Benzene functional group

Smith and Burr [126] studied the retention of 73 disubstituted benzenes (functional groups included alkyl, nitro, bromo, chloro, carboxyl, nitrile, amide, amino, hydroxyl, methoxy, and phenyl) on a C g column (A = 254nm) usmg a series of methanol/water (1.37 g NaH2P04 with 1.58 g Na2HP04 to pH 7) mobile phases. The V values for these compounds were tabulated for mobile phases ranging in composition from 40/60 to 80/20 methanol/buffer. 

Mono-substituted benzene, di-substituted benzene, functional groups, acute toxicity. Photobacterium phosphoreum, quantitative structure-activity relationships, octanol/water partition coefficient. 

In the preceding chapter the special stability of benzene was described along with reac tions in which an aromatic ring was present as a substituent Now we 11 examine the aromatic ring as a functional group What kind of reactions are available to benzene and Its derivatives What sort of reagents react with arenes and what products are formed m those reactions ... 

Chlorination is carried out m a manner similar to brommation and provides a ready route to chlorobenzene and related aryl chlorides Fluormation and lodmation of benzene and other arenes are rarely performed Fluorine is so reactive that its reaction with ben zene is difficult to control lodmation is very slow and has an unfavorable equilibrium constant Syntheses of aryl fluorides and aryl iodides are normally carried out by way of functional group transformations of arylammes these reactions will be described m Chapter 22... 

Nevertheless the Elbs reaction is a valuable method for the preparation of dihydroxy benzenes. The experimental procedure is simple, and the reaction conditions are mild a variety of functional groups is tolerated. 

In benzene or similar solvents, tris(triphenylphosphine)halogenorhodium(I) complexes, RhX[P(C6H5)3]3, are extremely efficient catalysts for the homogeneous hydrogenation of nonconjugated olefins and acetylenes at ambient temperature and pressures of 1 atmosphere (6). Functional groups (keto-, nitro-, ester, and so on) are not reduced under these conditions. 

Reactions of the type shown in (ii) and (34) are called substitution reactions. The substitution reaction is the characteristic reaction of benzene and its derivatives and is the way in which a multitude of compounds are prepared by the organic chemist. By this means he is able to introduce functional groups, which can then be... 

The rearrangement of dimethyl 5-hydroxy-l-bcnzothiepin-3,4-dicarboxylate (9, R = OH), the first example of a thermal rearrangement of a thiepin derivative without loss of sulfur,12 is analogous to the oxepin-benzene oxide-phenol rearrangement (cf. Section D,l. Introduction and Section 1.2.5.1). This process is catalyzed by the acidic hydroxy substituent. In fact, if this functional group is modified by an in situ acetylation (R = OAc), the usual loss of sulfur occurs. 

The 6-substituted 1,4-dioxocins can be used to prepare other 6-substituted derivatives by simple functional group transformations.4,8,9 Especially interesting is the synthesis of the 4/7-4-oxo-2,3-dihydropyran-2-yl-substituted derivative 16 from l,4-dioxocin-6-carbaldehyde (15) by a cyclocondcnsation with Danishefsky s diene.9 Dehydrogenation of 16 yields 2 which can be isomerized to the corresponding isomeric. sr/i-benzene dioxide 3 (X = 4/f-4-oxopyran-2-yl), which is identical with and proved the structure of the naturally occurring antibiotic LL-Z 1220.10... 

The CT values are numbers that sum up the total electrical effects (resonance plus field) of a group X when attached to a benzene ring. The treatment usually fails for the ortho position. The Hammett treatment has been applied to many reactions and to many functional groups and correlates an enormous amount of data quite well. Jaffe s review article lists p values for 204 reactions, many of which have different p values for different conditions. Among them are reactions as disparate as the following ... 

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