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Purchase, R.; Sainsbury, M., Science of Synthesis, (2009) 40, 396.
The Hofmann rearrangement[189–192] is a venerable reaction that is traditionally used for the conversion of a primary amide 156 into an amine 159 (Scheme 47). The classical reagents are bromine and aqueous sodium hydroxide (essentially sodium hypobromite), which initially give rise to an intermediate N-bromoamide 157; this species then undergoes deprotonation and loses bromide ion with concomitant migration of the substituent R1 to generate an isocyanate 158. After some debate, a concerted process is now generally favored[188] over a suggestion that a nitrene is formed at the point where bromide ion is lost and it is this species that undergoes rearrangement to the isocyanate.[193–196] At the end of the rearrangement step the isocyanate is often hydrolyzed to afford the corresponding amine or captured by an alcohol such as methanol to form a carbamate,[197] which is then hydrolyzed to give the amine.
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Meee eeeeee eeeeeeeee ee eeee ee eee Meeeeee eeeeeeeeeeeee eeeee 888 ee eeeeeeee eeeee 888 eee ee eeeeee ee eeeeeeeeee eeeeeee eeeeee eee eeeeeee eeeee ee eee eeeeeeee eeeee eee ee eee eeeeeeeeeeee eeeeeeeeee (Meeeee 88). Me eeee eeeee eeeeeeeeee, eeeeeee, ee ee eeeeeeeeeeee ee eeeeeeeeeeee eeeee eee eeeee eeee ee eeeeeeeeeeeee eeeeeee ee eeee eee eeeeeee eeeeee eeeeeeeeeee eeee eee eeee ee eeeeeeeeee eee eeeeeee eeeeeeeeeeeee.
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Meeee eeeeee eeeeeee eeeeeeeeeeee eeeeeee eeeeeee eee eeeeee eeeeeeeee (Meeeee M),[888,888] eeeeee eeeeeeeeeeee ee eeeeeee eeeeee eeeeeeeee (Meeeee M),[888,888] ee eeeeee eeeeeee ee eeeeeee eeeeee eeeeeeeee eeeeeeeeee e eeeeeeeee eeeeee ee eeeeee eeeeeee (Meeeee M)[888] (Meeeee 88), ee e eeeee eeeeee ee e eeeeeeeeee eeeeeeee eeeeeee.[888] Meee eeeeee eeeeeeeee ee eeee eee eeeee ee eeeee eee eeeeeeee eee eeeee eee ee eeeeeeeee ee eee eeeeee eee eeeee ee ee eeeeee ee eee eeeeeee ee eeeeee eeeeeeeee eeeee (eeeeeee eeeeee eeeeeeeeeee) eee eeee ee eee eee eeeeeeee ee eee eeeee[888,888] (ee ee eee e eeeeeeeeee eeeeeeee ee eeeeeee[888,888]) eeeeee eeee ee eee eeeeeee ee e eeeeeeeeee eeeeeeee ee ee eeeee eee eeeeee eeeeeeeee.[888,888] Me eee ee eeeee eeeee eeeeeeeeee (Meeeeee M–M) eee eeeee 888 (ee eeeeee) eee ee eeeeeeee eee eeeeeeee eeee eee eeeeeeee eeeeeee ee eeeee eeeeeeeeeeee. Mee ee eeeeeeeeeeee eeeeeeeee eee eee eeeeeeeeeee ee 888 (M8 = 8-Mee) eeeee Meeeee M, eee Meeeeee ee Meeeeeeee, Mee. 88e [Meeee—M (M = M, M) (Meeeeee 88.88.8.88.8)].
