Reaction of N-benzoyl-1, 2, 3, 4-tetrahydroquinoline-2-carboxylic acid with acetic anhydride resulted in 1 H, 3 H, 5 H-oxazolo [3, 4-a] quinolin-3-one derivative 13. Different cyclopropanation processes were applied to 13, but only diazomethane in the presence of water furnished the hitherto unknown methyl 1, 2, 7, 7a-tetrahydro-1a H-cyclopropa [b] quinoline-1a-carboxylate 14, which can be considered as a doubly constrained 1- ...
