Can someone please help, which ones are correct answers? Thank you so much in ad
ID: 553699 • Letter: C
Question
Can someone please help, which ones are correct answers? Thank you so much in advance!!
A13) Which one of the following statements regarding nitrogen-containing compounds is INCORRECT? A) Amines react with carboxylic acids to give amides. B) Amines react with alkyl halides to give a mixture of products. C) Amines react with acid chlorides to give amides. D) Amides have higher boiling points than esters of similar molecular weights. E) Amides cannot easily be hydrolysed. A14) Which one of the following molecules can be converted to an epoxide when reacted with sodium hydroxide? OH OH OH Br Br NH2 OHExplanation / Answer
A13) OPTION A. Amines react with carboxylic acids and acyl chlorides to yield amides. However, the direct reaction of a carboxylic acid with an amine would be expected to be difficult because the basic amine would deprotonate the carboxylic acid to form a highly unreactive carboxylate. So, when the ammonium carboxylate salt is heated to a temperature above 100 oC water is driven off and an amide is formed. When amines react with alkyl halides, they undergo N-alkylation and yield almost equal quantities of primary and secondary amines - a mixture. Due to the presence of intermolecular H-bonding from the nitrogen of amides to the hydrogens attached to another amide, they possess considerably higher boiling points than similar esters, which are devoid of intermolecular H-bonding. Finally, the reaction conditions neccessary for amide hydrolysis is harsh due to the high inactivity of amides and only under strongly acidic or basic conditions while refluxing do amides get hydrolysed.
A14) OPTION B. Reaction of halohydrins with strong bases like sodium hydroxide yields an epoxide. This dehydrohalogenation with ring-closure proceeds through a SN2 mechanism and thus, the epoxide formation is favoured only when the alcohol and halogen groups are anti to each other i.e. both 180o apart. Since in option A both groups are in the same side (syn), that substrate is not favoured for this transformation.