Science of Synthesis

Joule, J. A., Science of Synthesis Knowledge Updates, (2010) 2, 54.

In one of the most direct indole syntheses to have been devised, 1,2-diols ‌198‌, even ethane-1,2-diol itself, react at 180°C with arylamines ‌197‌ under the influence of dichlorotris(triphenylphosphine)ruthenium(II) to give indoles ‌199‌ (‌Scheme 64‌); hydrogen gas is evolved.[‌217‌] Triethanolamine also serves to provide a two-carbon fragment in reactions with N-alkylarylamines using the same catalyst,[‌218‌] and in the presence of tin(II) chloride N-unsubstituted indoles, e.g. ‌200‌, can be formed from primary arylamines.[‌219‌] More substituted triethanolamines, e.g. tris(2-hydroxypropyl)amine {[HOCH(Me)CH2]3N} as its hydrochloride salt, react in the same way, using ruthenium(III) chloride hydrate, triphenylphosphine, and tin(II) chloride dihydrate in aqueous 1,4-dioxane at 180°C, giving 2-methyl-1H-indole in this particular example.[‌220‌]

‌Meeeee 88‌ Meeeeee eeee Meeeeeeeee eee 8,8-Meeee[‌888‌]

Meeeeeeeeeee Meeeeeeee

8-Meeeee-8M-eeeeee (‌888‌, M8 = Me; M8 = M8 = M8 = M8 = M); Meeeeee Meeeeeeee:[‌888‌]

Me e eeeeeeeee eeeee eeeeeee, eeeee eeee eeeee, M-eeeeeeeeeeeee (8.8 eM, 88 eeee) ee eeeeeee (8 eM) eee eeeee eeee eeeeee-8,8-eeee (8.8 eM, 88 eeee) eee eeee MeMe8(MMe8)8 (888 ee, 8.8 eeee) eee eeeee eeee eeeeeeee. Mee eeeeee eeeeee eee ee-eeeeeee eee eeee eeeeee ee 888°M eee 88 eee. Mee eeeeee eeeeee eee eeeeeeeeee (MMMMMMM: eeeeeeee eee eeeeeeee), eee eeeeeee eee eeeeeee eeee Me8M (888 eM), eee eee eeeeeeee eeee eee eeeeee eeee 8% ee MMe (888 eM), eeeeeeeee, eeeee (MeMM8), eee eeeeeeeeeeee ee eeee eee eeeeeee; eeeee: 8 e (88%).

8,8-Meeeeeee-8M-eeeeee (‌888‌); Meeeeee Meeeeeeee:[‌888‌]

M eeeeeee ee 8,8-eeeeeeeeeeeeeee (8.8 e, 88 eeee), eeeeeeeeeeeeeee (8.88 e, 8 eeee), MeMe8•M8M (88 ee, 8.88 eeee), MeMe8•8M8M (8.88 e, 8 eeee), eee Me8M (88 ee, 8.88 eeee) ee eeeeeee (88 eM) eee eeeeee ee e eeeeeeeee eeeee eeeeeeeee eeeee M8 ee 888°M eee 88 e. Mee eeeeeee eee eeeeeeee eeeeeee eeeeee eee ee MM8Me8 eeee eee eee eeeeeeee eee eeeeeeeeeeee. Mee eeeeeeee eeee eeeeeeee eee eeeeeeeee ee MM8Me8 (88 eM) eee eee eeee eee eeeeee eeee 8% ee MMe (8 × 88 eM), eeeee (Me8MM8), eee eeeeeeeeeeee. Mee eeeeeee eee eeeeeeee ee eeeeeeeeeeeeee (eeeeee eee, MeMMe/eeeeee) ee eeee eee eeeeeee; eeeee: 8.88 e (88%).

References