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THE MCAT-ORGO
| Question | Answer |
|---|---|
| What shape has the lowest heat of conbustion and lowest potential energy? | cyclohexane |
| Can meso cpds have chiral centers? | YES --> although overall, they are achiral and optically inactive |
| Enantiomers have the same / different chemical properties. | same |
| Diastereomers have the same / different chemical properties. | different |
| How to calculate number of different stereoisomers? | 2^(*chiral centers) - # meso |
| Conformational isomers | same molecular formula, same connectivity, same stereochem, but rotate about a single bond |
| Rate conformational isomers based on decreasing stability. | Anti, gauche, eclipsed |
| Rank chair, boat, twist boat based on increasing stability. | boat, twist boat, chair |
| Normal light has EM fields in all directions but polarized light has EM fields in _____ direction | one |
| Chiral molecules will rotate polarized light either to the _____ or _______. | -left (-) or (l) -right (+) or (d) |
| According to rules for assigning priority, what factor dominates most? | MOLECULAR WEIGHT --> then look at more bonds to higher priority |
| Do racemic mix rotate polarized light? Are they optically active? | NO --> optically inactive |
| How to separate enantiomers through diastereomers? | -convert enantiomers to diastereomers -separate diastereomers -convert diastereomers back to enantiomers |
| How to separate enantiomers by biological means? | enzymes are highly specific and can differentiate between enantiomers |
| In nature, all proteins are made up of ___ amino acids | L |
| How many valence electrons / number of bonds for phosphorous? | -5 -3 or 5 |
| How many valence electrons / number of bonds for sulfur? | -6 -2 or 6 |
| How many valence electrons / number of bonds for silicon? | -4 -4 |
| VSEPR: 3 bonds, one unbonded electron pair | trigonal pyramidal |
| VSEPR: 2 bonds, 2 unbonded electron pair | bent |
| VSEPR: 4 bonds | trigonal bipyramidl |
| VSEPR: 4 bonds, one unbonded electron pair | seesaw |
| VSEPR: 3 bonds, 2 unbonded electron pair | T-shaped |
| VSEPR: 2 bonds, 3 unbonded electron pair | linear |
| VSEPR: 6 bonds | octahedral |
| VSEPR: 5 bonds, one unbonded electron pair | square pyramidal |
| VSEPR: 4 bonds, 2 unbonded electron pair | square planar |
| VSEPR: 3 bonds, 3 unbonded electron pair | T-shaped |
| VSEPR: 2 bonds, 4 unbonded electron pair | linear |
| Resonance: single C-C bonds are shorter and ? | stronger |
| Resonance: double C-C bonds are longer and ? | weaker |
| What are meso cpds? | made up of 2 halves that are mirror images |
| Why is chair most stable? | eliminates 3 types of strain |
| Why are boats unstable? | all atoms are eclipsed |
| Index of hydrogen deficiency | # = (2n+2) + N - H - X / 2 |
| What is bond energy? | energy required to break a bond |
| Why is a pi bond less stable/weaker than a sigma bond? | pi bonds are in higher energy level , less stable, more reactive |
| What is Huckel's Rule | 4n + 2pi |
| What is measured in IR-Spectroscopy? | bond vibrations |
| What is on x-axis / y-axis of IR spectroscopy? | -x-axis: frequency of vibration -y-axis transmittance |
| Where transmittance dips down in IR, what does it indicate? | region of absorbance |
| IR: What are broad peaks due to? | hydrogen bonding |
| IR: Below 1300 cm is called ____ | fingerprint region - unique for each cpd |
| IR: 1700 cm = | carbonyl group |
| IR: 3300 cm can be ______, ______, or _____. | -OH - broadest -NH - slightly sharper -alkyne CH - very sharp |
| IR: Anything around 2000 cm and below does not involve _______. | hydrogen (C=O, C=C, C-C, C-O) |
| Indicators: Red is ______ and blue is _______ and green is _____. | acidic / basic / neutral |
| H-indicator vs. Indicator | -At low pH, H-indicator and color will predominate -At high pH, indicator and color will predominate |
| valence vs. oxidation number | -valence = number of electrons in outermost shell -oxidation = number of valence electrons gained or lost |
| Formula for ammonia vs. ammonium? | NH3 vs. NH4+ |
| structural isomers | same molecular formula, different connectivity |
| positional isomers | a type of structural isomers that have the same functional groups but are positioned differently |
| constitional isomers | a type of structural isomers that have same molecular formula but completely different functional groups |
| What are stereoisomers? | diastereomers, enantiomers, cis / trans |
| D/L vs. d/l | -D/L = absolute configuration -d/l = relative configuration (how it rotates light) |
| Why are enantiomers difficult to separate? | similar physical properties |
| What creates a net spin in NMR? | odd number of protons |
| What is resonance frequency? | frequency of radio wave that is needed for proton to flip in spin and spin opposite to direction of external B-field |
