《有机化学》课程教学资源（教材文献，英文版）Glossary

GLOSSARY Absolute configuration(Section 7.5): The three-dimensional Activating substituent (Sections 12.10 and 12.12): A group rrangement of atoms or groups at a stereogenic center. that when present in place of a hydrogen causes a particular Acetal(Section 17.8): Product of the reaction of an aldehyde or reaction to occur faster. Term is most often applied to a ketone with two moles of an alcohol according to the substituents that increase the rate of electrophilic aromatic Active site(Section 27. 20): The region of an enzyme at which the substrate is bound. RCR′+2R"OH→>RCR′+H,O Acylation(Section 12.7 and Chapter 20): Reaction in which an acyl group becomes attached to some structural unit in a molecule. Examples include the Friedel-Erafts acylation and the conversion of amines to amides Acetoacetic ester synthesis(Section 21.6): A synthetic method Acyl chloride(Sections 2.3 and 20.1 ) Compound of the type for the preparation of ketones in which alkylation of the enolate of ethyl acetoacetate RCCI CCHCOCH_CH3 R may be alkyl or aryl. Acyl group(Sections 12.7 and 20. 1): The group the key carbon-earbon bond-forming step Acetyl coenzyme A (Section 26.1): A thiol ester abbreviated as R may be alkyl or aryl. that act source of acetyl groups in biosynthetic Acylium ion ( Section 12.7): The cation R-C Acetylene (S 1. 18 and 9.1): The simplest alkyne, HC≡CH is converted to another Achiral (Section 7. 1): Opposite of chiral. An achiral object is Addition(Section 6.1): Reaction in which a reagent X-Y ble on its mirror image. adds to a multiple bond so that x becomes attached to one Acid(Section 4.6): According to the arrhenius definition,a f the carbons of the multiple bond and Y to the other. substance that ionizes in water to produce protons. Accord 1, 2 Addition (Section 10.10): Addition of reagents of the type ing to the bronsted-towry definition, a substance that do X-Y to conjugated dienes in which X and Y add to adja- nates a proton to some other substance. According to the cent doubly bonded carbons Lewis definition, an electron-pair acceptor. Acid anhydride (Sections 2.3 and 20. 1): Compound of the type R2C=CH-CH=CR2 R2C-CH—CH=CR RCOCR 1. 4 Addition (Section 10.10): Addition of reagents of the type Both r groups are usually the same, although they need not X-Y to conjugated dienes in which X and Y add to the ter Acid dissociation constant Ka (Section 4.6): Equilibrium con- stant for dissociation of an acid R2C=CH—CH=CR2 R2C-CH=CH—CR2 H[A-] THAJ Addition-elimination mechanism (Section 23.6 ): Two-stage In G-1 Forward Main Menu TOC Study Guide Toc Student OLCMHHE Website

G-1 GLOSSARY Absolute configuration (Section 7.5): The three-dimensional arrangement of atoms or groups at a stereogenic center. Acetal (Section 17.8): Product of the reaction of an aldehyde or a ketone with two moles of an alcohol according to the equation Acetoacetic ester synthesis (Section 21.6): A synthetic method for the preparation of ketones in which alkylation of the enolate of ethyl acetoacetate is the key carbon—carbon bond-forming step. Acetyl coenzyme A (Section 26.1): A thiol ester abbreviated as that acts as the source of acetyl groups in biosynthetic processes involving acetate. Acetylene (Sections 1.18 and 9.1): The simplest alkyne, HCPCH. Achiral (Section 7.1): Opposite of chiral. An achiral object is superimposable on its mirror image. Acid (Section 4.6): According to the Arrhenius definition, a substance that ionizes in water to produce protons. Accord￾ing to the Brønsted—Lowry definition, a substance that do￾nates a proton to some other substance. According to the Lewis definition, an electron-pair acceptor. Acid anhydride (Sections 2.3 and 20.1): Compound of the type Both R groups are usually the same, although they need not always be. Acid dissociation constant Ka (Section 4.6): Equilibrium con￾stant for dissociation of an acid: Ka [H][A] [HA] RCOCR O X O X CH3CSCoA O X CH3CCH2COCH2CH3 O X O X RCR 2ROH H2O O X RCR W W OR OR H Activating substituent (Sections 12.10 and 12.12): A group that when present in place of a hydrogen causes a particular reaction to occur faster. Term is most often applied to substituents that increase the rate of electrophilic aromatic substitution. Active site (Section 27.20): The region of an enzyme at which the substrate is bound. Acylation (Section 12.7 and Chapter 20): Reaction in which an acyl group becomes attached to some structural unit in a molecule. Examples include the Friedel—Crafts acylation and the conversion of amines to amides. Acyl chloride (Sections 2.3 and 20.1): Compound of the type R may be alkyl or aryl. Acyl group (Sections 12.7 and 20.1): The group R may be alkyl or aryl. Acylium ion (Section 12.7): The cation . Acyl transfer (Section 20.3): A nucleophilic acyl substitution. A reaction in which one type of carboxylic acid derivative is converted to another. Addition (Section 6.1): Reaction in which a reagent X±Y adds to a multiple bond so that X becomes attached to one of the carbons of the multiple bond and Y to the other. 1,2 Addition (Section 10.10): Addition of reagents of the type X±Y to conjugated dienes in which X and Y add to adja￾cent doubly bonded carbons: 1,4 Addition (Section 10.10): Addition of reagents of the type X±Y to conjugated dienes in which X and Y add to the ter￾mini of the diene system: Addition—elimination mechanism (Section 23.6): Two-stage mechanism for nucleophilic aromatic substitution. In the R2CœCH±CHœCR2 R2C±CHœCH±CR2 W X W Y X±Y R2CœCH±CHœCR2 R2C±CH±CHœCR2 W X W Y X±Y R±CPO RC± O X RCCl O X

