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Organic Chemistry > Exam 4 > Flashcards

Exam 4 Flashcards

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1
Q

what is an acyl group?

A

an R group (carbons & hydrogens)

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2
Q

what is a carboxylic acid?

A

carbonyl group bonded to R and OH

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3
Q

what is a carbonyl group?

A

C=O

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4
Q

what is an acid chloride?

A

carbonyl group bonded to an R group and Cl

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5
Q

what is an anhydride?

A

carbonyl group bonded to an R group and an OCOR group

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6
Q

what is an ester?

A

carbonyl group bonded to an R group and an OR’ group

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7
Q

what is an amide?

A

a carbonyl group bonded to an R group and NR’2 - R’ can be an H or an alkyl group

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8
Q

What makes an amide a 1°, 2° or a 3°?

A

depends on the number of C atoms bonded directly to the N atom

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9
Q

what are cyclic esters called?

A

lactones

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10
Q

what are cyclic amides called?

A

lactams

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11
Q

how do you indicate ring size in a cyclic amide or ester?

A

greek letter
beta lactam is a 4-membered amide ring
gamma lactone is a 5-membered ester ring

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12
Q

what is a nitrile?

A

R-CtriplebondN

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13
Q

how does basicity of Z affect carboxylic acid derivaties (RCOZ)?

A

as basicity of Z increases, stability of RCOZ increases, because the more basic Z is, the more it donates its electron pair & the more the resonance structure is stabilized.

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14
Q

How do you name an acid chloride?

A

change -ic acid ending of parent carboxylic acid to -yl chloride
ring: change -carboxylic acid to -carbonyl chloride

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15
Q

how do you name an anhydride?

A

symmetrical: change acid ending of parent carboxylic acid to anhydride
mixed: alphabetize names for both acids (pretend O belongs to both) and replace the word acid with anhydride

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16
Q

How do you name an ester?

A
  1. name R’ group bonded to O atom as an alkyl group (ending in -yl)
  2. name acyl group (RCO-) by changing -ic acid of parent carboxylic acid to -ate.
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17
Q

how do you name a carboxylic acid?

A

IUPAC
change -e ending of parent alkane to -oic acid (or if bonded to a ring, name ring & add carboxylic acid to end)
common:
use common parent name followed by -ic acid
alpha, beta, gamma, delta carbons (one away from COOH etc.)
form-
acet-
propion-
butyr-
valer-

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18
Q

How do you name an amide?

A

1° replace -ic acid, -oic acid or -ylic acid with amide
2° or 3°:
1.name alkyl group (or groups) bonded to N atom of amide, use “N-“ preceding name of each alkyl group, alphabetize if different
2. name acyl group (RCO-) with suffix -amide

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19
Q

describe boiling and melting points of carboxylic acid derivatives

A

1° and 2° amides have higher boiling & melting points than the rest because they are capable of intermolecular hydrogen bonding between the N-H of one amide & the C=O of another
other carboxylic acid derivatives are similar to those of other polar compounds of comparable size & shape

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20
Q

describe solubility of carboxylic acid derivatives

A

all soluble in organic solvents regardless of size
most having less than or equal to 5 C’s are soluble in water, because they can H-bond with H2O, bigger than 5, the nonpolar alkyl portion is too big to dissolve in polar solvent

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21
Q

what is the characteristic reaction of carboxylic acid derivatives and why?

A

nucleophilic acyl substitution because RCOZ contains an electrophilic unhindered carbonyl C, and they have a leaving group Z on the carbonyl carbon

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22
Q

what is the mechanism for nucleophilic acyl substitution in carboxylic acid derivatives?

A

1) nucleophile attacks carbonyl group, cleaving pi bond & forming tetrahedral intermediate w/new C-Nu bond. pi electrons move up to O & make it negatively charged
2) Z electrons leave with it, extra O electrons reform carbonyl pi bond –> substitution product + Z-

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23
Q

what kinds of things can be nucleophiles?

