Ketones alcohols, cyclic

A second measure of the quality of simulated speara can be determined by performing a library search. In the search procedure, each simulated spectrum was compared to all speara contained in the spearal library to determine the most similar measured spectrum. The spectral library, compiled from data in the literature, contained 521 spectra from several chemical classes, including norbornanes and norbornanols, cyclic and acyclic alkanes and alcohols, cyclic ketones, steroids, PCBs, and an assortment of small molecules. The squared Euclidean distance metric was used to assess similarity. Sorted chemical shift values of each simulated and library speartun were compared, and the five library spectra having the smallest squared Euclidean distances for each simulated spearum were recorded. For each of the 32 reference compounds, the library spectrum that was retrieved with the smallest squared Euclidean distance, when compared with the simulated spearum, was its corresponding observed spectrum. Thus, in the library search, the correa spectrum was always retrieved as the most similar spearum to the simulated spectrum. 

Imaging/Labeling Applications Alcohols cyclic ketones epolactaene derivatives " iejimalide carbamate derivatives lysophospholipids macrolide analogs platelet-activating factor acetylhydrolase (PAF-AH) phosphonic acid-based NAALADase inhibitors uronium salts vinblastine analog ... 

Compounds which dissolve in concentrated sulphuric acid may be further subdivided into those which are soluble in syrupy phosphoric acid (A) and those which are insoluble in this solvent (B) in general, dissolution takes place without the production of appreciable heat or colour. Those in class A include alcohols, esters, aldehydes, methyl ketones and cyclic ketones provided that they contain less than nine carbon atoms. The solubility limit is somewhat lower than this for ethers thus re-propyl ether dissolves in 85 per cent, phosphoric acid but re-butyl ether and anisole do not. Ethyl benzoate and ethyl malonate are insoluble. 

Alcohols, esters (but not ethyl benzoate, ethyl malonate or ethyl oxalate), aldehydes, methyl ketones and cyclic ketones containing less than nine carbon atoms as well as ethers containing less than seven carbon atoms are soluble in 85 p>er cent, phosphoric acid. 

The procedure described is essentially that of Shioiri and Yamada. Diphenyl phosphorazidate is a useful and versatile reagent in organic synthesis. It has been used for racemlzatlon-free peptide syntheses, thiol ester synthesis, a modified Curtius reaction, an esterification of a-substituted carboxylic acld, formation of diketoplperazines, alkyl azide synthesis, phosphorylation of alcohols and amines,and polymerization of amino acids and peptides. - Furthermore, diphenyl phosphorazidate acts as a nitrene source and as a 1,3-dipole.An example in the ring contraction of cyclic ketones to form cycloalkanecarboxylic acids is presented in the next procedure, this volume. 

When a cyclic /3-amino alcohol—e.g. 1—is treated with nitrous acid, a deamination reaction can take place, to give a carbenium ion species 2, which in turn can undergo a rearrangement and subsequent loss of a proton to yield a ring-enlarged cyclic ketone 3. This reaction is called the Tiffeneau-Demjanov reactionit is of wider scope than the original Demjanov reaction ... 

The starting material for the Tiffeneau-Demjanov reaction is available by various methods. A common route is the addition of nitromethane to a cyclic ketone—e.g. cyclopentanone 7—followed by a hydrogenation of the nitro group to give the /3-amino alcohol, e.g. 1 ... 

In the case of substituted cyclic ketones, particularly cyclohexanones, the stereochemical outcome of an addition reaction is determined by the predominance of either equatorial or axial attack of the nucleophile, leading to axial or equatorial alcohols, respectively 25 -27 (Figure 8). 

The stereochemical outcome of nucleophilic addition reactions to cyclic ketones is the subject of numerous experimental and theoretical studies, with substituted cyclohexanones and cy-clopcntanones having been intensively studied. In addition reactions to substituted cyclohexanones 1 the problem of simple diastereoselectivity is manifested in the predominance of cither axial attack of a nucleophile, leading to the equatorial alcohol 2 A. or equatorial attack of the nucleophile which leads to the axial alcohol 2B. 

