Homocyclic compounds

The first three of a series of papers by Ridd and co-workers on Inductive and Field effects in Aromatic Substitution have appeared. Results of studies of the nitration of 4-phenylp5nidine and of 4-benzylpyridine in aqueous sulphuric acid were reported and use of the usual criteria (para 8.2) showed that in each case the conjugate acid was the species undergoing nitration. The values of where fm refers to the corresponding homocyclic compound (biphenyl or diphenylmethane) when plotted against r, the distance between the... 

There has been relatively little work on the mechanism of arylation of heterocyclic compounds, but the arylation of homocyclic compounds has been studied in great detail. Those mechanistic aspects of the reactions with heterocycles which have been examined parallel closely the corresponding aspects of the reactions of homocycles, and there is... 

Szwarc and his co-workers have measured the methyl affinities (that is, reactivities toward methyl radicals compared with that of benzene) of a number of heterocyclic compounds. These, together with the methyl affinities of some homocyclic compounds, are set out in Table IX. 

The mechanism of hydroxylation of heterocyclic compound has not been studied, but the mechanistic aspects of hydroxylation of homocyclic compounds may again serve as a basis for discussion. 

Cyclic Hydrocarbons. These are structures in which the carbon atoms form a ring instead of an open chain. They are also called carbocyclic or homocyclic compounds. They are divided into two classes alicyclic (or cycloaliphatic) and aromatic compounds. 

Dipole Moments. The dipole moments of quinoxaline, several derivatives, some pyrazine analogs, and comparable homocyclic compounds have been measured in an attempt to rationalize the values in terms of mesomeric effects and/or conformational isomerism. ... 

Elemental Sulfur and Homocyclic Compounds and Ions (R. Steudel)... 

Quoted in Seddon, (1972 41), from C. K. Ingold, E. A. Perren, and J. F. Thorpe, "Ring-Chain Tautomerism. Pt. III. The Occurrence of Tautomerism of the Three-Carbon (Glutaconic) Type between a Homocyclic Compound and Its Unsaturated Open-Chain Isomeride," JCS 121 (1922) 17651789. 

A homocyclic compound contains a homocyclic ring, i.e., a ring composed of atoms of the same element. 

As in the reaction of imidazole, no major isotope effect has been observed 3-deuterioindole reacts at about the same rate as indole. The diazo coupling of five-membered heteroaromatic substrates therefore appears similar to that of homocyclic compounds where, in the absence of steric hindrance, slow attack of the diazonium ion is followed by a fast proton loss.165... 

Waals distance of 400 pm as an upper limit. A stable homocyclic compound with a selenium-selenium double bond is not known. 

Mostly P-aminokctones, along with phenolic Mannich bases, arc usually employed in the synthesis of homo- and heterocyclic derivatives. As far as P-aminokctoncs are concerned, in particular, homocyclic compounds (Fig. 129) are prepared by the Diels-Aldcr reaction of the Mannich base, acting actually as dienophilc, with a conjugated dicnc. Interestingly, styryl ketobascs give styryl cycloalkenyl ketones (333, R = Ar—CH=CH—) by the same type of reaction, without any involvement of the styryl group. 

Fig. 129. Synthesis of acylated homocyclic compounds from Mannich ketoba.ses (bold lines represent the original skeleton of Mannich base).

Table 2.3 Absorotion frequencies typical of aromatic homocyclic compounds ...

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