Benzene rings monosubstituted

Spectrum 5.3 A benzene ring bearing a single fairly neutral substituent. 

Spectrum 5.4 shows a typical pattern of a benzene ring monosubstituted with an electron donating group (in this case, it s -NH2). 

Spectrum 5.5 shows the effect of a single deshielding substituent (carboxylic acid) on the benzene ring. 

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Wnte stmctural formulas and give the lUPAC names for all the isomers of C6H5C4H9 that contain a monosubstituted benzene ring... 

Anisotropy of molecular motion monosubstituted benzene rings, e.g. phenyl benzoate (44), show a very typical characteristic in the para position to the substituents the CH nuclei relax considerably more rapidly than in the ortho and meta positions. The reason for this is the anisotropy... 

First the five protons (integral) of the //NMR spectrum (Sfj = 7.50 - 7.94) in the chemical shift range appropriate for aromatics indicate a monosubstituted benzene ring with typical coupling constants 8.0 Hz for ortho protons, 1.5 Hz for meta protons.). The chemical shift values especially for the protons which are positioned ortho to the substituent Sn = 7.94) reflect a -M effect. Using the CH COLOC plot it can be established from the correlation signal hclS = 66.AI7.94 that it is a benzoyl group A. 

The ll NMR spectrum of each isomer shows peaks corresponding to live aromatic protons, so compounds A and B each contain a monosubstituted benzene ring. Only four compounds of molecular formula C8HnN meet this requirement. 

CHEMICAL SHIFTS OF PROTONS ON MONOSUBSTITUTED BENZENE RINGS... 

Incremental shifts from the carbon atoms of benzene for the aromatic carbon atoms of representative monosubstituted benzene rings (and shifts from TMS... 

Solution The IOU is [2(8) + 2 - 6]/2 = 6. Clearly this compound must have a monosubstituted benzene ring,... 

Next, look for elements of symmetry. Although the molecular formula indicates 11 carbons, only 7 peaks appear in the 13C NMR spectrum, indicating a plane of symmetry. Four of the 7 peaks are due to aromatic carbons, indicating a benzene ring that is probably monosubstituted. (Prove to yourself that a monosubstituted benzene ring has 4 different kinds of carbons). 

At this point, the unknown structure is a monosubstituted benzene ring with a substituent that contains CH2, C, and CH3 carbons. A structure for the unknown compound that satisfies all data ... 

The compound has nine degrees of unsaturation. The H NMR spectrum shows that the compound is symmetrical and that the only absorptions occur in the vinylic and aromatic regions of the spectrum. The IR spectrum shows peaks due to a monosubstituted benzene ring and to R2C=CH2 (890 cm -1). 

Table 3.10 Chemical Shifts of Protons on Monosubstituted Benzene Rings ...

A monosubstituted benzene ring has three different types of H atoms Hg, Hf and He. 

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