Under review — part of this question (a structure or an option) is not clear in the source scan. 4AB is checking it against the original book; the answer shown may change.
The correct sequence of reagents required for conversion of A to B is: i) Thionyl chloride ii) 4-chloropyridine iii) Piperidine
(a)i), ii), iii)
(b)i), iii), ii)
(c)ii), i), iii)
(d)iii), i), ii)
Answer
Under review — not yet confirmed.
Answer: C
Explanation
Do the SNAr with 4-chloropyridine first (ii). Then make the acid chloride (i) and form the piperidine amide (iii). This order prevents the free NH₂ from self-acylating (c).
Study loop for Reagents, Reaction Mechanisms & Named Reactions