The reaction of the enamines of cyclohexanones with a,ft-unsaluraled sulfones gives mixtures resulting from attack of the enamine at the a- and /(-carbons of the oc,/ -unsaturated sulfone. The ratio of x- and /1-adducts is dependent upon the reaction solvent, the geometry and structure of the sulfone1 4. The diastereoselectivity of these reactions is also poor. The reaction of lithium enolates of cyclic ketones with ( )-[2-(methylsulfonyl)ethenyl]benzene, however, gives bicyclic alcohols, as single diastereomers, that result from initial -attack on the oc,/ -unsaturated sulfone5. 

Both of these compds yield expls on nitration. It is claimed that these expis have a high detonation velocity, can be pouted at temps below 100°, and are stable when stored at 50° The same investigators proposed the use of nitrates of other cyclic keto-alcohols, such as tetramethylolcyclohexanone, tetramethylolcyclo-pentanone, etc, as expls. All of these alcohols can be prepd by condensing cyclic ketones with formaldehyde in the presence of alkalies or al-... 

Either or both of the R groups may be aryl. In general, dialkyl ketones and cyclic ketones react more rapidly than alkyl aryl ketones, and these more rapidly than diaryl ketones. The latter require sulfuric acid and do not react in concentrated HCl, which is strong enough for dialkyl ketones. Dialkyl and cyclic ketones react sufficiently faster than diaryl or aryl alkyl ketones or carboxylic acids or alcohols that these functions may be present in the same molecule without interference. Cyclic ketones give lactams. 

Cyclic ketones can also be cleaved by treatment with NOCl and an alcohol in liquid SO2 to give an m-oximinocarboxylic ester, for example, ... 

Cleavage of cyclic ketones with NOCl and an alcohol... 

The reaction proceeds via a cyclic TS involving coordination of both the alcohol and ketone oxygens to the aluminum. Computational (DFT) and isotope effect studies are consistent with the cyclic mechanism.190 Hydride donation usually takes place from... 

The formation of crystal inclusion of 47 and 48 with cyclic ketones of suitable ring size (cyclopentanone, cyclohexanone) and with cyclohexene oxide are also important facts. Corresponding inclusion compounds with alcohols or amines could not be obtained. With reference to the heterocyclic guest molecules, the suitability of the ring size is likely to be the decisive factor for guest inclusion. 

The organic compounds were dissolved or dispersed in an aqueous solution of the catalyst, with or without an organic cosolvent, and the net oxidations were carried out at applied potentials causing the oxidation of Ru11 to RuIV complex (0.6-0.8 V vs. SCE). It has been demonstrated that this electrocatalytic system is capable of providing a general and selective method for the oxidation of alcohols, aldehydes, cyclic ketones, and C—11 bonds adjacent to alkeneic or aromatic groups. 

The synthetic utility of the carbonylation of zirconacycles was further enhanced by the development of a pair of selective procedures producing either ketones or alcohols [30] and has been extensively applied to the synthesis of cyclic ketones and alcohols, most extensively by Negishi [22—27,29—33,65,87,131—134], as detailed below in Section I.4.3.3.4. The preparation of unsaturated aldehydes by carbonylation with CO is not very satisfactory. The use of isonitriles in place of CO, however, has provided a useful alternative [135], and this has been applied to the synthesis of curacin A [125]. Another interesting variation is the cyanation of alkenes [136]. Further developments and a critical comparison with carbonylation using CO will be necessary before the isonitrile reaction can become widely useful. The relevant results are shown in Scheme 1.35. 

As with the aldehyde reductases, ketone reductases are specific for NADPH as reductant. Also, some isoenzymes of ketone reductase have not been purified to homogeneity and therefore not fully characterized. It is clear, however, that the ketone reductases catalyze reduction of aromatic, aliphatic, cyclic, and unsaturated ketones to the corresponding alcohols. The ketone reductases also catalyze reduction of aromatic and aliphatic aldehydes to primary alcohols. The distribution and specificity of ketone reductases has been reviewed (103). 

Historically the biotransformations of cyclic enones have been important, not least Leuenberger s transformation of the appropriate cyclohexenedione into the saturated ketone (15), a precursor for tocopherol1541. Similarly 2-methylcyclohex-2-enone is reduced by the microorganism Yamadazyma fari-nosa (also known as Pichia farinosa) to give a mixture of saturated alcohols and ketone pyridinium chlorochromate oxidation of this mixture afforded 3(R)-methylcyclohexanone (95% ee) in 67% yield1551. 

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