204770-72-9Relevant academic research and scientific papers
Highly efficient enantioselective synthesis of 1,3-disubstituted 2,5-diketopiperazine derivatives via microwave irradiation
Han, Si Yeon,Gong, Young-Dae
supporting information, p. 3426 - 3434 (2019/11/03)
Chiral 2,5-diketopiperazine (2,5-DKP) derivatives have a broad range of biological activities in the medicinal field. The synthetic protocols of 1,3-disubstituted 2,5-DKPs via base-catalyzed cyclization of chloroacetamide have been reported. However, there are several drawbacks, such as an overly long reaction time, low to moderate yield, and racemization of the products. The sequence modified herein of 1,3-disubstituted 2,5-DKPs involves microwave-assisted cyclization. It increases yields and reduces reaction time. Furthermore, employing N-PMB protection prevents racemization, which frequently occurs in the base-catalyzed cyclization reaction. Consequently, the rapid synthetic method of enantiomerically pure 1,3-disubstituted 2,5-DKPs via microwave reaction was established successfully.
New findings in the alkylation and N-deprotection of (4S)-4-methyl-2- benzyl-2,4-dihydro-1H-pyrazino [2,1-b] quinazoline-3,6-diones
Buenadicha, Felix L.,Bartolome, M. Teresa,Aguirre, M. Jesus,Avendano, Carmen,Soellhuber, Monica
, p. 483 - 501 (2007/10/03)
Alkyl halides behave differently to benzyl halides in C-1 alkylation of the title compounds. The syn and anti 1,4-disubstituted diastereomers thus obtained show different regioselectivity by further alkylation leading to the 1,4,4-and 1,1,4-trisubstituted compounds, respectively. Alkylation is always directed anti with respect to the bulkier substituent at C-l or C-4. Debenzylation attempts on 2-benzyl-derivatives lb by treatment with HCOOH and C/Pd or H2/C-Pd/MeOH/H+ led to C-1 oxidised or 7,8,9,10-tetrahydro- derivatives. Deprotection of 2-p-methoxybenzyland 2-(2,4-dimethoxybenzyl)- derivatives with CAN and with TFA/anisole, respectively, was successful, but in the latter case epimerization at C-1 occurred.