GLOSSARY tage, the nucleophile adds to the carbon that bears Alkaloid(Section 22.5): Amine that occurs naturally in plants. ing group. In the elimination stage, the leaving The name derives from the fact that such compound weak bases Alkane(Section 2. 1 ): Hydrocarbon in which all the bonds are single bonds. Alkanes have the general formula CnH2n+? (Section 2.1): Hydrocarbon that contains a carbon-ea bon double bond (C=C); also known by the older name Alkoxide ion (Section 5.14): Conjugate base of an alcohol; a Alcohol (Section 4.2): Compound of the type roh Alcohol dehydrogenase(Section 15. 11): Enzyme in the liver Alkylamine(Section 22. 1 ) Amine in which the organic groups that catalyzes the oxidation of alcohols to aldehydes and ke- ttached to nitrogen are alkyl groups Alkylation(Section 9.6): Reaction in which an alkyl group is Aldaric acid (Section 25. 19): Carbohydrate in which car- attached to some structural unit in a molecule boxylic acid functions are present at both ends of the chain Alkyl group (Section 2.10): Structural unit related to an alkane Aldaric acids are typically prepared by oxidation of aldoses by replacing one of the hydrogens by a potential point of at- tachment to some other atom or group. The general symbol Aldehyde( Sections 2.3 and 17. 1): Compound of the type for an alkyl group is r Alkyl halide (Section 4. 1): Compound of the type RX, in which is a halogen substituent(f, Cl Br. D). RCH Alkyloxonium ion (Section 4.6): Positive ion of the type Alditol (Section 25. 18): The polyol obtained on reduction of Alkyne (Section 2. 1 ): Hydrocarbon that contains a carbon-ear the carbonyl group of a carbohydrate. bon triple bond Aldol addition(Section 18.9): Nucleophilic addition of an Allene(Section 10.5): The compound CH2=C=CH dehyde or ketone enolate to the carbonyl group of an Allyl cation(Section 10.2): The carbocation aldehyde or a ketone. The most typical case involves two molecules of an aldehyde, and is usually catalyzed by CH=CHCH The carbocation is stabilized by delocalization of the T ctrons of the double bond. and th shared by the two CH, groups. Substituted analogs of allyl 2RCHCH RCH,CHCHR cation are calle Aldol condensation (Sections 18.9-+8.10): When an aldol ad- dition is carried out so that the B-hydroxy aldehyde or ke- Allylic rearrangement(Section 10.2): Functional group trans formation in which double-bond migration has converted product is described as arising by an aldol condensation one allylic structural unit to another, as in: R,C=CHCH,X-R,CCH=CH 2RCHCH RCH,CH=CR +H,O CH=o Aldonic acid (Section 25. 19): Carboxylic acid obtained by oxi- Amide (Sections 2.3 and 20. 1): Compound of the type RCNR2 ation of the aldehyde function of an aldose. Amine( Chapter 22): Molecule in which a nitrogen-containing Aldose (Section 25. 1): Carbohydrate that contains an aldehyde group of the type -NH2, -NHR, or-NR, is attached to carbonyl group in its open-chain form. an alkyl or aryl group Alicyclic (Section 2.12): Term describing an aliphatic cycl a-Amino acid (Section 27. 1 ): A carboxylic acid that contains tructural unit an amino group at the a-carbon atom a-Amino acids are Aliphatic (Section 2.1): Term applied to compounds that do not the building blocks of peptides and proteins. An a-amino contain benzene or benzene-like rings as structural units mally exists (Historically, aliphatic was used to describe compounds de- rived from fats and oils. RCHCO, Alkadiene (Section 10.5): Hydrocarbon that contains two arbon-earbon double bonds; commonly referred to as Forward Main Menu TOC Study Guide Toc Student OLCMHHE Website

GLOSSARY G-2 Alkaloid (Section 22.5): Amine that occurs naturally in plants. The name derives from the fact that such compounds are weak bases. Alkane (Section 2.1): Hydrocarbon in which all the bonds are single bonds. Alkanes have the general formula CnH2n2. Alkene (Section 2.1): Hydrocarbon that contains a carbon—car￾bon double bond (CœC); also known by the older name olefin. Alkoxide ion (Section 5.14): Conjugate base of an alcohol; a species of the type . Alkylamine (Section 22.1): Amine in which the organic groups attached to nitrogen are alkyl groups. Alkylation (Section 9.6): Reaction in which an alkyl group is attached to some structural unit in a molecule. Alkyl group (Section 2.10): Structural unit related to an alkane by replacing one of the hydrogens