Part 6 Flashcards
Reductive amination
Process whereby an aldehyde or ketone is reacted with ammonia, a primary amine, or a secondary amine to form a primary, secondary, or tertiary amine, respectively.
Amine + (Aldehyde or Ketone) –>
Product: Imine
Additional reduction with hydrogen in presence of a catalyst (Raney Nickel) = amine.
Imine + (H2/Nickel) –>
Product: Amine
Imine
Nitrogen double bonded to a carbon and has about the same polarity as a carbonyl functionality.
DMSO
Good Polar Aprotic Solvent.
Therefore, good in SN2 reactions.
CN-
Strong nucleophile.
Good in SN2 reactions.
I-
Weak base, therefore good leaving group for SN2 reaction.
Definition of aromtaticity
(4n + 2) pi
So, can be 2, 6, 10, etc…
Cl2 + FeCl3 + Aromatic –>
Cl is Ortho, Para-directing, so will attach Cl to para or ortho positions depending on substituents.
KMnO4
Oxidizing agent
Change toluene to COOH.
HNO3/H2SO4 + toluene –> ?
R-groups are Ortho-, para- directing, so nitro will add to ortho or para position.
Wolff-Kishner Reduction
Aldehydes and ketones can be completely reduced to alkanes by this metho. The carbonyl is first converted to a hydrazone, which releases molecular nitrogen when heated and forms an alkane. Only useful under basic conditions.
(use H2NNH2/Base/heat)
Clemmensem Reduction
Where an aldehyde or ketone is heated with amalgamated zinc in hydrochloric acid.
Grignard Addition
Grignard reagents (RMgX) add to the carbonyl groups of ESTERS to form KETONES; however, the ketones are more reactive than the initial esters and are readily attacked with more grignard reagent to make TERTIARY ALCOHOLS.
Claisen Condensation
Important reaction of ESTERS.
Simplest case: two moles of ethyl acentate react under basic conditions to produce a beta-keto ester. Also called teh acetoacetic ester condensation.
Enolate ion of one ester acts as a nucleophile, attacking another ester.
Grignard reagent
RMgX (equivalent to R- nucleophile)
Transesterification
When a different alcohol attacks the ester, the ester is TRANSformed, and TRANSesterification results.
(ester into another ester)
NH3 + ester –> ?
Answer: amide + alcohol
Nitrogen bases such as ammonia will attack the electron-deficient carbon atom, displacing alkoxide, to yield an amide and an alcohol side product.
Hofmann Rearrangement
Converts amides to primary amines with the LOSS of the carbonyl carbon.
Involves the formation of a nitrene (nitrogen analog of carbene).
Reduction of Amides –> ?
Amides can be reduced with LAH to the corresponding AMINE, but NO carbon is lost.
KMnO4 + H2O2/OH-
Oxidation reagent. Will reduce to carboxylic acids.
