6-ISOPROPENYL-SUBSTITUTED 1,3-BENZOXAZINES AS ACID CORROSION INHIBITORS AND ANTIMICROBIALS

The article presents the results of studies on the synthesis of new N-substituted oxazine compounds obtained by triple condensation of 4-isopropenylphenol, formaldehyde and primary amines, as well as the study of their anti-corrosion (in 0.5 M H2SO4) 2 SO 4 ) and antimicrobial properties against microorganisms Staphylococcus aureus ATCC (R) 25923, Escherichia coli ATCC (R) 25922, Candida albicans NSTC- 3255/ATCC2091, Shigella flexneri ATCC (R) 12022, Salmonella enterica ATCC (R) 13076, , and Aspergillus niger (water isolate). The condensation reaction was carried out at a molar ratio of 4-isopropenylphenol, formaldehyde and amine 1:2:1, for 3 h and temperature 90 degrees C. n-Propylamine, n-hexylamine and benzylamine were used as amines. The results of their anti-corrosion gravimetric tests on St.3 steel in 0.5 M H2SO4 2 SO 4 at 25 and 40oC o C and for 3 h showed that they can be classified as inhibitors of blocking chemisorption action. At the concentrations of 20 and 50 mg/L, the compounds have antimicrobial properties. Among the synthesized N-substituted 6-isopropenyl-1,3-benzoxazines, N-hexyl6-isopropenylbenzoxazine has the best protective and bactericidal properties. The degree of protection against corrosion of steel St.3 at its concentration of 0.20 g/L is 93% (25oC) o C) and 86.3% (40oC), o C), which indicates the participation of a relatively long alkyl substituent in filling its surface. A compound containing a propyl radical at the nitrogen atom is slightly inferior to it in anti-corrosion properties (Z = 87.5% at 25oC o C and 82.6% at 40oC o C in the same concentration). In terms of bactericidal properties, the studied compounds are superior to the standard- amoxicillin at an identical concentration (50 mg/L). The bactericidal properties of the compounds were also confirmed by examining them under a microscope