by a potential point of at￾tachment to some other atom or group. The general symbol for an alkyl group is R±. Alkyl halide (Section 4.1): Compound of the type RX, in which X is a halogen substituent (F, Cl, Br, I). Alkyloxonium ion (Section 4.6): Positive ion of the type ROH2 . Alkyne (Section 2.1): Hydrocarbon that contains a carbon—car￾bon triple bond. Allene (Section 10.5): The compound CH2œCœCH2. Allyl cation (Section 10.2): The carbocation CH2œCHCH2 The carbocation is stabilized by delocalization of the electrons of the double bond, and the positive charge is shared by the two CH2 groups. Substituted analogs of allyl cation are called allylic carbocations. Allyl group (Sections 5.1, 10.1): The group CH2œCHCH2± Allylic rearrangement (Section 10.2): Functional group trans￾formation in which double-bond migration has converted one allylic structural unit to another, as in: Amide (Sections 2.3 and 20.1): Compound of the type Amine (Chapter 22): Molecule in which a nitrogen-containing group of the type ±NH2, ±NHR, or ±NR2 is attached to an alkyl or aryl group. -Amino acid (Section 27.1): A carboxylic acid that contains an amino group at the -carbon atom. -Amino acids are the building blocks of peptides and proteins. An -amino acid normally exists as a zwitterion. RCHCO2  W NH3 RCNR 2 O X R2CœCHCH2X R2CCHœCH2 W Y R±O  addition stage, the nucleophile adds to the carbon that bears the leaving group. In the elimination stage, the leaving group is expelled. Alcohol (Section 4.2): Compound of the type ROH. Alcohol dehydrogenase (Section 15.11): Enzyme in the liver that catalyzes the oxidation of alcohols to aldehydes and ke￾tones. Aldaric acid (Section 25.19): Carbohydrate in which car￾boxylic acid functions are present at both ends of the chain. Aldaric acids are typically prepared by oxidation of aldoses with nitric acid. Aldehyde (Sections 2.3 and 17.1): Compound of the type Alditol (Section 25.18): The polyol obtained on reduction of the carbonyl group of a carbohydrate. Aldol addition (Section 18.9): Nucleophilic addition of an aldehyde or ketone enolate to the carbonyl group of an aldehyde or a ketone. The most typical case involves two molecules of an aldehyde, and is usually catalyzed by bases. Aldol condensation (Sections 18.9—18.10): When an aldol ad￾dition is carried out so that the -hydroxy aldehyde or ke￾tone dehydrates under the conditions of its formation, the product is described as arising by an aldol condensation. Aldonic acid (Section 25.19): Carboxylic acid obtained by oxi￾dation of the aldehyde function of an aldose. Aldose (Section 25.1): Carbohydrate that contains an aldehyde carbonyl group in its open-chain form. Alicyclic (Section 2.12): Term describing an aliphatic cyclic structural unit. Aliphatic (Section 2.1): Term applied to compounds that do not contain benzene or benzene-like rings as structural units. (Historically, aliphatic was used to describe compounds de￾rived from fats and oils.) Alkadiene (Section 10.5): Hydrocarbon that contains two carbon—carbon double bonds; commonly referred to as a diene. 2RCH2CH O X RCH2CHœCR W CHœO H2O HO heat 2RCH2CH O X RCH2CHCHR W OH W CHœO HO RCH O X ArCH O X or X Y addition X elimination Y X  Y

GLOSSARY L-Amino acid (Section 27. 2): a description of the stereochem Antibonding orbital(Section 1. 14): An orbital in a molecule in istry at the a-carbon atom of a chiral amino acid. The which an electron is less stable than when localized on ar Fischer projection of an a-amino acid has the amino group isolated atom on the left when the carbon chain is vertical with the car Anticodon (Section 27 28): Sequence of three bases in a mole boxyl group at the top cule of tRNa that is complementary to the codon of mRNA for a particular amino acid Anti-Markovnikov addition (Sections 6.8, 6.11): Addition re- H3N action for which the regioselectivity is opposite to that pre dicted on the basis of markovnikov's rul protic solvent(Section 8.12): A solvent that does not have Amino acid racemization (Section 27. 2)a method fc easily exchangeable protons such as those bonded to oxy- archeological samples based on the rate at which gen of hydroxyl groups geochemistry at the a carbon of amino acid compon Ar-(Section 2.2): Symbol for an aryl group randomized. It is useful for samples too old to be Arene(Section 2. 1 ) Aromatic hydrocarbon. Often abbreviated dated byC decay ArH Amino acid residues (Section 27.7): Individual amino acid Arenium ion( Section 12.2): The carbocation intermediate components of a peptide or protein formed by attack of an electrophile on an aromatic substrate Amino sugar (Section 25. 11): Carbohydrate in which one of in electrophilic aromatic substitution. See cyclohexadienyl the hydroxyl groups has been replaced by an amino group cation Amylopectin (Section 25. 