Final Exam Flashcards
list 3 IMF weakest to strongest
LD, DD, hbond
as IMF strength increases, what happens to BP?
also increases
in analagous molecules, which has a high BP: alcohol or amine?
alcohol always
list classes of amines in increasing to decreasing BP
priamry higher than secondary higher than tertiary
when are amines soluble in water?
when contain 5 or fewer carbons per amino group
which is the stronger base: amines? or alcohols and ethers?
amines generally stronger bases than alcohols and ethers
localized or DL LP for better base?
localized
more or less electron density for a better base?
more
EDG or EWG for better base?
EDG
give the 3 types of electron donating groups
lone pair conjugated outside benzene; lone pair with res outside benzene, and alkyl groups; all ortho/para
give the 3 types of EWG groups
halogens (O/P), pi bonds conjugated outside the ring (like CN), are meta, and positive nitrogen or carbon attach to hella electronegative outside the ring, also meta
describe how aromaticity plays into basicity
if LP is what makes a molecule aromatic, it aint a good base; if non or antiaromatic in the first palce, less stable and better base
what are the 2 ways to make an amine from alykl halide?
- nitrile (CN) method (adds a carbon)
- azide (1. NaN3 2. LAH 3. H2O) method (not add carbon)
both SN2 so work great on methyl and primary halides, work ok on secondary, but no work on tertiary halides
how to make amine from carboxylic acid?
turn to acid chloride with SOCl2, then make amide with xs NH3, then reduce and remove C=O double bond with 1) LAH 2) H2O
how to make amines from benzenes or benzene derivatives?
use HNO3 and H2SO4 to make NO2 (keep in mind directing effects of any existing benzene groups) then use H2, Pt to reduce or the milder 1) metal (Fe, Zn, Sn, SnCl2), H3O+ 2) NaOH to not reduce any other groups too
why can’t use ammonia to make primary amine?
overalkylation occurs; will keep going until no lone pairs left and now have a quarternary ammonium salt
what 4 things need for reductive amination?
- carbonyl (aldehyde or ketone)
- acid
- nitrogen source
- NaBH3CN
what can be used to make secondary and tertiary amines?
reductive amination
why is NaBH3CN used in reductive amination instead of NaBH4?
the CN stabilizes boron and makes mroe selectively reductive; can use one pot apporach to reduce imine that forms between carbonyl and nitrogen source without reducing carbonly before reaction even starts
what is a substitution method to make primary amines without overalkylation without needing a carbonyl?
gabriel synthesis
what need for Gabriel synthesis?
- phtalamide
- KOH
- alkyl halide (pirmary or secondary, no tertiary)
- hydrazine (H2NNH2) to free amine
how do you make an aryldiazonium salt?
take an aniline and add NaNO2 plus HCl