Three-component cyclocondensations. An efficient synthesis of 4-amino-2-(methylthio)imidazolium salts via the reaction of methyl chlorothioimidates with benzaldimines and isocyanides. Autoxidation of the imidazole derivatives

Chameleonic reactivity of α-amino nitrile-derived ureas. Synthesis of highly functionalized imidazolidin-2-one and imidazolidine-2,4-dione derivatives

“…The cyclization was initially attempted by heating (S)-1a in refluxing MeOH. As shown in Table 1 (entry 1), after 15 min of reaction, the HPLC-MS analysis of the crude reaction mixture showed the presence of the epimeric mixture of 4-iminoimidazolidin-2-ones (RS)-2a, as minor products (9%), along with oxidation products, 31,32 the 5-hydroxy-4-iminoimidazolidin-2-ones (RS)-3a (78%) and the 5-benzylidene-4-iminoimidazolidin-2-one 4a (13%). To avoid oxidation, the next experiments were carried out under argon and MeOH was replaced by other solvents.…”

Reactions of Isocyanides and Pyridinium Triflates − A Simple and Efficient Route to Imidazopyridinium Derivatives

“…[7] The cycloaddition step is reminiscent of the cyclocondensation reactions of isocyanides with protonated diazabutadienes, which represent efficient routes to mono heterocyclic compounds. [5,6] Such a [4 ϩ 1] cycloaddition was also proposed as the key step in the three-component condensation of amidines, aldehydes and isocyanides, leading to fused 3-aminoimidazoles. [4] Scheme 2.…”

Addition of isocyanides to ?-(methylthio)-benzylidenamidinium iodides: A surprising access to 2-(dialkylamino)imidazoles and 3,5-diamino-2H-pyrrolium salts

“…Similarly, we described the preparation of 4-amino-2-(methylthio)imidazolium salts through the combined action of isocyanides and benzaldimines on methyl chlorothioimidates. Transient N-imidoylbenzylidenammonium chlorides were assumed to be trapped by isocyanides in such three-component condensations [8]. By the same reasoning, we have explored the treatment of chloroiminosulfides or phenyl chlorodithioformate with azines or aldimines in the presence of isocyanides as new routes to fused imidazolium [9] and 5-amino-2-(phenylthio)thiazolium salts [10].…”