Lactones, nomenclature

Lactones, nomenclature, 105 Linked-Atom Least-Squares analysis, 319 Lithium gellan, 386 Luteic acid, 8... 

Cyclic amides are called lactams. The size of the lactam ring is designated by Greek letters in a way that is analogous to lactone nomenclature (Section 17.7C) ... 

Ascorbic Acid [50-81-1] (1) is the name recognized by the lUPAC-IUB Commission on Biochemical Nomenclature for Vitamin C (1). Other names are L-ascorbic acid, L-xyloascorbic acid, and L-// fi (9-hex-2-enoic acid y-lactone. The name... 

In this chapter the proposed (5) division of secophthalideisoquinolines into the four subgroups and the nomenclature have been preserved. Since the publication of the most recent review (5), information about the synthesis of the missing ( )-narceine enol lactone (102) (87), the isolation of ( )-fumaramine (112) from Fumaria vailanti (88), and the discovery of a new seco alkaloid, coryrutine (118), from Corydalis rutifolia (89) has appeared. In the former plant fumaramine (111) (55) and in the latter N-methylhydrasteine... 

Because of space limitations, only meso- and macrocycles possessing heteroatoms and/or subheterocyclic rings are reviewed in general, lactones, lactams, and cyclic imides have been excluded. In view of the delayed availability of some articles appearing in previous years, several have been incorporated. The introduction of a systematic nomenclature of catenanes, rotaxanes, and derived assemblies has recently appeared <00JPC437> this should have appeared two decades ago, but is still timely in futuristic point of view. 

Although the most frequently used nomenclature for AHLs was initially based on a 3-5 letter codes based on names e.g. BHL for N-butyryl-L-homo-serine lactone, OHHL for AT-(3-oxohexanoyl)-L-homoserine lactone or OdDHL for N-(3-oxododecanoyl)-L-homoserine lactone, the rapid expansion in the range of AHL molecules discovered has led to changes in this nomenclature. Currently, the accepted abbreviations are a structure-based short-hand notations e.g. C4-HSL for N-butyryl-L-homoserine lactone, 3-oxo-C6-HSL (or 30,C6-HSL) for AT-(3-oxohexanoyl)-L-homoserine lactone or 3-hydroxy-C12-HSL (or 30H,C12-HSL) for N-(3-hydroxydodecanoyl)-L-homoserine lactone. 

We observed that cyclic esters (lactones) may be formed when the carboxyl electrophile and hydroxyl nucleophile are in the same molecule (see Section 7.9.1). Similarly, cyclic amides are produced when carboxyl and amine groups are in the same molecule, and are again most favoured when this results in the generation of strain-free five- or six-membered rings. Cyclic esters are termed lactones, whereas cyclic amides are in turn called lactams. The nomenclature of lactams is similar... 

In the field of furocoumarins, which includes a large number of compounds extracted from the Umbelliferae, the nomenclature is rather uncertain. Up to 1968, those compounds were looked upon (Chemical Abstracts) as S-lactones of Bz-o-hydroxybenzofurylacrylic acids more recently, as furochromenic derivatives.10 Some of those compounds have names related to their geographical or botanical origin, such as sachalinin (7), recently extracted from the roots of Angelica sachalinensis 11 it is then advisable to add the chemical name. 

Spirofuran-2(5H),2 (3 H)furo[2,3-6]furan synthesis, 4, 659 Spirofuranones synthesis, 3, 734 Spiro[3.3]heptane physical properties, 1, 590 Spiroindazoles irradiation, 5, 252 Spiroisoarsindolinium salts, 1, 544 Spiroisoxazolines synthesis, 6, 108 Spirolactones synthesis, 3, 846-847 Spiro-/3-lactones synthesis, 7, 395 Spiro nomenclature, 1, 26 Spirooxadiazoles synthesis, 4, 822 Spirooxaziridines photorearrangement, 7, 541 (8-scission, 7, 211 Spirooxetanes synthesis, 7, 393 Spirooxiranes cleavage... 

Very occasional deviations from this lUPAC principle may sometimes be made for ease of nomenclature, e.g., in the Dictionary of Natural Products for compounds containing both lactone and carboxylic acid functions, e.g., 3,14-dihydroxycard-20(22)-enolid-19-oic acid. CAS does not do this. 

The nomenclature of the oxidized forms of AA is badly in need of revision. Not only is dehydroascorbic acid a long and cumbersome name, but it is also confusing in inferring that the compound is an acid. As is discussed later in this chapter, the principle structure is a bicyclic compound containing both lactone and hemiketal groups. Names such as ascorbitone or dehydroascorbitone would be better trivial representations. 

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