TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The chlorinating agent is selected from thionyl chloride, phosphoryl chloride or oxalyl chloride.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: Preparation (P1) of the isoxazolyl penicillins (I), and its salt involves: a) preparing an intermediate, where the preparation of the intermediate is in-situ and is involving: reacting corresponding benzaldehyde derivative with hydroxylamine salt, followed by addition of chlorine in the presence of triethylamine, adding an ester in the presence of sodium methoxide followed by reaction with phosphorus pentachloride or any chlorinating agent; b) dissolving the intermediate directly in an ester without isolating the intermediate from the reaction mixture followed by reacting with basic solution of 6-aminopenicillanic acid followed by addition of a saturated salt solution, crystallization with sodium salt of ethyl hexanoic acid, filtration at a reduced pressure and inert atmosphere, and drying under mechanical stress and reduced pressure and temperature. In the process (P1), the intermediate obtained in first step is isolated from the reaction mixture; and the inert atmosphere during filtration is generated using nitrogen or a member form the inert gas family. In the process (P2), reaction of ortho-chlorobenzaldehyde with hydroxylamine salt is carried out at 30-50 (preferably 35-45) degrees C; and the inert atmosphere is generated using nitrogen or a member from the inert gas family. Preferred Components: The ester is selected from methyl acetate, ethyl acetate, propyl acetate, iso-butyl acetate, n-butyl acetate, tert-butyl acetate, methyl formate, ethyl formate and/or propyl formate. ACTIVITY - Antibacterial. No biological data given.    MECHANISM OF ACTION - None given.    SPECIFIC COMPOUNDS - Preparation of 4 compounds i.e. cloxacillin sodium (IA); dicloxacillin sodium; flucloxcillin sodium; oxacillin sodium is disclosed as the isoxazolyl penicillin compound.    EXAMPLE - Ortho-chlorobenzaldehyde (850 g) was dissolved in methanol (2.5-2.6 l) at room temperature. Hydroxylamine salt (516 g) was added and the reaction mixture was heated to 38-40 degrees C for 1 hour followed by addition of sodium carbonate (460-470 g). The pH was maintained at around 9.5 and the reaction mixture was cooled to room temperature. Triethylamine (4 g) was added and chlorine gas (510-520 g) was passed for 24 hours by maintaining a temperature of 0-5 degrees C. Nitrogen gas was purged for 4-5 hours. After the completion of the chlorination reaction, methanol (575 l) was added followed by addition of sodium carbonate (750-780 g) to reach a pH of around 7-7.5. Methylacetoacetate (686 g) and soda ash (50-100 g) was added to the reaction mixture till an exothermic reaction was achieved. The solution thus obtained was hydrolyzed by the addition of caustic flakes (460 g). Sulfuric acid was added and the pH was adjusted to around 8.6-8.8. After work up, ethyl acetate was added to the resulting solution of 3-(2-chlorophenyl)-5-methyl-4-isoxazole-carbonyl chloride. 6-Aminopenicillanic acid (300 g) was dissolved in ammonium hydroxide (260-270 ml) and pH was adjusted to 7-9. This solution was then added to the reaction solution containing 3-(2-chlorophenyl)-5-methyl-4-isoxazole-carbonyl chloride (377 g) and the pH were maintained to be around 2-2.3. Common salt (100 g) was added with constant stirring and the layers were allowed to settle. Organic layers were separated and the combined extracts were then washed with brine followed by addition of sodium-2-ethyl hexanoate (590-630 g) while maintaining the pH at 7.8-8.1. After work up, sodium salt of 6-((3-(2-chlorophenyl)-5-methyl-1,2-oxazole-4-carbonyl)amino)-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo(3.2.0)heptane-2-carboxylic acid (cloxacillin sodium) was obtained.