Organic Synthesis Flashcards Preview

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Flashcards in Organic Synthesis Deck (45):
1

Clean blue flame

Alcohol or ester

2

Yellow flame

Alkane

3

Smoky yellow flame

Unsaturated/aromatic compound

4

Insoluble in water; two layers form

London forces only in hydrocarbon

5

Partially soluble forming an emulsion

H-bonds in long chain alcohol or p.d.-p.d. or leave to settle

6

Soluble Homogenous Liquid

H-bonds in alcohol or acid

7

>C=C< test 1

Shake with Br water at room temp,
Orange--> colorless
RCH=CHR + HOBr --> RCHBrCHOHR (Bromoalcohol)

8

>C=C< test 2

Shake with dil. H2SO4 + KMnO4
Purple--> colourless (possible brown ppt)
RCH=CHR + [O] + H2O --> RCHOHCHOHR (Alkanediol)

9

C-Cl
C-Br
C-I

Use ethanol as solvent. warm with NaOH(aq). Acidify with dil. HNO3 and add AgNO3. ppt produced. add dil NH3, then conc. NH3

White ppt soluble in dil. NH3
Cream ppt soluble in conc. NH3
Yellow ppt insoluble in either

RCH3X + OH- --> RCH3OH + X-
X- + Ag- --> AgX (ppt)

10

C-OH test 1

PCl5, Anhydrous, room temp, test gas produced with conc. NH3

Steamy fumes produce white smoke with NH3

R-OH + PCl5 --> R-Cl + POCl3 + HCl
HCl + NH3 --> NH4Cl, white smoke

11

C-OH test 2

K2CR2O7 + Dil. H2SO4 (Acidified dichromate)

Orange sol. --> green/blue-green

12

C-OH test 3

Add small piece of sodium

Effervescence, sodium disappears, white solid produced

CH3CH2OH + Na --> CH3CH2O-Na+ H2(g)

13

Carbonyl Group Test

2,4-DNP + few drops conc. H2SO4 warm

Orange sol. forms orange/red crystals

2,4-dinitrophenylhydrazine--> 2,4-dinitrophenylhydrazone
practice mechanism

14

Test 1 to differentiate between aldehyde and ketone

Fehlings solution; add Fehlings A (Cu2+) and Fehlings B (tartrate) and warm

Blue solution-->red ppt

Cu2+(aq) + e- --> Cu+(s), therefore reducing group present, aldehyde
Aldehyde --> Carboxylic Acid

15

Test 2 to differentiate between aldehydes and ketones

Tollens Reagent; AgNO3(aq) + dil NH3 add to unknown and warm,

Colourless solution forms silver mirror on test tube sides

[Ag(NH3)2]+(aq) + e- --> Ag(s) + 2NH3(aq)
reducing agent present=aldehyde,
aldehyde--> carboxylic acid

16

Test for methyl ketone

Iodoform test; I2 crystal, shake with unknown, add dil. NaOH dropwise & warm

Pale yellow crystals with antiseptic smell

Crystals = CHI3, iodoform
RCHOHCH3 + [O] --> RCOCH3 + H2O, Methyl ketone

RCOCH3 + 3I2 + 4NaOH --> RCOO-Na+ + CHI3 + 3NaI + 3H2O
Sodium carbodylate salt + iodoform

17

RCOOH

litmus turns red

Add to carbonate e.g. NaHCO3, at room temp,
Effervescence, limewater turns milky
RCOOH --> RCOO- + H+
HCO3- + H+ --> H2O + CO2

Estherification; ROH, few drops of conc. H2SO4 and warm
Sweet smell
RCOOH + ROH --> RCOOR + H2O

18

Substitution: Nucleophilic

Halogenoalkane; RX

RX + OH- --> ROH + X-, alcohol

RX + CN- --> RCN + X-, nitrile (note, if carbon chain extends by, this probably has something to do with it

RX + NH3 --> RNH2 + HX, amine

19

Substitution: Electrophilic

Aromatics;

