Ch 18 Aromatic compounds Flashcards
Phenol
Ph-OH
Anisole
Ph-O-CH3
Aniline
Ph-NH2
Benzoic acid
Ph-COOH
Benzaldehyde
Ph-COH
Acetophenone
Ph-COCH3
Styrene
Ph-CH=CH2
Dimmethyl derivatives of benzene are called
Xylene
Huckel’s rule
A compound can only be aromatic if the number of pi electrons in the ring is 2,6,10,14,18 and so on, 4n+2’where n is a while number.
Anti aromatic
FIX: Special molecular instability associated with a closed loop of adjacent, parallel, overlapping p orbitals which contains 4n pi electrons (n = 0, 1, 2, 3, etc.)
Nonaromatic
Def:: A molecule that is neither aromatic or antiaromatic.
Annulenes
Compounds consisting of a single ring containing A fully conjugated pi system
Hetercycles
Cyclic compounds containing heteratoms (such as S,N or O)
Since the lone pair of pyridine does not participate in resonance or aromaticity , it is free to function as a_____.
Base. Pyridine can function as a base because protonation of the nitrogen atom does no destroy the aromaticity
Benzylic position
Any carbon atom attached directly to a benzene ring
Toluene
Ph-CH3
Chromic acid (Na2Cr2O7/H2SO4,H2O) will react with ______ but not benzene or alkanes. Draw reaction
Alkylbenzenes are readily oxidized by chromic acid but selectively at the benzylic position,the benzylic position must have a least one proton.
Free radical bromination (NBS) of a benzylic position is highly _____________.
Regions selective , bromination occurs primarily at the benzylic position due to resonance stabilization of the intermediate benzylic radical.this reaction is important because it allows us to install a functional group at the benzylic Position which can then be exchanged for a different group
Benzylic halide +H2O—->
Alcohol, benzylic halides undergo SN1 reactions very rapidly since the benzylic carbocations is resonance stabilized
When treated with (conc. H2SO4 or NaOEt) benzylic halides undergo _______.
Elimination reactions to form alkenes
PCC will convert an alcohol to an _____
Aldehyde
H2 followed by Pt/2 atm 25 C will _______ in the presence of an aromatic ring
selectively hydrogenate a vinyl in the presence of an aromatic ring
Three equivalents of molecular hydrogen in the presence of nickel at 100 atm,150C will __________ a benzene
Hydrogenate
Na,CH3OH/NH3 will reduce a benzene will be reduced to _______.
1,4-cyclohexadiene, birch reduction
Birch mech
Birch reductions will reduce EWG but not_____.
EDG
