297. Aliphatic nitro-compounds. Part XVIII. Interaction of ketones and nitro-paraffins

Nitroaldol-reaction of aldehydes in the presence of non-activated Mg:Al 2:1 hydrotalcite; a possible new mechanism for the formation of 2-aryl-1,3-dinitropropanes

“…33,35 However, during our synthesis we could not isolate the nitrostyrene or even detect its formation. This is in good agreement with the statements in the literature that hydrotalcites are usually unable to induce dehydration in aldol-type reactions, and with the results reported by Choudary et al 15,39 for the Henry reaction (Scheme 2).…”

“…[33][34][35][36] The mechanism of their formation was assumed to be a three-step base-catalysed reaction as follows: (1) nitroaldol addition to form the nitroalcohol;…”

Synthesis of the reported structure of piperazirum using a nitro-Mannich reaction as the key stereochemical determining step

“…A reductive nitro-Mannich reaction between nitroalkene 18 [54] and freshly prepared imine 19 in CH 2 Cl 2 followed by rapid flash chromatography gave β-nitroamine 20 with complete conversion and dr >95:5 [55]. As before immediate reduction with Zn/HCl gave the PMP-protected diamine 21 in 85% yield as a single diastereoisomer determined by 1 H NMR (Scheme 5).…”

Novel insecticidal oxathiolane and oxathiane oxime carbamates

“…2-Methyl-l-nitropropene (6b, R3 = R4 = CH3). 2-Methyl-l-nitropropan-2-ol (4b, R3 = R4 = CH3) was synthesized by condensation of acetone and nitromethane in the presence of sodium methoxide as described in the literature (Lambert and Lowe, 1947). The alcohol (120 g) was converted to the corresponding nitroalkyl acetate (5b, R3 = R4 = CH3) by condensation with 165 mL of isopropenyl acetate at 25-65 °C (exothermic) in the presence of 20 drops of sulfuric acid (nitro alcohol added over about 1 h allowing exotherm to 65 °C followed by equilibration at 50 °C for 72 h).…”