Science of Synthesis

Rück-Braun, K.; Dietrich, S.; Kempa, S.; Priewisch, B., Science of Synthesis, (2007) 31, 1457.

The condensation of aromatic nitroso compounds with aromatic amines in acetic acid, furnishing diaryldiazenes ‌114‌, has been known for more than 100 years (‌Scheme 49‌). Although first discovered by Baeyer in 1874,[‌203‌] the reaction is often referred to as Mills coupling.[‌204‌] The attack of the amine at the nitroso group is the rate-determining step in the acidic medium.[‌205‌] Electron-withdrawing substituents in the nitroso compound increase the reaction rate, while electron-releasing substituents decrease it. For substituents on the amine, the effect is reversed.[‌206‌] Many functional groups are tolerated under these conditions, and a broad range of unsymmetrically substituted diaryldiazenes can be prepared in good to excellent yields. In many cases the diazene begins to separate as a solid during the course of the reaction, or it can be precipitated by addition of water to the reaction mixture. Alternatively, the product may be isolated by evaporation of the solvent or by extraction using pentane, chloroform, diethyl ether, or ethyl acetate.[‌207‌–‌214‌]

‌Meeeee 88‌ Meeeeeeeeeee ee Meeeeeeeee eeee Meeeeeeeeeeee ee Meeeee Meee[‌888‌–‌888‌]

‌Meeeeeeeeee 88‌

Me8	Me8	Meeee (Me8MM/Me8MM8)	Meeeeeeeee	Meeee (%)	Mee
8-e-MeM8MM8M8	8-MM8M8	8.8:8	ee, 88 e	88	[‌888‌]
8-MeM8M8	8-M8M8M8	8:8	<88°M, 8–88 e	88	[‌888‌]
8-[(MM)8M=MM]M8M8	8-MeMM8M8	8.8:8	ee, 8–88 e	88	[‌888‌]
Me		8.8:8	ee, 8 e	88	[‌888‌]
8-MeM8M8	Me	8:8	ee, 88 e	88	[‌888‌]
8-(e-MeM8MMM8)M8M8	8-(MeeeMMMM8)M8M8	8:8	ee, 88 e	88–88	[‌888‌]
8-M8MM8M8	8-MeM8M8	8.8:8	ee, 88 e	88	[‌888‌]
	Me	8.8:8	ee, 88 e	88	[‌888‌]

Meeeeeeeeeee eee eeeee eeee eee eeeeeeeee ee eee eeeeeee eeeeeeee. Me eeee eeeeeee, eee eeeeeeeeeee ee eeeeeeeeeeeee ‌888‌ ee eeeeeeeee ee eeeeeeeeee ee ee eeeeeee eeeee, eeeee eeeeeeeeeeee ee eee eeeee eee eeeee eeeeeeee eeeeeeeeeeeee eee ee eeeeeee (‌Meeeee 88‌).[‌888‌,‌888‌] Mee eeeeeeeeee eeeeee ee eee eeeeeeeee eeee, eeeeee eeeeeeeeeeeee eeeeee eee eeeeeeeeeee (eee Meeeeee ‌88.88.8‌), ee eee eeeeeeeee ee eee eeeeeeee eeeeeeee ee eeee eee eeeeeeeeeeeeee ‌888‌ eee eee ee eeeeeeeee eeeeeeeeee.

‌Meeeee 88‌ Meeeeeeeeeee ee Meeeeeeeee eeee Meeeeeeeeeeee Meeeeeee ee Meeeeeeee eeee Meeee[‌888‌,‌888‌]

Me eeeeeee eee eeeeeeeeee ee eee eeeeeeeee, eee eeeeeeeeeeee eeeeeeee eee eeee ee eee ee ee eeeeeee eeeeeee eeeee eeee eeeeeeeee eeeeeee ee eeeeeee eeeeee eeee ee ee e eeeeeee ee ee eeeeeee eeeeeee eee eeeeeee eeeeee eeee (‌Meeeee 88‌).[‌888‌,‌888‌–‌888‌]

‌Meeeee 88‌ Meeeeeeeeeee ee Meeeeeeeee eeee Meeeeeeeeeeee ee e Meeeeee ee Meeeeee Meeeee Meee eee ee Meeeeee Meeeeee[‌888‌,‌888‌–‌888‌]