15): A polysaccharide present in Aromatic compound (Section 11.3): An electron-delocalized starch. Amylopectin is a polymer of a(1, 4)-linked glucose species that is much more stable than any structure written units, as is amylose(see amylose). Unlike amylose, amy for it in which all the electrons are localized either in co lopectin contains branches of 24-30 glucose units con- lent bonds or as unshared electron pairs nected to the main chain by an a(1, 6) linkage. Aromaticity (Section 11.4): Special stability associated with Amylose (Section 25. 15): The water-dispersible component of aromatic compounds starch. It is a polymer of o(1, 4)-linked glucose Arylamine(Section 22.1): An amine that has an aryl group at- Anabolic steroid (Section 26. 15): A steroid that promotes mus ached to the amin Aryne (Section 23.8): A species that contains a triple bond Androgen (Section 26.15): A male sex hormone within an aromatic ring Angle strain (Section 3. 4): The strain a molecule possesses be- Asymmetric(Section 7.1): Lacking all significant symmetry cause its bond angles are distorted from their normal values elements; an asymmetric object does not have a plane, axis, Anion (Section 1. 2): Negatively charged ion. center of symmetry. Annulene (Section 11. 19): Monocyclic hydrocarbon character- Asymmetric center (Section 7. 2): Obsolete name for a ste ed by a completely conjugated system of double bonds neogenic center Annulenes may or may not be aromatic. Atactic polymer(Section 7. 15): Polymer characterized by ran- Anomeric carbon (Section 25.6): The carbon atom in a fura- dom stereochemistry at its stereogenic centers. An atactic nose or pyranose form that is derived from the carbonyl car- polymer, unlike an isotactic or a syndiotactic polymer, is bon of the open-chain form. It is the ring carbon that is not a stereoregular bonded to two oxygens. Atomic number(Section 1. 1): The number of protons in the Anomeric effect(Section 25.8): The preference for an elec nucleus of a particular atom. The symbol for atomic number tronegative substituent, especially a hydroxyl group, to oc- is Z, and each element has a unique atomic number. cupy an axial orientation when bonded to the anomeric car Axial bond (Section 3.6): a bond to a carbon in the chair con- bon in the pyranose form of a carbohydrate formation of cyclohexane oriented like the six "up-and Anti (Section 3. 1): Term describing relative position of two down"bonds in the following: substituents on adjacent atoms when the angle between their bonds is on the order of 180. Atoms X and y in the structure shown are anti to each other (Section 22 19): Formation of a compound of the =NAr by reaction of an aryl diazonium salt with The arene must be strongly activated toward elec- aromatic substitution; that is, it must bear a power ful electron-releasing substituent such as-OH or-NR, Anti addition ( Section 6.3): Addition reaction in which the tw portions of the attacking reagent X-Y add to opposite faces of the double bond Forward Main Menu TOC Study Guide Toc Student OLCMHHE Website

G-3 GLOSSARY L-Amino acid (Section 27.2): A description of the stereochem￾istry at the -carbon atom of a chiral amino acid. The Fischer projection of an -amino acid has the amino group on the left when the carbon chain is vertical with the car￾boxyl group at the top. Amino acid racemization (Section 27.2) A method for dating archeological samples based on the rate at which the ste￾reochemistry at the carbon of amino acid components is randomized. It is useful for samples too old to be reliably dated by 14C decay. Amino acid residues (Section 27.7): Individual amino acid components of a peptide or protein. Amino sugar (Section 25.11): Carbohydrate in which one of the hydroxyl groups has been replaced by an amino group. Amylopectin (Section 25.15): A polysaccharide present in starch. Amylopectin is a polymer of (1,4)-linked glucose units, as is amylose (see amylose). Unlike amylose, amy￾lopectin contains branches of 24—30 glucose units con￾nected to the main chain by an (1,6) linkage. Amylose (Section 25.15): The water-dispersible component of starch. It is a polymer of (1,4)-linked glucose units. Anabolic steroid (Section 26.15): A steroid that promotes mus￾cle growth. Androgen (Section 26.15): A male sex hormone. Angle strain (Section 3.4): The strain a molecule possesses be￾cause its bond angles are distorted from their normal values. Anion (Section 1.2): Negatively charged ion. Annulene (Section 11.19): Monocyclic hydrocarbon character￾ized by a completely conjugated system of double bonds. Annulenes may or may not be aromatic. Anomeric carbon (Section 25.6): The carbon atom in a fura￾nose or pyranose form that is derived from the carbonyl car￾bon of the open-chain form. It is the ring carbon that is bonded to two oxygens. Anomeric effect (Section 25.8): The preference for an elec￾tronegative substituent, especially a hydroxyl group, to oc￾cupy an axial orientation when bonded to the anomeric car￾bon in the pyranose form of a carbohydrate. Anti (Section 3.1): Term describing relative position of two substituents on adjacent atoms when the angle between