Chem 1152: Exam 2 Review Naming Compounds

Rules for naming alcohols For single hydroxy (-OH) group Step 1: Identify longest chain that includes (-OH) group. Drop –e from hydrocarbon name, and replace with ending –ol. Step 2: Number this parent chain to give lowest number to carbon with attached (-OH) group. Step 3: Locate position of (-OH) group. Step 4: Locate and name all branches attached to parent chain. Step 5: Include names of all branches (still in alphabetical order) in prefix of compound name. Include location of (-OH) group. Note: Multiple (-OH) groups are named by addiing diol, triol, etc, to end of alkane without removing -e. 1 2 3 4 2 5 1 4 3 2-ethyl-1-pentanol 2-methyl-1,4-butanediol

Naming Alcohols 2,2,4-trimethyl-3-hexanol 5-bromo-3-ethyl-1-pentanol 1,2,4-hexanetriol 3-butyl-2,4-hexanediol 2,2-dimethylcyclopentanol 3-methyl-3-pentanol 1,2-cyclohexanediol 2-isopropyl-1-methylcyclopropanol 3-phenyl-1-propanol

Ethers Ether: Oxygen with carbon attached on either side. Naming ethers Common Names Name the two groups attached to the oxygen then add the word ether If both groups the same, can be named with prefix di-. IUPAC Names O-R group is alkoxy. The –yl ending of smaller R group is replaced by –oxy. butyl methyl ether 1-methoxybutane isopropyl propyl ether 1-isopropoxypropane p-methoxytoluene ethyl propyl ether 1-ethoxypropane dipropyl ether 2-methoxy-3,4-dimethylhexane 2-chloro-1-isopropoxypropane 1-propoxypropane

2-methyl-3-hexanethiol Thiols Thiols: Sulfur analogs of alcohols (-SH instead of –OH) Chemically- similar (i.e., form similar compounds) More volatile (lower BP) than alcohols but less water-soluble Thiols stink! This is how skunks defend themselves Chopped onions emit propanethiol Thiols found in garlic Ethanethiol added to natural gas (methane) so you can smell a leak IUPAC Names for simple thiols The –SH group is a sulfhydryl group. Follow the same steps for naming as you do for alcohols, but do not modify alkane ending; instead add –thiol to end of parent. butanethiol 2-butanethiol 2-methyl-3-hexanethiol

Naming Aldehydes pentanal 5-chloropentanal 5-chloro-4-ethylpentanal 2-ethylbutanal 3,4-dimethylhexanal 5-chloro-2-methylbenzaldehyde m-chloro-benzaldehyde 5-methoxy-2-methylbenzaldehyde

2-fluoro-5-methyl-4-hexanone Naming Ketones 2-pentanone 5-chloro-2-pentanone 1-chloro-3-pentanone 4-ethylcyclohexanone 2-fluoro-5-methyl-4-hexanone Ketone: Carbonyl group with two C attached. Named by replacing –e with –one (IUPAC). Numbered from end closest to carbonyl group

Chem 1152: Exam 2 Review Reactions

Addition reactions to alkenes

Addition reactions to alkenes

Alcohol Dehydration (Elimination Rxn): Alcohol Reactions Alcohol Dehydration (Elimination Rxn): Alcohol Hydration (Addition Rxn)

Alcohol Dehydration to produce alkene Alcohol Dehydration (Elimination Rxn): 2-butene 1-butene This rxn (at 180 °C) generates 2 products: 2-butene and 1-butene. The major product is 2-butene (90%) because both C=C bond carbons are attached to at least one other carbon. The minor product is 1-butene (10%) because only one of the C=C bond carbons is attached to at least one other carbon. The major product in these rxns will always be the one resulting in the highest number of carbon groups bonded to the C=C carbons.

Alcohol Dehydration to produce ether Alcohol Dehydration (Elimination Rxn): alcohol alcohol ether This rxn (at 140 °C) generates an ether and water. This rxn works mainly with primary alcohols. Primary (1°) Hydroxy bearing C is attached to either 0 or 1 other C

Alcohol Oxidation for Primary Alcohol aldehyde Primary alcohol Carboxylic acid Immediate product of oxidation of primary alcohol is aldehyde, which is then readily further oxidized to a carboxylic acid. The aldehyde product may be isolated before further oxidation by maintaining high temp. and boiling aldehyde out of rxn mixture. This is possible because aldehydes do not H-bond like alcohols and carboxylic acids.

Alcohol Oxidation for Secondary and Tertiary Alcohols Secondary alcohol ketone Product of oxidation of secondary alcohol is a ketone, which resists further oxidation. Tertiary alcohol

Multistep Rxns The synthesis of most alcohols may require multiple steps (i.e., to get product X from reactant A, a product (B, C …X) must be created). To solve these problems, work backwards from the final product. Oxidize 2° alcohol to form ketone. Use acid-catalyzed hydration (addition) to form alcohol. The completed series of rxns.

Hydrogenation Rxn – Aldehydes Aldehyde hydrogenation rxn Alcohol oxidation rxn Seager SL, Slabaugh MR, Chemistry for Today: General, Organic and Biochemistry, 7th Edition, 2011

Hydrogenation Rxns – Ketones Ketone hydrogenation rxn Alcohol oxidation rxn Seager SL, Slabaugh MR, Chemistry for Today: General, Organic and Biochemistry, 7th Edition, 2011

Addition of alcohol to aldehydes and ketones Hemiacetal intermediate acetal Hemiketal intermediate ketal Hemiacetal is unstable, hard to isolate. With excess alcohol and an acid catalyst, a stable acetal is formed. Note the bidirectional arrows

Hydrolysis of acetals and ketals aldehyde alcohol ketal ketone alcohol “Cutting by water” is essentially the reverse of the addition of alcohol to either aldehyde or ketone.

Intramolecular addition of alcohols to aldehyde CH2OH 1 6 * H OH H C OH 5 C O 2 H HO C H C C 1 3 4 OH H H C OH 4 C C 3 2 OH H H C OH 5 H OH CH2 OH 6 Intramolecular hemiacetal glucose C1 is hemiacetal carbon. Attached to it you will find: H, OH, OR and R, just like non-cyclical compounds.

Aldehyde Rxns – Testing for Aldehydes Tollens’ Reagent (reacts with all aldehydes) Benedict’s Reagent (reacts with some aldehydes) Benedict’s Reagent reacts with aldehydes that have an alcohol on the adjacent carbon (e.g., glucose) Products include a red precipitate of copper (I) oxide