Nomenclature of phenols

Alcohols are classified as primary (1°), secondary (2°), or tertiary (3°), depending on whether one, two, or three organic groups are connected to the hydroxyl-bearing carbon atom. 

Methyl alcohol, which is not strictly covered by this classification, is usually grouped with the primary alcohols. This classification is similar to that for carbocations (Sec. 3.10). We will see that the chemistry of an alcohol sometimes depends on its class. 

PROBLEM 7.3 Classify as r, 2°, or 3° the eleven alcohols listed in Section 7.1. 

Phenols are usually named as derivatives of the parent compounds. 

The hydroxyl group is named as a substituent when it occurs in the same molecule with carboxylic acid, aldehyde, or ketone functionalities, which have priority in naming. Examples are 

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IUPAC Nomenclature of Phenols Section 9.1C (a) 2-methylphenol (b) 3-bromophenol (c) 4-ethylphenol (ortho, meta, and para in a,b,c respectively is correct also) d) 4-methoxy-2-nitrophenol... 

Production of phenol and acetone is based on liquid-phase oxidation of isopropylbenzene. Synthetic fatty acids and fatty alcohols for producing surfactants, terephthalic, adipic, and acetic acids used in producing synthetic and artificial fibers, a variety of solvents for the petroleum and coatings industries—these and other important products are obtained by liquid-phase oxidation of organic compounds. Oxidation processes comprise many parallel and sequential macroscopic and unit (or very simple) stages. The active centers in oxidative chain reactions are various free radicals, differing in structure and in reactivity, so that the nomenclature of these labile particles is constantly changing as oxidation processes are clarified by the appearance in the reaction zone of products which are also involved in the complex mechanism of these chemical conversions. 

Figure 1-1. Nomenclature for substitution patterns of phenolic compounds. R, R and R2 are generic substituents.

An alternative mechanism for the oxidation of phenolic compounds is enzyme-catalyzed oxidation. Several classes of enzymes can catalyze this reaction. According to the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (NC-IUBMB), these enzymes are part of the E C. 1 class of oxidoreductases (see the Internet web site http //www.chem.qmul.ac.uk/iubmb/enzyme/ECl). The three main classes of enzymes that catalyze the oxidation of phenolic compounds are the oxidoreductases that use oxygen as electron acceptor (E.C. 1.10.3), the peroxidases (E.C. 1.11.1), and monophenol monooxygenase (E.C. 

The focus of this book is centered on structure, nomenclature and occurrence of phenolic compounds (Chapter 1), and their chemical properties (Chapter 2). Chapter 3 describes the biosynthetic pathways leading to the major classes of phenolics. This chapter presents an up-to-date overview of the genetic approaches that have been used to elucidate these pathways. Chapter 4 presents an overview of methods for the isolation and identification of plant phenolic compounds. Given that much of the recent... 

The nomenclature of benzene derivatives is described in Sec. 4.6. Common names and structures to be memorized include those of toluene, styrene, phenol, aniline, and xylene. Monosubstituted benzenes are named as benzene derivatives (bromobenzene, nitrobenzene, and so on). Disubstituted benzenes are named as ortho- (1,2-), meta- (1,3-), or para- (1,4-), depending on the relative positions of the substituents on the ring. Two important groups are phenyl (C6H5-) and benzyl (C6H5CH2-). 

Calix[ ]arenes are a family of macrocycles prepared by condensation reactions between n /v/ra-substituted phenols and n formaldehyde molecules under either base or acid catalysis. Different sizes of the macrocycles can be obtained (n = 4-20) (Stewart and Gutsche, 1999) depending on the exact experimental conditions, which were mastered in the 1960 s (Gutsche, 1998), but the most common receptors are those with n =4,6,8 (macrocycles with an odd number of phenol units are more difficult to synthesize). We use here the simplified nomenclature in which the number of phenolic units is indicated between square brackets and para substituents are listed first.4 Calixarenes, which can be easily derivatized both on the para positions of the phenolic units and on the hydroxyl groups, have been primarily developed for catalytic processes and as biomimics, but it was soon realized that they can also easily encapsulate metal ions and the first complexes with d-transition metal ions were isolated in the mid-1980 s (Olmstead et al., 1985). Jack Harrowfield characterized the first lanthanide complex with a calixarene in 1987, a bimetallic europium complex with p-terf-butylcalix[8]arene (Furphy etal., 1987). 

The classical Claisen rearrangement is the first and slow step of the isomerization of allyl aryl ethers to orf/to-allylated phenols (Figure 11.41). A cyclohexadienone A is formed in the actual rearrangement step, which is a [3,3]-sigmatropic rearrangement (see Section 11.1 for the nomenclature of sigmatropic rearrangements). Three valence electron pairs are shifted simultaneously in this step. Cyclohexadienone A, a nonaromatic compound, cannot be isolated and tautomerizes immediately to the aromatic and consequently more stable phenol B. 

