Science of Synthesis

Jahn, U., Science of Synthesis, (2010) 41, 388.

The N-nitration of anilines is one of the most frequently used methods for the synthesis of N-aryl-N-nitroamines. The yield and selectivity are, however, highly dependent on the substitution pattern of the starting aniline and the reagent used for nitration. Generally, aniline itself and donor-substituted anilines are nitrated on the ring, and N-aryl-N-nitroamines are rarely, if ever, observed. One can suspect that N-aryl-N-nitroamines are formed during nitration as fleeting intermediates, but undergo the N-nitroamine rearrangement under the reaction conditions. Acceptor-substituted anilines, in which the ring electron density is diminished, are nitrated at the amino group in moderate to good yields (‌Table 1‌). The most common nitrating agents are 90–100% nitric acid alone or in acetic acid, fuming nitric acid in acetic acid and acetic anhydride, or fuming nitric acid in sulfuric acid. However, nitronium tetrafluoroborate or dinitrogen pentoxide have also been used occasionally for this purpose. Using nitric acid, nitric acid in acetic acid, or nitric acid in acetic anhydride, N-nitroamines with unchanged substitution patterns can be isolated (entries 1, 2, 13–35, and 37).[‌165‌–‌178‌] Several functional groups in the starting anilines such as ortho- and para-sulfonate, para-carboxylate, para-formyl, and para-acyl groups are subject to exchange by a nitro group during nitration, giving nitro(nitroamino)benzenes (entries 3–12).[‌166‌,‌167‌] Other ring nitrations occur only rarely (entries 36 and 38).[‌177‌,‌178‌] Ring nitration in addition to N-nitration to nitro(nitroamino)benzenes is more favored when the nitric acid/sulfuric acid reagent is applied (entries 40–44 and 48–51).[‌168‌–‌170‌,‌179‌–‌184‌] The facile introduction of additional nitro groups may be due to the presence of sulfuric acid, which is commonly used to promote the N-nitroamine rearrangement. Sulfonate groups are concomitantly exchanged during the nitration process (entries 46 and 47).[‌181‌] Polynitrated N-nitroamines tend to transform into diazonium phenolates (diazophenols) under the reaction conditions {see Science of Synthesis, Vol. 28 [Quinones and Heteroatom Analogues (Section ‌28.11‌28.11)]}. There is great interest in N-nitroamines as agricultural products and explosives, and a large number of N-nitroanilines and their salts have appeared in the patent literature.[‌185‌–‌192‌]

MMMMMM: Meee eeee M-eeeee-M-(eeeeeeeeeeeee)eeeeee eee eeeeeeee eeeeeeeeee eee eee eeeeeeeee ee eeeee eee eeeeeeee.

‌Meeee 8‌ Meeeeeeee ee M-Meee-M-eeeeeeeeeee ee Meeeeeeee[‌888‌–‌888‌,‌888‌–‌888‌]

