Pure &App/. Chem., Vol. 67, Nos 819, pp. 1307-1375, 1995.
`Printed in Great Britain.
`(B 1995 IUPAC
`
`INTERNATIONAL UNION OF PURE AND APPLIED CHEMISTRY
`ORGANIC CHEMISTRY DMSION
`COMMISSION ON NOMENCLATURE OF ORGANIC CHEMISTRY (III. 1)
`COMMISSION ON PHYSICAL ORGANIC CHEMISTRY (III.2)
`
`GLOSSARY OF CLASS NAMES OF ORGANIC COMPOUNDS AND
`REACTIVE INTERMEDIATES BASED ON STRUCTURE
`(IUPAC Recommendations 1995)
`
`Prepared for publication by
`G.P. MOSS, P.A.S. SMITH and D. TAVERNIER
`Cornpodtion of the ZZZ.1 & 111.2 Working Party (1980-1994): H.J.T. Bos, A.J. Boulton, E.W. Godly,
`P. Griinanger, A.D. McNaught, G.P. Moss, R. PanicO, J. Rigaudy, P.A.S. Smith (Conwnorfiom ZZZ, I ) ,
`J.H. Stocker, D. Tavernier, R.A.Y. Jones, J. March, J.M. McBnde, P. Miiller (Conwnorfim 111.2).
`
`Membership of the Commission on Nomenclature of Organic Chemistry during the preparation of
`this document (1980-1994) was as follows:
`Titular Members: 0. Achmatowicz (Poland) 1979-1987; H. J. T. Bos (Netherlands) 1987- ,
`Vice-Chairman, 1991- ; J. R. Bull (Republic of South Africa) 1987-1993; H. A. Favre (Canada)
`1989- , Chairman, 1991- ; P. M. Giles, Jr. (USA) 1989- ; E. W. Godly (UK) 1987-1993.
`Secretary, 1989-1993 ; D. Hellwinkel (Federal Republic of Germany) 1979-1987, Vice-
`Chairman, 1981-1987; B. J. Herold (Portugal) 1994- ; K. Hirayama (Japan) 1975-1983; M. V.
`KisakUrck (Switizrland) 1994- ; A. D. McNaught (UK) 1979-1987; G. P. Moss (UK) 1977-
`1987, Chairinan, 198 1- 1987, Vice-Chainnun, 1979-1981; R. Panico (Francc) 198 1-1991, Vice-
`Chairman, 1989-1991; W. H. Powell (USA) Secretary, 1979-1989; J. C. Richer (Canada) 1979-
`1989, Vice-Chairman, 1987-1989; J. Rigaudy (France) 1967-1981, Chairman, 1977-1981; P. A.
`S. Smith (USA) 1983-1991, Chairman, 1987-1991; D. Tavernier (Belgium) 1991- ; J. G.
`Traynham (USA) 1991- , Secretary, 1994- ; 0. Weissbach (Federal Republic of Germany) 1987-
`1991; J. L.Wisniewski (Federal Republic of Germany) 1991-.
`Associafe Members: 0. Achmatowicz (Poland) 1987-1989; K. Bltlhat (Czech Republic) 1979-
`1987; H. J. T. Bos (Netherlands) 1983-1987; A. J. Boulton (UK) 1983-1987; J. R. Bull
`(Republic of South Africa) 1985-1987; F. CoUi (Italy) 1994- ; L. C. Cross? (UK) 1977-1981; D.
`R. Eckroth (USA) 1975-1983; F. Farifiat (Spain) 1989-1994 ; H. A. Favre (Canada) 1987-1989;
`J. H. Fletcher (USA) 1975-1983; P. M. Giles, Jr. (USA) 1983-1989; E. W. Godly (UK) 1979-
`1987; P. Griinanger (Italy) 1987-1993; H. Griinewald, (Federal Republic of Germany) 1989-
`1991; H. Gutmann (Switzerland) 1983-1989; J. Heger (Slovakia) 1985-1989; D. Hellwinkel
`(Federal Republic of Germany) 1987-1989; K. Hirayama (Japan) 1983-1987; R. J.-R. Hwu
`(USA; Chemical Society, Taipei) 1989- ; M. A. C. Kaplan (Brazil) 1989- ; M. V. Kisakiirek
`(Switzerland) 1987-1993; S. P. Klesney (USA) 1979-1985; A. J. Lawson (Federal Republic of
`Germany) 1991- ; W. Liebscher (Federal Republic of Germany) 1989- ; K. L. Loening (USA)
`1979-1983; N. Lozac'h (France) 1977-1987; A. D. McNaught (UK) 1987-1989; M. MikoIajczyk
`(Poland) 1989- ; G. P. Moss (UK) 1987-1989; J. Nyitrai (Hungary) 1994- ; R. Panico (France)
`1979-1981; J. Rigaudy (France) 1981-1985; Ch. Schmitz (France) 1989-1993; R. Schoenfeldt
`(Australia) 1981-1987; H. A. Smith, Jr. (USA) 1994- ; P. A. S. Smith (USA) 1979-1983; J. H.
`Stocker (USA) 1991- ; D. Tavernier (Belgium) 1987-1991; J. G. Traynham (USA) 1989-1991; F.
`V6gtle (Federal Republic of Germany) 1972-1983; 0. Weissbach (Federal Republic of Germany)
`1979- 1987.
`t - 4
`
`conrd. on the following page
`
`Hepiiblicotioii of this repnrt is pernrittrd without tlre treed for forniol IUPAC perniissioii oii rariditioii that aii
`w i t h fit11 r'efereiiiv logrtlier w i t h IUPAC copyright synihol (0 1995 IUPAC), is printed.
`cic~kiiou~lr~l~eirieiit,
`Piiblicutioii of 11 tr'uii.vlutioii i i i t o uiiotlicr loirgituge is strl,icct to the udditioiiul cniiditioii nf prior approvolfroni rke
`r'elewiit IUPAC Nutioiral Adlreriiig Orguirizutinii.
`
`Alnylam Exh. 1068
`
`

