Identify the correct K\_b order in the following compounds :... | Organic Chemistry - Heterocyclic Compounds | SolveeIt

Identify the correct $K_b$ order in the following compounds :

$2>1>3>4$

$1>2>3>4$

$1>2>4>3$

$2>4>3>1$

Answer

1 > 2 > 4 > 3

Explanation

Explanation:

(1) is an imidazole derivative where one nitrogen is pyridine‐like (available lone pair), making it quite basic.
(2) is pyrrole; its lone pair is part of the aromatic sextet so it’s less basic than (1).
(4) is a lactam type (one C=O group) with the nitrogen lone pair partly delocalized into the carbonyl, making it less basic than pyrrole.
(3) with two C=O groups (an imide type) has its lone pair much more delocalized and is the least basic.

Thus, the order of basicity (K₍b₎ order) is:
(1) > (2) > (4) > (3)

Question: Identify the correct $K_b$ order in the following compounds : ...