Meeee	Meeeeeee Meeeeeee	Meeeeeeeeee	Meeeeee	Meeeee (%)	Mee
8		888% MMM8		88	[‌888‌]
8		888% MMM8		eeeee	[‌888‌]
8		888% MMM8		e.e.	[‌888‌]
8		888% MMM8		e.e.	[‌888‌]
8		888% MMM8		e.e.	[‌888‌]
8		888% MMM8		e.e.	[‌888‌]
8		888% MMM8		e.e.	[‌888‌]
8		88% MMM8		eeeee	[‌888‌]
8		88% MMM8		88	[‌888‌]
88		88% MMM8		88	[‌888‌]
88		88% MMM8		88	[‌888‌]
88		88% MMM8		e.e.	[‌888‌]
88		88% MMM8		eeeee	[‌888‌]
88		88% MMM8, Me8M, MeMM		88	[‌888‌,‌888‌]
88		88% MMM8, Me8M, MeMM		88	[‌888‌]
88		888% MMM8, Me8M, MeMM		88	[‌888‌]
88		888% MMM8, Me8M, MeMM		e.e.	[‌888‌]
88		888% MMM8, Me8M, MeMM		88	[‌888‌]
88		888% MMM8, Me8M, eeeeeeeee		88	[‌888‌]
88		888% MMM8, Me8M, MeMM		88	[‌888‌]
88		888% MMM8, Me8M, MeMM		88	[‌888‌]
88		888% MMM8, Me8M, MeMM		e.e.	[‌888‌]
88		888% MMM8, Me8M, MeMM		e.e.	[‌888‌]
88		888% MMM8, Me8M, MeMM		e.e.	[‌888‌]
88		888% MMM8, Me8M, MeMM		e.e.	[‌888‌]
88		888% MMM8, Me8M, MeMM		e.e.	[‌888‌]
88		888% MMM8, Me8M, MeMM		e.e.	[‌888‌]
88		888% MMM8, Me8M, MeMM		e.e.	[‌888‌]
88		888% MMM8, Me8M, MeMM		e.e.	[‌888‌]
88		888% MMM8, Me8M, MeMM		e.e.	[‌888‌]
88		88% MMM8, Me8M, MeMM		e.e.	[‌888‌]
88		MMM8, Me8M, MeMM		88	[‌888‌]
88		888% MMM8, Me8M, MeMM		e.e.	[‌888‌]
88		888% MMM8, Me8M, MeMM		e.e.e	[‌888‌]
88		888% MMM8, MeMM		88	[‌888‌]
88		888% MMM8, MeMM		88	[‌888‌]
88		888% MMM8, MeMM		88	[‌888‌]
88		888% MMM8 (eeeeee), MeMM		88	[‌888‌]
88		88% MMM8, 88% MM8 ee M8MM8		88	[‌888‌]
88		88% MMM8, 88% M8MM8, MeMM		88	[‌888‌,‌888‌]
88		88% MMM8, 88% M8MM8		88–888	[‌888‌,‌888‌]
88		88% MMM8, 88% M8MM8		88	[‌888‌]
88		88% MMM8, 88% M8MM8		88	[‌888‌]
88		888% MMM8, 88% M8MM8		88	[‌888‌]
88		888% MMM8, 88% M8MM8		88	[‌888‌]
88		888% MMM8, 88% M8MM8		88	[‌888‌]
88		888% MMM8, 88% M8MM8		88	[‌888‌]
88		88% MMM8, 88% M8MM8		88	[‌888‌]
88		88% MMM8, 88% M8MM8		88	[‌888‌]
88		888% MMM8, 88% MM8 ee M8MM8		e.e.	[‌888‌]
88		888% MMM8, 88% MM8 ee M8MM8		e.e.	[‌888‌]
88		MM8+MM8−, 8,8-eeeeeeeeeeeeee		88	[‌888‌]
88		MM8+MM8−, MeMM		88	[‌888‌]
88		MM8+MM8−, MeMM		88	[‌888‌]
88		M8M8, MeMM		88	[‌888‌]
88		M8M8, Me8M		88	[‌888‌,‌888‌]
88e		M(MM)8, MMM		88–88	[‌888‌]
88e		M(MM8)8, MMM		88–88	[‌888‌]
88e		M(MM8)8, MMM		88–88	[‌888‌]
88e		M(MM8)8, MMM		88	[‌888‌]

e Me eeeeeee, eee eeeeee eeee eeee eeeeee ee eeee ee eeeeeee eeee ee eeeee eeeeeeeeeeeee ee M-eeeeeeeeeeeee.

e e.e. = eee eeeeeeee.

e Meeeeeee ee eee eeeeeee(MM) eeee.

e M = Me, Me, M, Me, Me.

Meee eeeeeeeeee M-eeee-M-eeeeeeeeeee eeee eeee eeee eeeeeeeeeee. 8,8,8,8-Meeeeeeeeeeeeeeeeeeee-8,8-eeeeeee ee eeeeeeee ee eeeeee eeee/eeeeeeee eeee ee 88% eeeee ee eeee eee eeeeeeee M,M′,8,8,8,8-eeeeeeeeeeeeeeeeeeee-8,8-eeeeeee.[‌888‌] Meeeeeeeeeeeeeeeeee eee eeeeeeee ee eeeeee eeee ee 88–888% eeeee. Mee eeeeeee eeeeeeeeeeee eeeeeee ee eee eeeeeeeeee eeeeeeeee ee eee eeeeeeee eeeeeeeee.[‌888‌] Mee M-eeeeeeeeee ee 8-eeeeeeeeeee-8,88-eeeeeee eee 8,8-eeeeeeeeeeeee-8,88-eeeeeee eee eeeeeeee ee eeeeeee ee 88–88% eeeeee.[‌888‌] M-Meeeeeeee ee 8-eeeeeeeeeeee-8,8-eeeeeeeeeeeee ee eeeeee eeeeeee eeeeeeeee ee eeee eeee eeeeee(MM) eeeeeee/eeeeee eeeeeeeee eeeee eee eeeeeeeeeeeee M-eeeeeeeeee ee 88% eeeee.[‌888‌]

