Investigations on the Cyclisation of "3-Aza-1,5-dicarbonyl-compounds"

Article abstract of DOI:10.1007/BF00900010

From 1b, 1c and 1d no "1,4-oxazines" are available under dehydrating conditions.Only reaction of 1c with PPA at room temperature yields 7, while 1d in dependence of the reaction time with PPA at 100 deg C undergoes cyclisation to the indoles 3b and 3c and