5-Bromo-5-nitro-1,3-dioxane:An interesting derivative of the 2-Bromo-2-nitropropane-1,3-diol is its reaction products with formaldehyde. The corresponding dioxane is more effective than 2-Bromo-2-nitropropane-1,3-diol.In particular, the fungicidal efficacy is greatly improved beyond any expected additive efficacy,which might be expected from formaldehyde. The preservative 5-Bromo-5-nitro-1,3-dioxane dates back to the 1970s and was introduced to the cosmetic industry in 1977.