478659-08-4Relevant articles and documents
Efficient microwave assisted syntheses of 2,5-diketopiperazines in aqueous media
Perez-Picaso, Lemuel,Escalante, Jaime,Olivo, Horacio F.,Rios, Maria Yolanda
experimental part, p. 2836 - 2849 (2009/12/06)
Aqueous in situ one-pot N-Boc-deprotection-cyclization of Nα-Boc-dipeptidyltert-butyl and methyl esters under microwave irradiation afforded 2,5-diketopiperazines (DKPs) in excellent yields. This protocol is rapid, safe, environmentally friendly, and high
Acid-promoted reactions in 1-hydroxy, 1-dimethylaminomethyl and 1-methylene-4-arylmethyl-2,4-dihydro-1H-pyrazino[2,1-b]quinazoline-3,6-diones
Heredia, María Luisa,De la Cuesta, Elena,Avenda?o, Carmen
, p. 6163 - 6170 (2007/10/03)
The 1-dimethylaminomethyl or 1-methylene group of the title compounds was introduced through a Mannich or a tandem of Mannich-Hofmann reactions as the final step of a protocol that is shorter than other previously described for these precursors of N-acyliminium species. In these compounds, the acid-promoted intramolecular cyclizations of Pictet-Spengler-type were restricted to the N(2)-unsubstituted compounds, while their N(2)-methyl substituted analogues gave instead dimerization products. The cyclization was effective with 1-hydroxy-1,2-disubstituted compounds, which were obtained through addition of a Grignard reagent to 2H,4H-pyrazino[2,1-b]quinazoline-1,3,6-triones.