| The more conjugated double bonds, the longer / shorter the wavelengths of absorbed radiation? | longer |
| Conjugated systems decrease / increase the energy of EM radiation that is absorbed? | decrease |
| What does UV spectroscopy measure? | detects conjugated double bonds by comparing intensities of 2 beams of light |
| What is a conjugated system? | double bond separated with single bond |
| Each additional conjugated double bond increases the wavelength absorbed by ___ nm | 30-40 nm |
| UV spectroscopy: UV photons are able to displace electrons to _____ and energy is absorbed. | LUMO |
| LUMO vs. HOMO | lowest unoccupied molecular orbital vs. highest occupied molecular orbital |
| What is the transition observed for UV absorption for hyperconjugation? | bonding and nonbonding orbitals --> anti-bonding orbitals |
| Carrots with beta-carotene absorb _____ light and emit _____ light. | blue / green orange |
| If a cpd has eight or more hyperconjugated bonds, absorbance moves into? | visible spectrum |
| mass spectrometry: parent peak | most rightfield peak that depicts ion without fragmentation -highest m/z ratio |
| mass spectrometry: base peak | most abundant species (tallest peak) |
| mass spectrometry: peaks clustered really close to each other | isotopes |
| What is mass spectrometry useful for? | measuring molecular weight of a molecule (m/z) ratio |
| mass spectrometry: m /z ratio | mass to charge ratio |
| How does NMR work? | EM radiation of certain frequency is shown on nuclei that can flip the spin of the nuclei |
| What is varied in NMR? | magnetic field strength -frequency is kept constant |
| Aldehydes have ____ ppm in NMR | around 9 |
| What does NMR depict? | neighboring hydrogens |
| When things are shielded, what happens? | rightward shift --> B-field is increasing |
| When things aren't shielded, what happens? | leftward shift --> B-field is decreasing |
| NMR: What do EWG do? | lower shielding and decrease B-field strength at which resonance takes place --> left shift |
| NMR: What do EDG do? | -increase shielding and increase field strength required for resonance --> right shift |
| What is extraction based upon? | like dissolves like |
| What are the steps for extraction? | -add strong acid - protonates bases - remove bases -add weak base - deP only strong acids - remove strong acids -add strong base - deP everything else - remove weak acids |
| fractional distillation | used to separate liquids with smaller diff in BP --> run vapor through glass beads so cpd with higher BP will condense |
| vacuum distillation | lowers BP for both so less decomposition / volatility |
| What problems do azeotropes create in distillation? | azeotrope can have higher / lower BP than either of the 2 pure substances |
| Gas-liquid chromatography - what is mobile phase and what is stationary phase | -mobile: gas phase -stationary: liquid coating the inside walls of column |
| Paper chromatography: what polarity is paper / solvent | -paper = polar -solvent = nonpolar |
| Calculate Rf factor | distance traveled by pigment / distance traveled by solvent |
| What is the basic idea behind chromatography? | cpds in mixture that have greater affinity for stationary phase move more slowly |
| column chromatography | solution is dripped down a column with beads containing the stationary phase --> polar cpds travel slower |
| Crystallization principle | -pure substances form crystals easier than impure substances -impurities should remain dissolved in solvent even when cpd crystallizes out --> iceberg in salt water |
| What type of solvent is good for recrystalization? | -solvent where cpd dissolves only at warm temp, not cold temp -impurities are highly soluble |
| Thin-layer chromatography vs. paper chromatography | TLC uses coated glass or plastic plate and results are visualized via an iodine vapor chamber |
| What is the boiling point of heptane? | 100C --> same as water |
| What does alkane combustion produce? | carbon dioxide and water |
| Alkane + halogen + free radical initiator (UV light or peroxides) = | alkyl halide |
| Substitution for halogen of an alkane will occur at more/less substituted carbon | more |
| What inhibits free radical mechanism? | antioxidants (eat up free radicals to inhibit rxn) |
| What does the free radical mechanism depend on? | presence of free radicals |
| What has the highest ring strain? lowest ring strain? | -cyclopropane (both Baeyer and torsional strain) -cyclohexane (neither) |
| After cyclohexane, what has the next lowest ring strain? | any ring with greater or equal to 14 carbons |
| What creates ring strain? | Baeyer Strain (deviation from ideal sp3-109.5) Torsional Strain-molecule having eclipsed instead of staggered |
| Do bicyclic molecules have more or less ring strain than monocyclic molecules? | MORE |
