Orthoamide, XLVI. Beiträge zur Chemie von Bis(dialkylamino)malononitrilen

Orthoamide und Iminiumsalze, CIII. Synthese von N,N′,N′′-peralkylierten Guanidiniumsalz-basierten ionischen Flüssigkeiten durch Anionenmetathese

N,N′,N′′-peralkylated guanidinium chlorides and N,N′,N′′-peralkylated guanidines were prepared from N,N′-peralkylated chloroformamidinium chlorides. The alkylation of the guanidines affords N,N′,N′′-persubstituted guanidinium chlorides bromides, iodides, alkylsulfates, and tetrafluoroborates. Guanidinium tricyanomethanides and tetracyanopropenides were prepared from the chlorides and iodides by anion metathesis. The reaction of guanidinium halogenides with borontrifluoride etherate, triethyloxonium tetrafluoroborate or sodiumtetrafluoroborate delivers guanidinium tetrafluoroborates. Guanidinium saccharinides, cyanates, thiocyanates, trifluoromethansulfonates, bis(trifluormethansulfonyl)imides, hexacyanoferrates(II/III), tetracyanonickolates and tetrathiocyanatocobaltates were prepared from the corresponding guanidinium chlorides and tetrafluoroborates by anion exchange.

Orthoamide und Iminiumsalze, XCIII. Darstellung und Umsetzungen eines vinylogen Orthoamid-Derivats der Kohlensäure mit CH2-aciden Verbindungena

The preparation of the vinylogue guanidinium salt 10c is described. The reaction of the vinylogue orthocarbonic acid amide derivative 12 with CH2-acidic compounds 14a–s affords the ketene aminals 15a–s. At room temperature the succinimide 19a is deprotonated by 12 to give the vinylogue salt 10e. The bis-ketene aminal 20 is formed in the reaction of 19a with 12 at elevated temperatures. Succinic acid esters 21 do not react cleanly with the orthoamide 12, but mixtures of ketene aminals 23 and bis-ketene aminals 22 are formed. From succinodinitrile (24) and 12 the bis-ketene aminal 25 could be obtained, which is also accessible by the action of the salt 10c with 24 in the presence of sodium hydride.

One-Pot Synthesis and Conformational Features of N,N‘-Disubstituted Ketene Aminals

N,N'-Disubstituted ketene aminals are bioisosteres of thioureas and are useful building blocks in many synthetic operations. A convenient one-pot synthesis of N,N'-disubstituted ketene aminals from activated methylene compounds and isothiocyanates is described. Most of these aminals exist in rotameric equilibrium around the central C=C bonds in solution, and the rotamers are stabilized by intramolecular hydrogen bonding both in solution and in solid states.