Carbonyl groups and derivatives

5-Fluoro-l-phenylpyrazole-4-carboxamides 304 have been formed by condensation of the 5-fluoro-l-phenylpyrazole-4-carboxylic acid 303 with amines (Equation 58) 2000EJ0823 . 4-Benzoyl-l-(4-nitrophenyl)-5-phenyl-l//-pyrazole-3-carboxylic acid 305 was converted via reactions of its acid chloride with alcohols or N-nucleophiles, into the corresponding ester or amide derivatives 306 (Equation 59) 2004CHE1039 . Resin-bound pyrazole-4-carboxylic 

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TETRAORGANOTIN COMPOUNDS CONTAINING CARBONYL GROUPS AND DERIVATIVES... 

As for the main volume caution should be exercised regarding the formulae used there. The tetraorganotin compounds containing carbonyl groups and derivatives listed in Table 112 are prepared by methods from the following scheme. 

R = organic group or hydrogen. Additional tetraorganotin compounds containing carbonyl groups and derivatives may be found in Chapters 2.5, 2.. 5, 2.5.5, and 2.6. 4-. 

Additional tetraorganotin compounds containing carbonyl groups and derivatives are listed in Table 112. 

Table 112. Tetraorganotin Compound s Containing Carbonyl Groups and Derivatives RnSnR 4.1 ...

The isopropyl group could be derived from a carbonyl group and a Grignard reagent in two ways ... 

There are large differences in reactivity among the various carboxylic acid derivatives, such as amides, esters, and acyl chlorides. One important factor is the resonance stabilization provided by the heteroatom. This decreases in the order N > O > Cl. Electron donation reduces the electrophilicity of the carbonyl group, and the corresponding stabilization is lost in the tetrahedral intermediate. 

To identify the carbonyl compound and the ylide required to produce a given alkene, mentally disconnect the double bond so that one of its carbons is derived from a carbonyl group and the other is derived from an ylide. Taking styrene as a representative example, we see that two such disconnections are possible either benzaldehyde or formaldehyde is an appropriate precursor. 

The reactivity of an acid derivative toward substitution depends both on the steric environment near the carbonyl group and on the electronic nature of the substituent, Y. The reactivity order is acid halide > acid anhydride > thioester > ester > amide. 

C ionization from the carbonyl group, and the HOMO ionization of the carbonyl oxygen lone pair were included, with similar conclusions. In Fig. 10 the results for the C=0 core ionization are summarized, with the stmcture of each derivative being indicated at the top of the figure. 

Polar C=Y double bonds (Y = NR, O, S) with electrophilic carbon have been added to suifinic acids under formation of sulfones. As in the preceding section one must distinguish between carbonyl groups and their derivatives on the one hand, and carboxylic acids (possessing leaving groups at the electrophilic carbon) on the other. Aldehydes " of sufficient reactivity—especially mono-substituted glyoxals - —and their aryl or arylsulfonyl imines have been added to suifinic acids (in a reversible equilibrium) to yield a-hydroxy or a-amino sulfones the latter could also be obtained from the former in the presence of primary amines (equation 26). 

The nitroaldol reaction of methyl nitroacetate (199, Scheme 38) with 1,2 3,4-di-0-isopropylidene-a-D-ga/acfo-hexodialdo-l,5-pyranose (200) and 2,3-O-isopropyli-dene-D-glyceraldehyde (202) catalyzed by silica gel proceeded in almost quantitative yield, with high selectivity for attack on the aldehyde carbonyl group, giving derivatives 201 and 203, respectively. Two of the four possible diastereomers were detected as main products, and were obtained as a mixture. For the nitroaldol reaction with 200 gave similar results in either the presence or absence of silica gel, whereas the reaction with 202 did not proceed in its absence, showing that catalytic action of silica is mandatory in this case.176... 

XXV). No evidence was presented by Ohle and his colleagues to support the formulation of these derivatives with a free carbonyl group, and further investigation of their structure and properties is desirable before relating them to the free osones. 

In general, 1-substituted derivatives of anthraquinone are more bathochromic than the corresponding 2-substituted isomers, in accordance with PPP-MO calculations [1]. Intramolecular hydrogen bonding is not possible between the carbonyl group and a 2-... 

Aldonolactones having their hydroxyl groups protected as ethers (mainly benzylated and silylated derivatives) have been employed for chain elongation through the carbonyl group, and therefore these type of derivatives are included in Section V. 

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