Q12 · CSIR-NET Chemistry, June 2015
Paper: CSIR-NET June 2015 · Subject: Organic Chemistry · Chapter: Natural Products · Topic: Natural Products – General · Marks: 2 · Difficulty: Medium
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.
Biogenetic precursors for the natural product umbelliferone among the following are 
umbelliferone
umbelliferone(a)L-tryptophan
(b)cinnamic acid
(c)L-methionine
(d)L-phenylalanine
Answer
Under review — not yet confirmed.
Answer: B
Answer: (b) cinnamic acid and (d) L-phenylalanine.
Explanation
Answer: (b) cinnamic acid and (d) L-phenylalanine — Umbelliferone is made by the shikimate/phenylpropanoid pathway: L-phenylalanine → (PAL) cinnamic acid → p-coumaric acid → ortho-hydroxylation, trans→cis isomerisation and lactonisation.
Study loop for Natural Products