Carbonyl group Esters Ketones

Bis-(4-methoxyphenyl)-[l,3,2,4]dithiadiphosphetane 2,4-disulfide, transforms the carbonyl groups of ketones, amides and esters into the corresponding thiocarbonyl compounds. Cf. Knorr thiophene synthesis. 

CO 2 Carbonyl group (aldehydes, ketones, esters, carboxylic acids)... 

Nitro is just one of a number of groups that are also deactivating towards electrophiles and metadirecting because of electron withdrawal by conjugation. These include carbonyl groups (aldehydes, ketones, esters, etc.), cyanides, and sulfonates and their ]H NMR shifts confirm that they remove electrons from the ortho and para positions. 

The discussion above emphasizes that the allyl-Ni reagents are quite selective for carbon halogen bonds, especially allyl, vinyl, and aryl halides. At the same time, modest reactivity as nucleophiles toward reactive carbonyl derivatives has been reported.Simple aldehydes, the more reactive ketones (such as cyclopentanone and benzoquinone), and certain epoxides will undergo 1,2-addition of the aUyl ligand to the carbonyl group. Esters, amides, and, most remarkably, acyl halides are inert toward the allyl Ni reagents under conditions where the reagents do not decompose thermally (<80 °C or so). 

Chu and coworkers observed that the indole ester (26) can be reduced selectively using pyridine-bo-rane/HCl (equation 81), but Fritz and coworkers found that the same conditions reduce both the indole double bond and the carbonyl group in ketone (27 equation 82) but only the indole double bond in amide (28 equation 83). ... 

The second reaction starts with nucleophilic attack by the amine on the more electrophilic carbonyl group - the ketone. Imine formation is followed by cyclization and this second step is i normal nucleophilic substitution at the carbonyl group of an ester (Chapter 12). The imine double bond moves into the ring to secure conjugation with the ester. 

Phenylthio)methyl metal (metal = Li or MgCl) adds to the carbonyl group of ketones and aldehydes 5-12.13 Benzoyl derivatives of these adducts are converted to alkenes by reductive eUminadoa with Li-NHs, TiCU-Zn or Ti. Transformation of (3) into an alkene via its phosphoric ester has also been repotted (equation 3). ... 

These reagents are interesting because aldehydes and ketones are affected in acidic media only, which permits the reduction of carbon-halogen bonds (Section 2.1) without affecting carbonyl groups, esters, or nitriles. 

Simple n bonds of this type are also found in molecules with carbonyl groups — aldehydes, ketones, carboxylic acids and esters (Structures 5.1). 

Similar to other molecules presenting a carbonyl group, esters are polar molecules (e.g., ketones and aldehydes) and therefore create dipole—dipole interactions as well as van der Waals dispersion forces. 

Enolate anions also add in this manner to the carbonyl groups of ketones and esters. 

All carbonyl groups including ketones, aldehydes, esters, etc. 

A Baeyer-Villiger oxidation converts a ketone to an ester by inserting an oxygen atom next to the carbonyl group. Cyclic ketones produce cyclic esters called lactones. 

Carbonyl gronp (C=0) All carbonyl groups, including ketones, aldehydes, esters, etc. + 1 0 JJ methylene group (CH2) = 12 ppm next to carbonyl = + 1.0 ppm H H L2.2ppmJ... 

A carbonyl group has a carbon atom and an oxygen atom connected with a double bond (i.e., C=0). Four kinds of organic compounds that contain only C, H, and O have a carbonyl group aldehydes, ketones, carboxylic acids, esters. 

The reaction of peroxycarboxylic acids with the carbonyl group of ketones produces esters. 

As already mentioned, it was observed that during photo-oxidative degradation of polymers there occur accumulations of new carbonyl groups with ketonic, carboxylic or ester structure [5]. It was noticed that, whilst in most cases carbonyl structure concentrations from polymer bulk increase with exposure time, concentration of hydroperoxide and peroxide stmctures rapidly reaches a stationary state at relatively low concentrations. An exemplification of such behavior is given in Table 3, in which the variation of hydroperoxide concentration with exposure time (luminous radiation with X > 300 nm) is represented in the case of photo-oxidative degradation of a vinyl-ester based polymeric structure, crosslinked by end double bonds, where BTAC is benzyltributylammonium chloride (Schemes 1, 2—reproduced with kind permission from Elsevier—license no. 3842460646409) [12]. 

The carbon atom of the carbonyl group of ketones is more electrophilic than the acyl carbon atom of esters. Therefore, a second mole of Grignard reagent adds to the ketone to give a tertiary alcohol. 

By IR-spectroscopy a decrease was observed in the keto-carbonyl groups (ester groups at 1740 cm aldehyde groups at 1720 cm and ketone groups at 1715 cm ) during microbial assimilation (i.e. biotic step) as a result of release of short-chain carboxylic as degradation products [5-8]. 

---