| Autor: |
Verardo, Giancarlo, Bombardella, Elisa, Venneri, Cesare Daniele, Strazzolini, Paolo |
| Zdroj: |
European Journal of Organic Chemistry; December 2009, Vol. 2009 Issue: 35 p6239-06244, 6p |
| Abstrakt: |
A simple and efficient twostep synthesis of unsymmetrically substituted ureas containing an amino acid derivative is reported. The procedure involves the reaction between the carbamoyl azides of αNprotected amino acids and ammonium hydroxide or a primary or a secondary amine. The reaction proved to be very fast 0.5 h with small, highly reactive ammonium hydroxide and slower 4 h with sterically hindered tertbutylamine. The 1H NMR spectra of the synthesized, new, unsymmetrical ureas carried out in [D6]DMSO suggest that the protons in the –αCH–NHCONH–CH– moiety assume a transconformation. Moreover, analysis of the mass spectra EI and ESI revealed some interesting common features. The reported synthesis represents the first example of the potential value of carbamoyl azides as versatile chiral starting materials for many synthetic purposes.© WileyVCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009 |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
Plný text