摘要 |
The present invention relates to processes for the preparation of (4R,12aS)-7-methoxy-4-methyl-6,8-dioxo-3,4,6,8,12,12a-hexahydro-2H-pyrido[1′,2′:4,5]pyrazino[2,1-b][1,3]oxazine-9-carboxylic acid by contacting a pyridinone carboxylic acid aldehyde with (3R)-3-amino-1-butanol. |