Meeeee 88 Meeeeee Meeeeeeeeeeeee ee Meeeee Meeeeeeeeeee[888,888–888]
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Meeeee 88 Meeeeee Meeeeeeeeeeee ee e Mee Meee ee eee Meeeeeeee ee Meeeeeeeeee[888]
Meeeee eeeeeeeeeeee ee eeeeeeeeeee eeee eeeeeeeee eeeeeeee eee eeeeeee, ee eeee e eeeee eeeeeee eee e eeeeee ee eeeeeeeee eeeeeeeee, ee eeee ee eeee eeeeee eeeeeeeeee 888 eeee e eeeee ee eeeeeeeee, eeeeeeee, eee eeeeeeeeeeee eeeeee 888 (Meeeee 88).[888]
Meeeee 88 Meeeeeeee ee Meeeee Meeeeeeeee eeee Meeeee[888]
Meeee eeeeeee eeeeeee eeee eeeee eee eee ee eeeeeee eee eeeeeeeee(eeeeee)eeeeeeee eeeeeeeeee eee eeeeee eeeeeeeee,[888] eee M-eeeeeeeeeeeeeeee eee eeeeee(M) ee eeeeeee(MM) eeeeeee eeeee eeeeee ee eeeee eeeeeeeeee[888,888] (ee eeeee eeeeeee eeeeeeeeee, eee eeeee 8,8-eeeeeee-8,8-eeeeeeeeeeeeeeeeeeeee-8,8-eeeee ee eeeee ee M-eeeeeeeeeeeeeeee).[888] Me eee eeee ee eeee eeeeeeeeee 888 eeeeeee eeee M-eeeeeeeeeeeeeeee eee 8,8-eeeeeeeeeeee[8.8.8]eeeee-8-eee ee eeeeeeee ee eeeeee ee eeeeeeeeee ee eeee eee eeeeeeeeeee eeeeee eeeeeeeeee 888. Mee 8-eeeeeeeeeeeeeeee eee 8-eeeeeeeeeeeeee e eeeeeeeeeee ee 88°M ee eeeeeeee ee eeeee eeeee eee eeeeeeeeee, eeeeeeee eee eeee eeeeeeee-eeee eeeeeeeeee, eeee ee 8,8-eeeeeeeeeeeeeeeeee ee 8-(eeeeeeeeeeeee)eeeeeeeee, eeeeee eeeeeeeeee eee eeeeeeee (–88°M ee ee) (Meeeee 88).[888]
Meeeee 88 Meeeeeeee ee Meeeee Meeeeeeeeeeeeee Meeee M-Meeeeeeeeeeeeeee eee 8,8-Meeeeeeeeeee[8.8.8]eeeee-8-eee ee Meeeeeee[888]
Meeeeee (ee eee eeeeeeeeee) eee eeee ee eeeeeeee eeeeeeeeeeeeeeeee eeee eeeeeeeee eeeeeeee eeeee eeeeeeeeeee eeeeeee eeeeeeeeee[888,888] eee eeee eeee ee eeeeeeeee eee eeee ee eeee eeee eeee eeeeeeeee eeee eeeee eeeeeee eeee eeeeee eeeeeee eee eeeeee eeeeeeeee eeee. Meee, eee eeeeeeeee a-eeeee eeee 888 ee eeeeeeee ee e eee eeeee eeee eee eeee-eeeeeeeeeeeeee-eeeeeeeee eeeeee eeeeeeeee 888; eeee, eee eeeeeeeee 888 ee eeeeeeee eeeeee ee eee eeee-eeeeeeeee eeeeeeeeeee ee eee eeeeeeee eeeeeeee (Meeeee 88).[888]
Meeeee 88 Meeeeeeeeeeeeeeee-Meeeeee Meeeeee Meeee Meeeeeeeeee[888]
Me eeeee eeeeeeeeee eeeeeeee ee eeeee eee eee ee eeeeeee ee eee eeeeeee eeeeee eee ee eeeee eee Meeeeee eeeeeeeeeeeeee eeeee eeeeee eeeeeeeeee eeeeeeeeeee eeeeee eeeeeeee eee eeeeeeee. Mee eeeeeee, eeeeeeeeeeeeee ee eeeeeee eeeeeeeeeeee eeeeeeeeee eeeeee eeee ee eeeeeeee ee eeeeeee e eeeeee ee eeeeee eeeeeeeeeeee 888 eeee eee eeeeeeeeeeeee eeeee eeeeeeeeeeeeee 888, eeeee eee eeeeeeeee eeeeee eeeeeeee 888 eee eeeeeee eeee eeeeeeeeeeee eeee (Meeeee 88).[888]
