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Chapter 12 Functional Groups II and Nomenclature II. Functional group = “a group of atoms where the reaction takes place”. 12.1 Aromatic Hydrocarbons: arenes Complete definition of aromatic compound: Ch 16 Aromatic = 향기로운 , 향기높은
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Chapter 12 Functional Groups II and Nomenclature II Functional group = “a group of atoms where the reaction takes place” OrgChem-Chap12
12.1 Aromatic Hydrocarbons: arenes Complete definition of aromatic compound: Ch 16 Aromatic = 향기로운, 향기높은 strong odor & unusually stable (because of the conjugated p orbitals) non-polar, high mp, wide occurrence in nature Basic nomenclature 1. parent name: benzene, toluene, naphthalene etc. Very stable isolated very early days of organic chemistry before the systematic names are made Toluene Not methylbenzene Naphthalene Benzene Not cyclohexatriene OrgChem-Chap12
2. The ring is numbered in the same manner as the ring of cyclohexane • No number is needed if only one group is attached to the ring • For rings with multiple substituents, begin numbering at one substituent and proceed in the direction that gives the lowest numbers to the remaining 4-butyl-1-ethyl-2-isopropylbenzene 3. disubstituted: o-, m-, p- or numbering (1,2-, 1,3-, 1,4-) ortho-, o- meta-, m- para-, p- OrgChem-Chap12
p-dimethybenzene or 1,4- dimethybenzene Common name = p-xyrene m-propyltoluene or 3-propyltoluene 4. as substituents: phenyl (Ph), benzyl (Bn), tolyl phenyl benzyl Example biphenyl OrgChem-Chap12
Physical properties of benzene melting point boiling point (oC) Benzene 5.5 80 Cyclohexane 6.5 80 Hexane -94 69 Symmetric shape gives higher melting temp. Interaction between the molecules determine the boiling point Reactivity of benzene lower than alkene R-CH=CH-R + Cl2 R-CHCl-CHCl-R Benzene + Cl2 No rxn + Cl2 + AlCl3 (Lewis acid) Chlorobenzene + HCl Cl2 + AlCl3 = Cl+ -AlCl4 More electrophilic OrgChem-Chap12
Conjugated p orbitals very stable • found in a wide variety of natural source • Ex) • 1) Benzene 1825 Michael Faraday • Oil residue condensed from gas • To light the street lamps of London • 2) Estrone: femaile sex hormone ( 469) • 3) benzo[a]pyrene carcinogen • After smoking, burned food OrgChem-Chap12
Application of benzene obtained from cracking • 1) Solvent • 2) Production of styrene Polystyrene • 3) o-Xyrene, p-xyrene, toluene, cumene (isopropyl benzene); solvent Focus On: 469, structure proof for dibromobenzene practice: 468, Problem 12.1 & 12.2 OrgChem-Chap12
12.2 Phenols Having a hydroxy group bonded directly onto an aromatic ring 3 x 109 lbs/yr: large production Application; disinfectant, bisphenol A (polymer) Stronger acid (pKa 10) than alcohols (16) Problem 11.5 practice: 472-3, Problem 11.3 ~ 11.6 OrgChem-Chap12
Parent name: phenol or other common names phloroglucinol phenol catechol m-chlorophenol p-methylphenol p-cresol OrgChem-Chap12
12.3 Aldehydes & Ketones carbonyl group Carbon-oxygen double bond acetaldehyde acetone benzaldehyde acetophenone Aldehyde: one hydrogen atom bonded to the carbonyl group Ketone: both of the atoms bonded to the carbonyl group must be carbons Nomenclature: the longest chain with the carbonyl group alkanal / alkanone: 474 & 475 ethanal or acetaldehyde from acetic acid 4-bromohexanal 4-ethyl-4-pentanal (double bond must be part of a root chain) OrgChem-Chap12
Benzaldehyde derived from benzoic acid 2-methylcyclopentanecarboxaldehyde acetone (common) or 2-propanone 4-methyl-4-hexen-2-one or 4-methylhex-4-en-2-one 5-methyl-2-cyclohexen-1-one (ketone have the priority, double bond have lower #) 1,3-cyclohexendione OrgChem-Chap12
Properties of aldehyde polarity: alcohol > aldehyde > ether (boiling point is in the same order) H-bonding No H-bonding See 45 acidic a-carbon: pKa 20 aldehyde can be oxidized to carboxylic acid, while ketone cannot (see 381, why? Study in ch 19). OrgChem-Chap12
Application of aldehyde and ketones 476-7 pleasant odors perfumes and flavoring • 1) citral: lemon odor found in lemon and orange • 2) cinnamaldehyde: strong cinnamon odor found in cinnamon • 3) vanillin: vanilla odor, component of natural vanilla • 4) camphor: from camphor tree liniments and inhalants (감염,통증,가려움증 완화) • 5) Muscone : from musk (사향) OrgChem-Chap12