`

`Membership of Commission III. 1 contd. from the preceding page
`
`Nafional Represenfalives: H. Y . Aboul Enein (Saudi Arabia) 1988-1989; 0. Achmatowicz
`(Poland) 1989-1991; A. T. Balaban (Romania) 1983-1989; R. Bicca de Alencastro (Brazil)
`1994- ; H. J. T. Bos (Netherlands) 1981-1983; J. R. Bull (RSA) 1983-1985; J. R. Cannon
`(Australia) 1982-1987; K. C. Chan (Malaysia) 1983-1987; S. Chandrasekaran (India) 1994- ;
`Q.-Y. Chen (Chinese Chemical Society) 1991- ; G. D6akt (Hungary) 1979-1992; F. Fariiiat
`(Spain) 1987-1989; M. J. GaSiC (Federal Republic of Jugoslavia) 1989-1993; E. W. Godly (UK)
`1994- ; P. GrUnanger (Italy) 1984-1987; B. J. Herold (Portugal) 1991-1993; W.-Y. Huang
`(Chinese Chemical Society) 1981-1987; S. Ikegami (Japan) 1986- ; A. K. Ikizler (Turkey) 1987-
`1992; J. Kahovec (Czech Republic) 1989- ; M. A. C. Kaplan (Brazil) 1983-1985; P. Kristian
`(Slovakia) 1994- ; G. L'abbB (Belgium) 1981-1985; Eun Lee (Republic of Korea) 1994- ; X. T.
`Liang (Chinese Chemical Society) 1987-1993; L. Maat (Netherlands) 1989- 1991; G. Mehta
`(India) 1983-1985; J. Nyitrai (Hungary) 1992-1993; L. J. Porter (New Zealand) 1987- ; J. A.
`Retamar (Argentina) 1980-1985; H. Schick (Federal Republic of Germany) 1987-1991; R.
`Schoenfeldt (Australia) 1980-1981; S. Swaminathan (India) 1985-1987; D. Tavernier (Belgium)
`1986-1987; A. Varvoglis (Greece) 1991-1993.
`
`Membership of the Commission on Physical Organic Chemistry during the preparation of this
`document (1980- 1994) was as follows:
`Titular Members: P. N. I. Ahlberg (Sweden) 1987-1991; E. M. Arnett (USA) 1985-1987; J.
`F. Bunnett (USA) 1973-1983, Chairman, 1978-1983; M. P. Doyle (USA) Secretary, 1987-1991;
`W. Drenth (Netherlands) Secretary, 1991- ; V. Gold? (UK) Chairman; 1983-1985; E. A. Halevi
`(Israel) 1987-1989; G. Illuminatit (Italy) 1977-1985; W. P. Jencks (USA) 1981-1985; R. A. Y.
`Jones (UK) 1981-1991, Secretary, 1987-1991; J. M. McBride (USA) 1987-1993; V. I. Minkin
`(Russia) 1991- ; P. MUller (Switzerland) 1985-1993, Chairman, 1987-1993; 0. M. Nefedov
`(Russia) 1981-1991; M. bki (Japan) 1987-1991; C. L. Perrin (USA) 1994- ; Z. Rappoport
`1989- ; Y. Takeuchi (Japan) 1991- ; T. T. Tidwell (Canada) Chairman 1994- .
`(Israel) 1991- ; K. Schwetlick (Federal Republic of Germany) 1977-1985; J. Shorter (UK)
`Associate Members: P. N. I. Ahlberg (Sweden) 1991- ; T. A. Albright (USA) 1987-1991; E.
`Baciocchi (Italy) 1994- ; J. F. Bunnett (USA) 1983-1985; M. P. Doyle (USA) 1979-1987; W.
`Drenth (Netherlands) 1987-1991; V. Goldt (UK) 1981-1983; R. D. Guthrie (USA) 1977-1987;
`E. A. Halevi (Israel) 1989-1993; R. A. Y. Jones (UK) 1977-1981; A. J. Kirby (UK) 1994- ;J. S.
`Littler (UK) 1977-1987; A. K. Maltsev (Russia) 1985-1987; J. March (USA) 1977-1987; V. I.
`Minkin (Russia) 1987-1991; P. MUller, (Switzerland) 1981-1985; 0. M. Nefedov (Russia) 1991-
`1993; J. R. Penton (Switzerland) 1981-1985; C. L. Perrin (USA) 1991-1993; D. J. Raber (USA)
`1991- ; M.-F. Ruasse (France) 1994- ; K. Schwetlick (Federal Republic of Germany) 1987-1989;
`H . 4 . Siehl (Federal Republic of Germany) 1994- ; Y. Takeuchi (Japan) 1987-1991; J. Toullec,
`(France) 1981-1985; P. Van Brandt (Belgium) 1987-1993; J. R. Wysiewicz (Australia) 1989-.
`National Representatives: J.-L. Abboud Mas (Spain) 1991-1993; P. N. I. Ahlberg (Sweden)
`1980-1987; E. Baciocchi (Italy) 1989-1993; A. T. Balaban (Rumania) 1981-1986; M. V. Bhatt
`(India) 1989-1991; J. A. Cavaleiro (Portugal) 1991- ; J. Chandrasekhar (India) 1994- ; W. Drenth
`(Netherlands) 1984-1987; J. J. E. Humeres Allende (Brazil) 1983-1987, 1991-1993; G. Ji
`(Chinese Chemical Society) 1994- ; X. Jiang (Chinese Chemical Society) 1987-1993; P. Laszlo
`(Belgium) 1987-1991; D. J. McLennan (New Zealand) 1982-1991; M. Lj. MihailoviC (Federal
`Republic of. Jugoslavia) 1979-1986; M. N6grfidi (Hungary) 1985-1987; Z. Rappoport (Israel)
`1987-1991; R. Sabbah (France) 1989-1993; J. A. Silva Cavaleiro (Portugal) 1991-1993; B. E.
`Smart (USA) 1987-1991; J. Suh (Republic of Korea) 1989-1993; 0. Tarhan (Turkey) 1988-1991;
`T. T. Tidwell (Canada) 1991-1993; M. TiSler (Slovenia) 1987-1993; J. Vaughan, (New Zealand)
`1980-1982; J. ZAvada (Czech Republic) 1987-1989; J. Zdysiewicz (Australia) 1987-1989.
`tDeceased
`Names of countries given after members names are in accord with the IUPAC Handbook 1994-
`1995.
`
`1308
`
`0 1995 IUPAC, Pure andApplied Chemistry07, 1307-1375
`
`

