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Study of the Reaction between Carbamoyl Azides of α‐ N ‐Protected Amino Acids and Hydrazine Monohydrate
Author(s) -
Verardo Giancarlo,
Venneri Cesare Daniele,
Esposito Gennaro,
Strazzolini Paolo
Publication year - 2011
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201001385
Subject(s) - chemistry , hydrazine (antidepressant) , alkyl , semicarbazide , azide , tetrahydrofuran , medicinal chemistry , aqueous solution , organic chemistry , chromatography , solvent
Two simple and efficient synthetic methods for the preparation of semicarbazide amino acid derivatives are reported. The procedures involve reaction between the carbamoyl azides of α‐ N ‐protected amino acids and hydrazine monohydrate: 4‐[(alkoxycarbonylamino)(alkyl)methyl]semicarbazides 1 are obtained when hydrazine is added to the separated tetrahydrofuran (THF) solution containing the carbamoyl azide at 0 °C, whereas 1‐[(alkoxycarbonylamino)(alkyl)methyl‐carbamoyl]‐4‐[(alkoxycarbonylamino)(alkyl)methyl]semicarbazides 4 are produced by adding hydrazine directly into the final THF/aqueous buffer (KH 2 PO 4 ) biphasic mixture containing the prepared carbamoyl azide at 50 °C, respectively. NMR experimental data obtained from samples dissolved in [D 6 ]dimethyl sulfoxide suggest a dimeric association for semicarbazides 4 with intermolecular hydrogen bonds. Moreover, the ESI–MS–MS spectra reveal some interesting common features.