Synthesis of a Spirocyclic Oxetane-Fused Benzimidazole.
A new synthesis of 2-oxa-7-azaspiro[3.5]nonane is described. Spirocyclic oxetanes, including 2-oxa-6-azaspiro[3.3]heptane were converted into o-cycloalkylaminoacetanilides for oxidative cyclizations using Oxone® in formic acid. The expanded spirocyclic oxetane successfully gave the [1,2-a] ring-fused benzimidazole. X-ray crystal structure of the resultant new tetracyclic system, 1',2'-dihydro-4'H-spiro[oxetane-3,3'-pyrido[1,2-a]benzimidazole] and the azetidine ring-opened adduct, N-(2-acetamido-4-bromophenyl)-N-{[3-(chloromethyl) oxetan-3-yl]methyl}acetamide are disclosed.
School of Chemistry, National University of Ireland Galway, University Road, Galway SW4 NUI, Ireland. m.gurry1@nuigalway.ie.
Michael
M
Gurry
School of Chemistry, National University of Ireland Galway, University Road, Galway SW4 NUI, Ireland. patrick.mcardle@nuigalway.ie.
Patrick
P
McArdle
School of Chemistry, National University of Ireland Galway, University Road, Galway SW4 NUI, Ireland. Fawaz.Aldabbagh@nuigalway.ie.
Fawaz
F
Aldabbagh
D001562:Benzimidazoles / Q000138:chemical synthesis* / Q000737:chemistry; D018360:Crystallography, X-Ray; D003500:Cyclization; D004988:Ethers, Cyclic / Q000138:chemical synthesis* / Q000737:chemistry; D010084:Oxidation-Reduction; D013141:Spiro Compounds / Q000138:chemical synthesis* / Q000737:chemistry
D001562:Benzimidazoles; D004988:Ethers, Cyclic; D013141:Spiro Compounds; C031000:benzimidazole; C005287:oxetane
4-membered rings; annulation; cyclization; diazole; heterocycle