TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The salts are chosen from glucosamine, sodium, calcium and potassium. The reducing agent is chosen from palladium, nickel, sodium dithionite, iron/hydrochloric acid, zinc/acetic acid and tin chloride/hydrochloric acid. The hydrolysis process is carried out in presence of base chosen from sodium carbonate, potassium carbonate, sodium hydroxide and lithium hydroxide.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (Claimed): The 3-(5-substituted oxy-2,4-dinitro-phenyl)-2-oxo-propionic acid ester compound is obtained by reacting a compound (II) with an ester and a base at -20 degrees C to 100 degrees C, preferably 0-40 degrees C for 60 minutes to 72 hours, preferably 60 minutes to 16 hours, and isolating obtained compound (I) by quenching, filtration and/or extraction. Preferred Process: The preparation of 4,5-dioxo-4,5-dihydro-1H-pyrrolo(2,3-f)quinoline-2,7,9-tricarboxylic acid and its salts further involves reacting the compound (I) with reducing agent to obtain a compound of formula (IV), converting the compound (IV) to a compound of formula (V) in presence of coupling agent, reacting the compound (V) with oxidizing agent to obtain a compound of formula (VI). Preferred Composition: The ester is oxalic acid ester chosen from dimethyl oxalate, diethyl oxalate, dibenzyl oxalate, diisopropyl oxalate and di-tert-butyl oxalate. The base is chosen from sodium methoxide, sodium ethoxide, potassium t-butoxide, sodium hydride and 1,8-diazabicyclo(5.4.0)undec-7-ene. The nitration mixture is chosen from mixture of nitric acid and sulfuric acid, calcium nitrate and acetic acid, and tert-butyl nitrite. The coupling agent is chosen from 4-oxo-pent-2-enedioic acid dimethyl ester, 4-oxo-pent-2-enedioic acid diethyl ester, 4-oxo-pent-2-enedioic acid diisopropyl ester and 4-oxo-pent-2-enedioic acid di-tert-butyl ester. The oxidizing agent is chosen from ceric ammonium nitrate. The preparation of 4,5-dioxo-4,5-dihydro-1H-pyrrolo(2,3-f)quinoline-2,7,9-tricarboxylic acid and its salts is carried out in presence of solvent chosen from water, tetrahydrofuran, methanol, ethanol, acetonitrile, dichloromethane, tetrahydrofuran, dimethylformamide and acetic acid. The conversion of compound (IV) is carried out in presence of acid chosen from hydrochloric acid, trifluoroacetic acid and p-toluenesulfonic acid. SPECIFIC COMPOUNDS - 1 3-(5-Substituted oxy-2,4-dinitro-phenyl)-2-oxo-propionic acid ester compound i.e. 3-(5-methoxy-2,4-dinitro-phenyl)-2-oxo-propionic acid methyl ester of formula (Ia) is disclosed.    EXAMPLE - 108 g Sodium methoxide and 136 mL diethyl oxalate were added to 100 g suspension of 1-fluoro-5-methyl-2,4-dinitro-benzene in 1.5 L methanol at -10 degrees C. The resulting orange color suspension was slowly heated to 15-20 degrees C for 2 hours and continuously stirred at 15-20 degrees C for 32 hours. The reaction mixture was quenched with 1.5 N hydrochloric acid, the obtained precipitated solid was filtered, dried under vacuum and 125 g 3-(5-methoxy-2,4-dinitro-phenyl)-2-oxo-propionic acid methyl ester compound was obtained as pale yellow solid.