| How do aldehydic protons appear in H-NMR? | singlet |
| How to extract amines? | -add HCl -->amines are protonated to create + charge and make it soluble |
| How does cis translate to chair drawing? How does trans? | -one equatorial and other axial -both equatorial / both axial |
| On the same dash/wedge, are 1,3 / 1,4 / 1,2 cis or trans? | -1,3 = trans -1,4 / 1,2 = cis |
| On different dashes / wedges, are 1,3 / 1,4 / 1,2 cis or trans? | -1,3 = cis -1,4 / 1,2 = trans |
| What is fractional distillation? | distillation based on different BP |
| Why do tertiary alcohols react faster with HCl? | carbocation stability |
| How to make the CH3MgBr Grignard reagent? | Mix CH3Br + Mg in diethyl ehter |
| Saponification | hydrolysis of ester in f.a. with NaOH |
| What is a f.a. made of? | alcohol and COOH |
| Where is most of the electron density in a sigma bond? | between the nuclei |
| How many bonds can boron form? | 3 |
| More highly substituted carbons have stronger or weaker bonds? | weaker |
| Which atoms normally hydrogen bond? | fluorine, oxygen, nitrogen |
| What is a vinylic carbon? | C = C |
| When does electron withdrawing occur? | a more electronegative atom draws away electorn density |
| A good nucleophile has high / low electron density? | high electron density |
| Why do EWGs make nucleophiles worse? | draw away electron density and nu becomes worse electron donor |
| More electronegative atoms withdraw more or less electron density and make for a poorer nucleophile? | more electron density |
| Shortcut to remember relative electronegativity? | FONClBrISCH |
| Steric repulsion theory | Electrons will repel electrons and will decrease bond angles |
| Can a proton be involved with resonance? | NO |
| What creates a strong acid in terms of its conjugate base? | a stable conjugate base (such as aromatic base) = strong acid |
| lewis acid / base | electron acceptor / electron donor |
| bronsted lowry acid / base | H donor / H acceptor |
| What is 5-10-15-20 rule for organic acids? | -pKa for COOH = 5 -phenol = 10 -alcohol = 15 -proton alpha to carbonyl = 20 |
| In COOH, the carbonyl oxygen is more likely to get protonated than the hydroxyl oxygen which means? | the carbonyl oxygen is more basic than the alcohol oxygen |
| Does a partial negative charge increase or decrease basicity? | increase |
| Bases like to get _____ acids like to get _______. | protonated / deprotonated |
| Does a larger/smaller atom create a stronger acid? Does this apply to periods or groups? | larger / groups |
| Does a more / less eN atom create a stronger? Does this apply to periods or group? Why is this so? | more eN / periods / stabilize high electron density and makes it easier to break bond |
| What hybridization creates a strong acid? Why? | sp / electrons are held closer to the nucleus so bond can be cleaved easier |
| An adjacent atom making a pi bond is EWG / EDG? Lone pair atom is EWG / EDG? | EWG / EDG |
| Where do EDG increase electron density in aromatic ring? | ortho and para --> O / P more nu so reacts with electrophiles at O/P |
| Where do EWG decrease electron density in aromatic ring | ortho and para --> O / P less nu. so reacts with electrophiles at meta |
| What do atomic size, eN, and hybridization deal with? | bond directly to acidic proton |
| What does inductive effect refer to? | EWG and EDG |
| In terms of lone pair, what creates a basic atom? | when lone pair is least shared |
| Do Van der Waals forces exist between all compounds? | YES --> forces are roughly equal too |
| What creates the strongest H-bond? | hydrogen on fluorine and lone pair from nitrogen |
| To have hydrogen bonding, where must the hydrogen be located? | on an F, O, N |
| To create a rigid phospholipid membrane, what type of fatty acid should be used? | long, saturated fatty acids --> maximize interactions between liid chains |
| Why is lard solid at room temperature while veggie oil is liquid? | lard is saturated structure which means more flexible which means individual molecules interact with each other strongly |
| Do unsaturated fats increase / decrease membrane fluidity? | increase |
| Do unsaturated or saturated fats have higher melting temperature? | saturated fats |
| solubility vs. miscibility | -ability of solid to dissolve into solution -ability of liquid to mix into another liquid |
| What are the types of IMF in polar, protic solvents? | H-bonds, dipole-dipole, van der Waals |
| What are the types of IMF in polar, aprotic solvents? | dipole-dipole and van der Waals |
| What are the types of IMF in nonpolar, aprotic solvents? | van der Waals |
| What creates the best micelle? | ionic head and long carbon chain |
| Where do sigma bonds share electron density vs. pi bonds? | -between nuclei -in plane above and below nuclei |
