Prefixes esters

Ester groups in R —CO—OR compounds are named (1) by the prefix alkoxycarbonyl- or aryloxycarbonyl- for —CO—OR when the radical R contains a substituent with priority for citation as principal group or (2) by the prefix acyloxy- for R —CO—O— when the radical R contains a substituent with priority for citation as principal group. Examples are... 

Carbonates are indexed in Chemicaly hstracts under carbonic acid, esters. Symmetrical diesters have the prefix di or bis. Unsymmetrical diesters are listed with the two radicals following each other. For example, ethyl phenyl carbonic diester is C2H OCOOC H. Table 6 Hsts commonly used carbonates, their Chemicaly hstracts Service Registry Number, and formulas. 

Thioesters are named like the corresponding esters. If the related ester has a common name, the prefix thio- is added to the name of the carboxylate acetate becomes thioacetate, for instance. If the related ester has a systematic name, the -oate or -carboxylate ending is replaced by -thioate or -carbothioate butanoate becomes butanelhioate and cyclohexanecarboxylate becomes cyclohexane-carbothioate, for instance. 

Another topical anesthetic, similar to benzocaine, is lidocaine, which is used to relieve the pain of shingles (herpes zoster) infections. Lidocaine is called an amide anesthetic, because it is not an ester (the alcohol is replaced by an amide, the nitrogen group). Amide anesthetics are metabolized by the liver, and are less prone to cause allergic reactions. If an anesthetic has the letter i in the prefix (lidocaine, prilocaine, bupivacaine), it is an amide anesthetic. 

Esters are named by prefixing the hydrocarbon radical name to the reminder of the name and replacing the ending -ic or -ous with -ate or -ite, respectively. For example, CH3P(0) (OC2H5)2 is named diethylmethylphosphonate or diethyl-methanephosphonate. 

The prefix terms used for phosphate esters in organic nomenclature ([14], p.65) are 0-phosphono- and O-phosphonato- for the groups (H0)2P(0)- and (0 )2P(0)-respectively, bonded to oxygen. 

For example, substitution can be made on an oxygen atom in the case of esters and ethers. It is characterised by the symbol O, which is placed after the locant. The compound prefix deoxy- is composed of the prefixes de-, meaning without in subtractive nomenclature, and oxy-, to indicate the subtraction of an oxy group from an -OH group C-O-H C-H. Such an operation is needed when an -OH group is replaced by another group, such as an amino group. 

Salts and Esters of Acids. Neutral salts of acids are named by citing the cation(s) and then the anion, whose ending is changed from -oic to -oate or from -ic to -ate. When different acidic residues are present in one structure, prefixes are formed by changing the anion ending -ate to -ato- or -ide to -ido-. The prefix carboxylato- denotes the ionic group —COO-. The phrase (metal) salt of (the acid) is permissible when the carboxyl groups are not all named as affixes. 

Aldehydes, acids, and esters have roots for one and two carbons that are usually form- and acet-, rather than meth- and eth-, because these prefixes had been used so long they were grandfathered into the naming system (formaldehyde and acetic acid, rather than methanal and ethanoic acid). Departures from IUPAC nomenclature often occur for very common substances and, fortunately, they rarely can be misunderstood (ethyl alcohol instead of ethanol). 

Simple diastereoselectivity may also occur in Diels-Alder reactions between electron-poor dienophiles and cyclopentadiene (Figure 15.30). Acrylic acid esters or fraus-crotonic acid esters react with cyclopentadiene in the presence or absence of A1C13 with substantial selectivity to afford the so-called emfo-adducts. When the bicyclic skeleton of the main product is viewed as a roof the prefix endo indicates that the ester group is below this roof, rather than outside (exo). However, methacrylic acid esters add to cyclopentadiene without any exo.endo-selectivity regardless whether the reaction is carried out with or without added A1C13 (Figure 15.30, bottom). 

Thioesters are named like esters, using the prefix thio- before the name of the carboxylic acid. 

Naming of carbohydrate boronates may be based on three principles (a), the central use of the ester heterocyclic rings 1,3,2-dioxaborolane (five-membered), 1,3,2-dioxaborinane (six-membered), and 1,3,5,2,4-trioxadiborepane (seven-membered, for example, 8 and 9) (b), the use of radical prefixes borylene (Chem. Abstr.) or boranediyl (I.U.P.A.C.) for /BH or (c), ester terminology. Thus, for example, according to these respective procedures, the glycerol derivative 10... 

Pyro-catechinol, i-2-Di-hydro3iy Benzene.—The ortho-di-hydroxy benzene is known as pyro-catechinol or pyro-catechin. The first name is preferable as the termination ol indicates its phenol character. Its name also indicates its relation to a resin known as catechu, obtained from an acacia tree. On distillation it yields the phenol, the prefix pyro meaning heat. It is also present in the dry distillation products of wood, coal or bituminous shale. Various plant materials such as resins and the leaves of ampelopsis yield it by alkali fusion. It is also associated with phenol as a sulphuric acid ester in the urine of horses. 

---