Functional carbonyl function

Hammen equation A correlation between the structure and reactivity in the side chain derivatives of aromatic compounds. Its derivation follows from many comparisons between rate constants for various reactions and the equilibrium constants for other reactions, or other functions of molecules which can be measured (e g. the i.r. carbonyl group stretching frequency). For example the dissociation constants of a series of para substituted (O2N —, MeO —, Cl —, etc.) benzoic acids correlate with the rate constant k for the alkaline hydrolysis of para substituted benzyl chlorides. If log Kq is plotted against log k, the data fall on a straight line. Similar results are obtained for meta substituted derivatives but not for orthosubstituted derivatives. 

The target compound is searched for a rctron. A retron is the structural subunit required to be present in the target in order to apply a transform. In Figure 10,3-30 the rctron of a Michael addition is a sequence of five carbon atoms with two carbonyl functions in the 1,5-position. For a Michael addition transform to be applied, it has to be present,... 

Lithium aluminium hydride LiAlH is a useful and conveuient reagent for the selective reduction of the carbonyl group and of various other polar functional groups. It is obtained by treatment of finely powdered lithium hydride with an ethereal solution of anhydrous aluminium chloride ... 

The success of the last reaction depends upon the inertness of the ester carbonyl groups towards the organocadmium compound with its aid and the use of various ester acid chlorides, a carbon chain can be built up to any reasonable length whilst retaining a reactive functional group (the ester group) at one end of the chain. Experimental details are given for l-chloro-2-hexanone and propiophenone. The complete reaction (formation of ketones or keto-esters) can be carried out in one flask without isolation of intermediates, so that the preparation is really equivalent to one step. 

Furthermore, the number of diene - dienoplrile combinations that can be expected to undergo a Lewis-acid catalysed Diels-Alder reaction is limited. Studies by Wijnen leave little doubt that the rate of typical Diels-Alder reactions, where the dienophile is activated by one or more carbonyl functionalities, does not respond to the presence of Lewis acids in aqueous solution , at least not beyond the extent that is expected for non-specific interactions (salt effects). No coordination of the Lewis acid to the dienophile was observed in these cases, which is perhaps not surprising. Water is... 

Apparently, 4.54 is extremely reluctant to undergo a retro Mannicli reaction. Riviere demonstrated that this behaviour is not unusual for (3-amino ketones. From the study of a large number of Mannich adducts. Riviere concludes that the retro Mannich reaction requires an aromatic group next to the carbonyl functionality. Qearly, 4.54 lacks this arrangement. 

Analysis the functional group is an acetal derived fiom alcohols and a carbonyl compound. 

When a molecule contains two functional groups, the best discoimection uses the two together. So if you consider TM 84 as an alcohol, and use the carbonyl group to guide your disconnection, what do you get ... 

In order for the transferability of parameters to be a good description of the molecule, force fields use atom types. This means that a sp carbon will be described by different parameters than a. sp - carbon, and so on. Usually, atoms in aromatic rings are treated differently from sp atoms. Some force fields even parameterize atoms for specific functional groups. For example, the carbonyl oxygen in a carboxylic acid may be described by different parameters than the carbonyl oxygen in a ketone. 

Although several experimental data concerning the functionalization of cumulenic anions are availab. a (for a review see Ref. 10) (Table I), it remains difficult to predict the compos tion of the product of a particular reaction on a rationalistic basis. Especially the outcome of reactions with carbonyl compounds seems to be... 

A classical reaction leading to 1,4-difunctional compounds is the nucleophilic substitution of the bromine of cf-bromo carbonyl compounds (a -synthons) with enolate type anions (d -synthons). Regio- and stereoselectivities, which can be achieved by an appropiate choice of the enol component, are similar to those described in the previous section. Just one example of a highly functionalized product (W.L. Meyer, 1963) is given. 