`

`Glossary of class names of organic compounds and
`reactive intermediates based on structure
`(IUPAC Recommendations 1995)
`
`Synopsis. This is a glossary of terms used to denote classes of compounds, substituent groups and
`reactive intermediates, in contrast to individual compounds. The overwhelming majority of the
`terms refer to organic compounds, but a few classes that may be considered inorganic are included
`for convenience. The principal criterion for inclusion is that the class be definable by structure.
`
`Introduction
`A class is a set of compounds sharing a common structural feature to which is attached a variable part (or
`parts) defining a specific compound of the class. The common feature is often a functional group to which
`one or a small number of variable parts are attached (e.g. aldehydes, ketones). The variable parts are in this
`glossary represented by hydrocarbyl groups (4.v.). The most simple representation of a class is thus
`defined. However membership of one class need not exclude membership of another class, and certain
`substitutions, as e.g. with heterocyclyl groups (4.v.) linked through a carbon atom in the R group, may be
`allowed. For instance, ethylamine as well as [ 1 -(furan-2-yl)ethyl]amine and (2-methoxyethy1)amine belong
`to the class amines. The common feature may also be a sizeable part of the molecular structure, or a repetitive
`part of the molecular structure, possibly but not necessarily devoid of functionalities (e.g. steroids,
`terpenoids); quite often the attached variable groups may be many and of any functionality.
`Classes defined by use, characteristics, or origin are excluded. Class names that are plurals of systematic
`names for parent compounds are occasionally cited. Some terms are included that are not actually class
`names, but are commonly encountered components of class names. These are mostly prefixes, and defining
`their meanings permits a host of class names beginning with them to be dispensed with.
`There is some overlap with other IUPAC documents, especially the 'Glossary of Terms Used in Physical-
`Organic Chemistry'. Because the viewpoints are sometimes different, the wording of the definitions may in a
`few cases differ but most are reproduced verbatim.
`The recommended class names, which are signalled by an asterisk, respect IUPAC nomenclature as
`presented in the 'Blue Book (Nomenclature of Organic Chemisby, Sections A, B, C, 0, E, F, and H, 1979
`edition), the 'Revised Nomenclature for Radicals, Ions, Radical Ions and Related Species,
`Recommendations 1992' and A Guide to IUPAC Nomenclature of Organic Chemistry, Recommendations
`1993, (including Revisions, Published and hitherto Unpublished, to the 1979 Edition of Nomenclature of
`Organic Chemistry).
`Some class names are explicitly defined in the Blue Book, for others the meaning is implicit. Many more
`class names are to be found in the chemical literature. A selection of the more important ones appears in this
`glossary. Some class names occurring mainly in the older literature have been included too. The compilers
`have considered customary usage and the need for clearly defined limits of meaning. Some compromises
`were necessary, but the definitions have survived scrutiny by the Commissions and consultants.
`Recommended class names carry a reference to an official IUPAC publication. The status of the remaining
`entries varies from unreserved acceptance to outright rejection. Class names not derived from an official
`source may carry a reference to other literature (a preference for the cited text over others is not implied). The
