Radical nomenclature systems

An older nomenclature system used the name of the radical (the name of the parent hydrocarbon with the -yl ending) plus the word alcohol. Thus, ethanol is also known as ethyl alcohol and, because it is the most familiar alcohol, even simply as alcohol. The formulas of organic compounds can be written in the reverse direction, so ethanol can be represented by HOCH2CH3, as well as by CH3CH2OH. 

Carbon atoms are the most frequently found radical centers with their electron septet occupying an intermediate position between the carbenium ions and the carbanions. Radicals are often called free radicals, a term that arose from early nomenclature systems in which a radical was a substituent group that was preserved as a unit through a chemical transformation. Thus, the CH3 group as a substituent was known as the methyl radical, so a neutral CHj group became a free radical. The terms radical and free radical are now used interchangeably. Some common examples of radicals include the methyl radical (1), vinyl radical (2), phenyl radical (3), triphenylmethyl radical (4), allyl radical (5), and benzyl radical (6) (Figure 4.1). 

Since the lUPAC nomenclature system relies totally on the pivotal concept of the parent structure to which, in a second sphere, substituents are assigned, it appeared advisable to maintain this division also for the chapters of this book. Thus, we begin with the exposition of the nomenclature rules for parent structures and, in the second chapter, proceed with the discussion of the different types of nomenclature for substituted systems, radicals, and ions in the third chapter specific classes of functional compounds are addressed, followed, in the forth chapter, by the treatment of metal organyls and, in the fifth, of carbohydrates. The concluding sixth chapter takes up once again the construction of the final names of complex compounds including isotopic modifiers and stereochemical descriptors. 

We begin by bringing you up to speed on mechanisms and reminding you how to push electrons around with those curved arrows. We jog your memory with a discussion of substitution and elimination reactions and their mechanisms, in addition to free radical reactions. Next you review the structure, nomenclature, synthesis, and reactions of alcohols and ethers, and then you get to tackle conjugated unsaturated systems. Finally, we remind you of spectroscopic techniques, from the IR fingerprints to NMR shifts. The review in this part moves at a pretty fast pace, but we re sure you can keep up. 

Suhstituth-e nomenclature. This system is used extensively for orjwnic compounds, but it has also been used lo name many inorganic compounds It is often bused on the concept of a parent hydride modified by substitution of hydrogen atoms by groups I radicals). (Sec Section I—6.J... 

System of Nomenclature for Hydrocarbon Terpene Radicals Acydics, Monocyclics, Bicyclics... 

No official action on the names of hydrocarbon terpene radicals was taken by the Nomenclature Committee of the ACS Organic Division at its meeting in New York City, September 1954, but general recommendations were discussed. It was agreed that the earlier acceptance of the system of nomenclature for the simple acyclic, monocyclic, and bicyclic terpene hydrocarbons implied the systematization of the hydrocarbon terpene radicals derived from these compounds. Therefore this Appendix F has been added here, but it has no official status. 

In this chapter the dithiadiazole family is reported for the very first time. Since these fascinating five-membered heterocyclic cations, radicals, and dimers were not covered in CHEC-I(1984) and CHEC-II(1996), the discussion encompasses all available literature rather than focusing solely on publications post-1995. Before any further discussion, an appreciation of the two isomeric forms and the nomenclature associated with each is essential. The 671 cyclic systems of 1,2,3,5-dithiadiazolium chloride 1 and 1,3,2,4-dithiadiazolium chloride 2 are shown below. As this chapter demonstrates, the 1,2,3,5-isomeric form dominates the literature in this field, reflecting the wider synthetic opportunity and stability associated with it. 

We find this objection so significant that we question the advisability of recommending the Stock nomenclature without radical alteration of it. At any rate we find it objectionable that the international rules mention Stock s system as the only one allowed for indicating the electrochemical valency. 

This paper focuses on heterophase free radical polymerizations. It is limited to processes where multiple phases, distinguished by the insolubility of reagents, exists at the onset of the reaction. It therefore does not consider precipitation polymerization [1], which occurs when the polymer is insoluble in the monomer and precipitates out from an initially homogeneous solution. It also does not address emulsifier-free polymerization or dispersion polymerization. This rather general nomenclature is now accepted as applying to specific systems where the heterophase nature is produced at the onset of the reaction by homogeneous nucleation of oligomers or polymer chains which have exceeded their solubility limit [2]. 

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