Intramolecular reactions between donor and acceptor centres in fused ring systems provide a general route to bridged polycyclic systems. The cts-decalone mesylate given below contains two d -centres adjacent to the carbonyl function and one a -centre. Treatment of this compound with base leads to reversible enolate formation, and the C-3 carbanion substitutes the mesylate on C-7 (J. Gauthier, 1967 A. Belanger, 1968). 

The only acid-resistant protective group for carbonyl functions is the dicyanomethy-lene group formed by Knoevenagel condensation with malononitrile. Friedel-Crafts acylation conditions, treatment with hot mineral acids, and chlorination with sulfuryl chloride do not affect this group. They have, however, to be cleaved by rather drastic treatment with concentrated alkaline solutions (J.B. Basttis, 1963 H. Fischer, 1932 R.B. Woodward, 1960, 1961). 

Another feature of the Pd—C bonds is the excellent functional group tolerance. They are inert to many functional groups, except alkenes and alkynes and iodides and bromides attached to sp carbons, and not sensitive to H2O, ROH, and even RCO H. In this sense, they are very different from Grignard reagents, which react with carbonyl groups and are easily protonated. 

Carbonylation of alkenes bearing suitable functional groups proceeds regio-selectively. Carbonylation of vinylsilane and / -substituted vinylsilanes pro-... 

The next step is attack at the carbon carrying the carbonyl function by the lone pair of nitrogen atom, giving rise to a new cyclic intermediate... 

Humphlett and Lamon (522) have recently studied the intermediary compounds of this reaction and have shown with the help of infrared and ultraviolet spectroscopy that 176 was not present in the reaction mixture (Scheme 90) instead, a compound containing an hydroxyl radical and not a carbonyl function was present (Scheme 91). 

Many compounds contain more than one functional group Prostaglandin Ei a hormone that regulates the relaxation of smooth muscles con tains two different kinds of carbonyl groups Classify each one (aldehyde ketone carboxylic acid ester amide acyl chloride or acid anhydride) Identify the most acidic proton in prostaglandin Ei and use Table 1 7 to estimate its pK ... 

Both the Clemmensen and the Wolff-Kishner reductions are designed to carry out a specific functional group transformation the reduction of an aldehyde or ketone carbonyl to a methylene group Neither one will reduce the carbonyl group of a carboxylic acid nor... 

Sodium borohydride and lithium aluminum hydride react with carbonyl compounds in much the same way that Grignard reagents do except that they function as hydride donors rather than as carbanion sources Figure 15 2 outlines the general mechanism for the sodium borohydride reduction of an aldehyde or ketone (R2C=0) Two points are especially important about this process... 

A major difference between alcohols and thiols concerns their oxidation We have seen earlier m this chapter that oxidation of alcohols gives compounds having carbonyl groups Analogous oxidation of thiols to compounds with C=S functions does not occur Only sulfur is oxidized not carbon and compounds containing sulfur m various oxida tion states are possible These include a series of acids classified as sulfemc sulfimc and sulfonic according to the number of oxygens attached to sulfur... 

Preparation of Alcohols by Reduction of Carbonyl Functional Groups... 

Like aldehydes ketone functions take precedence over alcohol functions double bonds halogens and alkyl groups m determining the parent name and direction of numbering Aldehydes outrank ketones however and a compound that contains both an aldehyde and a ketone carbonyl group is named as an aldehyde In such cases the carbonyl oxy gen of the ketone is considered an 0x0 substituent on the mam chain... 

Although substitutive names of the type just described are preferred the lUPAC rules also permit ketones to be named by functional class nomenclature The groups attached to the carbonyl group are named as separate words followed by the word ketone The groups are listed alphabetically... 

Ketones may also be named using functional class lUPAC nomenclature by citing the two groups attached to the carbonyl m alphabetical order followed by the word ketone Thus 3 methyl 2 butanone (substitutive) becomes isopropyl methyl ketone (functional class)... 

Compounds that contain both carbonyl and alcohol functional groups are often more stable as cyclic hemiacetals or cyclic acetals than as open chain compounds Examples of several of these are shown Deduce the structure of the open chain form of each... 

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