Meeeeeeee eeeee eeeeee eeeeeee eeeeeeeeee ee ee eeeeeeeeee eeeeeeeeeee ee eee eeeeeeeee eeeeeeeeee eeeee, eee eee eeeeeeeee eee eee eeee ee eeeeee eeeeeeee. Meeeeeeee eeeeeeeeeeeeeeeee ee eeee ee eeeeeee eeeeeeee; eee eeeeeeeee ee 8-eeeeeeeeeeeee eeeeee eeee eeeeeeee ee 88–88% eeeee (‌Meeee 8‌, eeeeeee 88 eee 88).[‌888‌,‌888‌] Mee M-eeeeeeeee ee eeeeeeee eeeee eeeeeeeee eeeeeeeeeeeeeeeeeee eee eeee eeee eeeeeeee.[‌888‌] M-Meeeeeeee ee eeeeeeee eee eeee ee eeeeeeeeeeee ee eeeeeeeee eeee eee eeeeeeeeee eeeeeeeee; eeeeeee, eee eeeeeeeeee ee eee eeeeeee ee eeee eeeeeeeee eee ee eeee ee eeee, eeeee eeeeeeeee eeeeeeee eeeee eeeeeee eeee eeeeeeee eeee ee eeeeeeeee eeeeee, eeeeee eeeeeeee, eee eeeee eeeeee. Meeeeeeeee eeeeeeeee eee ee eeee ee eeeeeeee eee eeeeee M-eeeeeeeeeeee ee 88% eeeee (eeeee 88),[‌888‌,‌888‌] eee 8-(eeee-eeeee-MMM-eeeee)eeeeeee ee eeeeeeee ee eeeeeeeeee eeeeeeeee ee 88% eeeee (eeeee 88).[‌888‌] Mee M-eeeeeeeee ee eeeeee eeeeeeeeeee eeeeeeee ee eeeeeeeeee eeeeeeeee eee eeeeeeeeeee M-eeeeeeeeee eeeeeeeeeeeee ee eeeeeeee ee 88% eeeee.[‌888‌] Mee M-eeeeeeeee ee 8- eee 8-eeeeeeeeeeeee ee eeeeeeeeeeeeeeee eeeee ee eeeeeeeeeeeeeeeee, ee eeeeeeeeeeeeeee eeeeeeeeeeee {MMMM, 8,8-eee[(eeeeeeee)eeeeee]eeeeeee-8,8-eeee eeeeeeeee} ee eee eeeeeeee ee eeeeee eeeee eeeeeeeeee eee eeee eeee eeeeeeee; eee eeeeeeeeeee eeeee eeeeeeee ee eeeee eeeeee eeeee eeeee ee 88–88% eeeee.[‌888‌] Meee eeee eeeeee, eee eeeeeeeeeeee ee eeeeeeeee eee eeeeeee eeeeee ee eeeeeee; ee ee, eeeeeee, eeeeeee ee eeeeeeee-eeeeeeeeeee M-eeeeeeeeeeeee eeee e eeee- ee eeee-eeeeeeeeeee ee eee eeeeeeeeeeee (eeeeeee 88–88). Me eeeee eeeeee eeeeeeeeee ee eeeeeeeeeee eeeeeeeee eeeeeeee eeee eeeeee eeeeeeeee ee eeeeeee ee eeee eeeeeeeee eee eee eeeeeeeeeee eeeeeeeee ee eeeeeeeeeeee eee eeee-eeeeeeee eeeeeeee.[‌888‌,‌888‌]

References