`definition of rejected class names is for information only; reasons for rejection are usually cited or indicated,
`and a cross-reference to the preferred class name is given.
`A compound may belong to two or more different classes, e.g. it may be a ketone as well as an ester. Quite
`often composite names are then used, one class being denoted by an adjective, the second by a noun. The
`adjective and noun are separated by a space, thus 0x0 ester. However in the name of a specific compound
`there is no space between the prefix, indicating a specific substituent, and the name of the parent. Contrast
`e.g. a-amino carboxylic acids (class name) and 2-aminopentanoic acid (specific compound name).
`
`0 1995 IUPAC
`
`1309
`
`

`

`1310 COMMISSIONS ON NOMENCLATURE OF ORGANIC CHEMISTRY AND PHYSICAL ORGANIC CHEMISTRY
`
`Symbols
`An asterisk (*) on an entry indicates that the definition is based on the contents of an official IUPAC source,
`Italicisation marks a relevant entry used in the definition of another entry. In formulae, charges are not circled
`and non-bonding electrons are not shown. However, in carbenes and related molecules, one electron pair is
`shown as a reminder of their lower-than-standard valency state. The dipolar bonds in sulfoxides, sulfones,
`etc., are represented by formal double bonds. In the formulae to be found in the definitions, the symbol R
`means any hydrocarbyl group (qv.) or H, unless its meaning is specifically qualified. When more than one
`R appears, it is to be understood that the R's may be the same or different, unless otherwise indicated. Two
`or more R's may be linked so as to form a ring, without changing the definition (e.g. R,C=O includes
`cyclopentanone as well as pentan-3-one and pentan-2-one). M indicates a metal or metal ion, Ar means an
`aryl group and Ph a phenyl group.
`The abbreviations used for some frequently cited sources are as follows:
`BNRD: Biochemical Nomenclature and Related Documents, Portland Press, London, 1992.
`2-Carb: Nomenclature of Carbohydrates, revised 1994, in preparation.
`CBN: Commission on Biochemical Nomenclature. IUPAC-IUB
`CNIC: Commission on Nomenclature of Inorganic Chemistry, IUPAC.
`CNOC: Commission on Nomenclature of Organic Chemistry, IUPAC.
`CPOC: Commission on Physical Organic Chemistry, IUPAC.
`EJB: European Journal of Biochemistry.
`GNOC: A Guide to IUPAC Nomenclature of Organic Compounds, Recommendations 1993, (including
`Revisions, Published and hitherto Unpublished, to the I979 Edition of Nomenclature of Organic
`Chemistry), Blackwell Scientific Publications, Oxford, 1993.
`GTPOC: Glossary of Terms Used in Physical Organic Chemistry, PAC 66,1077-1 184 (1994).
`JCBN: Joint Commission on Biochemical Nomenclature, IUBMB-IUPAC.
`NOC: Nomenclature of Organic Chemistry, Sections A, B, C, D, E, F and H , Pergamon Press, Oxford,
`1979.
`PAC: Pure and Applied Chemistfy.
`RNRI: Revised Nomenclature for Radicals, Ions, Radical Ions and Related Species, Recommendations
`1993, PAC 65, 1357-1455 (1993).
`
`acenes: *
`Polycyclic aromatic hydrocarbons consisting of fused benzene rings in a rectilinear arrangement. NOC Rule
`A-2 1.2, GNOC Recom. R-2.4.1.3.1.
`
`Glossary
`
`acetaIs:*
`Compounds having the structure R,C(OR'), ( R # H) and thus diethers of geminal diols. Originally, the
`term was confined to derivatives of aldehydes (one R = H), but now it applies equally to derivatives of
`ketones (neither R = H). NOC Rule C-331, GNOC Recom. R-5.6.4.1. Mixed acetals have different R'
`groups. See also acetonides, ketals. C$ acylals, hemiacetals.
`
`0 1995 IUPAC, Pure andApplied Chemistry, 67, 1307-1375
`
`