A

carbanions (R-)
Hydrides (H-)
Oxygen nucleophiles (-OH, H2O, ROH, RCOO-)
Nitrogen nucleophiles (NH3, RNH2, R2NH)

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24
Q

how do you draw a nucleophilic acyl substitution product?

A
  1. find sp2 hybridized C w/leaving group
  2. identify nucleophile
  3. substitute nucleophile for leaving group. if it is a neutral nucleophile, a proton has to be lost to make a neutral substitution product
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25
Q

list leaving groups of carboxylic acid derivatives in order of leaving group ability

A 
from least leave-ability to most:
-NH2
-OH and -OR' (similar to each other)
RCOO-
Cl-
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26
Q

how can you tell whether or not a substitution reaction will occur?

A

compare the leaving group ability of the incoming nucleophile and the departing leaving group

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27
Q

what is the order of reactivity with carboxylic acid derivatives?

A 
from least reactive to most:
amides
carboxylic acids (COOH) and esters (RCOOR')
anhydrides (RCOOCOR)
acid chloride (RCOCl)
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28
Q

How do you make an anhydride from an acid chloride?

A

add carboxylate anion (-COOR)

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29
Q

how do you make a carboxylic acid from an acid chloride?

A

add H2O + pyridine

pyridine neutralizes the HCl that is formed & makes an ammonium salt

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30
Q

what is the product of acid chloride + carboxylate anion?

A

anhydride

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31
Q

what is the produce of acid chloride and H2O?

A

+ pyridine = carboxylic acid & an ammonium salt

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32
Q

how do you make an ester from carboxylic acid?

A

add R’OH and acid H2SO4

also makes ammonium salt from the HCl byproduct

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33
Q

what is the product of acid chloride + R’OH (alcohol)?

A

ester and ammonium salt

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34
Q

how do you make a 1° amide from an acid chloride?

A

add 2NH3

also makes ammonium salt NH4+Cl- (from the second NH3 and HCl)

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35
Q

what do you get with acid chloride + NH3?

A

1° amide + ammonium salt

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36
Q

how do you make a 2° amide from acid chloride?

A

add 2R’NH2

also get R’NH3+Cl- ammonium salt

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37
Q

what is acid chloride + R’NH2? (2 equivalents)

A

2° amide + ammonium salt

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38
Q

what do you get with acid chloride + R’2NH (2 equivalents)?

A

3° amide + ammonium salt R’2NH2+Cl-

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39
Q

how do you make a 3° amide from acid chloride?

A

add R’2NH (2 equivalents)

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40
Q

what is the mechanism of acid chloride to anhydride conversion?

A

1) nucleophilic addition of R’COO- forms tetrahedral intermediate (negatively charged O attacked carbonyl C, pi electrons go to O
2) Cl leaves with it’s electrons as electron pair from O reform pi bond

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41
Q

what is the mechanism of acid chloride to carboxylic acid conversion?

A

1) nucleophilic attack by H2) forms tetrahedral intermediate
2) removal of proton from H2O by the pyridine (benzene ring with N: instead of 1 C) making benzine ring with N+-H instead of a C)
3) Cl leaves and O reforms pi bond with C

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42
Q

how do anhydrides react in nucleophilic substitution reactions?

A

nucleophile attacks at one of the carbonyl carbons, the 2nd carbonyl group becomes part of leaving group

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43
Q

how do you make a carboxylic acid from an anhydride?

A

add water

get 2 carboxylic acids (one from each carbonyl group)

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44
Q

what is anhydride + H2O =?

A

carboxylic acid (2 of them)

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45
Q

how do you make an ester from an anhydride?

A

add alcohol R’OH

also get carboxylic acid by-product

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46
Q

what is anhydride + R’OH?

A

ester and carboxylic acid

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47
Q

how do you make an amide from an anhydride?

A 
add NH3 (or RNH2 or R2NH) 2 equivalents
also get carboxylate salt RCOO-NH4+
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48
Q

what do you get with anhydride + NH3 (or 1°, 2° amine)

A

amide and carboxylate salt

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49
Q

what is an acetylation reaction?

