Title of article :
Microwave-assisted synthesis of the Schِllkopf chiral auxiliaries: (3S)- and (3R)-3,6-dihydro-2,5-diethoxy-3-isopropyl-pyrazine
Author/Authors :
Carlsson، نويسنده , , Anna-Carin and Jam، نويسنده , , Fariba and Tullberg، نويسنده , , Marcus and Pilotti، نويسنده , , إke and Ioannidis، نويسنده , , Panos and Luthman، نويسنده , , Kristina and Grّtli، نويسنده , , Morten، نويسنده ,
Abstract :
A practical and efficient methodology for the laboratory scale preparation of Schöllkopf’s bis-lactim ether chiral auxiliaries (3S)- and (3R)-3,6-dihydro-2,5-diethoxy-3-isopropyl-pyrazine has been developed. The key step is the preparation of the 2,5-diketopiperazine derivative by microwave-assisted heating in water. The protocol avoids reactions at low temperature and the use of high boiling solvents. Only inexpensive and readily available starting materials are required. The bis-lactim ethers were produced in high yields on a multigram scale.
