A one-pot selective synthesis of N-Boc protected secondary amines: Tandem direct reductive amination/N-Boc protection
A one-pot tandem direct reductive amination of aldehydes with primary amines resulting in N-Boc secondary amines using a (Boc)2O/sodium triacetoxyborohydride (STAB) system is reported. The tandem procedure is efficient, selective, and versatile, giving excellent yields of N-Boc protected secondary amines even in those cases where the products are prone to intramolecular lactamization.
Neelarapu, Raghupathi,Petukhov, Pavel A.
p. 7056 - 7062
(2012/08/28)
Indole cleavage with mebhydroline by sodium periodate - Part 2. Mechanism of the dilactam formation
The γ-carbolines 1a-d reacted with periodate by loss of one carbon - without available precursors - to the eight-membered dilactams 3a-c and the amino acid 9d. As possible intermediates of an indole cleavage α-aminoketones as models were examined. While the oxidation of chain-formed 13 afforded only a small amount of C-lost amide 23, the cyclic species 24 and 32 gave rise to considerably higher yields of the corresponding lactams 29 and 36. From the benzazepinone 32 with Hg(II)-EDTA the intermediate product 43, containing all genuine C-atoms, was formed, which could quantitatively cleaved by periodate to the lactam 36 and formic acid. This mechanism can be transferred to the reactions of the γ-carbolines 1a-d.
Moehrle,Rohn,Westle
p. 391 - 399
(2007/10/03)
Investigations into the mechanism of lactamization of lactones yielding in a novel route to biologically active tryptamine derivatives
The mechanism of lactamization of corresponding lactones was investigated by means of gas chromatography and synthesis of possible intermediates as references. Lactones react with amines via the amino acid with subsequent elimination of water to the corresponding lactams. In the first step, also hydroxyamides are in equilibrium with the lactones and amines, respectively, which are not able to form the amide though. This mechanism opens a new approach for the synthesis of Nβ-disubstituted tryptamines.