A

transferring one acetyl group (CH2CO-) from one heteroatom to another
heteroatom is anything that is not C or C

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50
Q

what is the mechanism of converting anhydride to an amide?

A

1) NH3 attacks one of the carbonyl C’s, forms tetrahedral intermediate
2) another NH3 takes a proton from the positively charged nucleophile
3) pi bond reforms between O & C, and RCOO- leaves (forming salt with NH4+)

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51
Q

what happens with carboxylic acids and strong base nucleophiles?

A

the nucleophile will react with the H on the OH first (removing the proton) before substitution can take place, making RCOO- and H-Nu

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52
Q

which nucleophiles result in acid-base reactions with carboxylic acids (rather than substitution)?

A

-OH and NH3

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53
Q

how do you make an acid chloride from a carboxylic acid?

A

add SOCl2

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54
Q

what is carboxylic acid + SOCl2?

A

acid chloride

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55
Q

how do you make a cyclic anhydride from a dicarboxylic acid?

A

heat

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56
Q

what is heat + dicarboxylic acid?

A

cyclic anhydride and H2O

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57
Q

how do you make an ester from a carboxylic acid?

A

R’OH and H2SO4

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58
Q

what is carboxylic acid + R’OH and H2SO4?

A

ester

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59
Q

how do you make an amide from a carboxylic acid?

A

NH3 and heat

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60
Q

what do you get with carboxylic acid + NH3 and heat?

A

amide

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61
Q

how else can you make an amide from a carboxylic acid?

A

R’NH2 and DCC

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62
Q

what is carboxylic acid + R’NH2 and DCC?

A

amide

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63
Q

what is the mechanism for converting carboxylic acid to acid chloride?

A

1) OH group on carboxylic acid attacks SOCl2, one of Cl’s leaves as intermediate is formed
2) Cl- takes proton from OH making OSOCl, a good leaving group
3) nucleophilic attack by Cl- on carbonyl C, pi bond cleaves & electrons to go O forming tetrahedral intermediate
4) OSOCl leaves, pi bond reforms making acid chloride, SO2 and Cl-

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64
Q

what is fischer esterification?

A

treatment of carboxylic acid w/alcohol in presence of acid catalyst (H2SO4) forming an ester and H2O
equilibrium reaction, so can be driven right by excess alcohol or removing water as it is formed

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65
Q

what is the mechanism of Fischer esterification?

A

all steps are equilibrium reactions

1) protonation of carbonyl O (making carbonyl group more electrophilic) by H of the H-A (leaving :A-)
2) R’OH attacks C of carbonyl group, cleaving pi bond & moving electrons to OH
3) :A- deprotonates R’OH forming neutral addition product and reforming H-A
4) protonation of OH group forms good leaving group and :A-
5) H2O leaves & pi bond is reformed between second OH and C
6) :A- deprotonates OH of double bonded C, reforming H-A again

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66
Q

what are the steps involved in converting a carboxylic acid to an amide?

A

1) acid-base reaction of RCOOH with NH3 to form ammonium salt
2) dehydration at high temperature to form amide and H2O

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67
Q

what is the mechanism of converting carboxylic acids to amides using DCC?

A

1) O of OH attacks C of DCC (DCC is C doubled bonded to 2 N’s which are each bonded to cyclohexane), cleaving one of the double bonded N’s & moving those electrons to the N (making it negatively charged)
2) H from the positively charged O-H transfers to negatively charged N, activating the carboxy group towards nucleophilic attack
3) nucleophilic attack of amine on activated carbonyl C, cleaving pi bond & moving elecgrons to O (now positive N and negative O)
4) dicyclohexyurea leaves, forming double bond between the O of that and the C (which is bonded to the two NH cyclohexane groups), pi bond reformed between O and C of original carbonyl bond - forming amide and dicyclohexylurea

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68
Q

what is ester + H2O and H+ or -OH?

A 
carboxylic acid (in acid)
or carboxylate anion (in base) + R'OH
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69
Q

how do you make carboxylic acid from an ester?

