GOB Chemistry
(i) carboxylic acid; (ii) amide; (iii) sulfide; (iv) amine
(i) carboxylic acid; (ii) amine; (iii) thiol; (iv) amide
(i) ester; (ii) amide; (iii) sulfide; (iv) amine
(i) ester; (ii) amine; (iii) thiol; (iv) amide