`

`Glossary of class names of organic compounds
`
`1313
`
`aldoketoses:*
`A now less preferred synonym for ketoaldoses. 2-Carb-1.5.
`aldonic acids: *
`Polyhydroxy acids having the general formula HOCH2[CH(OH)],C(=O)OH and therefore derived from an
`aldose by oxidation of the aldehyde function. 2-Carb-1.9. E.g. NCPH
`D-glUCOniC acid
`
`aldoses: *
`Aldehydic parent sugars (polyhydroxyaldehydes H[CH(OH)] ,C(=O)H, n 2 2) and their intramolecular
`hemiacetals. 2-Carb- 1.2. See also monosaccharides. E.g. D-glucose
`
`CHzOH
`
`H
`
`q
`
`major
`
`H
`
`H O
`
`
`
`OH
`OH
`I
`CH,OH
`very minor
`
`HOCHZ H*
`7 H2°
`
`H
`
`HO
`lor very mu
`
`b H
`
`
`aldoximes: *
`Oximes of aldehydes: RCH=NOH. GNOC Recom. R-5.6.6.1.
`alicyclic compounds:
`Aliphatic compoundr having a carbocyclic ring structure which may be saturated or unsaturated, but may not
`be a benzenoid or other aromatic system.
`aliphatic compounds:
`Acyclic or cyclic, saturated or unsaturated carbon compounds, excluding aromatic compoundr.
`a1 kaloids :
`Basic nitrogen compounds (mostly heterocyclic) occurring mostly in the plant kingdom (but not excluding
`those of animal origin). Amino acids, peptides, proteins, nucleotides, nucleic acids, amino sugars, and
`antibiotics are not normally regarded as alkaloids. By extension, certain neutral compounds biogenetically
`related to basic alkaloids are included.
`alkanes: *
`and therefore consisting
`Acyclic branched or unbranched hydrocarbons having the general formula C,H,+,,
`entirely of hydrogen atoms and saturated carbon atoms. NOC Rule A-1.1. Cf. cycloalkanes.
`alkanium ions:
`Carbocations derived from alkanes by C-hydronation containing at least one pentacoordinate carbon atom.
`RNRI Rule RC-82.1.1.2. C'
`carbonium ions. E.g. +CH5 methanium, [C2H,]+ ethanium.
`alkenes: *
`Acyclic branched or unbranched hydrocarbons having one carbon-carbon double bond and the general
`formula C,H2, . Acyclic branched or unbranched hydrocarbons having more than one double bond are
`alkadienes, alkatrienes, etc. NOC Rule A-3.1. See also olefins.
`
`0 1995 IUPAC, Pure andApplied Chemistry, 67,1307-1375
`
`