A

add H2O and H+

70
Q

how do you make a carboxylate anion from an ester?

A

H2O and -OH

you also get ROH

71
Q

what is ester + NH3 (or RNH2 o R2NH)

A

amide + ROH

72
Q

what is the mechanism of acid-catalyzed hydrolysis of an ester to a carboxylic acid?

A

all equilibrium

1) protonation of carbonyl group from H in H-A to make carbonyl more electrophilic (leaving an :A-)
2) nucleophilic addition of H2O onto carbonyl C, cleaving O=C pi bond
3) :A- takes proton from attached H2O, reforming acid & making neutral addition product
4) OR’ group is protonated by H of H-A, leaving :A- and making a good leaving group (R’OH)
5) R’OH leaves & C=O bond is reformed (O is actually an OH)
6) :A- deprotonates the double bonded OH reforming acid H-A and making a neutral product - carboxylic acid

73
Q

what is saponification?

A

basic hydrolysis of an ester (to a carboxylate anion)

74
Q

what is an ester + OH- (a base) and H2O

A

carboxylate anion + alcohol

75
Q

what is the mechanism of base-promoted hydrolysis of an ester to a carboxylic acid?

A

all equilibrium:

1) -OH attacks carbonyl C, pi bond is cleaved, tetrahedral intermediate
2) -OR’ leaves & pi bond is reformed
3) -OR takes H from OH (proton transfer) making neutral alcohol & carboxylate anion — acid-base reaction because -OR is a strong base

76
Q

how can you protonate a carboxylate anion to make a neutral carboxylic acid?

A

add strong acid

77
Q

what is an amide + H2O and H+

A

carboxylic acid + R’2NH2+

78
Q

what is amide + H2O and -OH?

A

carboxylate anion and R’2NH

79
Q

how can you make a carboxylic acid from an amide?

A

add H2O + H+

80
Q

how can you make a carboxylate anion from an amide?

A

H2O + OH-

81
Q

what is the mechanism for amide hydrolysis in base?

A

all equilibrium

1) nucleophilic addition of -OH, pi bond cleaved
2) NH2 leaves, O reforms pi bond with C
3) acid-base reaction occurs b/c carboxylic acid is strong acid & NH2- is a strong base, NH2 takes H from OH and forms carboxylate anion + NH3

82
Q

what is the quirk with amide hydrolysis?

A

NH2 has to leave instead of OH, and OH is a stronger leaving group, so most of the time, the reactant is just reformed when OH leaves.

83
Q

what are keto and enol tautomers?

A

keto had C=O and additional C-H bond

eol has O-H group bonded to C=C

84
Q

which is favored in equilibrium, an enol or a keto?

A

usually the keto because C=O is much stronger than C=C
BUT with 2 carbonyl groups separated by 1C, enol can be more stable because of conjugation and intramolecular hydrogen bonding
C=C is conjugated with carbonyl group - delocalization of e- density in pi bonds AND OH of enol can H bond to O of nearby carbonyl group - forming 6 member ring - way stable

85
Q

what is the mechanism of tautomerization in acid?

A

all equilibrium
1) acid protonates doubled bonded O to make resonance stabilized cation
2) H2O (leftover from H3O that protonated the O in step 1) deprotonates the beta carbon forming the enol. electrons from H that is taken by H2O form the C=C
result is movement of double bond & a proton

86
Q

what is the mechanism of tautomerization in base?

A

equilibrium:
1) base deprotonates H from beta carbon forming resonance-stabilized enolate (double bond goes between two carbons and C-O)
2) protonation of enolate with H2O forms enol and reforms base
C=C-OH

87
Q

how do enols react?

A

enols are electron rich so they react as nucleophiles - OH group has electron-donating resonance effect, and there are 2 resonance structures
enols react with electrophiles to form new C-E bond on alpha carbon substituting H for E on the alpha C

88
Q

what is an enolate?

