Nitroacetamide, Methyl

At lower acidities the iV-nitrobenzamides and /V-methyl-.V-nitrobenzamides have a hydrolysis mechanism that is not acid-catalyzed for these cases plots of log kv - log h2o are linear, as for the acyhmidazoles discussed above. N-Nitroacetamide also hydrolyzes in this way.291 The proposed mechanism is given in Scheme 17, written for TV-nitroacetamide if the hydration shown is a pre-equilibrium (this is a carbonyl compound with a strong electron-withdrawing group attached, so this is likely), only one water molecule will appear in the rate expression (the difference between 3 and 2), as observed.287 Some evidence for hydroxide-catalyzed processes at the very lowest acidities was also found for some of these compounds.287... 

R = H), and 4-p-nitrophenylpyrimidine (123, R = NO2) by reaction with cyclopentanone, acetophenone, and / -nitroacetophenone, respectively. The yields are, however, quite low (15-30%) and the reaction is found to be applicable to restricted substrates. In some of these reactions A -methyl-a-nitroacetamide could be isolated as the other reaction product. 

The mechanism of this conversion was formulated to occur by an initial addition of the ammonia at position 2 and of the anion of the keto compound (or the enamine) at position 6, i.e., formation of 124. It is of course possible that this addition pattern can be reversed addition of the ammonia at position 6 and of the anion at position 2. In both addition products an internal cyclization occurs by attack of the nitrogen of the amino group on the keto function, yielding the tricyclic intermediate 125. Aromatization occurs by loss of A-methyl-a-nitroacetamide (Scheme III.62). 

The nitration of methyl methacrylate afforded as by-product the nitroacetamide 37 (Scheme 10) <1997J(P1)1559>. Its regiochemistry suggested that the putative ct-carbonyl cation 35, which was then trapped by acetonitrile, may be the intermediate in its formation. However, AMI calculations showed that the tertiary cation 35 may also be in equilibrium with l,2-oxazetidin-2-onyl cation 36, the latter being calculated to be about 1 kcal mol-1 lower in energy. 

There are no significant reports updating the reactivity of substituents attached to ring carbon atoms. To explain the formation of the allylic nitro compound 44 as the major product of the nitration of methyl methacrylate 43 (Scheme 12) versus nitroacetamide 45, a plausible mechanism postulated by Murphy and co-workers... 

An H acidity function scale has been constructed for methoxide ion in methanol and its mixtures with DMSO (10-80%, v/v) using the dissociation of 11 amides (114) as the anchors for the scale.The degradation pathways of the anti-flammatory and analgesic lomoxicam (115), which contains an amide bond, have been examined recently. In acid, cleavage of the amide bond was the main reaction path and in alkaline and neutral solution the proton shift of the enolic hydroxyl initiated the major degradation pathway. The mechanism of hydrolysis of some A-nitrobenzamides (116) in strong acid follow an -1 mechanism with O-protonation but, in more moderate acid, they exhibit a neutral water-catalysed mechanism. /V-Methyl-/V-nitroacetamide (117) shows only the neutral water-catalysed process. Nitrourea follows an, 4-1 acid-catalysed mechanism. ... 

Condensations of active nitro compounds with electron-poor dipolarophUes slowly occur in water even without base catalysis, as illustrated by the reaction of A-methyl nitroacetamide with acrylamide, which is complete after 26 h. However, the same reaction carried out with addition of 0.1 equiv of base is complete within less than 2h (Figure 8.3) [72]. 

FIGURE 8.3 Kinetic prohles of the condensation of A-methyl nitroacetamide with acrylamide (a) with (solid squares) and (b) without (open squares) base catalysis. 

TABLE 8.2 Competition Between Conjugate Addition and Condensation of Ethyl Nitroacetate and iV-Methyl Nitroacetamide at 60 °C in Various Conditions. Conversion was Complete, but 86% (Entry 7), 94% (Entry 10), 20% (Entry 15) [72,86]... 

Competition in selected reactions of ethyl nitroacetate and iV-methyl nitroacetamide with Michael acceptors 19 is reported in Table 8.2. 

In aqueous solution, Al-methyl nitroacetamide reacts with a base, and Al, Al -dimethyl-3,4-bis-carbamoylfuroxan is detected (15%) besides other unidentified products (see Section 8.4.1) [72]. 

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