Organic Chemistry Introduction Functional Groups Alkanes Alkenes Alkynes Alcohols Acids, Esters and Amides Introduction Organic chemistry is the study of carbon- containing compounds The field of organic chemistry is very important for a wide variety of reasons. A huge number of carbon-containing compounds are known. Most of the advances in the pharmaceutical industry are based on a knowledge of organic chemistry. Life as we know it is based on organic chemistry. Introduction Most organic compounds have a “skeleton” that is composed of C-C bonds. The C-C bonds may be single bonds, double bonds, or triple bonds. Carbon forms a total of 4 bonds. The “skeleton” of an organic compound has H’s attached to it. other “heteroatoms” like O, halogens, N, S, and P may be present as well H O Introduction C C O H H H O H C C O H Some familiar organic compounds: H H H H C H H H H H H C C C H H H H propane methane H O H H C C H acetylene H C C H C H H acetone Introduction Some familiar organic compounds: H O H C C O H H Acetic acid H H H C C O H H H Ethyl alcohol H H H H H C C O C C H O H H H “ether” C OH aspirin O C CH3 O H Introduction Organic compounds are commonly classified and named based on the type of functional group present. An atom or group of atoms that influences the way the molecule functions, reacts or behaves. The center of reactivity in an organic compound Functional Groups On your exam, you will be responsible for recognizing and naming the various common functional groups that are found in organic compounds: Use Table 25.4 and the following slides to help you study Functional Groups Class of Compound Functional Group Alkane None Cycloalkane None Alkyl halide C X Alkene C C Alkyne C C Alcohol C OH Ether C O C Functional Groups Class of Compound Aldehyde Ketone Carboxylic Acid Ester Functional Group O C C H O C C O C O OH C O C Functional Groups Class of Compound Amine Amide Nitrile Aromatic ring Functional Group C N O C N C R R' R R' N Alkanes Contain C-C single bonds no functional group Tetrahedral electron domain geometry H H H C C H sp3 H H H C H HH hybridized carbonsH H H H C C H H C C C H H H H H H H C 3C CH CH CH 2 3 H H H H H H H H H H HCH CH H C C C HC H H C HC C H H H H H H H H H CH3CH2CH3 CH CH CH CH CH CH 3 2 3 3 2 3 CC C H around single bonds Free rotation H H H H C C H H H propane Cycloalkanes Contain C – C with at least 3 of the carbons arranged in a cyclic (ring) structure No functional group Tetrahedral sp3 hybrid orbitals CH2CH2CHCH2CH3 H H H H c c c c H H H c H H H Alkyl Halides H H H CH2=CHCH3 H H H H H C H H C C C H Contain C-halogen bondH H H HC F, Cl, Br, or I H CH2=CHCH3 CH2=CHCH3 C C H C H H H H H C C H H H H C C C HH C C C C H H Br H H H Br H H H C H H H CH C HC C C H H C H H Br H H CH3CH(Br)CH2CH3 CH3CH(Br)CH2CH3 CH3CH(Br)CH2CH3 Br Br Br Alkenes H Contain C=C (carbon-carbon HH H double bonds) 1 sigma bond & 1 pi bond H H sp2 hybridized carbons C C H CC CC HH H CH H 3 C CH 3 H H CH2=CHCH3 Trigonal planar geometry Which atoms must be coplanar in an alkene? C H CH2=CHCH3 C H H C H H CH2=CHCH3 1-propene Alkenes The C=C present in an alkene is composed of 1 sigma (s) bond and 1 pi (p) bond. H H H C C ethylene H Double bonds are rigid and cannot rotate freely. Rotation would cause loss of overlap of the p orbitals, destroying the p bond. Alkynes C C H C C CHH3 H H Contain C CH triple bondsH C 1 sigma bond H 2 pi bonds Linear electron domain C3 CH2=CHCH H H geometry C H C C H H C H H C C C H H H CH2=CHCH3 H C C sp hybridized carbons H H H H C C C C H C H C C C H HC CH3 H atoms must Which H co-linear in an C CbeH H HC alkyne? C H C H C H C Ph H Aromatic Ring H H H Planar ring system with alternating single and double bonds does not react like