A

a deprotonated alpha carbon to a carbonyl group

base removes it

89
Q

what factors increase acidity?

A

resonance stabilization of the conjugate base (CH2=CHCH3 more acidic than CH3CH2CH3, CH3COOH is more acidic than CH3CH3OH)
and placing a negative charge on O in the conjugate base (CH2CH2OH is more acidic than CH3CH2CH3, CH3COCH3 is more acidic than CH2=CHCH3, CH3COOH (with 2 O atoms) is more acidic than CH3COCH3)

90
Q

how does pKa relate to acidity?

A

the lower the pKa, the stronger the acid

91
Q

how can you form lots of enolate?

A

use a very strong base (LDA - nonnucleophilic base, or Na+H-) NaH forms H2 - very weak acid.

92
Q

are enolates nucleophiles or electrophiles?

A

nucleophiles

93
Q

what is an ambident nucleophile?

A

a nucleophile with 2 reactive sites
enolates are ambident nucleophiles because the C and O that bear negative charges can both react - they could form 2 different products, one with a new bond at the C, one with a new bond at the O

94
Q

which part of the enolate usually reacts and why?

A

usually reacts at the C end because it that end is more nucleophilic.

95
Q

what is the general reaction of an enolate with carbonyl compounds?

A

usually:

1) reaction of a carbonyl compound with base forms an enolate
2) reaction of the enolate with an electrophile forms a new bond on the alpha carbon

96
Q

what is a ketone or aldehyde + base or acid + X2?

A

substitution of X for H on the alpha carbon

97
Q

what is the mechanism of acid-catalyzed halogenation at the alpha carbon of a ketone or aldehyde?

A

ketone is converted to its enol tautomer
1) protonation of carbonyl O from H on acid
2) A- deprotonates alpha carbon, double bond forms between carbonyl carbon & alpha carbon, pi bond between carbonyl C & O is cleaved making OH neutral
reaction of enol with halogen
3) pi bond attacks X2, O double bond is reformed, leaving X- and positively charged O
4) X- attacks H on OH, H’s electrons go to the O
results in substitution of H by X on the alpha carbon & HX formed as side product

98
Q

what is the problem of halogenation of ketones or aldehydes in bases?

A

often difficult to stop reaction after addition of just 1 halogen to alpha carbon
because once an X is on the atom, it stabilizes the second enolate so the remaining alpha H’s are even more acidic

99
Q

what is the mechanism of halogenation at the alpha carbon in base?

A

1) base deprotonates alpha carbon, forming weak acid and carbanion
2) carbanion attacks X2, leaving X- and substituted alpha carbon - one alpha H is replaced by one X on the alpha carbon

100
Q

what is the mechanism of the haloform reaction (and what is it)?

A

halogenation in methyl ketones with excessive X2 and base
base reacts with 3 alpha H’s on alpha C to replace CH3 with CX3
1) base takes an alpha H making an enolate (carbanion on a carbonyl group)
2) carbanion attacks X2 and takes an X to form neutral product & X-
repeats twice more
Oxidative cleavage with OH-
3) OH- attacks carbonyl group, cleaving O pi bond
4) CX3 group leaves, pi bond is reformed
5)proton transfer, CX3- group takes H off of OH to form carboxylate anion & HCX3 (HCI3 is iodoform)

101
Q

what do you get with a methyl ketone, excessive X2 and base?

A

oxidative cleavage

RCOO- and HCX3 (haloform)

102
Q

what are the 2 reactions of alpha-halo carbonyl compounds?

A

1) elimination with base

2) substitution with nucleophiles

103
Q

how do you turn a ketone into an -enone? (a double bond one away from the ketone?

A

1) bromination of alpha carbon with Br2 in CH3COOH

2) elimination of Br and H with Li2CO3 and LiBr in DMF

104
Q

what is an alpha-halo carbonyl + CH2NH2 (or another nucleophile?)

A

substitute the NHCH3 for the Br - SN2 reaction

105
Q

what is ammonia?

A

NH3

106
Q

what is the special property of an amine?