| To create a bonding orbital, add/subtract nuclei? antibonding orbital? | add / subtract |
| Is a bonding orbital less or more stable than antibonding orbitals? | more stable |
| Are sigma bonds more or less stable than pi bonds? | more stable |
| How to tell if 2 isomers are structural isomers? | have different IUPAC names |
| Is it possible to rotate around a double bond? | NO --> p-orbitals would no longer be coplanar breaking the pi bond |
| Do alkenes have lower or greater entropy than alkanes? | lower entropy |
| On an energy diagram for conformational isomers, if greatest substituents repel each other, then which orientation is most stable with lowest energy? | anti |
| On energy diagram for conformational isomers, if greatest substituents attract each other, which orientation is most stable with lowest energy? | gauche (like vicinol diol) |
| On a newman projection, the substituents behind the plane are on the right or left? substituents in front of the plane? | right / left |
| Which ring structures are most stable / least stable? | -5/6 membered rings -3/4 membered ring |
| In a chair, cis refers to? | up / up or down down |
| In a chair, what does trans refer to? | up / down |
| What do wedges translate to on chair diagram? | up |
| What do dashes translate to on chair diagram? | down |
| What is the formula for the PE that is associated with H-NMR spectroscopy? | PE = 1/2 kx^2 |
| What does no broad peaks above 2500 cm-1 indicate? | no OH bond |
| IR: What do peaks in the 1300-1400 range indicate? | C-C bonds |
| In organic chemistry, what must a compound have in order to be UV-visibly active? | pi bond |
| For UV spectroscopy, as conjugation increases, does energy gap between pi and pi* decrease or increase? How does this affect wavelength of max. absorbance | decreases / increases |
| When more conjugation is added, where does the absorbance shift into? | visible range |
| What does color result from? | excessive conjugation |
| What do infrared photons affect that is different from UV and visible photons? | -infrared affects vibrational energies -UV and visible affect electronic energy levels |
| For H-NMR, where is upfield and does that mean low or high B-field strength? | right --> high B-field strength |
| For H-NMR, where is downfield and does that mean low or high B-field strength? | left --> low B-field strength |
| EWG lower shielding and cause a right/left shift in H-NMR? | decrease the B-field strength at which resonance takes place -left |
| EDG raise shielding and cause a right/left shift in H-NMR? | increase B-field strength at which resonance takes place -right |
| In H-NMR, what is special about alcohol? | has broad peak from 1-5 ppm |
| In H-NMR, what is special about phenol? | has broad peak from 4-7 ppm |
| In H-NMR, what is there is no adjacent hydrogens? | singlet |
| In H-NMR, what is special about benzene? | has peak around 7 ppm |
| In H-NMR, When you see a triplet and quartet in a 3:2 ratio, what does that indicate? | H3C-CH2- |
| In H-NMR, when you see a doublet and a septet in a 6:1 ratio, what is it? | isopropyl group [(H3C)2CH-] |
| What is the suffix for an ester? | -oate |
| What is the pascal's triangle ratio for a triplet? | 1:2:1 |
| What is the pascal's ratio for a quartet? | 1:3:3:1 |
| What is pascal's ratio for a quintet? | 1:4:6:4:1 |
| A doublet of a doublet is indicative or ortho,meta, para? | para |
| What does it mean to be aprotic? | no hydrogens bonded to F, O, N |
| Is there a problem when protic / aprotic solvents are dissolved in D2O? | protic --> undergo exchange |
| What type of solvent used for H-NMR? | one with NO hydrogens |
| On a fischer projection, what happens when you interconvert 2 substituents? | change chirality of stereogenic center |
| On a Fischer projection, what happens when you interconvert 3 substituents? | nothing |
| How do diastereomers compare in their physical properties? | Have different physical properties including MP, BP, and density |
| How many chiral centers are in a meso compound and in what orientation? | even number / opposite chirality |
| What is the net optical rotation of a meso compound? | 0 degrees --> optically inactive |
| The reflection of a meso compound can be classified as? | reflects identical and original compound |
| When 2 enantiomers are they formed in equal or unequal quantity? DIastereomers? | -equal quantity -unequal --> major and minor product |
| How can enantiomers be formed in an unequal ratio? | chiral catalyst is present to create enantiomeric excess |
| Syn addition means? | symmetric addition (both wedges or both dashes) |
| Anti addition means? | unsymmetric addition (wedge and dash) |
| Do enantiomers rotate light? | NO |
| Equation for enantiomeric excess | % = measured specific rotation / specific rotation of pure enantiomer * 100% |
