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40.1.1.5.4.5.1.4 Method 4: Sequential N-Demethylation–N-Acylation with Palladium(II) Acetate and Acetic Anhydride

DOI: 10.1055/sos-SD-140-00180

Scammells, P. J.Science of Synthesis Knowledge Updates, (20132436.

Certain N-methyl alkaloids have been found to undergo a one-pot oxidative N-demethyl­ation–N-acylation sequence when treated with a palladium catalyst and an acid anhydride (Table 4).[‌26‌] The best results are obtained with palladium(II) acetate as the catalyst using acetic anhydride in benzene or dioxane, or in the absence of a solvent. For example, hydrocodone is converted into the N-acetyl derivative in 80% yield using this process (Table 4, entry 1).[‌26‌] However, only N-demethylation to the free amine is observed when the reaction is performed with excess palladium(II) acetate (2.5 equiv) in the absence of any anhydride, albeit in only 40% yield. Various tropane alkaloids also undergo this reaction (Table 4, entries 2–5).[‌26‌]

Meeee 8 Meeeeeeeee M-Meeeeeeeeeeee/M-Meeeeeeee ee Meeeeeeeeee eee Meeeeee Meeeeee Meeeeeeee[‌88‌]

Meeee Meeeeeee Meeeeeee Meeeeee Meeee (%) Mee
8 88e [‌88‌]
8 88 [‌88‌]
8 88 [‌88‌]
8 88 [‌88‌]
8 88 [‌88‌]

e Meeeeeeeee: Me(MMe)8 (8.8 eeeee), Me8M/eeeeeee (8:8), 88 °M.

Meee eeeeeeee, eeee eeeeee eee eeee eeeeeeee ee ee eeeeeeee eeeeeeeee ee eee eeeeee eeeeee eeeeeeeeeeeeee eeeeeeeeee eeeeeeeeeeeee. Meee, eee M-eeeeee eeeeeeeee ee eeeeeeeee eeee eee eeeeeeeeeeeee M-eeeeee eeeeeeeeee 88 ee 88% eeeee eeeee e eeeeee(MM) eeeeeee eeeeeeeeee (Meeeee 8).[‌88‌] Mee M-eeeeeeeeeeeee ee eeeeeeeeeee, ee eeee eee eeeeeeeeeeeee eeeee 88, eee eeee eeeeeeee ee 88% eeeee ee eeeeeeeee eeee eeeeee(MM) eeeeeee eee eeeeeeee eeeeeeeeeeeeeee (Meeeee 8).[‌88‌]

Meeeee 8 Meeeee-Meeeeeee M-Meeeeeeeeeee[‌88‌,‌88‌]

Meeeeeeeeeee Meeeeeeee

8-{(8eM,8M,8M,8eM,88eM)-8-[(M)-8-Meeeeee-8,8-eeeeeeeeeeeee-8-ee]-8,8-eeeeeeeee-8,8,8,8,8,8e-eeeeeeeee-8e,8-eeeeee-8,88-eeeeeeeeeeeeeeee[8,8-e]eeeeeeeeeee-8(8M)-ee}­eeeeeeee (88); Meeeeee Meeeeeeee:[‌88‌]

M eeeeeee ee eee eeeeeeee M-eeeeeeeeeee (88 ee, 8.88 eeee), Me(MMe)8 (8.8 ee, 8.88 eeee), Me(MMe)8 (8.8 ee, 8.88 eeee), Me8M (888 ee, 8.8 eeee), eee eeeeeee (8 eM) eee eeeeeee ee 88 °M eee 88 e. Mee eeeeeee eee eeee eeeeeeeeeeee ee eeee e eeeee eee eee eeeeeee eeee MM8Me8 (8 eM). Mee eeeeeeeee eeeeeee eee eeeeee eeee eee. MeMMM8 eeee (88 eM) eee eee eeeeeee eeeee eee eeeeeeeee eeee MM8Me8 (8 × 8 eM). Mee eeeeeeee eeeeeee eeeeee eeee eeeeee eeee M8M eee eeeee, eeeee (Me8MM8), eee eeeeeeeeeeee. Meeeee eeeeeeeeeeeeee (MeMMe) eeeeeeee eee eeeeeee eeeeeee ee e eeeeeee ee eeeeeeeeee eee eeeee eeeeeee (8.8:8); eeeee: 88 ee (88%).

(8eM,88eM)-8-Meeeee-8-eeeeeee-8,8,8,8e,8,8-eeeeeeeee-8M-8,88-eeeeeeeeeeeeeeee[8,8-e]eeeeeeeeeee-8(8eM)-eee (88); Meeeeee Meeeeeeee:[‌88‌]

Me(MMe)8 (88 ee, 8.8 eeee) eee (MM8)8M8M8 (88 ee, 8.8 eeee) eeee eeeee ee e eeee ee eee eeeeeeee M-eeeeeeeeeee (88 ee, 8.8 eeee) eeeeeeeee ee MeMM/M8M (8:8; 8 eM). Mee eeeeeee eee eeeeeee ee ee eee 88 e, eee eee eeeeeeee eee eeee eeeeeeee eeee 88% ee Me8M8M8. Mee eeeeeee eeeeeee eee eeeeeee eeeee eeeeeee eeeeeeee, eee eee eeeeeee eee eeeeeeee ee eM 8 eeee eeeee ee MM8MM, eee eeee eeeeeeeee eeee MM8Me8 (8 ×). Mee eeeeeee eeeeee eeee eeeeeeee, eeeee (MeMM8), eee eeeeeeee, eee eee eeeeeeeee eeee eeeeeee eeeee eeeeee ee eeee e eeeee eeeeeee. Meee eeeee eeeeeeee eee eeeeeeeee ee eeeee eeeeee eeeeeeeeeeeeee (eeeeee eee, MMMe8/MeMM/MM8MM 88:8:8) ee eeeeee eee eeeeeeeeeeee eeee eeeeeee; eeeee: 88%.

References


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