their bonds is on the order of 180°. Atoms X and Y in the structure shown are anti to each other. Anti addition (Section 6.3): Addition reaction in which the two portions of the attacking reagent X±Y add to opposite faces of the double bond. X Y CO2  H3N H R Antibonding orbital (Section 1.14): An orbital in a molecule in which an electron is less stable than when localized on an isolated atom. Anticodon (Section 27.28): Sequence of three bases in a mole￾cule of tRNA that is complementary to the codon of mRNA for a particular amino acid. Anti-Markovnikov addition (Sections 6.8, 6.11): Addition re￾action for which the regioselectivity is opposite to that pre￾dicted on the basis of Markovnikov’s rule. Aprotic solvent (Section 8.12): A solvent that does not have easily exchangeable protons such as those bonded to oxy￾gen of hydroxyl groups. Ar± (Section 2.2): Symbol for an aryl group. Arene (Section 2.1): Aromatic hydrocarbon. Often abbreviated ArH. Arenium ion (Section 12.2): The carbocation intermediate formed by attack of an electrophile on an aromatic substrate in electrophilic aromatic substitution. See cyclohexadienyl cation. Aromatic compound (Section 11.3): An electron-delocalized species that is much more stable than any structure written for it in which all the electrons are localized either in cova￾lent bonds or as unshared electron pairs. Aromaticity (Section 11.4): Special stability associated with aromatic compounds. Arylamine (Section 22.1): An amine that has an aryl group at￾tached to the amine nitrogen. Aryne (Section 23.8): A species that contains a triple bond within an aromatic ring (see benzyne). Asymmetric (Section 7.1): Lacking all significant symmetry elements; an asymmetric object does not have a plane, axis, or center of symmetry. Asymmetric center (Section 7.2): Obsolete name for a ste￾reogenic center. Atactic polymer (Section 7.15): Polymer characterized by ran￾dom stereochemistry at its stereogenic centers. An atactic polymer, unlike an isotactic or a syndiotactic polymer, is not a stereoregular polymer. Atomic number (Section 1.1): The number of protons in the nucleus of a particular atom. The symbol for atomic number is Z, and each element has a unique atomic number. Axial bond (Section 3.6): A bond to a carbon in the chair con￾formation of cyclohexane oriented like the six “up-and￾down” bonds in the following: Azo coupling (Section 22.19): Formation of a compound of the type ArNœNAr by reaction of an aryl diazonium salt with an arene. The arene must be strongly activated toward elec￾trophilic aromatic substitution; that is, it must bear a power￾ful electron-releasing substituent such as ±OH or ±NR2.

GLOSSARY Benzylic carbon (Section 11.10): A carbon directly attached to Baeyer strain theory (Section 3.4): Incorrect nineteenth-cen a benzene ring. a hydrogen attached to a benzylic carbon is tury theory that considered the rings of cycloalkanes to be a benzylic hydrogen. A carbocation in which the benzylic planar and assessed their stabilities according to how much carbon is positively charged is a benzylic carbocation. A the angles of a corresponding regular polygon deviated free radical in which the benzy lic carbon bears the unpaired from the tetrahedral value of 109,5o lectron is a benzylic radical. aeyer-illiger oxidation( Section 17.16): Oxidation of an Benzyne(Section 23.8): The compound hyde or, more commonly, a ketone with a peroxy acid The product of Baeyer-Villiger oxidation of a ketone is an ester RCR Ball-and-stick model(Section 1.10): Type of molecular model n which balls representing atoms are connected by sticks Benzyne is formed as a reactive representing bonds. Similar to ball-and-spoke models of of aryl halides with very stror Learning By Modeling Base(Section 4.6): According to the Arrhenius definition, Bile acids (Section 26.13): Steroid derivatives biosynthesized ubstance that ionizes in water to produce hydroxide ions the liver that aid digestion by emulsifying fats. According to the Bronsted-towry definition, a substance Bimolecular (Section 4.7): A process in which two particles re- that accepts a proton from some suitable donor. According act in the same elementary ster to the Lewis definition, an electron-pair donor. Biological isoprene unit (Section 26.8): Isopentenyl pyrophos- Base pair(Section 27. 27): Term given to the purine of a nu phate, the biological precursor to terpenes and steroids: cleotide and its complementary pyrimidine Adenine(A)is omplementary to thymine(T), and guanine(G)is comple entary to cytosine( C). Base peak (Section 13.21): The most intense peak in a mass spectrum. The base peak is assigned a relative intensity of Birch reduction(Section 11.11): Reduction of an aromatic ring 100, and the intensities of all other peaks are cited as a per- to a 1, 4-cyclohexadiene on treatment with a group I metal entage of the base (i, Na, K)and an alcohol in liquid ammonia. Basicity constant Kb(Section 22. 