| What creates a good leaving group? | stable base --> weaker base --> more acidic |
| Can diastereomers ever produce racemic mixture? | NO |
| What defines a favorable nucleophilic substitution? | forms a stronger bond than one is broken |
| What type of electrophiles are used for SN2? | primary, secondary, tertiary |
| What type of nucleophile is favored with SN2? | good nucleophile |
| What type of solvent is favored with SN2? | polar, aprotic solvent like ethers and ketones |
| What type of electrophiles are used for SN1? | tertiary, secondary, primary |
| What type of solvent is favored with SN1? | polar, protic solvent like alcohol |
| What type of nucleophile is favored with SN1? | poor nucleophile |
| What is the SN1 rate? SN2 rate? | rate = k[electrophile] rate = k[electrophile][nucleophile] |
| Why is it important to keep substitution reactions at low temperatures? | prevents competing E2 reaction |
| Does SN2 or SN1 have an intermediate? | SN1 |
| Does SN2 or SN1 require a good nucleophile? | SN2 |
| What does catalyst do? | stabilizes transition state complex and lowers Ea |
| How do enantiomers compare with physical properties? | identical physical properties |
| Does a racemic mix have a higher or lower MP and density than either enantiomers? | -greater -> think of two hands clasping --> stronger connection |
| Which is nonsuperimposable: enantiomers or diastereomers? | NEITHER ARE |
| Are enantiomers or diastereomers mirror images? | enantiomers |
| When do racemic mixes form vs. diastereomers? | -racemic forms when there is no preexisting chirality -diastereomers form when one of the reagents has a chiral center at a non-reactive site |
| Aliphatic | straight chain form of alkane |
| For alkanes, how does increasing molecular mass affect BP and MP? Branching? | -increase -BP decreases |
| What type of free radicals are best for halogenation of alkanes? | tertiary free radicals |
| During halogenation, what happens during propagation? | goes from one free radical to another free radical |
| During halogenation, what happens during termination? | two free radicals combine to no free radicals |
| During halogenation, what happens during initiation? | goes from zero free radicals to two free radicals |
| Why are slower reactions more selective than faster ones? | more time to select the best site for reacting |
| In halogenation, is chlorination or bromination faster? Which is more selective/ | chlorination / bromination |
| In halogenation, is bromination or chlorination more reversible? | bromination slower than chlorination --> reversible |
| As energy is added, are more or less stable products formed? | less stable |
| When does rearrangement occur? | with carbocations |
| Why are there minimal di-halogenated products in free radical halogenation? | after first X added, weakest bond is C-X and not C-H --> easier to remove X than H |
| What are the characteristics for E2 reactions in terms of base, electrophile, and temperature? | strong bulky base, hydrocarbon with leaving group, high temp |
| In what orientation must the leaving group be for E2 reactions? | anti |
| What type of conditions are best for E1 reaction? | acidic and high temperatures |
| Assign "acidic / basic" to E1 and E2. | E1 = acidic E2 = basic |
| How can carbocations undergo rearrangement? | alkyl or hydride shifts |
| During electrophilic addition, where is the positive charge situated after the pi bond attacks electrophile? | most substituted carbon |
| What type of nu should be used for electrophlic addition? | weak base otherwise it will deprotonate intermediate to regenerate alkene |
| What type of conditions are electrophilic additions carried out in? | acidic conditions |
| What can a protic solvent do? | form H-bonds and transfer protons |
| If there is no optical activity in the reactants, can there be in the products? | NO |
| When 2 substituents add at the same time, syn / anti? Add at different times? | syn / anti |
| Markovnikov addition in alkenes | electrophile adds to less substituted carbon and nu adds to more substituted carbon |
| Anti-Markovnikov addition in alkenes | electrophile adds to more substituted carbon and nu adds to less subst. carbon |
| Kinetic control refers to the more stable ____ while thermodynamic control refers to the more stable ______. | intermediate / product |
| Thermodynamic control favors higher or lower temperature | higher temperature |
| Lower energy intermediate leads to kinetic / thermodynamic product? HIgher energy intermediate? | kinetic / thermodynamic |
| Boltzmann distribution law | As temperature increases, higher energy levels become more populated to absorb energy increase --> more primary carbocations than at lower temp |
| Kinetic control favors what type of 1,2 or 1,4 addition to conjugated dienes? | 1,2 addition --> monosubstituted alkene is least stable |
