Nomenclature of diols

Diols are almost always given substitutive lUPAC names As the name of the prod uct m the example indicates the substitutive nomenclature of diols is similar to that of alcohols The suffix dwl replaces ol and two locants one for each hydroxyl group are required Note that the final e of the parent alkane name is retained when the suffix begins with a consonant ( diol) but dropped when the suffix begins with a vowel ( ol)... 

The common names of glycols can be awkward and confusing because the -ene portion of the name implies the presence of an alkene double bond, but the glycol does not contain a double bond. We will generally use the IUPAC dk>l nomenclature for diols, but be aware that the names ethylene glycol (automotive antifreeze) and propylene glycol (used in medicines and foods) are universally accepted for these common diols. 

IUPAC Nomenclature of Unsaturated Alcohols Section 9.1A (a) 3-buten-2-ol (b) 4-ethyl-2-hexyn-1-ol (c) 2,4-hexadien-1,6-diol ... 

Although earlier reviews by Haslam (134-136) discuss the many problems that have arisen about the systematic classification and nomenclature of proanthocyanidins, it seems useful to repeat the definition of the term proanthocyanidin as initially established by Freudenberg and Weinges (116) - the proanthocyanidins are all the colorless substances isolated from plants which, when treated with acid, form anthocyanidins. Thus the leucoanthocyanidins (now restricted to the flavan-3,4-diols), the condensed tannins (Sect. 7.7), and any other colorless flavonoid derivatives that produce anthocyanidins on heating with acid should be grouped under this class of compounds. 

There has in the past been some confusion in the use of the term alkyd, which is said to have been derived from alcohol plus acid. The definition offered by Kienle [1], discussed later, is broad enough to include all polyesters derived essentially from diols and dicarboxylic acids, and consequently linear polyesters were initially included in this class of polymer. On the other hand, Bjorksten et al. [2], in their 1956 compilation of published information about polyesters, restrict the term polyester to the polycondensation products of dicarboxylic acids with dihydroxy alcohols, and say that this definition does not include materials commonly known as alkyds . At the present time, there are still problems of nomenclature in the fibre field arising from the use of polyester as a generic term to cover fibres containing only a very restricted range of chemical groups. 

Figure 27. Epoxide hydrolase catalyzed kinetic resolution of c/.v-2-ethyl-3-methyloxirane and formation of 2i ,3f -2,3-pentanediol as monitored by complexation gas chromatography on 0.08 M nickel(II) bis[3-(heptafluorobutanoyl)-(1 / )-camphorate] in methylpolysiloxane [25 m x 0.25 mm (i.d.) glass capillary column. 95CC, 1.1 bar nitrogen]191 2,3-pentanediol as acetonides 0.14 M nickel(ll) bis[3-(heptafluo-robutanoyl)-(l /t,2S)-pinan-4-onatc]151 in SE-30. Note that there is a change in the numbering of the chiral carbon atoms of the oxiranc vs. the diol due to nomenclature requirements.

Ebelman and Bouquet prepared the first examples of boric acid esters in 1846 from boron trichloride and alcohols. Literature reviews of this subject are available. B The general class of boric acid esters includes the more common orthoboric acid based trialkoxy- and triaryloxyboranes, B(0R)3 (1), and also the cyclic boroxins, (ROBO)3, which are based on metaboric acid (2). The boranes can be simple trialkoxyboranes, cyclic diol derivatives, or more complex trigonal and tetrahedral derivatives of polyhydric alcohols. Nomenclature is confusing in boric acid ester chemistry. Many trialkoxy- and triaryloxyboranes such as methyl, ethyl, and phenyl are commonly referred to simply as methyl, ethyl, and phenyl borates. The lUPAC boron nomenclature committee has recommended the use of trialkoxy- and triaryloxyboranes for these compounds, but they are referred to in the literature as boric acid esters, trialkoxy and triaryloxy borates, trialkyl and triaryl borates or orthoborates, and boron alkoxides and aryloxides. The lUPAC nomenclature will be used in this review except for relatively common compounds such as methyl borate. Boroxins are also referred to as metaborates and more commonly as boroxines. Boroxin is preferred by the lUPAC nomenclature committee and will be used in this review. 

