LE3 .A278 2021

2021

Jha, Amitabh

Acadia University

Bachelor of Science

Honours

Chemistry

Chemistry

A new synthetic methodology was developed to obtain novel naphthopyrans decorated with functional groups amenable for further chemical manipulation. Starting for commercially available 2-naphthols, paraformaldehyde, cyclic secondary amines and diethyl ethoxymethylenemalonate, the synthesis was achieved in two steps. First, 2-naphthols, paraformaldehyde, cyclic secondary amines were converted to Mannich bases. Subsequently, the Mannich bases were reacted with diethyl ethoxymethylenemalonate in a microwave reactor to yield diethyl 3-(alkylamino)-1H-naphtho[2,1-b]pyran-2,2(3H)-dicarboxylates as products. The mechanism of this reaction involved a cascade of a) deamination of 2-naphthol Mannich bases to ortho-quinone methides, b) the reaction of liberated amine with diethyl ethoxymethylenemalonate to yield diethyl 2-(alkylaminomethylene)malonate, and finally c) the hetero Diels-Alder reaction of the ortho-quinone methides with in situ generated diethyl 2-(alkylaminomethylene)malonate to form the final naphtho[2,1-b]pyran products.

The author retains copyright in this thesis. Any substantial copying or any other actions that exceed fair dealing or other exceptions in the Copyright Act require the permission of the author.

https://scholar.acadiau.ca/islandora/object/theses:3606