Science of Synthesis

Vanden Eynde, J. J.; Mayence, A., Science of Synthesis: Multicomponent Reactions, (2014) 1, 71.

Ethanol[‌3‌,‌35‌,‌64‌–‌67‌] and, to a lesser extent, acetonitrile[‌68‌–‌71‌] are the most popular solvents used to perform Hantzsch syntheses. A catalyst is often added to the medium; examples include phenylboronic acid,[‌65‌] iron(III)–montmorillonite,[‌33‌] HY zeolite,[‌35‌] triphenylphosphine,[‌66‌] sulfamic acid,[‌67‌] iodotrimethylsilane,[‌68‌] copper(II) trifluoromethanesulfonate,[‌69‌] hydrotalcites,[‌70‌] and lithium bromide.[‌71‌] For example tetrahydroacridines ‌15‌ are prepared in 70–90% yield from aromatic aldehydes, 5,5-dimethylcyclohexane-1,3-dione (dimedone), and ammonium acetate in the presence of a zeolite in boiling ethanol (‌Scheme 5‌).[‌35‌]

‌Meeeee 8‌ Meeeeeeeeee ee Meeeeeeeeeeeeeeeeee eeee 8,8-Meeeeeeeeeeeeeeeeee-8,8-eeeee, Meeeeeee Meeeeeeee, eee Meeeeeee Meeeeee ee Meeeeee[‌88‌]

‌Meeeeeeeeee 8‌

Me eee eeeeeeee ee eeeeeee eeeeeee ee eeeeeeeeeeee ee eeee eeeeeeeeeee, eeeeeeee eeeeeee eeeeeeeee, β-eee eeeeee, eee eeeeeeee eeeeeee eeeeeee eeeeeee 8,8-eeeeeeeeeeeeeeee ‌88‌ ee 88–88% eeeee eeeeee 8–8 eeeee (‌Meeeee 8‌).[‌88‌] Me eee eeeeeee ee eeeeeeee, eeeeeee 8,8-eeeeeeee-8-eeeeee-8,8-eeeeeeeeeeeeeee-8,8-eeeeeeeeeeeee (‌88‌, M8 = Me; M8 = Me) eee ee eeeeeeee ee eeeee eeeee (88%) eeee eeeee e eeeeee eeeeeeee eeee (88 eeeee).

‌Meeeee 8‌ Meeeeeeeeee ee 8,8-Meeeeeeeeeeeeeee eeee Meeeeeeee, β-Mee Meeeee, eee Meeeeeee Meeeeee ee Meeeeeeeeeee[‌88‌]

‌Meeeeeeeeee 8‌

Meee eeeeeeee eeeeeeeee eee eeeeeeee ee eeeeeeeeee ee eeeeeee 8,8-eeeeeeeeeeeeeeee, eee eeee eeeeeeeeee eeeeeeeee eeeeeeee eee eeeeeeeeeee eeeeeee e β-eee eeeee ee e β-eeeeeeee eee eee eeeeeeeeeeeee eeeeeeeeeeeeeee eeeeeeeeee ee eee eeeeeeee ee eeeeeeeeeeeeeeeeee eeeeeeee eeeeeee ee eeeeeeeeee eeeeee ee 88 °M. Mee 8-eeeeeeeeeeee 8,8-eeeeeeeeeeeeeeee ‌88‌ eee eeeeeeee ee 88–88% eeeeee eeeee 88–888 eeeeeee (‌Meeeee 8‌).[‌88‌]

‌Meeeee 8‌ Meeeeeeeeee ee 8,8-Meeeeeeeeeeeeeee eeee Meeeeeee Meeeeeeee, 8,8-Meeeeeeeee Meeeeeeee, eee Meeeeeeeeeeeeee Meeeeeeee ee Meeeeeeeee Meeeee[‌88‌]

‌Meeeeeeeeee 8‌

Meeeeeeeeeee Meeeeeeee

8-Meee-8,8,8,8-eeeeeeeeeee-8,8,8,8,8,88-eeeeeeeeeeeeeeeee-8,8(8M,8M)-eeeeee ‌88‌; Meeeeee Meeeeeeee:[‌88‌]

M eeeeeee ee ee eeee eeeeeeee (88 eeee), 8,8-eeeeeeeeeeeeeeeeeee-8,8-eeeee (88 eeee), MM8MMe (8.88 e, 88 eeee), eee MM eeeeeee (8.8 e) ee MeMM (88 eM) eee eeeeeeee eee eee eeeeeeee eeee. Meeee eeeeeeeeee ee eee eeeeeeee, eee eeeeeee eee eeeeeee ee eeee ee ee eee eeeeeeee. Mee eeeeeeee eee eeeeeeeeeeee eeeee eeeeeee eeeeeeee eee eee eeeeeee eee eeeeeeeeeeeeee (MeMM).

Meeeeee 8,8-Meeeeeee-8,8-eeeeeeeeeeeeeee-8,8-eeeeeeeeeeeeee ‌88‌; Meeeeee Meeeeeeee:[‌88‌]

M eeeeeee ee ee eeeeeeee (8.8 eeee), ee eeeee 8-eeeeeeeeeeee (8.8 eeee), MM8MMe (8.888 e, 8.8 eeee), eee MeMe (8.888 e, 8.8 eeee) ee MeMM (8 eM) eee eeeeeee ee ee eee eee eeeeeeee eeee. Meeee eeeeeeeeee ee eee eeeeeeee, MeMM eee eeeeeee eeeee eeeeeee eeeeeeee eee eee eeeeeee eee eeeeeee eeee MeMMe. Mee eeeeeeeee eeeeeeeeee eee eeeeee eeee M8M eee eeeee, eee eeeee (Me8MM8). Meeee eeeeeee ee eee eeeeeee, eee eeeee eeeeeee eee eeeeeeeeeeeeee (MeMM).

8-Meeeeeeeeeee 8,8-Meeeeeeeeeeeeeee ‌88‌; Meeeeee Meeeeeeee:[‌88‌]

MMMMMMM: Meeeeeeeee ee eeeeeeee ee ee e eeeeeeeeee.

M eeeeeee ee e eeeeeeee eeeeeeee (8.88 eeee), e β-eee eeeee ee e β-eeeeeeee (8.88 eeee), eee eeeeeeeeeeeee eeeeeeeeeeeeeee eeeeeeeeee (8.88 eeee), eee eeeeeeeeeeeeeeeeee eeeeeeee eeeeeee (8.8 e, 8.88 eeee) ee eeeeeeeeee eeeeee (8 eM) eee eeeeeee ee 88 °M eee eee eeeeeeee eeee. Meeee eee eeeeeee eee eeee eeeeee, ee eee eeeeee eeee eeeeeee eee. Mee eeeee eeeeeee eee eeeeeeee ee eeeeee eeeeeeeeeeeeee (eeeeee eee, MMMe8/MeMM 88:8).

References