| Thermodynamic control favors what type of 1,2 or 1,4 addition to conjugated dienes? | 1,4 addition --> disubstituted alkene is most stable |
| Does a meso compound have an enantiomer or diastereomer? | only diastereomer |
| The diene is nu/e while the dieneophile is nu/e? | nucleophilic / electrophilic |
| EDG benefit dienes or dienophiles? | dienes |
| EWG benefit dienes or dienophiles? | dienophiles |
| Cope rearrangement | converts 1,5-diene into another 1,5 diene |
| Claisen rearrangement | converts 1,5-diene into either an aldehyde or ketone |
| What are the building blocks of steroids? | isoprene units |
| Are terpenes UV active? | YES --> pi bonds |
| Differences in conjugation and pi bonds results in differences in? | UV absorption |
| How does steam distillation protect integrity when distilling natural oils? | allows oils to vaporize at a temperature lower than their BP |
| Do strong bases make good nucleophiles? | NO --> chance for deprotonation |
| Does an alcohol or aldehyde receive higher priority? | aldehyde --> most oxidized carbon receives highest priority |
| All ketones are associated with ketals / acetals. All aldehydes are associated with ketals / acetals. | ketals / acetals |
| In basic conditions, ketones turn into hemiketal / ketal? aldehydes turn into? | hemiketal / hemiacetal |
| In acidic conditions, ketones turn into hemiketal / ketal? | ketal / acetal |
| How to form a ketal or acetal? | react aldehyde/ketone with alcohol |
| Transesterification | esters exchange alkoxy group in presence of alcohol and acid |
| How are acid anhydrides formed? | condensation (dehydration) reaction between 2 COOH at elevated temperatures |
| When you add water to an acid anhydride, what is produced? | 2 COOH |
| Addition of heat to 2 COOH yields? | acid anhyride |
| How to reduce amides into amines? | strong reducing agent like LiAlH4 |
| Do amino acids contain amide bonds? | NO |
| Where are amide bonds formed? | peptide bonds in px, guanine, uracil |
| Rank reactivities of carbonyl with anhydride, halogen, ester, amide | halogen, anhydride, ester, amide |
| What dictates the reactivity of the carbonyl? | acidity of the conjugate acid of leaving group |
| With a bulky base, does the kinetic or thermodynamic product get formed? Small base? | kinetic / thermodynamic |
| What happens during oxidation in terms of loss/gains of O and loss/gains of H? | gain O / lose H |
| What happens during reduction in terms of loss/gains of O and loss/gains of H? | lose O / gain H |
| What are the steps of oxidation for a primary alcohol? | primary alcohol --> aldehyde --> COOH |
| What are the steps of oxidation for a secondary alcohol? | secondary alcohol -->ketone |
| Can a tertiary alcohol get oxidized? | NO |
| Oxidizing agents have lots of ____ while reducing agents have lots of _____. | oxygens / hydrogens |
| What reagent allows oxidation from primary alcohol to aldehyde only? | PCC |
| What does FADH2 reduce? | hydrogenation of a pi bond |
| What does hydrazine (H2NNH2) reduce aldehydes and ketones to? | alkanes |
| What does LiAlH4 reduce? | COOH and Esters back to primary alcohols |
| What does NaBH4 reduce? | aldehydes and ketones back to primary and secondary alcohol |
| What does a Gignard reaction produce? | new carbon-carbon bond |
| The 4th step of glycolysis is what type of reaction? | retro-aldol reaction with aldolase |
| Wittig Reaction | converts a ketone into an alkene with a phosphorous ylide |
| Pinacol rearrangement | converts a vicinal diol into a ketone |
| Iodoform Reaction | Converts a methyl ketone into a COOH and a haloform -haloform = CX3 |
| Wolff-Kishner Reduction | uses hydrazine under basic conditions to reduce a ketone/aldehyde into an alkane C=O + NH2NH2 --> -CH2- + N2 |
| Protecting groups turn aldehydes, ketones, and alcohols into? | acetals, ketals, silyl ethers |
| Where do oxidations and reductions take place in the cell? | -oxidations - mito matrix (glycolysis is exception) -reductions - cytoplasm |
| Is anabolism an oxidative or reductive process? Catabolism? | Reductive / oxidative |
| Are NAD+ / FAD oxidizing or reducing agents? | oxidizing agent |
| Rank boiling points of alcohols based on primary, secondary, tertiary. | primary > secondary > tertiary |
| Water solubility is high for carbonyls with ___ carbons | four |
| Alcohol + COOH = ? | ester |
| Can a Grignard add twice to a carbonyl? | YES if there is a leaving group |
| Difference between D vs. L | D: H --OH L: OH --H |
| Difference between (+) and (-) | All stereocenters are switched between the two |
| epimers | diastereomers that differ around one chiral center |
| What type of sugar is fructose? | ketohexose |
| When sugars are D and L, it also means that one has to be _ and the other _. | + / - |