`

`1318 COMMISSIONS ON NOMENCLATURE OF ORGANIC CHEMISTRY AND PHYSICAL ORGANIC CHEMISTRY
`
`2. Salts formed by replacement of a nitrogen-bound hydron of aniline by a metal or other cation. E.g.
`NaNHPh sodium anilide.
`annulenes: *
`(n is an even number)
`Mancude monocyclic hydrocarbons without side chains of the general formula C,H,
`or CnH,+l ( n is an odd number). In systematic nomenclature an annulene with seven or more carbon atoms
`may be named [nlannulene, where n is the number of carbon atoms. GNOC Recom. R-2.3.1.2. E.g.
`[glannulene for cyclonona- 1,3,5,7-tetraene.
`annulenylidenes:
`Carbenes, derived by formal insertion of a divalent carbon atom into an even-membered annulene.
`E.g.
`
`0
`
`cycloheptatrienylidene
`
`ansa compounds:
`Benzene derivatives having para positions (or meta) bridged by a chain (commonly 10 to 12 atoms long)
`(Latin ansa, handle). By extension, any arene bridged by a chain constrained to lie over one of the two faces
`
`of the arene. Cf: cyclophanes. n
`
`anthocyanidins:
`Aglycons of anthocyanins; they are oxygenated derivatives of flavylium (2-phenylchromenylium) salts. Cfi
`flavonoids.
`
`anthocyanins:
`Plant pigments of thefluvonoid class; they are glycosides that on hydrolysis yield coloured aglycons called
`anthocyanidins.
`antiaromatic compounds:
`Compounds that contain 4n (n # 0 ) n-electrons in a cyclic planar, or nearly planar, system of alternating
`single and double bonds. Cf: aromatic compoundr. E.g. cyclobuta- 1,3-diene.
`arenes: *
`Monocyclic and polycyclic aromatic hydrocarbons. NOC Rule A-12.4. See aromatic compounds.
`arene epoxides:
`Epoxides derived from arenes by 1 ,2-addition of an oxygen atom to a formal double bond.
`
`0
`
`0 5,6-epoxycyclohexa- 1,3-diene.
`
`E.g*
`(Common usage has extended the term to include examples with the epoxy group bridging nonadjacent
`atoms.)
`arene oxides: See arene epoxides.
`arenium ions:
`Cations derived formally by the addition of a hydron or other cationic species to any position of an arene.
`E.g. C,H,+, benzenium. Cf. aryl cations.
`
`0 1995 IUPAC, Pure andApplied Chemistry, 67,1307-1375
`
`

`

`1320 COMMISSIONS ON NOMENCLATURE OF ORGANIC CHEMISTRY AND PHYSICAL ORGANIC CHEMISTRY
`arsinic acids: *
`H2As(=O)OH and its As-hydrocarbyl derivatives. NOC Rule D-5.51. E.g. Me2As(=O)OH dimethylarsinic
`acid.
`arsinidenes: See arsanylidenes.
`arsinous acids: *
`H2AsOH and its As-hydrocarbyl derivatives. NOC Rule D-5.21.
`arsonic acids: *
`HAs(=O)(OH)~ and its As-hydrocarbyl derivatives. NOC Rule D-5.51.
`arsonium compounds: *
`Salts (including hydroxides) [R4As]+ X- containing tetracoordinate arsonium ion and the associated anion.
`NOC Rule D-5.31. See also onium compounds.
`arsonous acids: *
`HAs(OH)~ and its As-hydrocarbyl derivatives. NOC Rule D-5.21.
`arsoranes:*
`The mononuclear hydride AsH5, systematically named h5-arsane, and its hydrocarbyl derivatives. NOC
`Rule D-5.7 1. See also arsanes. By extension the term also applies to arsonium ylides. See under ylides.
`aryl cations:
`Carbocations formally derived by removal of a hydride ion from a ring carbon atom of an arene. Cf:
`
`arenium ions. E.g. o+
`
`phenyl cation or phenylium
`
`aryl groups: *
`Groups derived from arenes by removal of a hydrogen atom from a ring carbon atom. NOC Rule A-13.5.
`Groups similarly derived from heteroarenes are sometimes subsumed in this definition (see heteroaryl
`groups). E.g. a C H 3
`
`o-tolyl.
`
`/
`arylene groups: *
`Bivalent groups derived from arenes by removal of a hydrogen atom from two ring carbon atoms. A
`synonym is arenediyl groups. NOC Rule A-13.5. E.g.
`
`o-phenylene or a
`01 benzyne
`
`arynes:
`Hydrocarbons derived formally from arenes by the abstraction of two hydrogen atoms from adjacent carbon
`atoms; thus 1,2-didehydroarenes, Arynes are commonly represented with a formal triple bond. Cf.
`benzynes, dehydroarenes, heteroarynes. E.g. /
`
`benzene- 1,2-diyl
`
`azamines: See isodiazenes.
`azanes:
`Saturated acyclic nitrogen hydrides having the general formula NnH,+2.
`azides:*
`1. Compounds bearing the group -N3, viz. -N=N+=N-; usually attached to carbon. NOC Rule C-941.1.
`E.g. PhN3 phenyl azide or azidobenzene. -
`
`0 1995 IUPAC, Pure and Applied Chemistry, 67, 1307-1375
`
`

