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UPSC Combined Geo-Scientist

Chemist

  • 3 descriptive papers
  • 200 marks each
  • 3 h per paper

Mains Paper III covers analytical and organic chemistry.

UPSC Combined Geo-Scientist, Mains · 2021 · Mains Paper III

Q7(a). Phenol to salicylaldehyde to a coumarin ester

Question

Complete the following reaction while sketching the suitable mechanism: phenol →(CHCl₃, KOH) I →(diethyl malonate, piperidine) II [scheme given in the paper]

Answer in brief

I = salicylaldehyde, by the Reimer–Tiemann reaction; II = ethyl coumarin-3-carboxylate, by Knoevenagel condensation followed by lactonisation.

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Topic notes: reactive intermediates (carbocations, carbanions, radicals, carbenes, nitrenes, benzyne), with every Civil Services, IFoS and Geo-Scientist PYQ →

CoversReimer–Tiemann reactiondichlorocarbeneKnoevenagel condensationsalicylaldehydecoumarin

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