(S)-4-ethyl-4-hydroxy-6-iodo-3-oxo-1H-pyrano[3,4-c]-8-pyridone

(S)-4-ethyl-4-hydroxy-6-iodo-8-methoxy-1,4-dihydro-pyrano[3,4-c]pyridin-3-one

[1,4']Bipiperidinyl-1'-carboxylic acid 4-aminophenylester

[1,4']Bipiperidinyl-1'-carboxylic acid 4-formylaminophenylester

(+/-)-4-ethyl-4-hydroxy-8-methoxy-6-(trimethylsilyl)-1,4-dihydro-3H-pyrano[3,4-c]pyridin-3-one