A

they are stronger bases and better nucleophiles than other neutral organic compounds
the N atom has a nonbonded electron pair

107
Q

what is an amine + electrophile?

A

ammonium salt (compounds with 4 bonds to N)

108
Q

what is the geometry of an amine N?

A

sp3 hybridized & trigonal pyramidal, bond angles 109.5°

109
Q

which atom is most electronegative, C, H or N

A

N

110
Q

How do you name an amine?

A

1° find longest C chain bonded to amine N, change -e ending of parent alkane to -amine
common: name alkyl group bonded to N atom & add -amine (methylamine common, methanamine, iupac)
2° use di- or tri- with the name of the primary amine for symmetrical amines
asymmetrical: designate longest chain bonded to N as parent amine & assign common or IUPAC name, 2) name other groups on N atom as alkyl groups, alphabetize them, and put N- before each substituent name

111
Q

how do you name an aromatic amine?

A

named as derivatives of aniline (benzyl ring with NH2 attached)
like N-ethylaniline or o-bromoaniline

112
Q

what is pyridine?

A

benzene ring with N instead of one C

113
Q

what is pyrrole?

A

5 member ring, one of points is NH, 2 double bonds

114
Q

what is piperidine?

A

cyclohexane with NH replacing one of the C’s

115
Q

what is pyrrolidine?

A

cyclopentane with NH replacing one of the C’s

116
Q

what are the physical properties of amines?

A

dipole-dipole interactions because of polar C-N and N-H bonds
primary & secondary also capable of intermolecular H bonding because they have N-H bonds BUT weaker than inter-molecular O-H bonds because N is less electronegative than O

117
Q

what are the boiling & melting points of amines?

A

1° and 2° have higher bp’s than ethers (ethers are not capable of H bonding) but lower bp’s than alcohols, because alcohols have stronger intermolecular H bonds
3° amines have lower bp’s than primary & secondary because they have no N-H bonds, so no H-bonding

118
Q

what is the solubility of amines?

A

soluble in organic solvents
less than or equal to 5C’s water soluble because they can H bond with water
greater than 5 C’s, not soluble because nonpolar alkyl portion too large to dissolve in polar solvent.

119
Q

how can you synthesize an amine?

A

1) nucleophilic substitution
2) reduction of other nitrogen-containing functional groups
3) reductive amination of aldehydes and ketones

120
Q

what is the mechanism of nucleophilic substitution when preparing an amine?

A

1) nucleophilic attack of nitrogen nucleophile forms an ammonium salt R-X + NH3 –> (NH3R+ or NH2RR’+ or NHR’2R+ or NR’3R+) and X-
2) removal of a proton on N forms the amine (removed by another NH3) —> amine + NH4+ (or R’NH3+ or R’2NH2+)

121
Q

when is nucleophilic substitution useful in preparing amines?

A

useful for 1° when there is a large excess of NH3 and for quaternary ammoniom salts by alkylating any N nucleophile with 1 or more equivalents of alkyl halide

122
Q

what is a stronger base, ammonia or NH3R?

A

N with R group - stabilizes product cation because of inductive effect of R group (donates electrons to the N

123
Q

what is a zwitterion?

A

molecule having a positive and a negatively charged group

124
Q

what is a stronger base, an amine in a chain or an aromatic amine?

A

chain is stronger base than aromatic ring because lone pair contributes to ring resonance for zwitterion on ring
(methyl group on ring will make it more basic, because it stabilizes the lone pair - electron donating makes ring more basic, electron withdrawing makes it more acidic)

125
Q

how acidic must something be to react with amine?

A

pKa of starting acid must be less than 10 for equilibrium to favor products, because protonated amine pKa is usually between 10-11
equilibrium favors acid with higher pKa

126
Q

How can you tell whether an amine is going to react as a base or as a nucleophile?

A

will react as a base with a compound that contains acidic protons
will react as nucleophile with compound that contains electrophilic C (cation)

127
Q

How can you compare the basicity of 2 compounds?

