Abstract N,N,N′,N′-Tetramethylurea diethylacetal reacts with CH2-acidic compounds as benzylcyanide, cyanoacetic acid derivatives malonodinitrile and nitromethane to give ketene aminals or ketene-O,N-acetales. Low polar solvents favour mostly the formation of ketenaminals. The yields of ketenaminals and ketene-O,N-acetals can be improved in some cases by addition of trimethylsilyldimethylamine. The reactions of the urea acetal with diethylmalonate, ore acetyl acetone, stops at the stage of the N,N′,N″-permethylated guanidinium salts with carbanionic counterions. The formation of bis(dimethylamino)methylene-diethylmalonate from the urea acetal and diethylmalonate can be initiated by addition of trimethylsilyldimethylamine/trimethylsilylcyanide. N,N,N′,N′,N″,N″-Hexamethylguanidinium cyanide is formed in the analogous reactions of the urea acetal with N,N-dimethylcyanacetamide or diethylsuccinate. The N,N′,N″-Hexamethyl-guanidinium nitrite can be obtained from the urea acetal and nitropropane.

中文翻译：

---

Orthoamide 和 Iminiumsalze，CIa。Umsetzungen von N,N,N',N'-Tetramethylharnstoffdiethylacetal mit CH2-aciden Verbindungen

摘要 N,N,N',N'-四甲基脲二乙缩醛与苯乙腈、氰基乙酸衍生物丙二腈和硝基甲烷等CH2-酸性化合物反应生成乙烯酮缩醛胺或乙烯酮-O,N-缩醛。低极性溶剂主要有利于酮烯胺的形成。在某些情况下，通过添加三甲基甲硅烷基二甲胺可以提高烯酮胺和烯酮-O,N-缩醛的产率。脲缩醛与丙二酸二乙酯、乙酰丙酮矿石的反应在 N,N',N'-全甲基化胍盐与负碳离子反离子的阶段停止。通过加入三甲基甲硅烷基二甲胺/三甲基甲硅烷基氰化物可以引发由脲缩醛和丙二酸二乙酯形成双(二甲氨基)亚甲基-二乙基丙二酸酯。N,N,N',N',N", N″-六甲基氰化胍是在脲缩醛与 N,N-二甲基氰乙酰胺或琥珀酸二乙酯的类似反应中形成的。N,N',N"-六甲基-亚硝酸胍可以从尿素缩醛和硝基丙烷中得到。