amines, amides and amino acids Flashcards
why are amines considered ‘basic’?
the lone pair on the nitrogen can accept a proton, so amines can act as bases (forming a protonated amine, NH3+)
they also react with acids (e.g HCl) to make salts (e.g NH4+Cl-)
preparation of aliphatic amine
haloalkane + ethanolic NH3 ———> ammonium salt
ammonium salt + NaOH ———> primary amine + sodium halide + H2O
preparation/prevention of secondary and tertiary amines from primary amines
once a primary amine has been prepared, it can react again to produce a secondary amine due to the lone pair on the nitrogen.
to produce a tertiary amine, use excess haloalkane. to keep the amine as primary, use excess ammonia.
preparation of an aromatic amine (phenylamine)
nitrobenzene + 6[H] ———> phenylamine + 2 H2
1. tin + c.HCl
2. excess NaOH
what kind of reaction produces a phenylamine from nitrobenzene?
reduction
why do we use excess NaOH in the reduction of nitrobenzene?
reacting nitrobenzene with tin + c.HCl forms phenylammonium chloride. reacting this with NaOH then forms a phenylamine
what is the formula for an amine functional group?
NH2
what is the formula for an amide functional group?
O
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C — N…
amidification of acyl chloride
acyl chloride + NH3———> primary amide + ammonium chloride
acyl chloride + primary amine ———> secondary amide + methylammonium chloride
formula for alpha-amino acid
RCH(NH2)COOH
reactions of amino acid carboxyl group
-COOH + alkali (aq) ———> salt + water
-COOH + alcohol ———> ester + water
reactions of amino acid amine group
-NH2 + acid ———> salt + water
define primary/secondary amides?
primary: one C atom bonded to N
secondary: two C atoms bonded to N
naming secondary/tertiary amines
longest chain directly in front of “amine”
the rest are ordered alphabetically with the locant “N-“
e.g. N-methyl,N-propylbutylamine