4):A measure of bas Boat conformation (Section 3.5): An unstable conform cyclohexane, depicted a Kb=IRyNH*HO-I IRa Bending vibration(Section 13. 19): The regular, repetitive mo- tion of an atom or a group along an arc the radius of whic is the bond connecting the atom or group to the rest of the T bond ( Section 1. 17): In alkenes, a bond formed by overlap of type of molecular orbitals in a side-by-side manner. A T bond is weaker than motion that gives rise to a peak in the infrared spectrum. a o bond. The carbon -earbon double bond in alkenes con- Benedict's reagent (Section 25. 19): A solution containing the ists of two sp-hybridized carbons joined by a g bond and citrate complex of CuSO4. It is used to test for the presence of reducing sugars o bond (Section 1.14): A connection between two atoms in Benzene(Section 11. 1): The most typical aromatic hydrocar hich the electron probability distribution has rotational symmetry along the internuclear axis. A cross section per- pendicular to the internuclear axis is a circle Bond dissociation energy (Section 1.3): For a substance A: B, the energy required to break the bond between A and b so that each retains one of the electrons in the bond table 4.3 (Section 4.17)gives bond dissociation energies for some representative compounds Bonding orbital(Section 1. 14): An orbital in a molecule in which an electron is more stable than when localized on an Benzyl group (Section 11.7): The group C6HSCH isolated atom. All the bonding orbitals are normally doubl occupied in stable neutral molecules Forward Main Menu TOC Study Guide Toc Student OLCMHHE Website

GLOSSARY G-4 Baeyer strain theory (Section 3.4): Incorrect nineteenth-cen￾tury theory that considered the rings of cycloalkanes to be planar and assessed their stabilities according to how much the angles of a corresponding regular polygon deviated from the tetrahedral value of 109.5°. Baeyer—Villiger oxidation (Section 17.16): Oxidation of an aldehyde or, more commonly, a ketone with a peroxy acid. The product of Baeyer—Villiger oxidation of a ketone is an ester. Ball-and-stick model (Section 1.10): Type of molecular model in which balls representing atoms are connected by sticks representing bonds. Similar to ball-and-spoke models of Learning By Modeling. Base (Section 4.6): According to the Arrhenius definition, a substance that ionizes in water to produce hydroxide ions. According to the Brønsted—Lowry definition, a substance that accepts a proton from some suitable donor. According to the Lewis definition, an electron-pair donor. Base pair (Section 27.27): Term given to the purine of a nu￾cleotide and its complementary pyrimidine. Adenine (A) is complementary to thymine (T), and guanine (G) is comple￾mentary to cytosine (C). Base peak (Section 13.21): The most intense peak in a mass spectrum. The base peak is assigned a relative intensity of 100, and the intensities of all other peaks are cited as a per￾centage of the base peak. Basicity constant Kb (Section 22.4): A measure of base strength, especially of amines. Kb Bending vibration (Section 13.19): The regular, repetitive mo￾tion of an atom or a group along an arc the radius of which is the bond connecting the atom or group to the rest of the molecule. Bending vibrations are one type of molecular motion that gives rise to a peak in the infrared spectrum. Benedict’s reagent (Section 25.19): A solution containing the citrate complex of CuSO4. It is used to test for the presence of reducing sugars. Benzene (Section 11.1): The most typical aromatic hydrocar￾bon: Benzyl group (Section 11.7): The group C6H5CH2±. H H H H H H [R3NH][HO] [R3N] RCR O X RCOR O X RCOOH O X Benzylic carbon (Section 11.10): A carbon directly attached to a benzene ring. A hydrogen attached to a benzylic carbon is a benzylic hydrogen. A carbocation in which the benzylic carbon is positively charged is a benzylic carbocation. A free radical in which the benzylic carbon bears the unpaired electron is a benzylic radical. Benzyne (Section 23.8): The compound Benzyne is formed as a reactive intermediate in the reaction of aryl halides with very strong bases such as potassium amide. Bile acids (Section 26.13): Steroid derivatives biosynthesized in the liver that aid digestion by emulsifying fats. Bimolecular (Section 4.7): A process in which two particles re￾act in the same elementary step. Biological isoprene unit (Section 26.8): Isopentenyl pyrophos￾phate, the biological precursor to terpenes and steroids: Birch reduction (Section 11.11): Reduction of an aromatic ring to a 1,4-cyclohexadiene on treatment with a group I metal (Li, Na, K) and an alcohol in liquid ammonia. Boat conformation (Section 3.5): An unstable conformation of cyclohexane, depicted as bond (Section 1.17): In alkenes, a bond formed by overlap of p orbitals in a side-by-side manner. A bond is weaker than a  bond. The carbon—carbon double bond in alkenes con￾sists of two sp2 -hybridized carbons joined by a  bond and a bond.  bond (Section 1.14): A connection between two atoms in which the electron probability distribution has rotational symmetry along the internuclear axis. A cross section per￾pendicular to the internuclear axis is a circle. Bond dissociation energy (Section 1.3): For a substance A:B, the energy required to break the bond between A and B so that each retains one of the electrons in the bond. Table 4.3 (Section 4.17) gives bond dissociation energies for some representative compounds. Bonding orbital (Section 1.14): An orbital in a molecule in which an electron is more stable than when localized on an isolated atom. All the bonding orbitals are normally doubly occupied in stable neutral molecules. OPP H H H H

