Conversion of N-Aromatic Amides to O-Aromatic Esters

Abstract

[reaction: see text] N-Aromatic secondary amides can be transformed into O-aromatic esters in high yield via N-nitrosamide intermediates. The amides can be generated in situ from the corresponding aromatic amines or nitro compounds, and phenols can easily be made from the esters. The reaction can be modified by addition of methyl methacrylate or toluene at 0 degrees C to give polymerization or deamination, respectively. The rearrangement mechanism may involve radical formation and recombination.

A new approach towards the synthesis of pseudaminic acid analogues

“…Accordingly, exposure of the methyl ester -methyl glycoside 10 of Neu5Ac to sodium nitrite (2 molar eq.) in acetic anhydride and acetic acid under the conditions described by Glatzhofer et al 42 (0˚C for the addition of NaNO 2 , then 2 hours at 0˚C and overnight at RT) afforded a modest (~20%) yield of the KDN derivative 11 along with several other minor components. 43 The modest yield of KDN from this attempt was disappointing, but following from the pivotal work by White during the 1950's, [44][45][46] we felt that increasing the excess of sodium nitrite and increasing the reaction temperature after the formation of the N-nitroso intermediate may be beneficial.…”

“…40 In 2002, Glatzhofer et al reported the direct conversion of N-aromatic secondary amides into O-aromatic esters via Nnitrosamide intermediates using sodium nitrite in a mixture of acetic anhydride and acetic acid. 42 We wondered if this type of conversion could be applied to aliphatic secondary amides like that found in Neu5Ac. Accordingly, exposure of the methyl ester -methyl glycoside 10 of Neu5Ac to sodium nitrite (2 molar eq.)…”

Total Synthesis of (+)‐Aquaticol by Biomimetic Phenol Dearomatization: Double Diastereofacial Differentiation in the Diels–Alder Dimerization of Orthoquinols with a C2‐Symmetric Transition State

“…Hydroxycuparene ( 3 ) was prepared as the racemate from (±)‐cuparene ( 4 ) (Scheme 2) 6. The nitration of 4 7 was followed by conversion of the resulting nitrocuparene into an acetate through the elegant two‐step one‐pot procedure described by Glatzhofer et al 8. Alkaline hydrolysis of this acetate then furnished 3 in 57 % yield from 4 (see the http://www.wiley-vch.de/contents/jc_2002/2007/z604610_s.pdf).…”

Synthesis of new planar chiral [2.2]paracyclophane Schiff base ligands and their application in the asymmetric Henry reaction

“…10 Enantiopure 1 can be transformed to enantiopure 4-acetoxy-13-bromo [2.2]paracyclophane 3 by means of a modified N-nitrosamide rearrangement. 11 The key intermediate in our strategy, enantiopure 4-hydroxy-13-bromo[2.2]paracyclophane 4, was prepared from 3 by hydroxide-catalyzed transesterification in ethanol (Scheme 1). 12 Starting from (4S p ,13R p )-4 and (4R p ,13S p )-4, several 4,5,13-trisubstituted planar chiral [2.2]paracyclophane building blocks were synthesized.…”