`

`1330 COMMISSIONS ON NOMENCLATURE OF ORGANIC CHEMISTRY AND PHYSICAL ORGANIC CHEMISTRY
`cyclitols: *
`Hydroxylated cycloalkunes containing at least three hydroxy groups, each attached to a different ring carbon
`atom. BNRD, Nomenclature of Cyclitols (p. 149).
`cycloalkanes: *
`Saturated monocyclic hydrocarbons (with or without side chains). See alicyclic compounds. NOC Rule
`A- 11.1. E.g. HzC-CHz
`cyclobutane. Unsaturated monocyclic hydrocarbons having one endocyclic double
`I
`I
`
`HzC-CHz
`or one triple bond are called cycloalkenes and cycloakynes, respectively. Those having more than one such
`multiple bond are cycloalkadienes, cycloalkatrienes, etc. The inclusive terms for any cyclic hydrocarbons
`having any number of such multiple bonds are cyclic olefins or cyclic acetylenes.
`cycloalkyl groups: *
`Univalent groups derived from cycloalkunes by removal of a hydrogen atom from a ring carbon atom. E.g.
`cH3-HTf
`2-methylcyclopropyl. NOC Rules A- 1 1.1, A- 1 1.2.
`H-
`
`HZ
`cyclodepsipeptides: See depsipeptides.
`cyclodextrins:
`Cyclic oligoglucosides containing 5 to ca. 10 glucose residues in which an enclosed tubular space allows
`reception of a guest molecule to form a clathrate. The synonymous term Schardinger dextrins is not
`recommended. (a-Cyclodextrin has 6 glucose residues; P-cyclodextrin has 7.) Semi-systematically
`a-cyclodextrin is called cyclomaltohexaose. 2-Carb-37.4.1. See also dextrins.
`
`CHzOH pk
`
`@
`
`cyclohexadienyl cations:
`A subclass of arenium ions.
`cycloph anes :
`The term originally applied to compounds having two p-phenylene groups held face to face by -[CH,],-
`systems, or assemblies of mancude-ring
`bridges. It now designates compounds having (i) &cude-ring
`systems, and (ii) atoms and/or saturated or unsaturated chains as alternate components of a large ring.
`GNOC Recom. R-2.4.5. Many chemists include in this class any bridged aromatic system, irrespective of
`the attachment positions of the bridge. E.g.
`[2.2](1,4)(1,4)cyclophane or
`1(1,4),4( 1,4)-dibenzenacyclophane
`according to the provisional CNOC
`document on Phane Nomenclature, Part 1.
`F.N. Diederich, Cyclophanes, The Royal Society of Chemistry, 1991.
`cyclosilazanes: *
`Compounds having rings of alternating silicon and nitrogen atoms:
`NOC Rule D-6.42.
`cyclosiloxanes: *
`Compounds having rings of alternating silicon and oxygen atoms. NOC Rule D-6.23.
`E.g.
`* 1 (
`00‘ I
`HzSi 1 Si CH3k
`0 5 4 . 3 ~
`‘Sl’
`
`n
`
`2,2-dimethylcyclotrisiloxane.
`
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`

`

`1340 COMMISSIONS ON NOMENCLATURE OF ORGANIC CHEMISTRY AND PHYSICAL ORGANIC CHEMISTRY
`
`hetarenes: Synonymous with heteroarenes.
`hetaryl groups: Synonymous with heteroaryl groups.
`hetarynes: Synonymous with heteroarynes.
`heteroalkenes:
`Analogues of alkenes in which a doubly bonded carbon atom is replaced by a heteroatom. E.g. H2Si=CH2
`methylidenesilane (silene less preferred), MeN=CH2 N-methylmethanimine.
`he teroarenes:
`Heterocyclic compounds formally derived from arenes by replacement of one or more methine (-C=) andor
`vinylene (-CH=CH-) groups by trivalent or divalent heteroatoms, respectively, in such a way as to maintain
`the continuous n-electron system characteristic of aromatic systems and a number of out-of-plane n-electrons
`corresponding to the Huckel rule (4n + 2); an alternative term is hetarenes. Comprehensive Heterocyclic
`Chemistry, Vol. 1, Ed. 0. Meth-Cohn, Pergamon, 1984, p. 3. E.g.
`
`\ (2
`
`heteroaryl groups:
`The class of heterocyclyl groups derived from heteroarenes by removal of a hydrogen atom from any ring
`atom; an alternative term is hetaryl. E.g.
`
`I a
`0
`Katritzky, Vol. 4, Academic-Press, 1965, p. 121. E.g. a, a;
`
`2-pyridyl (pyridin-2-yl),
`
`indol- 1 -yl.
`
`heteroarynes :
`Compounds derived from heteroarenes by replacement of a formal carbon-carbon double bond by a formal
`triple bond (with loss of two hydrogen atoms). Also known as hetarynes and as 1,2-didehydroheteroarenes.
`See arynes. H. J. den Hertog and H. C. van der Plas, in Advances in Heterocyclic Chemistry, Ed. A. R.
`
`heterocumulenes:
`Cumulenes in which one or more carbon atoms of the cumulative bond system have been replaced by
`heteroatoms. E.g. O=C=C=C=O, but not CH,=C=O, ketene, nor O=C=O, carbon dioxide, which are
`heteroallenes.
`heterocyclic compounds:
`Cyclic compounds having as ring members atoms of at least two different elements. E.g. quinoline, 1,2-
`thiazole, bicyclo[3.3.l]tetrasiloxane. Cf: homocyclic compounds, carbocyclic compounds.
`heterocyclyl groups:
`Univalent groups formed by removing a hydrogen atom from any ring atom of a heterocyclic compound.
`E.g. 4-pyridy1,
`H
`
`0
`
`pyrrolidin-2-yl. See organyl.
`
`cN-
`
`pyrrolidin-1-yl,
`
`homocyclic compounds:
`Cyclic compounds having as ring members atoms of the same element only. E.g. benzene, pentazole,
`cyclohexasilane.
`hydrazides: *
`(1 # 0) by replacing -OH by -NRNR2 (R groups are
`Compounds derived from oxoacids RkE(=0),(OH),
`commonly H), as in carbohydrazides, RC(=O)NHNH2, NOC Rule C-921.5, (GNOC Recom. R-5.7.8.4),
`
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`

