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CHM 256 Lab Final
| Question | Answer |
|---|---|
| Purpose of the epoxidation lab | To use an epoxidation reaction to synthesize cholesterol epoxide. |
| Epoxide | C-O-C in a ring |
| Reaction of expoxidation lab | MCPBA + cholesterol + OH2Cll2 ---> 3-chlorobenzoic acid + 5a,6a epoxycholestor-3-ol *Stereospecific |
| Why is the epoxidation reaction sterospecific | Because of the alkene configuration preventing free rotation around the pi bond (only form trans -OH) |
| What are two ways to convert an alkene to an epoxide? | 1. MCPBA/CH2Cl2 2. (1)Cl2/H2O, (2)NaOH/H2O |
| Structure of steroids | 4 ringed |
| Principle component in gallstones | cholesterol |
| Estrone | Female sex hormone (C18H22O2) |
| Structural difference between a carboxylic acid and a percarboxylic acid | Percarboxylic acid has an O between the carbon and alcohol substituent |
| Purpose of What's that Smell lab | To synthesize a commercially important fragrance in 2 steps by using (2) a chemoselective reduction reaction and (2) a polymer supported reaction |
| What are the 8 notes of the olefactory spectrum? | musky, fruity, green, marine, floral, spicy, woody, ambery |
| How does the structure for isoeugenol compare to methyl diantilis | The same except one of the -o- groups in methyl diantilis is a -=- in isoeugenol |
| Chemoselectivity vs. Regioselectivity | Chemo - selective reaction of one functional group in the presence of others; Regio-leads to the selective formation of one structural isomer |
| Carbonyl + NaBH4/ethanol ---> | Replace carbonyl with alcohol in ketones & aldehydes; Won't react with esters; Pulls hydrogen off carboxylic acid |
| Carbonyl + LiAlH4 ---> | Replace carbonyl with alcohol (Reduces every carbonyl functional group!) |
| Is methyl diantilis at room temperature liquid or solid? | liquid |
| Use of polymer-supported reagents in organic chemistry has become much more widespread since the "explosive growth" in what field of chemistry? | combinational |
| Who is credited for the invention of Methyl Diantilis and who did her work for? | Paul Ochsner; Givaudan |
| Why would you add sodium bicarbonate to a reaction mixture during work up of a reaction? | To neutralize and separate any acid in the crude product |
| Why would Amberlyst 15 be washed with methanol? | To ensure purification, wash is with a solvent it is not soluble in |
| What is used in industrial preparation of methyl diantilis instead of Amberlyst 15? | Convert the alcohol functional group to an ether using NaHSO4 |
| What range indicates purity due to melting point? | +/- 2 degrees |
| Purpose of Oxidation Aromatic lab | Use an oxidation reaction to convert toluene to benzoic acid; Oxidation = KMno4/heat/H2SO4 |
| What is a benzylic C-H bond? | C-H bond adjacent to the benzene ring (Benzene - RH3) |
| Why do reaction occur preferentially at the benzylic position in aromatic compounds with an alkyl side chain? | Resonance; benzine ring alone is resistant to reaction with reagents that normally attack alkanes |
| What is the brown solid formed as the oxidation of toluene proceeds? | MnO2 |
| What does an aromatic side chain have to have in order to be able to undergo oxidation to produce a carboxylic acid functional group? | benzylic hydrogen |
| What are two aromatic substituents that are unchanged by conditions required to oxidize an alkyl side chain on the aromatic ring? | halogen & nitro substituents |
| Purpose of esterification lab | Synthesize benzocaine from p-aminobenzoic acid via an esterification reaction |
| Zwitterion | An overall neutral molecule that has two separated and opposite formal charges within the molecule |
| Fischer esterification | Conversion of a carboxylic acid and an alcohol to an ester |
| Functional groups present in benzocaine and novocaine (3) | Benzene ring, ester, amine |
| What substance could potentially contaminate dry benzocaine product but wouldn't show up on a TLC plate under UV light? | Na2CO3 |
| What is the function of benzocaine in commercial products? | anesthetic because slight numbing capabilities |
| Purpose of calcium lab | To synthesize a calcium channel blocker by using 3 small organic molecules (benzaldehyde, ethyl acetoacetate, urea) |
| What are calcium channel blockers and how do they function? | Antihypertensives that inhibit movement and binding of calcium ions leading to a relaxing of vascular smooth muscles and reduction of vascular resistance |
| How have we monitored the progress of reactions while they're happening? | TLC |
| What substance is used as the solvent for the Bignelli reaction in the calcium blocker experiment? | ethanol |
| What is the max height at which the solvent should condense during reflux and why? | Halfway up the condenser or all of the solvent may not run back into the reaction flask |
| Purpose of aldol lab | Determine whether or not the temperature affects the reaction pathway for a "green" aldol reaction |
| In the aldol lab which product was heated and which was at room temperature? | Heated: condensation product (double bond); Room temp: aldol product (-OH) |
| Why must samples of 2-acetylpyridine be kept in a hood? | It can cause respiratory tract infection if inhaled via gases and is flammable |
| What species are involved in the key C-C bond forming step of an acid-catalyzed aldol reaction? | enolate C woul dact as a base |
| What is the difference between aldol addition and aldol condensation | Aldol addition --> -OH; -H20 aldol condensation --> C=C |
| 4 reactions that form C-C bonds | aldol, grignard, biginelli, wittig |
| Crossed aldol reaction | Two different carbonyl compounds react |
| _________ carbonyl containing compounds would not undergo an aldol reaction under basic conditions | symetrical |
| Aldol reaction requires | aldehyde or unsymmetrically substituted ketone (2) + base |
| Equilibrium constant is large when... | products are favored over reactants |
| How to calculate Rf values | distance spot moved / distance solvent moved |
| Why was the aldol reaction considered "green"? | Used water |
| Purpose of EAS to Synthesize p-Nitrochlorobenzene lab | 1. Synthesize p-nitrochlorobenzene from chlorobenzene using an EAS reaction; 2. use flash column chromatography to purify the synthesized p-nitrochlorobenzene |
| Electrophilic aromatic substitution reaction | There is substitution of an electrophile for a hydrogen on an aromatic ring |
| Why couldn't you use acetone in the p-Nitrochlorobenzene lab? | Acetone and nitric acid form an explosive material |
| What electrophile is generated by the reaction of nitric acid and sulfuric acid? | NO2+ (nitronium ion) |
| Why can't p-nitrochlorobenzene be made in the presence of a lewis acid and catalyst such as FeCl3 or AlCl3? | Nitro on benzene is too strong of an e- with drawing group and would form meta if you were able to get it to react. |
| What is the rate determining step and is it endo or exo thermic in electrophilic aromatic substitution? | Attack of strong electrophile by the weak nucleophilic pi electrons of the aromatic ring to form the carbocation intermediate. Endothermic due to high activation energy needed to break up aromaticity |
| NO2 is ortho, meta, or para reacting? | meta |
| Activating vs deactivating substituents on benzene ring in EAS | Activating/(o/p): NH2, NHR, OH, OR (lone pairs, alkyl, aromatic, halogens(meta)); Deactivating/meta: CCl3, NO2, NH3,+, CN (fully substituted, carbonyl w/o lone pairs) |
| How to add nitro group to benzene | HNO3/H2SO4 |
Created by:
jkmccord11
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