Organic Synthesis

Question 1

Benzene → Nitrobenzene

Answer 1

Electrophilic substitution (nitration). Concentrated H2SO4 + concentrated HNO3 at 50 °C

Question 2

Phenylalkyl ketone → Alkylbenzene

Answer 2

Reduction. Zn + concentrated HCl

Question 3

Ester → Carboxylic acid

Answer 3

Nucleophilic substitution- hydrolysis. Aqueous NaOH; heat and then dilute acid

Question 4

Acid chloride or Acid anhydride → Ester

Answer 4

Nucleophilic substitution- condensation. Alcohol and a base

Question 5

Alkene → Dibromide (Dihalide)

Answer 5

Electrophilic addition. Aqueous Br2 (or aqueous halogen)

Question 6

Carboxylic Acid → Acid anhydride

Answer 6

Nucleophilic substitution. P2O5

Question 7

Amide → Carboxylic acid

Answer 7

Nucleophilic substitution - hydrolysis. 5 mol dm^-3 HCl; heat for 24 hours

Question 8

Primary amine → Secondary amine

Answer 8

Nucleophilic substitution. Halogenoalkane in ethanol solvent; heat

Question 9

Carboxylic Acid → Ester

Answer 9

Nucleophilic substitution - condensation. Alcohol with concentrated H2SO4

Question 10

Carboxylic acid → Acid chloride

Answer 10

Nucleophilic substitution. PCl5 or SOCl2

Question 11

Halogenoalkane → Primary amine

Answer 11

Nucleophilic substitution. Excess concentrated NH3 in ethanol solvent; heat

Question 12

Alkane → Halogenoalkane

Answer 12

Free-radical substitution. Halogen with UV light to initiate

Question 13

Alkene → Alkane

Answer 13

Reduction. H2 and Ni (hydrogen and nickel catalyst)

Question 14

Alcohol → Alkene

Answer 14

Elimination- dehydration. Concentrated H2SO4; heat

Question 15

Phenylamine → Amide

Answer 15

Nucleophilic substitution (acylation). Acyl chloride

Question 16

Primary alcohol → Aldehyde

Answer 16

Partial oxidation. K2Cr2O7 and dilute H2SO4; distil

Question 17

Benzene → Cyclohexane

Answer 17

Reduction. H2 + Ni catalyst at 150 °C

Question 18

Secondary amine → Tertiary amine

Answer 18

Nucleophilic substitution. Excess halogenoalkane in ethanol solvent; heat

Question 19

Acid anhydride → Amide

Answer 19

Nucleophilic substitution - condensation. Ammonia or amine

Question 20

Aldehyde → Carboxylic acid OR Secondary alcohol → Ketone

Answer 20

Full oxidation. Excess K2Cr2O7 and dilute H2SO4

Question 21

Halogenoalkane → Nitrile

Answer 21

Nucleophilic substitution. KCN in ethanol; heat

Question 22

Nitrile → Primary amine

Answer 22

Reduction. LiAlH4 in ethoxyethane solvent

Question 23

Acid chloride OR Acid anhydride → Carboxylic acid

Answer 23

Nucleophilic substitution- hydrolysis. H2O

Question 24

Alkene → Alcohol

Answer 24

Electrophilic addition - hydration. Catalytic H2SO4 in water

Question 25

Tertiary amine → Quaternary ammonium salt

Answer 25

Nucleophilic substitution. Large excess of halogenoalkane in ethanol; heat

Question 26

Benzene → Phenylalkyl ketone

Answer 26

Electrophilic substitution (Friedel-Crafts). Acyl chloride + AlCl3; heat

Question 27

Nitrobenzene → Phenylamine

Answer 27

Reduction. Sn + concentrated HCl followed by NaOH

Question 28

Carboxylic acid → Amide

Answer 28

Nucleophilic substitution - dehydration. Amine and heat

Question 29

Allene → Halogenoalkane

Answer 29

Electrophilic addition. Aqueous HBr (gives bromoalkane)

Question 30

Nitrile → Carboxylic acid

Answer 30

Hydrolysis. Heat with dilute H2SO4

Question 31

Aldehyde OR Ketone → Hydroxynitrile

Answer 31

Nucleophilic addition. Concentrated solution of HCN and acidification