Synthesis of Poly(ethylene glycol) Supported Benzazepines

Significance

The synthesis of a series of novel benz­azepines supported by poly(ethylene glycol) (PEG 3400) was described. α-Methylene β-amino esters 1a-k were prepared by an aza-Baylis-Hillman reaction involving PEG-SES-NH₂ (for 1a-g) or SES-NH₂ (for 1h-k), an aldehyde and methyl acrylate in the presence of DABCO. Compounds 2a-g were obtained by alkylation of 1a-g with 2-bromobenzyl bromide and converted into the cyclized benz­azepines 3a-g by the intramolecular Heck reaction using Pd(OAc)₂ as a catalyst in the presence of K₂CO₃ or Oct₃N as a base in DMF. In the case of substrates 1h-k, 3h-k, which are not linked to PEG, were obtained via the Heck cyclization performed in PEG 3400-OH as a solvent instead of DMF.