G-5 GLOSSARY ond-line formula (Section 1.7): Formula in which connec- Carboxylate ion( Section 19.5): The conjugate base of a car tions between carbons are shown but individual carbons boxylic acid, an ion of the type RCO2 and hydrogens are not The bond-line formula Carboxylation (Section 19. 11): In the preparation of a car- boxylic acid, the reaction of a carbanion with carbon diox ide. Typically, the carb RMgX RCOH presents the compound (CH3)2 CHCH,CH3 undary surface(Section 1. 1 ) The surface that encloses the Carboxylic acid(Sections 2.3 and 19.1): Compound of the typ region where the probability of finding an electron is high (90-95%) Branched-chain carbohydrate (Section 25.12): Carbohydrate RCOH. also written as RCO, H. which the main carbon chain bears a carbon su Carboxylic acid derivative (Section 20. 1): Compound that in place of a hydrogen or hydroxyl gre yields a carboxylic acid on hydrolysis. Carboxylic acid de- romohydrin( Section 6.17): A halohydrin in which the halo- rivatives include acyl chlorides, anhydrides, esters, and gen is bromine(see halohydrin) amides Bromonium ion(Section 6.16): A halonium ion in which the Carotenoids (Section 26. 16): Naturally occurring tetrater halogen is bromine(see halonium ion). peroid plant pigments Bronsted acid See acid Cation (Section 1.2): Positively charged ion. Bronsted base see base Cellobiose (Section 25. 14): A disaccharide in which two glu Buckminsterfullerene(Chapter 11, box, "Carbon Clusters cose units are joined by a B(1, 4)linkage Cellobiose is ob Fullerenes, and Nanotubes"): Name given to the Cso cluster tained by the hydrolysis of cellulose. with structure resembling the geodesic domes of R. Buck- Cellulose(Section 25. 15): A polysaccharide in which thou- Ister Fuller. see front cover sands of glucose units are joined by B(1, 4) linkages. n-Butan (Section 2.5): Common name for butane Center of symmetry(Section 7.3): A point in the center of a CHaCHCh,cH structure located so that a line drawn from it to any element n-Butyl group(Section 2.10): The group CHa CH, CH, CH2-. of the structure, when extended an equal distance in the op sec-Butyl group (Section 2.10): The group posite direction, encounters an identical element. Benzene, for example, has a center of symmetry CH3CH_CHCH3 Chain reaction(Section 4. 18): Reaction mechanism in which a sequence of individual steps repeats itself many times, usu- tert-Butyl group(Section 2.10): The group(CH3)3C- ally because a reactive intermediate consumed in one step regenerated in a subsequent step. The halogenation of alkanes is a chain reaction proceeding via free-radical Cahn-ngold-Prelog notation(Section 7.6): System for spec- intermediates ifying absolute configuration as R or S on the basis of the Chair conformation (Section 3.5 ): The most stable conforma- order in which atoms or groups are attached to a stereogenic center. Groups are ranked in order of precedence according to rules based on atomic number Carbamate(Section 20. 17): An ester of carbamic acid Carbanion(Section 9.5): Anion in which the negative charge is Chemical shift (Section 13.4): A measure of how shielded the borne by carbon. An example is acetylide ion. Carbene(Section 14. 13): A neutral species in which one of the have different chemical shifts. and nuclei of the same atom carbon atoms is associated with six valence electrons have chemical shifts that are sensitive to their molecular Carbinolamine (Section 17.10): Compound of the type environment. In proton and carbon-13 NMR, chemica shifts are cited as 8, or parts per million(ppm), from the hy drogens or carbons, respectively, of tetramethylsilane HO-C-NR, Chiral(Section 7. 1): Term describing an object that is not su- perposable on its mirror image. Carbinolamines are formed by nucleophilic addition of an Chiral carbon atom ( Section 7. 2): a carbon that is bonded to amine to a carbonyl group and are intermediates in the for- four groups, all of which are different from one another. mation of imines and enamines Also called an asymmetric carbon atom. A more modern term Is stereogenIc center Carbocation (Section 4.9): Positive ion in which the charge re- Chiral center(Section 7.2): See stereogenic center sides on carbon. An example is tert-butyl cation, (CH3)C Carbocations are unstable species that, though they cannot Chlorohydrin(Section 6.17): A halohydrin in which the halo- normally be isolated, are believed to be intermediates in gen is chlorine(see halohydrin certain reactions Forward Main Menu TOC Study Guide Toc Student OLCMHHE Website

