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Alkylation of 2,3‐Dihydro‐1,4‐diazepinium Salts
Author(s) -
Calsy Adrianne,
King James,
Lloyd Douglas,
Reichardt Christian,
Struthers Margot
Publication year - 1986
Publication title -
liebigs annalen der chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0170-2041
DOI - 10.1002/jlac.198619860809
Subject(s) - chemistry , steric effects , salt (chemistry) , vicinal , dimethylformamide , alkylation , alkyl , potassium carbonate , ring (chemistry) , medicinal chemistry , nitrogen , potassium , nmr spectra database , stereochemistry , organic chemistry , spectral line , physics , astronomy , solvent , catalysis
N ‐Unsubstituted 2,3‐dihydro‐1,4‐diazepinium salts 4a – d are N ‐methylated readily (→ 5a – d ) by using iodomethane and potassium carbonate in dimethylformamide. The 2,3‐dihydro‐5,7‐diphenyl‐1,4‐diazepinium salt 4d could be N ‐ethylated but not N ‐isopropylated, presumably for steric reasons. Vicinal crowding between, 1,4‐alkyl and 5,7‐phenyl substituents at the dihydrodiazepinium ring is evident from NMR spectra. 2,3‐Dihydro‐6‐(hydroxyphenyl)‐1,4‐diazepinium salts ( 2a, b ) are methylated first at the nitrogen atoms (→ 1a, b ) and only then at the hydroxy group (→ 3a, b ).