylene serves as a source of formal dehyde. In addition-to the compounds listed, condensations of 2 pente nal, ° o-tolualdehyde, methyl ethyl ketone, diethyl ketone, methyl hexyl ketone, cyclopentanone, and phenyl t-butyl ketone are noteworthy. 

CO, CH4, CO2, acetone, ketene. ethene. propene. 1-butene, benzene, toluene, xylene, cydopentene, methyl ethyl ketone, diethyl ketone, methyl-n-propyl ketone, di-n-propyl ketone, methyl vinyl ketone, methyl Isopropenyl ketone, methyl isopropyl ketone, ethyl vinyl ketone, trace amounts of methyl-n-bulyl ketone, cyclopentanone, cydohexanone. acrolein, ethanal. butanal. chain fragments, some monomer CO. CH4, COj, ketene, 1-butene, propene, acetone, methyl ethyl ketone, methyl n-propyl ketone, 1,4-cyclohexadiene. toluene, l-methy. l.3-cydohexadlene, 2-hexanone, cydopentene, 1-methyl cydopentene. mesityl oxide, xylenes, benzene, ethene, cyclopentanone, 1.3-cyclopentad iene, diethyl ketone, short chain fragments, traces of monomer CO, CH4, COi, ketene, 1-butene, propene, acetone, methyl ethyl ketone, methyl isopropyl ketone, methyl-n-propyl ketone, diethyl ketone, methyl propenyl ketone, 3-hexanone. toluene, 2-hexanone. 1,3-cydopentadiene, cyclopentanone, 2-melhylcydopenlanone, mesityl oxide, xylenes, benzene, propionaldehyde, acrolein, acetaldehyde ethene, short chain fragments, traces of monomer CO, COj, H2O, CH4. acetone, ketene, ethene, propylene, 1-butene, methyl vinyl ketone, benzene, acrylic add, toluene, xylene, short chain fragments such as dimer to octamer with unsaturated and anhydride functionalities... 

Other chemosignals from the temporal gland are composed of mixtures of several compounds. These mixtures may include compounds of homogeneous molecular weight and volatility, or of widely varying volatility. One example of a reasonably homogeneous mixture is the C6—C12 aldehydes, which at times elicit responses from male conspecifics, although no behavioral responses to these components have been observed (Rasmussen, unpublished). In contrast, a mixture of seven ketones, an alcohol, a cyclic ketone, and frontalin that elicits behavioral avoidance by females is not only a chemically complex mixture, but the physical properties of the compounds differ (Perrin et al., 1996). The cyclic ketone, cyclopentanone, and the terpene, frontalin may persist as components of the... 

The asymmetric bromination of (3-dicarbonyl compounds was accomplished using a catalytic amount of a chiral primary amine catalyst, with pyridine dicarboxylic acid (PDA) as the co-catalyst and 3,3-dibromo-5,5-dimethylcyclo-hexa-l,3-dione as the bromine source (Scheme 13.25) [55]. The substrate scope was quite broad and included cyclic and acyclic (3-ketoesters, acycfic p-diketones, and the cyclic ketones cyclopentanone and cyclohexanone. Additionally, the conditions for chlorination of (3-dicarbonyl compounds using the benzoylquinidine catalyst depicted in Scheme 13.15 were adapted for the bromination of two substrates [35]. 

Aldolase antibodies 38C2 and 33F12 generated by immunization with diketone 1 are capable of accelerating more than 100 different aldol reactions [4, 8, 11, 15, 16]. Some examples of cross-aldol reactions are shown in Table 6.1. For cross-aldol reactions, a variety of ketones are accepted as donors, including aliphatic open-chain ketones (for example acetone to pentanone), aliphatic cyclic ketones (cyclopentanone to cycloheptanone), functionalized open-chain ketones (hydroxyacetone, dihydroxyacetone, fluoroacetone), and functionalized cyclic ketones (2-hydroxycyclohexanone). As with the donors, the antibodies also accept different kinds of aldehyde substrate, for example benzaldehyde derivatives 8-10, a,j5-unsaturated aldehyde 11, and aliphatic aldehydes 12 and 13 with products as indicated in Table 6.1. 

Butane-2,3-diol undergoes a reaction with ketones to form a ketal derivative as shown in Figure 50.12. The absolute configurations of acyclic ketones, cyclopentanones, and cyclohexanones with a preference for the chair conformation can be assigned based on an examination of the NMR spectra of the ketal derivatives. Butane-2,3-thiol can be used in the same manner and gives larger enantio meric discrimination, but it is not commercially available. 

Ethylene, butene-1, isobutene, acetylene, CO2, CH4, CO, acetone, isopropylaldehyde, methacrolein, butyraldehyde, methyl ethyl ketone, benzene (trace), methyl isopropyl ketones, methyl isopropenyl ketone, diethyl ketone, methyl n-propenyl ketone, cyclopentanone, methyl... 

Monomer, phthalic anhydride, diethylene glycol, C2H4, propylene, CO2 CO2, alkenes, CH4, CO, propanal methanol (major), acetone, 2-methyl propanal, methacrolein, butanal, methyl ethyl ketone, methyl isopropyl ketone, methyl isopropenyl ketone, methyl methacrylate (major), methyl prop-2-enyl ketone, toluene, di-isopropyl ketone, cyclopentanone, 2-methyl cyclopentanone, 2,5-dimethyl cyclopentanone, 2,5-di-methyl cyclopent-3-enone. Relative yields depend upon salt and copolymer composition... 

Ketones can also be used in this transformation, but sometimes enolizable ketones lead to the formation of the vinyl chloride derived from the enol. This is usually more of a problem for six-membered ring ketones than for five-membered ring ketones. Cyclopentanone yields predominantly the 1,1-dichloroalkene (eq 33), while cyclohexanone provides mainly the vinyl chloride (eq 34). ... 

The lactone can be made from the corresponding ketone (cyclopentanone). 

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