Structure and Classification of Alcohols 425 10-3 Nomenclature of Alcohols and Phenols 427 10-4 Physical Properties of Alcohols 430 10-5 Commercially Important Alcohols 433 10-6 Acidity of Alcohols and Phenols 435 10-7 Synthesis of Alcohols Introduction and Review 438 Summary Previous Alcohol Syntheses 438 10-8 Organometallic Reagents for Alcohol Synthesis 440 10-9 Addition of Organometallic Reagents to Carbonyl Compounds 443... 

The term calix[n]arenes indicates a class of phenolic metacyclophanes derived from the condensation of phenols and aldehydes. The name was coined by Gutsche and derives from the Latin calix because of the vase-like structure that these macrocycles assume when all the aromatic rings are oriented in the same direction.1 The bracketed number indicates the number of aromatic rings and hence defines the size of the macrocycle. To identify the phenol from which the calixarene is derived, the para substituent is designated by name. Thus the cyclic tetramer derived from p-f-butylphenol and formaldehyde is named p-f-butylcalix[4]arene, or with a more systematic but still simplified nomenclature proposed by Gutsche and used in this chapter 5,11,17,23-Te trakis( 1,1 -dimethylethyl)-25,26,27,28-tetrahydroxy calix [4] arene, 1 (Scheme 7.1). The systematic name reported by Chemical Abstracts is pentacyclo[19.3.1.13,7.19 13.115 19]octacosa-l (25),3,5,7(28),9,11,13(27),15,17, 19(26), 21,23-dodecaene-25,26,27,28-tetrol-5,l l,17,23-tetrakis(l, 1 -dimethylethyl). 

The vibrational modes of the ground-state phenol were examined by a number of spectroscopic techniques including UV-VIS - , IR for the vapour ", and the IR and Raman spectra in the solid and liquid phases - and microwave spectroscopy ", see also References 164-166. They are collected in Table 8, where both nomenclatures by Wilson and coworkers and VarsanJ i are used. Recently, the vibrational modes of phenol have become a benchmark for testing ab initio and density functional methods " . The Hartree-Fock calculations of the vibrational spectrum of phenol were first performed using the 6-31G(d,p) basis set. An MP2 study with the same basis set was later carried out. A combination" of three methods, viz. HF, MP2 and density functional BLYP, in conjunction with the 6-31G(d,p) basis was used to study the phenol spectrum and to make the complete and clear assignment of its vibrational modes (see Table 9). 

FIGURE 8. The normal displacements of the vibrational modes of phenol according to the Wilson s nomenclature. The B3LYP/6-31+G(d,p) method is employed. The assignments of the vibrational... 

The calixarenes are a popular and versatile class of macrocycle formed from the condensation of a p-substituted phenol (e.g. p-tert-butylphenol) with formaldehyde. Since they contain bridged aromatic rings, they are formally members of the cyclophane family (Section 6.5). In cyclophane nomenclature they are termed substituted [l.l.l.ljmetacyclophanes . The descriptive name calixarene was coined by C. David Gutsche (Washington University, USA) because of the resemblance of the bowl-shaped conformation of the smaller calixarenes to a Greek vase called a calix crater (Figure 3.78). The number of phenolic residues is denoted by a number in square brackets. Thus the most common cyclic tetramer with p-f-butyl substituents is termed p-t-butyl-calix[4]arene (3.118). It is easy to understand why this appealing nomenclature has found wide acceptance within the field when it is compared to the Chemical Abstracts systematic name for 3.118, [19.3.1.U U l ]octacosa-l(25),3,5,7(28),9,ll,... 

In 1912, Grafe takes over the confused nomenclature of previous studies in regarding Kaffeol , Kaffeon , Cafeone and KaffeeoP as the group of aromatic substances obtained with a yield of 0.3-0.45% by hydrodistillation of roast coffee powder and ether extraction. He contributes no notable advance in mentioning that 38% of the extract consists of acetic and valerianic acid, that 50% is furfurylic alcohol and other furans, and that the rest is a mixture of phenols with the odor of creosote and a pyridinic derivative that could be responsible for coffee s specific aroma. His article includes a comparative analysis of the components of normal coffee and decaffeinated coffee, the method for which had recently been patented. 

In a similar manner to the fatty acids, monohydric, dihydric and phenolic members invariably exists as a mixture of saturated, monoene, diene and triene constituents and rarely in the pure form as one of these four. In the nomenclature of this series a comprehensive system which takes account of the chain length, double bond position and its stereochemistry has not been widely agreed and accepted. Trivial and systematic names thus both abound and because of their dual functional nature as aromatic and acyclic these compounds have remained relatively unclassified. For example, cardanol is a well-known member consisting of saturated, monoene, diene... 

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