an alkene CH CHCH 3 Trigonal planar H C CC C C H CCH3CHCH3 CC H H H C benzene C C HC H C C H C C C Ph H C C H C C H C C H H 3 H CH3CHCH3 C CH3CHCH3 C C Ph sp2 hybridized carbons C Benzene ring is a very common Ph aromatic ring. CH C C C C C C C H C H C H Ph C C H C C H N H .. N pyridine H H C C Functional Groups Alkanes are often called saturated hydrocarbons Organic compounds composed of carbon and hydrogen that contain the largest possible number of hydrogen atoms per carbon atom. Alkenes, alkynes, and aromatic hydrocarbons are called unsaturated hydrocarbons Organic compounds composed of carbon and hydrogen that contain less hydrogen than an alkane having the same number of carbon atoms Alcohols CH3CH(OH)CH2CH(CH3)2 CH3CH(OH)CH2CH(CH H Contain C-O-H bond hydroxyl group H Alcohols form hydrogen H bonds. H O C C H H C H H H H C C C H H H C C H OH H CH CC H H HH H H CH(CH C H) OH CH CH(OH)CH H How does hydrogen bonding H 3 affect boiling point??? Amphoteric H 2 H H OH H O H H H C C C C C 3 2 H Ethers H CH3CH(OH)CH2CH(CH3)2 O Contain bond H C C C-O-C H H H H C O C H H H H C C H H CH3CH2OCH2CH O C C H (CH CH )O tetrahedral e.d. geometry H 3 2 2 H H H H H H H CH(CH ) H CH3CH(OH)CH 2 3 2) CH3CH(OH)CH CH(CH 2 3 2 CH3CHO H C C O C C H O HH HH CH2OCH2CH3 3 H CH H H H CH CH2OCH2CH3 H H 3 H H C H bent C HH H O H C C H HH H H H C C H molecular C OOHC C H H C geo. H H H H H H H H H C C O OH (CH3CH2)2O (CH3CH2)2O O Amines Contain C-N-R H H H C H H HH H HH H H H H H H H H H H H C C C H CHC NHC CC HH C C H H H CC C C C C C CC CN NC C H H H H R’ R and R’ can be H or C H H H HH HH H HH H H H H H HH HH HH H H CH CH2CH2CH2CH CH3CH2CH2CH2CH NHCH 2 3 3 CH CH CH NHCH CH CH CHCH CHCH CH NHCH 22 2 3 3 3 2 2 2 2 2 3 Primary and secondary amines form hydrogen bonds. Common organic bases lone pair of e- on N CH3NH2 o 1 primary H HH N NN CH3NHCH3 o 2 secondary H N (CH3)3N o 3 tertiary Aldehydes H HO O O Contain C - H (-CHO) H H Carbonyl (C=O) always on the 1st or last carbon in a chain C C H H H H O O H H C H CH CHO CHCH CHO CHO 3 3 CH3CHO O O trigonal planar geometry H O sp2 hybrid orbitals H H HC C C C H H O H H C C H C H H Ketones H Contain C-C-C Carbonyl attached to middle of chain CH3C(O)CH3 H e.d. O H geo. Trigonal planar C O C C H O H H C H sp2 hybridized C CH3CHO C H H H CH3CHO H CH3C(O)CH3 C H H H C H O H C C H O C H O C H H HH H 3C(O)CH3 CH CH H 3CHO C C O O H HH H H O H H C H H C C CHH H C H C H C C H H H H H CH3CHO N N Carboxylic Acids H CH3NH NHCH3 (CH )3NH 3)3N CH2 3NHCH 3 CH3NHCH 3 (CH 2 3 O H H H O C C C o o o o H Contain carboxyl group O O H H 1 2 3 1 2 3 H H H H C C C O H o -CO2-CO H 2H o O C HC C O C H C O H CH3CH2CO2H H H -COOH -COOH H H H H H Form hydrogen bonds trigonal planar sp2 hybridized carbon C CH CHCH COCH H CO H 2 2 CH3CH23CO2H 3 2 2 O OH OH H HO C H HH C O C O OH OH H H C C Esters H C OH O Contain -CO2R where R OOH HH HH HH H O H H H H H H O CO HH C C CC CCC OOH CC C C C H H C C C O C C H H H HH HH H H H H group = alkyl HH HH H H CC H H H H CHCH CHCO COCH CHCH CH3 CH3CH2COCH CH 3CH 2 2 2 3 2 2 2 3 2 2 3 CH3CH2CO2CH CH 2 3 trigonal planar sp2 hybridized O O H H H H H H H O HH H H O H H H C H H O C H H C O C C HOO C C CH C H H C C C H C C H H C C C C C C OH H H H H H HH HHHO H OO H H H -CO2R where R = alkyl group -CORR=where R = alkyl group -CO R where alkyl group Amides H Contain H H O where R and R’H = CH or C CC H H H H H H HH H C H C C O H H H H H CHCH CH2CONHCH CONHCH2CH CH CH 33 2 2 3 3 CH3CH2CONHCH2CH3 hybridized H O N C C H H HHC CH CC CC N C C H H HH HH N C HHC HHH H C=O is trigonal planar & sp2 H O O HH H H NH H H H C H O C H H C H H C C C OO C H H C C CH O HH H C C HH H H H O HH -CO2R where R = alkyl group -CO2R where R = alkyl group H O H H H C H