Carbonyl group definition

It is evident from Table 2 that the chemical shift data are very similar in both states of aggregation. Only the carbonyl carbon show a small but definite shifts, 2 ppm. In the solution state, in acetone -d6 solution the relaxation times T1 of the pyranose carbon atoms are very similar and only slightly smaller than those of the carbon atom of the methyl group in the acetyl substituent, while the T1-value of the carbon atom of the carbonyl group is considerably higher. 

In this technique almost all groups absorbs characteristically within a definite range. Thus a strong IR band at 1800 to 1600 cm 1 in the IR spectrum of an unknown compound indicates that a carbonyl group is present. Identical compounds have identical IR spectra. Molecules with identical or similar shapes of their IR spectra in the finger print region have the same or a similar skeleton of atoms. 

From these results, it was concluded that the configuration of the molecule has a definite effect upon the direction of attack on the carbonyl group. Thus, the hydride attacks the keto group of the a anomer, trans to the purine, producing an axial OH-2 (91), whereas, in the case of the ft anomer, this attack occurs52 cis, leading to an equatorial OH-2 (90a and 90b). 

Hydroxylatnine reacts with carbonyl group =CO of aldehydes, ketones or quinones. yielding oximes, white solids, of definite melting point and used in identification of aldehydes and ketones, e.g.. acetaldehyde oxime CHtCH NOH ... 

Cyclopropanation reactions are one set in an array of C-C bond-forming transformations attributable to metal carbenes (Scheme 5.1) and are often mistakenly referred to by the nonspecific term carbenoid. Both cyclopropanation and cyclopropenation reactions, as well as the related aromatic cycloaddition process, occur by addition. Ylide formation is an association transformation, and insertion requires no further definition. All of these reactions occur with diazo compounds, preferably those with at least one attached carbonyl group. Several general reviews of diazo compounds and their reactions have been published recently and serve as valuable references to this rapidly expanding field [7-10]. The book by Doyle, McKervey, and Ye [7] provides an intensive and thorough overview of the field through 19% and part of 1997. 

The carbonyl group in an aldehyde is by definition at the terminal position in the carbon chain (R CH2 CH2 CHO). Branching in the carbon chain, or the presence of a functional substituent group, is located by systematic numbering letters of the Greek alphabet may be used to specify in general terms substituents relative to the carbonyl carbon. Illustrative representations are shown below for ... 

Definition a, p-Unsaturated aldehydes and ketones are aldehydes and ketones that are conjugated with a double bond. The a-position is defined as the carbon atom next to the carbonyl group, while the P-position is the carbon atom two bonds removed ... 

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