Abstract
The cyclization reaction of 4-(2-carbamoylaminopheny1)-1, 2, 5, 6-tetrahydropyridine derivatives (9) and a4-(2-methoxycarbonylaminophenyl)-1, 2, 5, 6-tetrahydropyridine derivative (4) with halogen was investigated.Treatment of the former (9) with bromine or N-chlorosuccinirriide (NCS) under acidic conditions gave the corresponding 3'-halogeno-2-amino-spiro [4H-3, 1-benzoxazine-4, 4'-piperidine] derivatives (11) and with iodine under basic conditions gave5, 6-dihydro-3-iodospiro [pyridine-4 (1H), 4'(3'H)-quinazolin]-2'(1'H)-one derivatives (14), which were converted to spiro [piperidine-4, 4'(3'H)-quinazolin]-2'(1'H)-one derivatives (15and17).Treatment of the latter (4) with bromine under acidic conditions gave3'-bromo-spiro [4H-3, 1-benzoxazine-4, 4'-piperidin]- 2 (1H)-one derivatives (5and6).
