Efficient and Chemoselective Deoxygenation of Amine N-Oxides Using Polymethylhydrosiloxane [1]

Abstract

Deoxygenation of aromatic and aliphatic amine N-oxides to the corresponding amines is achieved under mild conditions. The reagent combination employed for this transformation is polymethylhydrosiloxane (PMHS) in the presence of either tetrakis (triphenylphosphine) palladium (0) [Pd(PPh₃)₄], titanium (IV) isopropoxide [Ti(i-PrO)₄] or palladium on carbon (Pd/C).

Key words

amine N-oxides - polymethylhydrosiloxane - palladium catalysis - titanium(IV)isopropoxide

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IICT Communication No. 4744.

References

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IICT Communication No. 4744.

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Spectroscopic data of the products(4e): ¹H NMR (CDCl₃): δ 2.56-2.38 (m, 4 H), 2.04 (m, 1 H), 1.9 (m, 1 H), 1.78-1.6 (m, 4 H), 1.55-1.15 (broad m, 8 H), 0.96-0.85 (d, 3 H, J = 7 Hz); IR (Neat): 2927, 2856, 1459, 1283, 772 cm^-1; MS (m/z): 167 (M⁺); Anal. Calcd. for C₁₁H₂₁N: C, 78.98; H, 12.65. Found: C, 79.01; H, 12.63.(4f1): ¹H NMR (CDCl₃): δ 7.41-7.02 (m, 5 H), 6.58-6.44 (d, 1 H, J = 17.6 Hz), 6.3 (m, 1 H), 3.14-3.06 (d, 2 H, J = 6.1 Hz), 2.51-236 (m, 4 H), 1.7-1.54 (m, 4 H); IR (Neat): 2964, 2856, 143, 1360, 759 cm^-1; MS (m/z): 187 (M⁺); Anal. Calcd. for C₁₃H₁₇N: C, 83.37; H, 9.15. Found: C, 83.34; H, 9.12.(4g1): ¹H NMR (CDCl₃): δ 8.3-8.12 (dd, 2 H, J = 8.4, 16.8 Hz), 7.72-7.46 (dd, 2 H, J = 8.4, 16.8 Hz), 3.68 (s, 2 H), 2.58-2.46 (m, 4 H), 1.88-1.76 (m, 4 H); IR (Neat): 2966, 2797, 1519, 1346, 849 cm^-1; MS (m/z): 206 (M⁺); Anal. Calcd. for C₁₁H₁₄N₂O₂: C, 64.06; H, 6.84. Found: C, 64.08; H, 6.86.(4h1): ¹H NMR (CDCl₃): δ 7.42-7.3 (m, 5 H), 7.26-7.14 (dd, 2 H, J = 8.2, 14.3 Hz), 6.96-6.8 (dd, 2 H, J = 8.2, 14.3 Hz), 5.2 (s, 2 H), 3.5 (s, 2 H), 2.54-2.4 (m, 4 H), 1.8-1.64 (m, 4 H); IR (Neat): 2963, 2801, 1453, 1232, 771 cm^-1; MS (m/z): 267 (M⁺); Anal. Calcd. for C₁₈H₂₁NO: C, 80.86; H, 7.92. Found: C, 80.85; H, 7.91.