2-Cyclopenten-1-one → HCID 19841322, compound

Participants

Reaction Conditions

Reaction Steps

To a stirring solution of 0.35 gram of H2NOH'HCl in 5 ml of water is added 0.42 grams of solid NaHCO3. A solution of 1.8 grams of (6) prepared from above in methyl alcohol is added to the system. After stirring for one day, the reaction mixture is concentrated. The crude material is recrystallized from ethanol. The purified oxime (1.5 grams) is placed in 40 ml of ethanol. Two grams of Raney nickel is added, and the system is placed under a hydrogen atmosphere. After one day, the catalyst is removed by filtration, and the filtrate is concentrated. The residue is dissolved in 2.5 ml of THF. While stirring this solution, 50 ml of 0.1M aqueous NaOH is added. The reaction mixture is heated at about 65° C. for four hours and concentrated. The resulting solid is slurried in 1M aqueous HCl and collected by suction filtration. The solid is rinsed with 1M aqueous HCl, ethanol, and ether. The solid is dissolved in water, and this solution is brought to pH=7 with saturated aqueous NaHCO3. The resulting free base 1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(3-aminocyclopentyl)-1,8-naphthyridine-3-carboxylic acid (I) is collected by suction filtration and dried in a vacuum oven. (Z= ##STR26## A=N, R=cyclopropyl, R3 =H, R1 =OH). Alternatively, the condensation between (4) and (5) (Example 2a) may be catalyzed by other Lewis acids such as ZnCl2 or TiCl4 or sources of fluoride ion such as KF or nBu4NF. The same product may also be obtained by condensation of the dienolate derived from cyclopentenone and a strong base such as LDA with compound (1).

Provenance & Evidence