Octahydro- (we have used this nomenclature throughout) or perhydrobenzo[c]thiophene (35) exists as the cis and trans isomers and is more commonly named 2-thiahydrindane or 8-thiabicyclo-[4.3.0]nonane. Each stereoisomer may be prepared by treating the corresponding isomer of l,2-di(bromomethyl)cyclohexane with sodium sulfide (details of the products are given in Table IV).45 Cyclization of the cis isomer may be effected partially with thiourea via the formation of cis-hexahydro-o-xylylenebis(isothiouronium bromide) with sodium disulfide it gives a mixture of cis-octahydro-benzo[c]thiophene and cis-2,3-dithiadecalin.46 Optically pure ( —)-(8 R,9I )-lran -octahydrobenzo[c]thiophene has been prepared from (+ )-dicarboxylic acid via reduction of the diacid to the diol, tosylation, and ring closure of the bistosylate with sodium sulfide.47... 

Rigorous application of nomenclature to the hnal example, 7-6, would treat the cyclic acetal as a fused dioxole. The alternative that names the compound as a derivative of the 16,17-diol is more common. The name thus becomes 21-chloro-9a-fluoro-l l)8,16a,17a-trihydroxypregn-l,4-dien-3,20-dione 16,17-acetonide. 

The name cyclic sulfate originates from the sulfate ester of alcohols. Because in the present case the diol forms a part of the cyclic system, it is known as a cyclic sulfate. To avoid ambiguities, a systematic lUPAC nomenclature is required. Thus, the cyclic sulfite esters of 1,2-diols are named 1,3,2-dioxathiolane 2-oxides (1), and the corresponding cyclic sul-... 

Carotenoids that contain an oxygenated functionality are collectively referred to as xanthophylls. They retain the systematic naming system of carotenes, with the additional functionalities named according to the usual nomenclature rules previously discussed. For example, p,P-carotene-3,3 -diol (zeaxanthin) (Figure 3.10a). Methoxy, carboxy, aldehyde, epoxy, and ketone derivates are also common. 

Fig. 13.3. Illustration of nomenclature rules (I) 5a-androstan-3a-ol, (II) 5a-androstan-3 -ol, (III) androst-5-ene, (IV) androst-5-ene-3, l 7 -diol, (V) 3 -hydroxyandrost-5-en-l 7-one (dehydroepian-drosterone), (VI) 11 -21-dihydroxypregn-4-ene-3,20-dione (corticosterone), and (VII) 21-hydroxy-pregn-4-ene-3,l 1,20-trione (11-dehydrocortico-sterone). (Dorfman and Ungar, 1965.)...

In the early days of macromolecular chemistry, synthetic polymers were simply labeled according to the monomer from which they were prepared. Thus, ethylene polymers became poly(ethylenes), styrene polymers became poly(styrenes), and those from lactams became poly (lactams). In other cases, the choice of name was provided by a characteristic group occurring in the final polymer. Thus, polymers from diamines and dicarboxylic acids were called polyamides, and those from diols and dicarboxylic acids were called polyesters. This phenomenological nomenclature fails, of necessity, when more than one kind of monomeric unit can be formed from a given monomer. 

As polyurethane intermediates react rapidly and stoichiometrically with each other, a system of nomenclature is widely used to describe the structure of individual block copolymers. Suppose, for example, a typical polyurethane consisted of polycaprolactone,4,4 -diphenylmethane diisocyanate, and 1,4-butane diol, present in the molar ratio 1 3 2, then such a polymer is reported as a 1 3 2 block copolymer and this represents a simple, convenient and rapid method of identifying the basic urethane polymer structure. The ratio of each component in the block copolymer has a dramatic effect on its properties, as shown by the data in Table 2.2. 

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