Meeeee 88 Meeeeeeee ee Meeee Meeeeeeeeeeeee Meeee Meeeeeeeeeeeee[888]
Me e eeeeeee eee [eee(eeeeeeeeeeeeeeee)eeee]eeeeeee eee ee eeee ee eeee eeeeee ee eeeee ee eeeeeee eee eeeeeeeeeeee 888 eeee eee eeeee eeeeeeeeeeeeee 888 eee eeeee eeeeeeeeeeeeeeeee 888 (Meeeee 88).[888–888]
Meeeee 88 Meeeeeeee ee Meeee Meeeeeeeeeeeee Meeee [Mee(eeeeeeeeeeeeeeee)eeee]eeeeeee[888,888,888]
[Mee(eeeeeeeeeeeeeeee)eeee]eeeeeee ee eeeeeeeeeeee ee eeee ee eeeeeeeee eeeeeee eeee eeeee ee eeeeeee B-eeeeeeeeeeeeeeeeeee eeee eeeeeeeeee-8-eeee,[888] eee eee eeee eeeeeee eeeeee ee eeeeeeee ee eee eeeeeeeee ee eeeeeeeee eeeeee a-eeeee eeeeeeee 888 eeee eee eeeeee eeeeeeeeeeee 888 (Meeeee 88).[888]
Meeeee 88 Meeeeeeee ee Meeeee a-Meeee Meeeeeee eeee Meeeee Meeeeeeeeeee[888]
Me eeeee eeeee [eeeeeee(eeeeeeee)eeee]eeeeeee ee eeee eeeeeeeeeee, eee eeee eeeeeee ee eeee ee eeeeeee eeee eeee-eeeee eeeeeeeeeeee 888 eeee eee eeeeeeeeeeeee eeeeeeee 8-eeeeeeeeeeeeeeeee 888 (Meeeee 88).[888–888]
Meeeee 88 Meeeeeeeeee Meeeeeeeeeee Meeee [Meeeeee(eeeeeeee)eeee]eeeeeee[888–888]
(Meeeeeeeeeeee)eeeeeee ee eeee ee eeeeeeeeeeeeeee eeeeeeee eeeeeeeeee eeeeee eeeeeee ee eeeeeeeee eee eeeeee eeeee 888 eeee eee eeeeeeeee 888. Mee eeee 888 ee eeeeeeee ee e eeeeeeeee (Meeeee 88).[888] Meeeeeeee, eee eeee eeeeeee, eee eee ee eee eeeeeeee ee e eeee, eeeeee 8,8-eeeeeeeeeeee[8.8.8]eeeee-8-eee ee eeeeeee eeeeeeeeeeeeeeee, eeeeeeee eee eeeeeeeee eeeeee 888 (e = 8, 8) eeee eeeeeeeeee-8-eeee 888 (e = 8) ee eeeeeeeeeeeeeeeeeee-8(8M)-eeee 888 (e = 8) ee eeeeeeeeeee (Meeeee 88).[888]
Meeeee 88 Meeeeeeeeee ee Meeeeeeeeeee eeee Meeeee eee Meeee Meeeeeeeeee Meeee (Meeeeeeeeeeee)eeeeeee[888,888]
M eeeeeeeee ee eee Meeeeee eeeeeeeeeeeee ee eeeeeee eeeee eeee eeeeee eee eeeeeee eeee eeee(MM) eeeeeee. Meee eeeee, eeeeeeeeeee eee eeeeeeee eee eeee eee ee eeeeeeeee eeeeeeee eeee eee eeeeeeeeeeeee eeeeee; eeeeeee, ee eee eeeeeeeeeee eee eeee eeeee eeee eeeeee eeee, eeeeeeeee eeee eee eeeeeee, ee eeeeee eeeeee eee eeeee, ee eee ee eeeeeeeeeeee ee eeee eeee ee eeeeee ee eeeeeee ee eeee eeeeeeeeee eee ee eeeeeeee eee eeeeeeee, eeeee ee eeeeeeeeee ee eee eeeeee.[88,888–888]
References
Meeeeee Meeeeeeeeee
- 8.Meeeee-Meee, (8888) 88/8, 888.
- 8.Meeeee-Meee, (8888) M 88e8, 8888.
- 8.Meeeee-Meee, (8888) M 88e, 8888.
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