Synthesis routes Flashcards by Joe Wright-Laprugne

How is the carbon chain extended when synthesising new compounds?

Refluxing the alkane with potassium cyanide in ethanol to form a nitrile. Turning the nitrile into an amide and then hydrolysing it, forming a carboxylic acid

How well did you know this?

Not at all

Perfectly

Reducing a phenylketone

Reduce using NaBH4 to break the C=O bond and add 2 hydrogens

How well did you know this?

Not at all

Perfectly

Aromatic amine + halogen

Replaces H with halogen at positions 2, 4, and 6

How well did you know this?

Not at all

Perfectly

Amine + acid

N forms a dative covalent bond with the proton, making a quaternary salt

How well did you know this?

Not at all

Perfectly

Amino acid carboxylic group + base

Water + sodium carboxylate salt

How well did you know this?

Not at all

Perfectly

Amino acid carboxylic group + alcohol

Water + ester made from COOH of amino acid

How well did you know this?

Not at all

Perfectly

Amino acid carboxylic group + metal ion

Metal carboxylate salt + hydrogen/CO2/water

How well did you know this?

Not at all

Perfectly

Amino acid amine group + acid

Quaternary amine salt

How well did you know this?

Not at all

Perfectly

Amino acid amine group + R-X

R added to nitrogen, H+ removed, H+ and X- left over

How well did you know this?

Not at all

Perfectly

Primary amide + hot acid and water

Carboxylic acid + ammonium ion

How well did you know this?

Not at all

Perfectly

Secondary amide + hot acid and water

Carboxylic acid + RNH3+

How well did you know this?

Not at all

Perfectly

Primary amide + Hot OH- and water

Carboxylate + ammonia

How well did you know this?

Not at all

Perfectly

Secondary amide + Hot OH- and water

Carboxylate + RNH2

How well did you know this?

Not at all

Perfectly

Preparation of aromatic amines

Nitrobenzene + Sn + conc HCl under reflux => Phenylamine

ArNO2 + 6[H] + HCl => ArNH3+ + Cl- + 2H2O
ArNH3+ + Cl- + NaOH => ArNH2 + NaCl + H2O

How well did you know this?

Not at all

Perfectly

Reduction of nitriles

A reducing agent turns the -C≡N group into -C-NH2
Agents:
anhydrous LiAlH4: 4[H]
anhydrous Na (alcohol): 4[H]
Ni (catalyst): 2H2

How well did you know this?

Not at all

Perfectly

How can you control the major product of the reaction between haloalkanes and ammonia?

Excess ammonia means the major product is the primary amine

Excess haloalkane means the major product is the quaternary salt

How well did you know this?

Not at all

Perfectly

Formation of an aliphatic amine

Haloalkane + anhydrous ethanol + NH3 => Halide ion + Amine salt
Halide ion + amine salt + OH- => Amine + H2O + Halide ion

How well did you know this?

Not at all

Perfectly

Extending the carbon chain

Reflux a solution of the haloalkane, potassium cyanide and ethanol
C-Cl becomes C-C≡N

C-C≡N can be reduced to an amine
H2O and H+ turns C-C≡N into CONH2
H2O and H+ turns CONH2 into COOH

CH3COOH + SOCl2 =>

Anhydrous conditions

CH3COCl + SO2 + HCl

Overall reaction of acyl chlorides (RCOCl)

RCOCl + HX => RCOX + HCl

HX can be water, an alcohol, phenol, ammonia, or an amine

What happens in the initiation stage of the halogenation of an alkAne?

The UV light splits the halogen molecule into 2 radicals (Br₂ => 2Br•)

What happens in the propagation stage of the halogenation of an alkAne?

Radicals react with non-radicals, building up the products of the reaction

C₂H₆ + Br• => •C₂H₅ + HBr
•C₂H₅ + Br₂ => C₂H₅Br + Br•

What happens in the termination stage of the halogenation of an alkAne?

The radicals come together to form stable products

2Br• => Br₂
2•C₂H₅ => C₄H₁₀
•C₂H₅ + Br• => C₂H₅Br

Hydrogenation of an alkEne

Converts alkEne to alkAne

C₂H₄ + H₂ => C₂H₆

150 degrees, nickel

Hydration of an alkEne

Acid and steam, produces an alcohol.

How do you determine the major product of a reaction between a hydrogen halide and an asymmetrical alkene?

Use Markownikoff's rule: The hydrogen bonds to the carbon atom already bonded to the most hydrogens to begin with. This is because carbocations with other carbons bonded to the C+ are more stable, meaning they react less easily

What happens when a primary alcohol is fully oxidised by K2Cr2O7?

Water and a carboxylic acid are formed

What happens when a secondary alcohol is heated under reflux with K2Cr2O7?

Water and a ketone are formed

What happens when you gently heat a primary alcohol with an oxiding agent (such as K2Cr2O7), and distil immediately?

The alcohol is partially oxidised to an aldehyde, and water is formed

Describe esterification

An alcohol and a carboxylic acid react in the presence of an acid catalyst to form an ester. This reaction is slow and reversible.

What happens when an alcohol is heated with a strong acid?

The -H and the -OH are removed from the carbon backbone, forming water and an alkene

How are esters formed in the lab?

Alcohol and carboxylic acid mixed in test tube. Sulfuric acid is added and the tube is kept in a hot water bath

How are alcohols dehydrated in the lab?

Alcohol is heated under reflux with sulfuric or phosphoric acid for 40 minutes

How do hydrogen halides react with alcohols?

They form a haloalkane and water.

How can you predict the product of the dehydration of an alcohol?

Primary alcohol => One alkene Secondary alcohol => Two alkenes (stereoisomers) Tertiary alcohol => No reaction

Describe the nitration of benzene

Warm benzene is added to concentrated nitric acid and sulfuric acid. This releases electrophilic NO2+ ions into the solution. An electron from the delocalised electron ring in the benzene molecule bonds the NO2+ to one of the carbons. The H bonded to the same carbon donates its electron back to the delocalised ring and becomes a free H+ ion

How can you form a salt from phenol?

Phenol is weakly acidic, so it reacts with NaOH to form sodium phenoxide and water. It also does the same with sodium.

What are the conditions for making chlorobenzene?

Chlorine gas and solid aluminium chloride (completely anhydrous)

How is nitromethylbenzene produced from benzene?

Benzene requires nitration and alkylation. The nitro group is 3-directing, whereas the methyl group would be 2, 4 and 6-directing.

Describe the nitration of phenol

Phenol reacts with dilute nitric acid to form two isomers of nitrophenol, and water. Due to the increased reactivity of phenol compared to benzene, it doesn't require a catalyst

What is Friedel-Crafts alkylation?

A reaction that puts an alkyl group (such as methyl) on a benzene ring using a haloalkane and a halogen carrier. The reaction is C6H6 + RX + AlCl3 => (reflux) C6H5R + HCl

What is Friedel-Crafts acylation?

A reaction that substitutes a H in benzene for an acyl group. The reaction is C6H6 + RCOCl + AlCl3 => (reflux) C6H5COR + HCl. If R is a hydrogen, the product is benzaldehyde, otherwise it's a phenylketone

Carbonyl + acid + cyanide

=O becomes -OH, CN added