Abstract:
Aryl dibromonitromethyl sulfones, new compounds, wherein aryl is phenyl or lower alkyl phenyl, are effective as antimicrobials at a concentration of about 100 parts per million.

Description:
SUMMARY OF THE INVENTION 
     This invention concerns aryl dibromonitromethyl sulfones wherein aryl is phenyl or lower alkyl phenyl, and their use as antimicrobials. The compounds are useful at concentrations approximating 100 parts per million (hereinafter ppm), advantageously at a pH of about 5 to about 7. The compounds are used in an aqueous medium which contains a minimum solubilizing amount of an organic solvent such as, for example, acetone, dimethylformamide (hereinafter DMF) or a glycol ether such as, for example, propylene glycol methyl ether, commercially available as Dowanol.sup.(R) PM glycol ether. In practice, a stock aqueous solution, for example, containing 0.1 percent total of one or more of the compounds is conveniently prepared containing a minimum solubilizing amount of acetone, DMF or Dowanol.sup.(R) PM glycol ether as solvent. The compounds are effective in areas which are subject to antimicrobial attack, particularly slime formation. Among these, an important use is in and about pulp and paper mills. In the specification and claims, lower alkyl designates a 1 to 4 carbon alkyl group. 
     The compounds are made by mixing and refluxing together a 1:1 mixture of an equimolar proportion of bromonitromethane containing dibromonitromethane as impurity with a sodium arylsulfinate, as defined, in methanol until reaction is complete, about 15 hours. The solvent is removed in vacuo and the residue is taken up in chloroform and water. The organic phase is separated and evaporated to dryness. Recrystallization of the residue from aqueous methanol gives the aryl nitromethyl sulfone. The latter is dissolved in aqueous dilute NaOH, the solution is chilled in ice and bromine is added until the red color persists. After about one hour, the aryl dibromonitromethyl sulfone product is filtered off and recrystallized from aqueous methanol to give purified product. The reaction scheme is represented by the following equation: ##STR1## wherein X = H or C 1-4  alkyl ##STR2## 
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following additional description and examples further describe the invention and the manner and process of making and using it to enable the art skilled to make and use the same and set forth the best mode contemplated by the inventors of carrying out the invention. 
    
    
     EXAMPLE 1: Dibromonitromethyl p-Tolyl Sulfone 
     A solution of 22 g of a 1:1 mixture of dibromonitro- and bromonitromethane, and 17.8 g (0.1 mole) of sodium p-toluenesulfinate in 250 ml of methanol was refluxed 15 hours. The solvent was removed in vacuo and the residue taken up in chloroform and water. The organic phase was separated and evaporated to dryness. Recrystallization of the residue from aqueous methanol gave 4 g of nitromethyl p-tolyl sulfone. The latter was dissolved in a solution of 1.6 g of NaOH in 200 ml of water. The solution was chilled in ice and bromine was added thereto until the red color persisted. After one hour, the dibromonitromethyl p-tolyl sulfone product was filtered off and recrystallized from aqueous methanol to give 4.3 g of white crystals: mp 123°-124° C. 
     Anal. Calcd. for C 8  H 7  Br 2  NO 4  S: C, 25.76; H, 1.89; Br, 42.85; N, 3.75; S, 8.59. Found: C, 26.74; H, 2.01; Br, 40.00; N, 4.00; S, 9.01. 
     The procedure of Example 1, when repeated substituting sodium benzenesulfinate in place of sodium p-toluenesulfinate, gives dibromonitromethyl phenyl sulfone. 
     EXAMPLE 2: Activity of Dibromonitromethyl p-Tolyl Sulfone in Conventional Agar Tests 
     Dibromonitromethyl p-tolyl sulfone in conventional agar tests gave complete kills of the following microorganisms at 100 ppm: 
     P. aeruginosa 
     E. coli 
     C. albicans* 
     T. mentagrophytes 
     B. subtilis* 
     A. aerogenes* 
     A. terreus 
     C. pelliculosa 
     P. pullulans (Aureobasidium pullulans) 
     S. typhosa 
     Pseudomonas Sp. Strain 10 
     M. phlei 
     R. nigricans 
     Ceratocystis IPS 
     C. fragans 
     Trichoderm Sp. Madison P-42 
     *slime-forming organisms 
     Dibromonitromethyl phenyl sulfone and the C 2-4  alkylphenyl homologs of the compound of Example 1 have similar antimicrobial activity. The compounds of this invention may be used separately or in mixtures of two or more to give the advantageous antimicrobial results described above.