G-5 GLOSSARY Bond-line formula (Section 1.7): Formula in which connec￾tions between carbons are shown but individual carbons and hydrogens are not. The bond-line formula represents the compound (CH3)2CHCH2CH3. Boundary surface (Section 1.1): The surface that encloses the region where the probability of finding an electron is high (90—95%). Branched-chain carbohydrate (Section 25.12): Carbohydrate in which the main carbon chain bears a carbon substituent in place of a hydrogen or hydroxyl group. Bromohydrin (Section 6.17): A halohydrin in which the halo￾gen is bromine (see halohydrin). Bromonium ion (Section 6.16): A halonium ion in which the halogen is bromine (see halonium ion). Brønsted acid See acid. Brønsted base See base. Buckminsterfullerene (Chapter 11, box, “Carbon Clusters, Fullerenes, and Nanotubes”): Name given to the C60 cluster with structure resembling the geodesic domes of R. Buck￾minster Fuller; see front cover. n-Butane (Section 2.5): Common name for butane CH3CH2CH2CH3. n-Butyl group (Section 2.10): The group CH3CH2CH2CH2±. sec-Butyl group (Section 2.10): The group tert-Butyl group (Section 2.10): The group (CH3)3C±. Cahn—Ingold—Prelog notation (Section 7.6): System for spec￾ifying absolute configuration as R or S on the basis of the order in which atoms or groups are attached to a stereogenic center. Groups are ranked in order of precedence according to rules based on atomic number. Carbamate (Section 20.17): An ester of carbamic acid (H2NCO2H); a compound of the type H2NCO2R. Carbanion (Section 9.5): Anion in which the negative charge is borne by carbon. An example is acetylide ion. Carbene (Section 14.13): A neutral species in which one of the carbon atoms is associated with six valence electrons. Carbinolamine (Section 17.10): Compound of the type Carbinolamines are formed by nucleophilic addition of an amine to a carbonyl group and are intermediates in the for￾mation of imines and enamines. Carbocation (Section 4.9): Positive ion in which the charge re￾sides on carbon. An example is tert-butyl cation, (CH3)3C. Carbocations are unstable species that, though they cannot normally be isolated, are believed to be intermediates in certain reactions. W W HO±C±NR2 CH3CH2CHCH3 W Carboxylate ion (Section 19.5): The conjugate base of a car￾boxylic acid, an ion of the type RCO2 . Carboxylation (Section 19.11): In the preparation of a car￾boxylic acid, the reaction of a carbanion with carbon diox￾ide. Typically, the carbanion source is a Grignard reagent. Carboxylic acid (Sections 2.3 and 19.1): Compound of the type , also written as RCO2H. Carboxylic acid derivative (Section 20.1): Compound that yields a carboxylic acid on hydrolysis. Carboxylic acid de￾rivatives include acyl chlorides, anhydrides, esters, and amides. Carotenoids (Section 26.16): Naturally occurring tetrater￾penoid plant pigments. Cation (Section 1.2): Positively charged ion. Cellobiose (Section 25.14): A disaccharide in which two glu￾cose units are joined by a (1,4) linkage. Cellobiose is ob￾tained by the hydrolysis of cellulose. Cellulose (Section 25.15): A polysaccharide in which thou￾sands of glucose units are joined by (1,4) linkages. Center of symmetry (Section 7.3): A point in the center of a structure located so that a line drawn from it to any element of the structure, when extended an equal distance in the op￾posite direction, encounters an identical element. Benzene, for example, has a center of symmetry. Chain reaction (Section 4.18): Reaction mechanism in which a sequence of individual steps repeats itself many times, usu￾ally because a reactive intermediate consumed in one step is regenerated in a subsequent step. The halogenation of alkanes is a chain reaction proceeding via free-radical intermediates. Chair conformation (Section 3.5): The most stable conforma￾tion of cyclohexane: Chemical shift (Section 13.4): A measure of how shielded the nucleus of a particular atom is. Nuclei of different atoms have different chemical shifts, and nuclei of the same atom have chemical shifts that are sensitive to their molecular environment. In proton and carbon-13 NMR, chemical shifts are cited as , or parts per million (ppm), from the hy￾drogens or carbons, respectively, of tetramethylsilane. Chiral (Section 7.1): Term describing an object that is not su￾perposable on its mirror image. Chiral carbon atom (Section 7.2): A carbon that is bonded to four groups, all of which are different from one another. Also called an asymmetric carbon atom. A more modern term is stereogenic center. Chiral center (Section 7.2): See stereogenic center. Chlorohydrin (Section 6.17): A halohydrin in which the halo￾gen is chlorine (see halohydrin). RCOH O X RMgX RCO2H 1. CO2 2. H3O