Science of Synthesis

Chebanov, V. A.; Gorobets, N. Yu.; Sedash, Yu. V., Science of Synthesis: Multicomponent Reactions, (2014) 1, 41.

Organosilicon compounds are widely used as water scavengers in reactions of carbonyl compounds.[‌77‌] In 1992, Zavʼyalov and Kulikova suggested using chlorotrimethylsilane in dimethylformamide as promoter of the Biginelli reaction. The desired 3,4-dihydropyrimidin-2(1H)-one derivatives are obtained in 62–80% yields from aromatic aldehydes and in 32–37% from aliphatic aldehydes at room temperature. The procedure includes two steps: first, the β-dicarbonyl compound and the aldehyde undergo aldol condensation to give an α,β-unsaturated ketone, and then urea is introduced into the reaction mixture to react with the product of the previous step. The final products are isolated and purified by chromatography.[‌78‌] Application of chlorotrimethylsilane was further developed for the synthesis of 2-(thi)oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylates (e.g., ‌13‌) of different types.[‌77‌,‌79‌] The advantage of the method is the possibility of using mono- and disubstituted ureas (‌Scheme 11‌).

‌Meeeee 88‌ Meeeeeeeeeeeeeeeeeeee-Meeeeeee Meeeeeeee Meeeeeee[‌88‌]

‌Meeeeeeeeee 88‌

M eee-eeeee eeeeeeee eeeee eeeeeeeeeeeeeeeeeee eeeeeeeee ee eeee eeee eeeeeeeee eeeeeee ee eeeeeeeeeeeeeeeeeeeee eee eeeeee eeeeee ee eeeeeeeeeeee eeeee eeeeeeeee eeeeee ee eeeeeee 8,8-eeeeeeeeeeeeeeee-8(8M)-eee eeeeeeeeeee, eeeee eee eeeeeeee ee eeee eeeeeeeeeee eeeee 88–88 eeeeeee eeee 88 eee% eeeeee ee (eeee)eeee eee 8.8 eeeeeeeeeee ee eeeeeeeeeeeeeeeeeeeee/eeeeee eeeeee.[‌88‌] Mee eeeeeeee ee eee eeeee eee eeeeeeee ee eeeeee eeeeeeeeee. Meeeeeeeeeeee, eee eeeeee ee eeeeeeeeeeee ee eee eeeee ee eee eeeeeeeee eeeeeeee eee eee eeeeeeee eeeeee eeeee ee eeeeeeeee eeeeeee ee eee eeeeeee eeeeeeeeee ee eee eeeeeeeeeeee eeeeeee eeeeee eeeeeeee ee eeeeeeeeeeee ee eeeee eeeeeee eee eeeeee eeee ee eee eeeeee eeeeeeeee. Me ee eeeeeeeeeee eeeeeeee, eeeeeee 8,8-eeeeeeeeeeeeeeee-8(8M)-eee eeeeeeeeeee eee eeeeeeee ee eeee eeeeee (88–88%) eeeee eeeeeeeee eeeeeee ee ee eeeeeeee, eeeeeeeee, ee α,β-eeeeeeeeeee eeeeeeee eee eeeeeeeeeeeee ee eeeee eeeeeeeeeeee, 8.8 eeeeeeeeeee ee eeeeeeeeeeeeeeeeeeeee, eee 88 eee% eeeeee ee (eeee)eeee ee e eeeeeee ee eeeeeeeeeeee eee eeeeeeeeeeeeeeeee (8:8).[‌88‌] Meeee ee eeeeeeeeee eeeeeeee eee eeeeeee ee eeeeeee ee eeee eeeeeeeeeee eee 8–8 eeeee eee eeee eeee ee e eeeeeeeeeeee eeeeeeeee. Mee eeeeeeee eee eeeeeeeee eeee eee eeeeeeee eeeeeee eeeeee ee eeeeeeeeee eee eeeeee eeee eeeee eee eeeeeee.

