methyl 4-[5-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-quinoxalinyl)-2-thienyl]benzoate

5,5,8,8-Tetramethyl-5,6,7,8-tetrahydro-quinoxaline-2-carboxylic acid 4-(2-trimethylsilanyl-ethoxycarbonyl)-phenyl ester

ethyl 4-{[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-quinoxalinyl)carboyl]amino}benzoate

methyl 4-[(E)-3-oxo-3-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-quinoxalinyl)-1-propenyl]benzoate

methyl 4-[4-oxo-4-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-quinoxalinyl)butanoyl]benzoate