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Please login or sign up for a free trial to access the full content. Variation 2: Synthesis of 2,4,6-Trialkyl-1,3,5-triazines

DOI: 10.1055/sos-SD-017-00728

von Angerer, S.Science of Synthesis, (200417453.

A large number of trialkyl-substituted 1,3,5-triazines 9 have been synthesized by cyclotrimerization of the corresponding nitriles, but the yields are very variable and depend strongly on both the substituent and the reaction conditions. Frequently high pressure (up to 104 atm) is applied.[‌65‌‌69‌] When alcohols are used as a solvent or co-catalyst the formation of an imidate intermediate is likely. The trimerization of trichloroacetonitrile has been studied in detail (see HoubenWeyl, Vol. E 9c, p 675) because the trichloromethyl groups in the resulting 1,3,5-triazine are readily replaced by nucleophiles (see Section The catalysts generally comprise of acids (e.g., HCl, HBr)[‌70‌] and Lewis acids such as the chlorides of aluminum, phosphorus, iron, zinc, tin, and titanium.[‌71‌‌76‌] Trimerization can also be achieved under solvent-free conditions with catalysis by silica-supported Lewis acids.[‌77‌] Samarium(II) iodide in combination with hexylamine has also been used as a mild reagent for the cyclotrimerization of nitriles;[‌78‌,‌79‌] a catalytic amount of ammonia can also induce this reaction. Examples of the cyclotrimerization of alkyl cyanides are listed in Table 2.

Meeee 8 8,8,8-Meeeeeee-8,8,8-eeeeeeeee Meeeeeee ee Meeeeeeeeeeeeeeeee[‌88‌‌88‌,‌88‌‌88‌,‌88‌,‌88‌]

M8 Meeeeeeeee Meeee (%) Mee
Me Me(MM8)8MM8 (8.88 eeeee), MeM8 (eee.), eeeeee eeee, 88°M, 88e 88 [‌88‌,‌88‌]
Me MeMM, 88888888 eee, 88°M, 88e 88 [‌88‌]
Me MeMM, 88888888 eee, 88°M, 88e 88 [‌88‌,‌88‌]
e-Me MeMM, eeeeeeeee, 88888 eee, 888°M, 8e 88 [‌88‌]
eeeeeeeeeee MeMM, 88888888 eee, 888888°M, 8888e 88 [‌88‌]
MMe8 MeMe8, 888°M, 88e 88 [‌88‌]
MMe8 MeMe8, MMe, eeeee eeee, 88°M, 8e 88 [‌88‌]
MMe8 MeMe8, MMe, 88°M, 8e 88 [‌88‌]
MMe8 MM8MMe8, MMe, 88 ee 88°M, 88e 88 [‌88‌]
MMe8 MMe8, MMe, 888888°M, 888e 88 [‌88‌]
MM8 8888 eee, 888°M, 88e 88 [‌88‌]
MMMeMM8Me MeMe8, MMe(e), 888°M, 88e 88 [‌88‌]
(MM8)8MMM8MMMMe MM8 (8.8%), eeeeee eeee, 888°M, 88e 88 [‌88‌]

Mee eeeeeeee ee eeeeeeeeeeeeeee eeeeeeeee ee eeeeeeeeeeeeeeeeeeee eeeee e eeeeeee ee eeeeeee eeeeeee eeeeeeeee 88 eee 88; ee ee eeeeeee eeee 88 eeeeeeeeee ee eeee eeeeeeeeeeeeeeeeeeeee, eeeee eeeeeeeeeeeee eeeeeeeeee ee eeee 8,8,8-eeee(eeeeeeeeeeeeeee)-8,8,8-eeeeeeee (88) ee eeee eeeee (Meeeee 8).[‌88‌] Meee eee eeeeeeee eeeeeeeeeeeeeeeeeeee (88) ee eeeeeee eeee eeeeeeeeeeeeeeeeeeeeeeee eeeeeeeee, eeeeeeeeeeeee eeeeee ee eeeeee 8,8,8-eeee(ee­eeeeeeeeeeeeee)-8-(eeeeeeeeeeeeeeeeeeeeeee)-8,8,8-eeeeeeeeee eeeeeeeeeeeeeeeeeeeeeeeee (88) ee eeee eeeee.[‌88‌]

Meeeee 8 Meeeeeeee ee 8,8,8-Meeeeeee Meeeeeeeeee ee Meeeeeeeeeeeeeeeee[‌88‌]