12.4 Carboxylic Acids: RCO2H carbonyl (C=O) + hydroxy (OH) Root with the carboxyl group at one end with the suffix –oic acid is added 5-phenylhexanoicacid 3-butynoicacid 2-chlorocyclopentanecarboxylicacid Cyclic compounds with the carboxy group attached to the ring use the name of the ring with the suffix- carboxylic acid benzoic acid OrgChem-Chap12
carboxyl group malonic acid terephthalic acid phenylacetic acid • Natural carboxylic acid • Ant (Latin: fomica) formic acid HCO2H • Vinegar (Latin: acetum acetic acid CH3CO2H • Butter (Latin: butyrum) butyric acid CH3(CH2)2CO2H, from rancid butter Properties more polar & hydrogen bonding: high mp & bp acidic proton: pKa 5 AcOH ( 3 x 109 lbs/yr), aspirin, ibuprofen(항염증제): 479 OrgChem-Chap12
12.5 Carboxylic Acid Derivatives (I): RCO-Y • parent name: alkan(o)ic acid OrgChem-Chap12
acryloyl chloride succinic anhydride ethyl acetate N,N-dimethylformamide acetonitrile monosodium glutamate (MSG) • practice: 483, Problem 12.14~15 OrgChem-Chap12
Acid chloride Acetic acid Acetyl chloride Ethanoic acid Ethanoic chloride ----ic acid ---yl chloride 2-butenoyl chloride Acid anhydride Loss of water Acetic anhydride Ethanoic anhydride ---ic anhydride + Benzoic anhydride benzoic acid OrgChem-Chap12
Ester ----yl---ate Alcohol Carboxylic acid Propyl benzoate propanol + benzoic acid (2-methylbutyl) 3-methyl-1-cyclohexanecarboxylate 2-methylbutanol + 3-methyl-1-cyclohexanecarboxylic acid OrgChem-Chap12
Amide Primary amide Secondary amide Tertiary amide ----e ---amide Pentane pentanamide N-ethyl-4-methyl-2,5-hexdienamide --ic acid, --oic aicd ---amide N,N-dimethylformaide (DMF) N,N-dimethylacetamide (DMAc) OrgChem-Chap12
Nitrile or cyano group +NH3 -H2O -H2O 1) 3-pentynenitrile ---- ---nitrile ----oic acid ----ic acid ---nitrile Benzonitrile benzoic acid 2) Complex compound cyano Methyl 4-cyanobenzoate (priority) see p. 490 table 11.3 OrgChem-Chap12
Carboxylate salt carboxylate anion + cation --ic acid cation ---ate Sodium acetate Ammonium 3-methylbenzoate characteristics: mp & bp Polarity , bp & mp interaction Order: HC < ether < ester < aldehyde < ketone < alcohol < carboxylic acid < amide H-bonding amides: charged resonance structure very polar, highest mp and bp OrgChem-Chap12
Acid halide, acid anhydride, and nitrile rare in nature too reactive with water Ester and amide abundant in nature relatively stable 485-6 Ester; pleasant order of fruit and flower isopentyl acetate (CH3CO2CH2CH2CH(CH3)2 : banana odor methyl butanoate (CH3CH2CH2CO2CH3): rum (liquor), 당밀, 사탕수수를 발 효 시킨 액체 향 fat: ester glycerol + octadecanoic acid (= stearic acid) 485 Amide; physiological activity acetaminophen: pain reliever diethylamide of lysergic acid: hallucinigen (환각제) DMF and DMAc: aprotic polar sovent no acidic proton but very polar even some salts can be dissoved OrgChem-Chap12
Elaboration: fragrance & flavor, 486~7 • hydrolysis of ester & oxidation of aldehydes Carboxylic acid Ester, aldehyde, ketone: pleasant odor major component of natural scent and flavors isopentenyl acetate: juicy fruit gum ethyl phenylacetate: honey benzyl acetate + -pentylciccamaldehyde: jasmine butanal: buttery Acid: undesirable odor major component of natural scent and flavors butanoic acid: rancid butter hexanoic acid (=caproic acid): smell of goat 2-methylpropanoic acid: component of sweat OrgChem-Chap12
12.6 Sulfur and phosphorus Compound Sulfur • directly beneath oxygen in the periodic table similar to oxygen • d-orbital: six bonds are possible • RSH: thiols (mercaptans); alkanethiol CH3CH(CH3)CH2CH2-SH: 3-methyl-1-butanethiol stinky odor, stronger acid, better nucleophile • R-S-R’: sulfides; alkylalkyl sulfide (CH3-S-CH3: dimethyl sulfide) OrgChem-Chap12
sulfoxides & sulfones: DMSO & dimethyl sulfoxide sulfonic acids: strong organic acid, • derivatives: similar to those of carboxylic acids OrgChem-Chap12
Phosphorus: P NH3: amine nitrogen PH3:phosphine phosphorus PH3 phosphine phosphate • phosphoric acid (H3PO4) triphenyl phosphine: PPh3 Dialkyl hydrogen phosphate PH3: phosphine, a toxic gas with bad odor PPh3: good nucleophile & transition metal ligand (RO)2P(O)OH: phosphate, backbone for RNA/DNA phosphatidylcholine: constituent of membranes practice: 491 Problem 12.17~18 OrgChem-Chap12
12.7 Nomenclature of Compounds with Several Functional Groups CC-OH :–ynol C=C-C=C-CO- : dienone priority 492 Table 12.3, next page High priority, in the suffix 5-hydroxy-3-hexanone O Ethyl 3-oxobutanoate 3-cyano-6-hydroxy-4-pentenal OrgChem-Chap12
Common name: often more convenient for very complicated compounds, 494 OrgChem-Chap12