| Alpha/beta anomers, is alpha pointing up or down? Beta? What does it really mean in terms of cis/trans? | alpha-down (trans with last carbon) beta-up (cis with last carbon) |
| Mutarotation | conversion between anomers |
| Is the alpha or beta anomer more favored in vivo? | beta |
| Going from dashes/wedges to Fischer, dashes are on the right/left? | right |
| Going from dashes/wedges to Fischer, wedges are on the right/left? | left |
| Ketose-aldose as well as glucose isomerization proceeds through what type of intermediate? | enediol intermediate |
| How many carbons does glyceraldehyde have? | 3 |
| The sugars in amylose and glycogen have what type of linkages? Cellulose? | alpha / beta |
| Branching is created from what type of linkages? | 1,6 |
| Which polysaccharides have branching? Which do not? | -Amylopectin and glycogen have branching -cellulose and amylose do not have branching |
| Natural sugars have what type of chirality? | D |
| What does nitric acid sugar oxidation test for? | optical activity |
| How does osazone test work? | phenylhydrazine is used to form an osazone --> C2 epimers ield the same osazone |
| What does Tollen's test test for? | tests for distinguishing between aldehyde and ketone --> aldehyde are readily oxidized while ketones are not |
| What are reducing sugars? | hemiacetal or aldose |
| For Tollen's test, if a silver mirror forms, what doe sthat mean? | presence of an aldose |
| What does the periodate test (IO4-) do? | oxidizes sugar by cleaving all C-C bonds |
| What does Kiliana-Fischer synthesis do? | adds new carbon through cyano group that is converted to an aldehyde --> creates 2 epimers not in 50/50 ratio |
| Addition of cyanide is involved with which process? | Kiliani-Fischer synthesis |
| Ruff degradation (and Wohl degradation) | decreases chain length by one carbon when CO2 leaves (1st carbon) --> bromine in water |
| What reagent does nitric acid sugar oxidation use? | HNO3 |
| What reagent does Kiliani Fischer synthesis use? | KCN and H2/Pd |
| What reagent does Ruff degradation use? | Br2 and H2O |
| What is the difference between Type O and Type A/B in terms of glycoproteins? | Type O has 3 sugars (one is L) while Type A/B has 4 sugars |
| How can you tell the number of valence electrons? | look at group number --> different from oxidation number |
| amide | O=C-NH2 |
| Imine | C=N-R |
| Hydrazone | C=N-NH2 |
| Nitro | O=N-O |
| Diazo | C=N=N |
| Azide | N=N=N |
| Sulfate vs. sulfite | 4 oxygens vs. 3 oxygens |
| syn periplanar eclipse | bulky groups eclipse each other |
| anticlinal eclipsed | bulky groups eclipse hydrogen |
| polarized left rotation | - / l |
| polarized right rotation | + / d |
| Separate enantiomers? | Convert E --> D, separate D, convert back to E |
| What does UV absorption show? | molecular orbital transitions from bonding to antibonding orbitals results in UV absorption |
| Why do double bonds absorb UV? | pi electrons transition from bonding and nonbonding molecular orbitals to antibonding orbitals |
| What is mass spectroscopy? | bombard a molecule with electrons and it fragments into ions |
| What does mass spectroscopy NOT detect? | uncharged molecules |
| What is a neighboring hydrogen in NMR? | 3 bonds away |
| In extraction, what 2 phases are there? | organic and aqueous phase |
| In extraction, what does the organic phase solvent consist of? | nonpolar solvent like oil, chloroform |
| Basic premise behind chromatography? | stuff that sticks to stationary phase will come out slower |
| What is recrystallization? | barely dissolving cpd and letting it recrystallize out of solution (more pure) |
| What type of solvent for recrystallization? | solvent in which cpd is soluble at warm temp but not at cool temp --> impurities are highly soluble |
| What alkane has the same BP as water? | heptane |
| What is the best protecting groupfor alcohols? | Cl-Si-Me3 --> deprotect with F- |
| R-OH + SOCl2 --> ? | R - Cl -SO2 + HCl |
| R-OH + PBr3 --> | R - Br -H3PO3, R3PO3, HBr |
| What are the use of mesylates and tosylates? | transform -OH into a good leaving group by reacting with MsCl or TsCl |
| Toluene | Ph - CH3 |
| What creates an ester? | carboxylic acid + alcohol |
| How to create an inorganic ester? | replace carbon of esters with different atoms (like P or S) |
| What is a phosphodiester linkage? | 3'-OH attacks 5'-phosphate |
| Rank BP: COOH, ketones, alcohol | COOH > OH > ketones |
| How many equivalents of alcohols do aldehydes/ketones react with to make hemiacetals? | 1 |
| How many equivalents of alcohols do aldehydes/ketones react with to make acetals? | 2 |
| primary amine + aldehyde/ketone =? | imine: -N=C |
| secondary amine + aldehyde/ketone =? | enamine -N-C=C | |
| What happens during a haloform reaction? | methyl ketone reacts with Cl, Br, or I in the presence of hydroxide ions to give a carboxylate and a haloform --> halogenates at alpha position |