A

any factor that increases electron density on N atom increases amine’s basicity (makes conjugate acid weaker)
any factor that decreases electron density on N decreases amine’s basicity (makes conjugate acid stronger)
increase density - increase basicity
decrease e density - decrease basicity

128
Q

what does more basic mean?

A

it wants a proton more than a weak base (because a strong base forms a weak conjugate acid - an acid that holds onto the H)

129
Q

what kinds of compound can protonate an amine?

A

strong inorganic acids (like HCl and H2SO4) and carboxylic acids

130
Q

what do you get with NH3 (H can be R) + epoxide?

A

beta amino alcohol (OH on one of the C’s and NRH on the other C)

131
Q

How do you make an amine from an amide?

A

part 1: reduction of aminde to imine use LiAlH4
1) H from H-AlH3 takes H from NH2 group on carbonyl, cleaves pi bond on O and forms C=N + H2
2) electrons on O attack AlH3- to form OAlH3 leaving group
3) H3Al-H (the H part) attacks C, C=N bond cleaves & pi electrons go to N
4) O-AlH3 leaves, C=N reforms (that’s an imine)
part 2: reduction of imine to an amine
5) H from H3Al-H attacks C, C=N bond cleaves & pi electrons go to N
6) H2O protonates NH- and forms amine + OH-

132
Q

How do you make an amine from a nitrobenzene (and what is a nitrobenzene)

A

nitrobenzene is NO2 on a benzene ring

add H2 and Pd-C, substitutes an NH2 on the ring for the NO2

133
Q

How do you make an imine from a ketone or an aldehyde?

A

add R’‘NH2 - only works with 1 or 2 degree amine
1) nucleophilic attack of amine (N goes to C, C=O bond cleaved & electrons go to O)
2) proton transfers from the NH2R” to the O- to make :O: and neutral NHR” (with R”NH2 help)
part 2 - elimination of H2O forms imine
3) H from R”NH3 protonates OH to form leaving group
4) H2O leaves along with electrons, N electrons form double bond with C to make positively charged N
H2O takes extra H from N group to form imine

134
Q

what do you get with ketone or aldehyde + R”NH2?

A

C=O bond is replaced by C=NR”

135
Q

what is an enamine?

A

nitrogen atom bonded to a double bond (alkene + amine)

136
Q

How do you make an enamine from an aldehyde or ketone?

A

part 1 nucleophilic addition forms carbinolamine
1) HNR2 attacks carbonyl C, O= cleaves, electrons go to O, added NHR2 is +
2) proton transfers from NHR2 to O to form neutral N & OH (carbinolamine)
part 2 elimination of H2O forms examine
3) H3O protonates OH
4) H2O leaves, electron pair on N forms double bond with C=N forming resonance stabilized iminium ion
5) H2O removes proton from adjacent C-H bond to make C=C forming enamine

137
Q

what is an imine?

A

C=NR

138
Q

what is aldehyde or ketone + R2NH plus mild acid

A

replace O with NR2, make double bond on adjacent carbon - enamine

139
Q

How do you make an amine from an imine?

A

add NaBH3CN

R=NR + NaBH3CN —> replace double bond with an H on the N and an H on the C

140
Q

What is R=NR + NaBH3CN

A

amine - replaces R=N with H on the R and on the N

141
Q

what is enamine + H2/Pd

A

amine

removes double bond & adds H’s to each C

142
Q

how do you make an amine from an enamine?

A

H2/Pd

143
Q

what is a polymer?

A

large molecule made up of repeating units of smaller molecules called molecules

144
Q

How do you figure out how to make a polymer from a monomer?

A

draw 3 or more alkene monomers, break double bond & connect the alkenes with single bonds (C to C from alkene part - the rest sticking out)

145
Q

what is a monomer?

A

repeating unit

146
Q

what is a dimer

A

2 units

147
Q

what are the functional groups of a carbohydrate?

A

OH and C=O
Ca(H2O)b
H and O are always 2:1 ratio
carbons and waters

148
Q

what is a monosaccharide?

