Q7(a)(ii). 2-Naphthoic acid to a urethane: Curtius rearrangement
Identify ‘A’, ‘B’ and ‘C’ in the following sequence of reactions. Also provide mechanism for conversion of ‘A’ to ‘B’. [naphthalene-2-carboxylic acid: (i) SOCl₂ (ii) NaN₃ → A; Δ → B; C₂H₅OH → C; scheme given in the paper]
Answer in brief
A = 2-naphthoyl azide, B = 2-naphthyl isocyanate, C = ethyl N-(naphthalen-2-yl)carbamate. A → B is the Curtius rearrangement.
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CoversCurtius rearrangementacyl azideisocyanatecarbamateurethanenitrene
All parts of Question 7
- 7(a)(i) p-Cresol: Reimer–Tiemann reaction, then a cyanohydrin5 marks
- 7(a)(ii) 2-Naphthoic acid to a urethane: Curtius rearrangement5 marks
- 7(b)(i) 6π electrocyclic ring closure: thermal and photochemical modes5 marks
- 7(b)(ii) Furil to furilic acid: benzilic acid rearrangement5 marks
- 7(c)(i) 4-Methoxybenzaldehyde with NaCN: benzoin condensation5 marks
- 7(c)(ii) Norrish Type II against Type I in two ketones5 marks