| What is a haloform? | alkyl halide with 3 X substituents |
| What is the iodoform test? | the use of haloform reaction to identify methyl ketones because iodoform is a yellow solid |
| Can aldehydes undergo the haloform reaction? | ONLY acetylaldehyde |
| Is the haloform a good or bad leaving group? | good L.G. |
| What do 1,3-dicarbonyls create? | internal H-bonding from tautomerism -H-bond btwn carbonyl and alcohol |
| Is the keto or enol form more stable? | keto --> predominant form |
| Do EWG or EDG make an alpha proton more acidic? | EWG |
| Do COOH's act both as nucleophiles and electrophiles? | YES -electrophilic carbonyl and nucleophilic -OH |
| What is a beta-keto acid? | carboxylic acid with a ketone group in beta position from carboxylic acid |
| For what type of acids does decarboxylation occur? | beta-keto acid |
| Steps to halogenation of COOH at alpha position ONLY. | -COOH --> acyl halide -enolize -alpha attacks electrophile -revert back to COOH |
| Generally, is COOH a strong or weak acid? | weak acid |
| What is the pKa of H+? | 0 |
| What creates a good acid no matter what? | resonant stability of conjugate base |
| Suffix for anhydrides | -oic anhydride |
| What is the IR-spectrum for acid chloride? | around 1800 cm-1 |
| What is the IR-spectrum for anhydride? | 2 bands between 1700 and 1800 cm-1 |
| What is the IR-spectrum for amide? | -NH at 3300 cm-1 -C=O at 1700 cm-1 |
| What is the IR-spectrum for an ester? | -C=O at 1700 cm-1 -C-O at 1200 cm-1 |
| COOH + SOCl2 --> | acid chloride |
| COOH + COOH + heat --> | anhydride |
| acid chloride + COOH + base --> | anhydride |
| acid chloride + alcohol + base --> | ester |
| acid chloride + amine --> | amide |
| acid chloride + water --> | COOH |
| Are COOH more or less stable than aldehydes and ketones and why? | more stable --> resonance |
| What is the reactivity of carboxylic acid derivatives? anhydride, ester, Cl, amide | Cl > anhydride > ester > amide |
| What does Hofmann Rearrangement do? | takes away the C=O of an amide |
| How to cause decarboxylation? | beta-keto COOH are heated |
| What is the leaving group for the hydrolysis of amides? | neutral amine |
| Can amide bonds rotate? | NO --> partial double bond characteristic between C-N |
| What is a beta-lactam? Does it have high or low ring strain? | 4-membered cyclic amide --> high ring strain |
| Why do beta-lactams have higher ring strain? | can't rotate to achieve more stable configuration |
| How to synthesize acetoacetic ester, a beta-keto ester? | Claisen condensation of 2 ethylacetates |
| Why can beta-keto acids undergo decarboxylation? | beta-keto group stabilizes resulting carbanion via enol formation |
| What is acetoacetic ester synthesis used for? | acetoacetic ester is used to synthesize a new ketone -->alpha acidic proton, attack new R group, decarboxylation |
| How to turn acid chloride, anhyride, ester, and amides back to COOH? | add water |
| Are tertiary amines chiral / racemic? | Chiral --> racemic (spontaneous inversions) |
| Are quarternary amines chiral / racemic? | chiral and stay chiral |
| What is the IR-spectrum for primary amines? | 2 peaks around 3300 cm-1 |
| amine + acid derivative with good L.G. --> | amide |
| What is the reaction between a primary amine and nitrous acid? | -NH2 + HONO --> -N2+ |
| Can the amine group be alkylated? | YES |
| Hoffman Elimination | amine + methyl iodide --> exhaustive methylation of amine --> elimination with methylated amine as leaving group |
| Does Hoffman Elimination form more or less substituted double bond? | less |
| Zaitsev vs. Hofman | Zaitsev - more substituted Hofman - less substituted |
| Zaitsev vs. Hofman: E1 vs. E2 forms which? | -E1 = Zaitsev -E2 with bulky base = Hofman |
| Think about BL base-do bases like to gain or lose protons? | gain protons |
| Are protons lost easier in amines or amides? | amides --> resonance |
| Are aromatic amines weaker or stronger bases than aliphatic amines? | weaker bases --> donates electron density to aromatic ring |
| Ortho effect | introduce any bulky substituent at the ortho position to another substituent -due to steric repulsions, planarity of ring is lost, resonance reduced --> more acidic |
| What will give a positive Tollen's Reagent test? | any sugar in hemi acetal form --> acetal sugars are nonreducing |
| How to tell if reducing / non-reducing? | look for available anomeric carbon -available - hemiacetal -not available - acetal |
| Typically, how to generalize reducing vs. nonreducing? | reducing = aldoses, ketoses nonreducing = surcrose and disaccharides |
| Hemiacetal vs. acetal | -hemiacetal - alcohol and ether on same carbon -acetal - 2 ethers on same carbon |
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