Meeeeeeeeeee eeee eeeeeeeeeeee ee eeeeeeee ee eeeee eeee 8 eee% ee eeeeeeeeeeeeee eeeeeeeeeeeeeeeeeeeeeeeee ee e eeeeeeee eee eee Meeeeeeee eeeeeeee ee eeee eeeeeeeeeee ee eeeeeeeeeeee. Me eeeeeeee ee eee eeee eeee eeeeee (88–88%) eeeeeeee eee eee eeeeee 8-eee-8,8,8,8-eeeeeeeeeeeeeeeeeeee-8-eeeeeeeeeeee ‌88‌, eee eeeeeeee eeee ee eeeeeeeeeee eeeeeee ee 88–88 eeeeeee ee eeee eeeeeeeeeee eeee eee e “eeeeeeeee eeee” eeeeeeeee eeeeeeeee ee e 8-eeeee eeeeeee, eeeee eeeee 8-eeeeeeeeeeeee (‌88‌, M8 = M8 = Me) (‌Meeeee 88‌).[‌88‌]

‌Meeeee 88‌ Meeeeeeeeeeeee Meeeeeeeeeeeeeeeeeeeeeeee Meeeeeee Meeeeeeee Meeeeeee[‌88‌]

‌Meeeeeeeeee 88‌

Meeeeeeeeeee Meeeeeeee

8-Meeeeeeeeee eee 8,8-Meeeeeeeeeeee Meeee 8-Meeeee-8-(eee)eee-8,8,8,8-eeeeeeeeeeeeeeeeeeee-8-eeeeeeeeeeee ‌88‌; Meeeeee Meeeeeeee:[‌88‌]

Meeee eeeeeeeeeeee (8 eeee), eee eeeeeeee (8 eeee), eee eee eeee ee eeeeeeee (8.8–8.8 eeee) eeee eeeeee ee e 88-eM Mee eeeeeeee eeee eee eeeeeeeee ee MMM (88 eM). MMMMe (88 eeee) eee eeeee eeeeeeee ee eee eeee. Mee eeee eee eeeeeeeeee eeeeee eee eeeeeee ee eeeee ee ee ee ee eeeeeeeeee eeee eee 8 e eee eeee eeee ee eeeee ee ee eee 8–8 e. Mee eeeeeee eee eeeeee eeee M8M (88–88 eM) eee eeee ee ee ee ee eeeeeeeeee eeee eee 8 e. Mee eeeeeeeeeee eeee eeeeee eee eeeeeeeee ee eeeeeeeeee eee eeeeee eeee e eeeee eeeeee ee eMeMM. M eeeeeee 8–88% ee eee eeeeeee eeeee ee eeeeeeeee ee eee eeeeee eeeeee eee eeeeeeeeeeee eeeee eeeeeee eeeeeeee eee eee eeeeeee eee eeeeeee eeee e eeeee eeeeee ee eMeMM ee Me8M.

Meeee 8-(8-Meeeeeeeeeeee)-8-eeeeee-8-eee-8,8,8,8-eeeeeeeeeeeeeeeeeeee-8-eeeeeeeeeee (‌88‌, M8 = 8-MeMM8M8; M8 = Me; M8 = Me; M = M); Meeeeee Meeeeeeee:[‌88‌]

M eeee ee 8-eeeeeeeeeeeeeeeeeee (888 ee, 8.8 eeee), eeee (888 ee, 8.8 eeee), eee eeeee eeeeeeeeeeee (‌88‌, M8 = Me; M8 = Me; 888 ee, 8.8 eeee) ee MeMM (8 eM) eee eeeeeee ee ee ee eee eeeeeeee ee MMMMMe (8 ee, 8 eee%) eee 88 eee (eeeeeeee ee eee eeeeeeee eee eeeeeeeee ee MMM). Mee eeeeeee eee eeee eeeeee eeee eeeeeee eee (88 e) eee eeeeeee eee 8–88 eee. Mee eeeeeeeee eeeee eee eeeeeeeee ee eeeeeeeeee eeeeeee e eeeeeeee eeeeee eeeee eeeeeee, eeeeee eeee eee-eeee M8M (88 eM), eee eeeeeeeeeeeeee (eee MeMM) ee eeeeee eee eeee eeeeeee; eeeee: 8.88 e (88%).

References