A

3-7 C atoms in a chain, carbonyl group on C1 or C2, hydroxy group on the rest
draw vertically w/carbonyl @ top

149
Q

what are the 2 kinds of monosaccharides?

A

aldoses - carbonyl at C1 (aldehyde)

ketoses (carbonyl at C2 (ketone))

150
Q

How do you name a monosaccharide?

A
  • ose ending, prefix = # of C’s in chain

i. e. aldopentose (5 carbons, carbonyl @ C1)

151
Q

How do you know how many stereoisomers a molecule has?

A

2n (n is the number of chiral centers)

152
Q

How do you draw a fischer projection?

A

vertical lines are what goes behind, horizontal are what comes forward, C is at the cross, CHO is at the top (or 2nd)

153
Q

what do the D and L label on monosaccharides mean?

A

D = R (ReD) configuration of stereogenic center FARTHEST from carbonyl group, D sugar has OH on the lowest C on the right
L = S (SaiL) configuration of stereogenic center farthest from carbonyl
L sugar has OH group on Left

154
Q

which kinds of sugars are naturally occurring?

A

D-sugars

farthest down OH is on the right (ReD)

155
Q

how are D’s and L’s related?

A

they are enantiomers - non-superimposable mirror images at every stereogenic center

156
Q

on the sugar chart, how are the sugars in each row related?

A

they are diastereomers of that aldose group

157
Q

what is an epimer?

A

diastereomer that only has one different stereo center

158
Q

what is an anomer?

A

stereoisomers of a cyclic monosaccharide that differ in the position of the OH group at the hemiacetal carbon (a hemiacetal is an OH group on a carbonyl group C to an OR and to an OH)

159
Q

what does pyranose mean?

A

6 member ring containing an O atom

160
Q

what is furanose?

A

5 member ring containing an O atom

161
Q

to draw a hemiacetal from a fischer projection

A

1) count down 5 or 6 atoms from carbonyl to find the O that connects to the top
2) rotate last part so that all of the atoms needed for the ring are in a vertical line (switch the OH to the bottom, move the others clockwise until it lines up)
3) draw fischer projection the new way
4) draw the ring with the top and the bottom connected and the other atoms projecting up and down

162
Q

what are alpha and beta anomers of monosaccharides?

A

alpha anomer has OH group and the CH2OH group trans
beta has OH group and CH2OH group cis
AlphA trAns
beta cis

163
Q

How do you draw a hawthorn projection from an acyclic monosaccharide

A

1) put O atom in upper right hand corner of a hexagon & put CH2OH group on first C counter clockwise from O
D sugars has CH2OH up, L sugars CH2OH goes down
2) C1 is first C clockwise from O. alpha puts the OH down, beta puts the OH up (carbonyl carbon becomes anomeric carbon - a new stereogenic center)
3) add substituents clockwise around the ring, right side of fischer projection go down, left side of fischer projection go up

164
Q

How do you convert a hawthorn projection to the acyclic form?

A

1) draw carbon skeleton, placing CHO at the top and CH2OH at the bottom
2) classify sugar as D or L (if CH2OH is up, it’s D, if if CH2OH is down, it’s L). D sugar has last OH on the right
3) add the remaining stereogenic centers. Ups go on the left, downs go on the right (Lups)

165
Q

what is a peptide?

A

2 or more amino acids joined together by amide bonds

166
Q

what is a protein?

A

long group of amino acids - usually 40 or more

167
Q

what is the backbone of a protein?

A

NH-C–C-NH-C-C-NH-C-C with alternating R and =O on the C’s

168
Q

what is the general feature of an amino acid?

A

amino group bonded to alpha carbon of a carboxy group

169
Q

what is the N-terminal amino acid?

A

the amino acid with a free amino group when bonded to another amino acid

170
Q

what is the C-terminal amino acid?

A

the amino acid with the free carboxy group

171
Q

which order do you draw amino acid chains?

A

with N-terminal on left and c terminal on right

Organic Chemistry (6 decks)

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