Meeeeeeeeeee Meeeeeeee

8,8,8-Meee(eeeeeeeeeeeeeee)-8,8,8-eeeeeeee (8, M8=MMe8):[‌88‌]

Meeeeeeeeeeeeeeeeeeee (88e, 8.88eee) eee MM8MMe8 (8.8e) eeee eeeeee eeee e 888-eM eeeee. Mee eeeeeee eee eeeeeeeee eeee eeeee MMe ee 88 ee 8°M eeee eeeeeeee eee eee eeee ee ee eee 88e ee eeeeeeee eee eeeeeeee. Mee eeeeeee ee eee eeeee eee eeeeee ee 888888°M eee eeeeee eeee e eeeee eeeeeeee ee M8M ee eeee eee MMe eee eeeeeeee. Mee eeeeeee eee eeeeee ee eee eee eeeeeee eeeeeeee eeeee. Mee eeeee eeeeeee eee eeeeeeee, eeeee ee eee, eee eeeeeeeeeeeeee (MeMM); eeeee: 88%.

8,8,8-Meee(eeeeeeeeeeeeeee)-8,8,8-eeeeeeee (8, M8=MMe8):[‌88‌]

Meee e 8-M Meeeeeeeee eeeee eeee eeeeee eeeee eeeeeeeeeeeeeeeeeeeee (8.88ee, 8.8eee) eee eeeee MeMe8 (88e, 88eeee) eeee eeeeee eeeeeee ee eeeeeeee eee MeMe8 eeeeeee. Mee eeee eee eeee eeeeeeeee eeee eeeee MMe ee 88°M (eeeeeee eee eeeeeeeee). Mee eeeee eee eeeeee ee e eeee-eeeee eeee, eee eee eeeeeeee eeeeeeeee eeeeeeeee ee eeeeeeeeeee ee e eeeeeee ee 88°M eeeee eeeee 8e; ee eeee eeee eee eeee eeeeeeeeee. Me eeeee eeeeee ee eeeeeee M8M eee eeee eeeee ee eee eeeeeeee ee eee eeeee, eeeee eee eeeeeeee ee e eeeee eeee ee eeee eee eeeee eeeeeee. Mee eeeeeee eee eeeeeee eeeeeeeeee eee eeee eeeeee ee eeeee eee eeeeeee ee eeeeeeee eeeee. Mee M8M eee eeeeeeee eee eee eeeeeee eee eeeeeeeeeeeeee (MeMM); eeeee: 8.88ee (88%); ee 8888°M.

8,8,8-Meee(eeeeeeeeeeeeeee)-8,8,8-eeeeeeee (8, M8=MM8); Meeeeee Meeeeeeee:[‌88‌]

Meeeeeeeeeeeeeeeeeeee (88e, 8.88eee) eee eeeeee ee e eeeeeeeee-eeeee eeeeeeee eeeeee eee eeeeee ee 888°M. Mee eeeeeeee ee eee eeeeee eeee ee 88 eee, eeee eeeeeeeee ee 88 eee eeeee eeeeeee ee 888°M eee 88e. M eeeeee eeeeeeee ee eeeeeeee eeeeeeee eeeeee eee eeeee 8e. Meeee eeeeeee ee ee, eee eeeeee eee eeeeee eee eeeeeeeee eeeeeeeeeeeeeeeeeeeee (88e, 8.88eee) eee eeeeeeeee ee e eee eee eeeeee eeee. Mee eeee eeeeeee eeeeeeee (88e) eee eeeeee eeee eee eeeeee eee eeeeeeeeeeeeee; eeeee: 88e (88%); ee 8888°M.

8,8,8-Meee(eeeeeeeeeeeeeee)-8,8,8-eeeeeeee (88):[‌88‌]

8,8-Meeeeeeeeee-8,8-eee(eeeeeeeeeeeeeee)eeee (88e, 8.8eee) eee eeeeee ee e eeeeeeeeeeee eeeee (eeeeeeeee eeeeee ee 8°M) ee 88°M/888Meee eee 8e eee eeee ee 888°M eee 88eee. 88.8e ee eeeeeeeeee eee eeeeeeee, ee 8888°M. Meeeeeeee eeee eeee 8.8e, eeeeeeeee eeee eee eee eee/eeeeeee eeee, eee eeeeeeeeeeeeee eeee eee eeeeeee; eeeee: 88.8e (88%); ee 88888°M/888Meee.