20091-81-0Relevant articles and documents
New Synthesis of 11-Acyl-5,11-dihydro-6H-pyridobenzodiazepin-6-ones and Related Studies
Kovac, T.,Oklobdzija, M.,Comisso, G.,Decorte, E.,Fajdiga, T.,et al.
, p. 1339 - 1349 (2007/10/02)
New synthesis of 11-acyl-5,11-dihydro-6H-pyridobenzodiazepin-6-ones (42-44) is reported.The crucial steps (Scheme VI) represented N-oxidation of 1 (1A) to 35 (35A), facilitated ring-closure of 36 into 37, its subsequent N-α-chloroacetylation to 38, aminolysis to 39-41 (involving N-O anchimeric assistance as depicted in 38A) and deoxygenation to 42-44 (Scheme VII).The central intermediate 37 is also obtained on oxygenation of 2, a new synthesis of which was reported in the previous paper of this series .Other attempts of cyclisation "from the top" or "from the bottom" (Scheme I) are described.Thus, interaction of 1 with acetamide afforded 3 and 4 instead of the expected 2A.Compound 5 cyclised into 3-pyridoquinazolone 6 while its 2-(4'-methylpiperazin-1'-yl) analogue 9 was observed to be unstable for the attempted ring-opening and reclosure to 42. "From the bottom" cyclisations of 10A-10C, via intermediary amines 11A-11C failed and pyridoquinazolinone 13 was isolated (Scheme V).The attempted oxidative cyclisation of the compounds 15 and 18 into 2 and 42, respectively, 13 afforded imidazolopyridine derivative (18-19), while 15 remained unchanged. 3-Acylamino-2-arylaminopyridines (21-24), cyclised into the imidazolopyridines 29-30.Model compounds 45-50 were prepared to study selective aminolysis of the chlorine atoms in 2-chloro-3-(2'-chlorobenzoyl)aminopyridine 1, and its N-oxide 35.