Benzene + HNO3/H2SO4 --> Nitrobenzene

Benzene + Cl2 AlCl3/FeCl3 --> Chlorobenzene

Benzene + RX/AlCl3 --> Alkyl benzene

Benzene + RCOCl/AlCl3 --> acylbenzene

20

Substitution: Free Radical

Alkanes + Halogen, X

Alkane + X2/UV --> Halogenoalkane

21

Addition: Nucleophilic

Carbonyl compounds + HCN --> Hydroxynitryl

22

Addition: Electrophilic

Alkene + Cl2 --> dichloroalkane

Alkene + HCl --> Chloroalkane

23

Addition: Polymerisation

Alkenes --> polymers

24

Oxidation: alkene

reagents and conditions: KMnO4 and dil NaOH(cold)/Diol

Product: Diol

25

Oxidation: Alcohol

reagents and conditions: distillation, acidified dichromate, K2Cr2O7 + dil. H2SO4

Product: Aldehyde

26

Oxidation: Aldehyde

Reagents and conditions: Reflux, acidified dichromate

Product: Carboxylic Acid

27

Reduction: Alkene

Reagents and conditions: Heated nickel catalyst or room temp Pt catalyst, H2 Hydrogenation

Product: Alkane

28

Reduction: Aldehyde

Reagents and conditions: NaBH4 or LiAlH4 sol. room temp

Product: Alcohol

29

Reduction: Carboxylic acid

Reagents and conditions: LiAlH4, dry ether followed by dil. HCl Hydrolysis

Product: alcohol

30

Reduction: Ketone

Reagents and conditions: NaBH4 sol. room temp

Products: Secondary alcohol

31

Reduction: Nitrobenzene

Reagents and conditions: Sn and conc. HCl, heat under reflux followed by dil. NaOH

Products: Phenylamine

32

Reduction: Nitrile

Reagents and conditions: LiAlH4, dry ether, followed by dil. NaOH

Products: Amine

33

Carboxylic acid + alcohol

Reagents and conditions: Conc. H2SO4, anhydrous, warm

Product: Ester

34

Acid Chloride + H2O/ROH/NH3/RNH2

Reagents and conditions: add the two at room temp or warmed

Product: Carboxylic acid, ester, (N-substituted) amide

35

Hydrolysis: Ester

Reagents and conditions: Strong acid/based hydrolysis under reflux

Products: Carboxylic acid + alcohol

36

Hydrolysis: Nitrile

Reagents and conditions: dil. HCl or dil. NaOH, under reflux

Products: Carboxylic acid + Carboxylate salt

37

Elimination

Reagents and conditions: Ethanolic KOH under reflux

Products: Alkene

38

Acid/Base: Alcohol + Na

Reagents and conditions: room temp, small piece of sodium

Products: Sodium Alkoxide

39

Acid/Base: Carboxylic acid + alkali

Reagents and conditions: room temp

Products: carboxylate salt + water

40

Acid/Base: Amine + HCl

Reagents and conditions: room temp

Products: alkyl ammonium salt

41

Decreasing carbon skeleton: Iodoform

e.g.1: primary alcohol, CH3CH2OH + 3I2 + 4NaOH --> HCOO-Na+ + CHI3 + 3NaI + 3H2O

e.g.2: methylketone, CH3COCH3 + 3I2 + 4NaOH --> CH3COO-Na+ + CHI3 + 3NaI + 3H2O

42

Decreasing Carbon skeleton: Ester hydrolysis

RCOOR + H2O (dil.acid or alkali, reflux) ---> RCOOH/RCOO-Na+ + ROH

43

Increasing carbon skeleton by one

HCN + Carbonyl compound
RCOR + HCN (KCN + alkaline buffer or ethanol) --> RCOH(CN)R

KCN + halogenoalkane
RCl + KCN (ethanol, reflux) --> RCN + KCl

44

Increasing carbon skeleton by one or more: Alkylation

Catalyst AlCl3 to produce electrophile
AlCl3 + RCl --> AlCl4- + R+

Electrophilic addition
C6H6 + R+ --> C6H5R + H+

45

Increasing carbon skeleton by one or more: acylation

Catalyst AlCl3 to produce electrophile
AlCl3 + RCOCl --> AlCl4- + RCO+

Electrophilic addition
C6H6 + RCO+ --> C6CH5COR + H+