O C H C C Nitriles C C C N C C H H O HH H H H H H Contain H O O O Linear 2CH3 CH2 CONHCH H 3 CH3CNH2 CH3CNHCH3 CH3CN(CH3)2 N sp hybridized C o o o 1 2 3 H O HH H C H O C C H CC C N N CH3CN H O HHH O O H H CH3 H Functional Groups Example: Identify the functional groups present in the following compounds. OH I I HO O I I thyroxine NH2 CH2CHCOOH O testosterone NH Functional Groups HO2C Identify the functional groups in the N Example: following compounds. H NH2 O C HO2C N N H H O Lisinopril C O OH OH OCH3 Vanillin N O C O Depicting Structures of Organic Compounds Organic compounds can be depicted using a variety of formulas: Empirical formula Molecular formula Lewis structure Full structural formula Three dimensional drawings Condensed structural formula Line angle drawings Depicting Structures of Organic Compounds Ethyl acetate is an organic molecule with: empirical formula = C2H4O molecular formula = C4H8O2 Depicting Structures of Organic Compounds Ethyl acetate is an organic molecule with: Lewis structure: . .. . H O depicts all covalent bonds using H a straight line and shows all nonbonding pairs of electrons C H . . Full structural formula: a Lewis structure without the nonbonding electrons C .. O .. H H C C H H H .. .. H O C C H H O H H C C H H H Depicting Structures of Organic Compounds . .. Ethyl acetate is .an organic .. molecule with: 3-d drawing:H . . H H O O H O H HH C.. C HO C C CH H .. H C H C C H OH H H H H H Condensed C C H formula H C C Ostructural H H H CH3CO2CH2CH3 Line angle drawing CH3CO2CH2CH3 O .. O Alkanes Some of the simplest alkanes: Condensed Formula CH4 Name methane CH3CH3 ethane CH3CH2CH3 propane CH3CH2CH2CH3 butane CH3CH2CH2CH2CH3 pentane You must know these!!! Alkanes Some of the simplest alkanes: Condensed Formula Name CH3CH2CH2CH2CH2CH3 hexane CH3CH2CH2CH2CH2CH2CH3 heptane CH3CH2CH2CH2CH2CH2CH2CH3 octane CH3CH2CH2CH2CH2CH2CH2CH2CH3 nonane CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3 decane You must know these!!! Alkanes The previous alkanes are also called straight- chain hydrocarbons: all of the carbon atoms are joined in a continuous chain Alkanes containing 4 or more carbons can also form branched-chain hydrocarbons (branched hydrocarbons) some of the carbon atoms form a “branch” or side-chain off of the main chain Alkanes An example of a straight chain hydrocarbon: C5H12 CH3CH2CH2CH2CH3 pentane Examples of a branched hydrocarbon: C5H12 CH3CHCH2CH3 CH3 2-methylbutane CH3 CH3CCH3 CH3 2,2-dimethylpropane Alkanes The three structures shown previously for C5H12 are structural isomers: compounds with the same molecular formula but different bonding arrangements Structural isomers generally have different properties: different melting points different boiling points often different chemical reactivity Alkanes Organic compounds can be named either using common names or IUPAC names. You must be able to name alkanes, alkenes, alkynes, and alcohols with 10 or fewer carbons in the main chain using the IUPAC naming system. Alkanes Alkane Nomenclature: Find the longest continuous chain of carbon atoms and use the name of the chain for the base name of the compound: longest chain may not always be written in a straight line 1 CH3 -2 CH - CH3 3 CH2 - CH2 - CH2 - CH3 4 5 6 Base name: hexane Alkanes Alkane Nomenclature: Number the carbon atoms in the longest chain beginning with the end of the chain closest to a substituent groups attached to the main chain that have taken the place of a hydrogen atom on the main chain 1 A substituent CH3 -2 CH - CH3 3 CH2 - CH2 - CH2 - CH3 4 5 6 Alkanes Alkane Nomenclature: Name and give the location of each substituent group A substituent group that is formed by removing an H atom from an alkane is