`1366 COMMISSIONS ON NOMENCLATURE OF ORGANIC CHEMISTRY AND PHYSICAL ORGANIC CHEMISTRY
`
`silasesquioxanes: *
`Compounds in which every silicon atom is linked to three oxygen atoms and every oxygen atom is linked to
`two silicon atoms, and having the general formula (SiH),,03,. NOC Rule D-6.61. By extension
`hydrocarbyl derivatives are commonly included.
`silasesquithianes: *
`Compounds in which every silicon atom is linked to three sulfur atoms and every sulfur atom is linked to
`two silicon atoms, and having the general formula (SiH),,S,,. NOC Rule D-6.61. By extension
`hydrocarbyl derivatives are commonly included.
`silathianes: *
`Compounds having the structure H3Si[SSiHz],SSiH3 and branched-chain analogues. They are analogous in
`structure to siloxanes with -S- replacing -0-. NOC Rule D-6.31. By extension hydrocarbyl derivatives are
`commonly included.
`silazanes:*
`Saturated silicon-nitrogen hydrides, having straight or branched chains. They are analogous in structure to
`siloxunes with -NH- replacing -0-. NOC Rule D-6.41. E.g. H,SiNHSiH,NHSiH,
`trisilazane. By extension
`hydrocarbyl derivatives are commonly included.
`silicones:
`Polymeric or oligomeric siloxunes, usually considered unbranched, of general formula [-OSiR,-1, (R # H).
`siloxanes: *
`Saturated silicon-oxygen hydrides with unbranched or branched chains of alternating silicon and oxygen
`atoms (each silicon atom is separated from its nearest silicon neighbours by single oxygen atoms). The
`general structure of unbranched siloxanes is H,Si[OSiH,], OSiH,. See also silicones. NOC Rule D-6.21.
`H,Si[OSiH,], OSiH[OSiHzOSiH3], is an example of a branched siloxane. By extension hydrocarbyl
`derivatives are commonly included.
`silyl groups:
`1. In a strict sense, the silyl group is H3Si- . NOC Rule D-6.12.
`2. A name commonly applied to hydrocarbyl derivatives of the silyl group: R,Si-.
`silyl radicals:
`1. In a strict sense, the silyl radical is H,Si'. NOC Rule D-5.81.
`2. A name commonly applied to the silicon-centered radicals: R,Si'.
`silylenes: *
`Carbene analogues having the structure R2Si:. RNRI Rule RC-8 1.1.3.1.
`spiro compounds:
`Compounds having one atom (usually a quaternary carbon) as the only common member of two rings. NOC
`Rule A-41. E.g.
`
`spiro[cyclopentane- 1,2'-indene],
`
`spiro[4.4]nonane
`
`s tannox anes :
`Compounds having the structure H3Sn[OSnH2], OSnH,. Thus tin analogues of siloxanes.
`stannylenes: See stannylidenes.
`stannylidenes: *
`Carbeneunalogues having the structure R&:
`recommended. RNRI Rule RC-81.1.3.2.
`
`. The older synonymous term stannylenes is no longer
`
`0 1995 IUPAC, Pure and Applied Chemistry, 67,1307-1375
`
`