5,8-Dihydro-5-ethyl-8-oxofuro-[3,2-b]-1,8-naphthyridine-2,7-dicarboxylic acid → DJ 6783
Reaction equation
[CH2:1]([N:3]1[C:12]2[N:11]=[C:10]3[CH:13]=[C:14](C(O)=O)[O:15][C:9]3=[CH:8][C:7]=2[C:6](=[O:19])[C:5]([C:20]([OH:22])=[O:21])=[CH:4]1)[CH3:2]>[Cu].C(OCC)(=O)C1C(=CC=CC=1)C(OCC)=O>[CH2:1]([N:3]1[C:12]2[N:11]=[C:10]3[CH:13]=[CH:14][O:15][C:9]3=[CH:8][C:7]=2[C:6](=[O:19])[C:5]([C:20]([OH:22])=[O:21])=[CH:4]1)[CH3:2]Participants
4
Reactant 1
Product 1
Reagents, catalysts & solvents 2
Procedure
A mixture of 9.5 g of 5,8-dihydro-5-ethyl-8-oxofuro-[3,2-b]-1,8-naphthyridine-2,7-dicarboxylic acid (Compound X where R1 =C2H5), 0.8 g of copper powder and 250 ml of diethyl phthalate was heated at 250° to 260° C. for 25 minutes. After cooling, the reaction mixture was separated by partitioning between chloroform and aqueous potassium carbonate solution. The aqueous layer which separated out was acidified with hydrochloric acid and extracted with chloroform. The extract was treated with charcoal, and washed with water, dried and concentrated. The crystals precipitated by adding ethanol were collected by filtration to obtain 4.2 g of 5,8-dihydro-5-ethyl-8-oxofuro[3,2-b]-1,8-naphthyridine-7-carboxylic acid (Compound Ia where R1 =C2H5).