called an alkyl group: Name alkyl groups by dropping the “ane” ending of the parent alkane and adding “yl” Alkanes Alkane Nomenclature: Common alkyl groups (substituents): CH3 CH3CH2 CH3CH2CH2 CH3CH2CH2CH2 1 methyl ethyl propyl butyl Know these! CH3 -2 CH - CH3 3 CH2 - CH2 - CH2 - CH3 4 5 6 2-methylhexane Alkanes Alkane Nomenclature: Halogen atoms are another common class of substituents. Name halogen substituents as “halo”: Cl chloro Br bromo I iodo F fluoro Alkanes Alkane Nomenclature: When two or more substituents are present, list them in alphabetical order: Butyl vs. ethyl vs. methyl vs. propyl When more than one of the same substituent is present (i.e. two methyl groups), use prefixes to indicate the number: Di = two Tri = three Know these. Tetra = four Penta = five Alkanes Example: Name the following compounds: CH3CH2CHCH2CH3 CH3 CH2CH2CH3 CH3CHCHCH3 CH3 Alkanes Example: Name the following compounds: CH3CH2CHCH3 CH2CH2Br CH2CH2CH3 CH3CHCHCH3 Cl Alkanes You must also be able to write the structure of an alkane when given the IUPAC name. To do so: Identify the main chain and draw the carbons in it Identify the substituents (type and #) and attach them to the appropriate carbon atoms on the main chain. Add hydrogen atoms to the carbons to make a total of 4 bonds to each carbon Alkanes Example: Write the condensed structure for the following compounds: 3, 3-dimethylpentane 3-ethyl-2-methylhexane 2-methyl-4-propyloctane 1, 2-dichloro-3-methylheptane Alkenes Alkenes: unsaturated hydrocarbons that contain a C=C double bond Alkene Nomenclature: Names of alkenes are based on the longest continuous chain of carbon atoms that contains the double bond. Alkenes Alkene Nomenclature Find the longest continuous carbon chain containing the double bond. Change the “ane” ending from the corresponding alkane to “ene” butane butene propane propene octane octene Alkenes Alkene Nomenclature Indicate the location of the double bond using a prefix number designate the carbon atom that is part of the double bond AND nearest to the end of the chain Name all other substituents in a manner similar to the alkanes. Use a prefix to indicate the geometric isomer present, if necessary. Alkenes Alkene Nomenclature Different geometric isomers are possible for many alkenes. Compounds that have the same molecular formula and the same groups bonded to each other, but different spatial arrangements of the groups cis isomer trans isomer Alkenes Alkene Nomenclature Cis isomer: two identical groups (on adjacent carbons) on the same side of the C = C double bond Trans isomer: two identical groups (on adjacent carbons) on opposite sides of the C = C double bond Alkene CH3 CH3 CH3 C=C H H C=C H cis-2-butene H CH3 trans-2-butene Alkene For an alkene with the general formula A P C=C B Q cis and trans isomers are possible only if A = B and P=Q Alkene Example: Name the following alkenes: CH3CH2 H C = C CH3CH2 CH3CHCH2 CH3 H H C = C H CH2CH3 Alkenes Example: Draw the structures for the following compounds: 2-chloro-3-methyl-2-butene trans-3, 4-dimethyl-2-pentene cis-6-methyl-3-heptene Alkynes Alkynes: unsaturated hydrocarbons that contain a C C triple bond Alkyne Nomenclature: Identify the longest continuous chain containing the triple bond To find the base name, change the ending of the corresponding alkane from “ane” to “yne” Alkynes Alkyne Nomenclature: Use a number to designate the position of the triple bond number from the end of the chain closest to the triple bond just like with alkenes Name substituents like you do with alkanes and alkenes Alkynes Example: Name the following compounds: CH3CH2C CCHCH3 CH2CH3 ClCH2CH2C CH Alkynes Example: Draw the following alkynes. 4-chloro-2-pentyne 3-propyl-1-hexyne