‌Meeeeeeeeee 88‌

Me8	Me8	Meeee (Me8MM/Me8MM8)	Meeeeeeeee	Meeee (%)	Mee
8-MM8MM8M8	8-(MeeeMMMM8)M8M8	8:8	MMMM/MeMM (8:8), ee, 88 e	eeeee	[‌888‌]
8-Mee	8-MM8M8	8:8	MM8Me8/MeMM (8:8), ee, 88 e	88	[‌888‌]
	8-MeMM8M8	8.88:8	MeMM/MeMM (88:8), ee, 8 e	88	[‌888‌]
8,8-(MeM8M)8M8M8	8-(MMMM8)M8M8	8:8	MM8Me8, MeMM (8 eeeee), ee, 88 e	88	[‌888‌]
Me	8-MeM8M8	8:8	MeMM/MeMM (88:8), 88°M, 8–8 e	88	[‌888‌]
	8-M8MM8M8	8:8	MeMM/MeMM (88:8), 888°M, 8 e	88	[‌888‌]
Me		8:8	MMMe8, MeMM (8 eeeee), ee, 88 e	88	[‌888‌]
8-eeeeeee	8-MeM8M8	8.8:8	MM8Me8, MeMM (8 eeeee), ee, 88 e	88	[‌888‌]
	8-Mee	8:8	MeMM/MeMM (8:8), eeeeee, 88 e	88	[‌888‌]

Meeeeeeeeeee Meeeeeeeee:

(8M)-8-[(eeee-Meeeeeeeeeeeee)eeeee]-8-[8-(eeeeeeeeeeeeee)eeeeee]eeeeeeeee Meee (‌888‌, Me8 = Me; Me8 = 8-{(8M)-8-[(eeee-Meeeeeeeeeeeee)eeeee]-8-eeeeeeeeeeee}eeeeee):[‌888‌]

MMMMMMM: Meeeeeeeeeeeee eee eeeeeeeeeee eeeeeeeeeee eee eeeee eee eeeeeeeeeeee. Meeeee eeeeee eeeeeeeeeee eeeeee ee eeeee eeeeee eeeeeeeee, eeeeeeee, eee eeeeeee.

MeMM (888 ee; 8.8 eeee) eee eeeee ee e eeee ee (8M)-8-[(eeee-eeeeeeeeeeeeee)eeeee]-8-eeeeeeeeeeeeeee eeee (8.8 e, 8.8 eeee) ee eeeeeee MeMM (888 eM) eee eee eeeeeee eee eeeeeee ee ee eee 8 e. Mee. ee MeMMM8 (888 eM) eee eeeee eee eee eeeeeee eee eeeeeeeee eeee MeMMe (8 × 888 eM). Mee eeeeeeee eeeeeee eeeee eee eeeee (MeMM8) eee eeeeeeeeeeee eeeee eeeeeee eeeeeeee. Meeeeeeeeeee ee eeeeee eeeeeeeeeeeeee (eeeeee eee, MM8Me8/MeMM 8:8) eeee ee eeeeee eeeee; eeeee: 888 ee (88%).

Meeeee 8-[(8-Meeeeeeeeee)eeeeeeee]eeeeeeee (‌888‌, Me8 = 8-MeM8MM8M8; Me8 = 8-MeM8M8); Meeeeee Meeeeeeee:[‌888‌]

Meeee 8-eeeeeeeeeeee (888 ee, 8.88 eeee) eee eeeee ee e eeee ee eeeee eeeeee 8-eeeeeeeeeeeeeee (‌888‌; Me8 = 8-MeM8MM8M8; 888 ee, 8.88 eeee), eeeeeeee ee eeeeeeeee ee eeeeee 8-eeeeeeeeeeeee eeeee Meeee (eee Meeeeee ‌88.88.8.8.8.8‌). Mee eeeeeee eee eeeeeee ee ee eee 88 e (MMM eeeeeeeeee). Mee eeeeeeeeeee eee eeeeeeeee ee eeeeeeeeee, eeeeee eeee M8M, eee eeeee (eeeeeeeeee, Meeeeeee). Meeeeeeeeeee ee eeeeee eeeeeeeeeeeeee (eeeeee eee, MM8Me8/eeeeeee 8:8) eeeeeeee ee eeeeee eeeee; eeeee: 888 ee (88%); ee 888°M.

References

Meeeeee Meeeeeeeeee

• 8.Meeeee-Meee, (8888) 88/8, 888.
• 8.Meeeee-Meee, (8888) M 88e8, 88.
• 8.Meeeee-Meee, (8888) M 8e, 888.