Microwave Radiation Applied in the N-Aryl-N′-Aminoеthylureas

The paper considers methods for the N-aryl-N'-aminoethylureas synthesis. The methods can be used as base products for the preparation of potential cytokinin active compounds with oxamate and oxamide functional groups. The previous studies showed that upon the interaction between aryl isocyanates and ethylenediamine, symmetric bisureas become the main reaction products, while the yield of the target 2-aminoethylureas is no more than 10 %. The high yield of N-aryl-N'-(oxamoylamino)ethylurea is also not provided by using one group aminoprotected ethylenediamine. Thus, when using Boc-protection, the yield of target products does not exceed 13 %. In this research, we used the methodology of microwave synthesis in acylation and aminolysis reactions. As a result, N-2-aminoethyl-N'-arylureas with various substituents in the aromatic ring were obtained in good yields. We compared the microwave radiation aminolysis of N,N'-bis(arylcarbamoyl)ethylenediamines, N-aryl-carbamoylimidazoles and diarylureas with ethylenediamine under microwave conditions. Findings of research show that reactions without microwaves proceed with the formation of only trace amounts of the target compounds, which are used for synthesis of structural analogs of phytoactive compounds, in the molecules of which carbamate and urea groups are replaced by oxamate ones

Dearomative syn-1,2-Diamination of Benzene and Naphthalene

We report the palladium-catalyzed, dearomative syn-1,2-diamination of the non-activated arenes benzene and naphthalene using aryl isocyanates. This reaction proceeds with exclusive syn-1,2-selectivity and provides a complementary regio- and stereoselectivity to previously described arenophile-based transformations. The products are amenable to further synthetic elaboration, including selective diene functionalization and heterocycle cleavage. Overall, this dearomatization provides synthetic access to unprecedented saturated nitrogen-containing heterocyclic motifs and syn-1,2-diaminated cyclohexane products.

Experimental results and computational insight into sequential reactions of β-(2-aminophenyl)-α,β-ynones with aryl isocyanates/benzoyl isothiocyanate

The selective formation of quinazoline vs. benzoxazine and benzothiazine derivatives from β-(2-aminophenyl)-α,β-ynones and aryl isocyanates/benzoyl isothiocyanate was explored. DFT calculations provide a plausible rationale.

Synthesis and evaluation of 5-imino-4-thioxoimidazolidin-2-one derivatives as antibacterial and antifungal agents

Objective: It was of interesting to synthesize some new 5-imino-4-thioxoimidazolidin-2-one derivatives with different halogenated and alkylated aromatic substituent at N-(1) and N-(3) and evaluation of their expected antibacterial and antifungal activities. Methods: New 5-imino-4-thioxoimidazolidin-2-one derivatives were synthesized through the reaction of different halogenated and alkylated N-arylcyanothioformamides with halogenated and alkylated aryl isocyanates. Results: 5-Imino-4-thioxoimidazolidin-2-ones were obtained in high yields with excellent purity. The activities of imidazolidines as antibacterial and antifungal agents were studied. Some of imidazolidine derivatives displayed significant antibacterial and antifungal activities. Conclusion: 5-Imino-4-thioxoimidazolidin-2-ones were obtained in 77-90% yields with excellent purity. The antibacterial and antifungal activities suggest that some of the imidazole derivatives possess significant antimicrobial activity against B. subtilis, K. pneumonia and C. albicans and moderate activity against S. aureus.

Transformation of cyanothioformanilides into halogenated and alkylated imidazolidineiminothione derivatives and evaluation of antibacterial and antifungal activities

Aim and Objective: It was of interest to synthesizing some new imidazolidineiminothione derivatives with different halogenated and alkylated aromatic substituent at N-(1) and N-(3) and evaluation of their antibacterial and antifungal properties. Materials and Methods: New imidazolidineiminothione derivatives were synthesized through the reaction of different halogenated and alkylated N-arylcyanothioformamide derivatives with halogenated and alkylated aryl isocyanates. Results: The imidazolidineiminothione derivatives were obtained in high yields with excellent purity. The activity of imidazolidineiminothione derivatives as antibacterial and antifungal agents was studied. Some of imidazolidineiminothione derivatives displayed significant antibacterial and antifungal activities.

One-Pot Regioselective Synthesis of 2,5,6,7-Tetrahydroimidazo [1,2-a]imidazol-3-ones Starting from (Vinylimino)phosphoranes

A new, one-pot, regioselective preparation of 2,5,6,7-tetrahydroimidazo[1,2-a]imidazol-3-ones by a sequential aza-Wittig/nucleophilic addition/cyclization reaction was developed. The aza-Wittig reactions of ethyl (2Z)-3-aryl-2-[(triphenylphosphoranylidene)amino] acrylates with aryl isocyanates produced carbodiimide intermediates that were then treated sequentially with 2-aminoethanol and tosyl chloride/triethylamine to give the corresponding (2Z)-2-[(substituted)benzylidene]-2,5,6,7-tetrahydro-3H-imidazo[1,2-a]imidazol-3-ones in good overall yields and with high regioselectivity.

Cu(i) catalysed annulation of isothiocyanates/isocyanates with 2-iodo-sulfonamides: synthesis of benzodithiazines, benzothiadiazinones, benzothiazinylidene-anilines and benzothiazolylidene-anilines

Cu(i)-catalysed reaction of 2-iodobenzene sulfonamides with aryl isothiocyanates leads to benzodithiazines but the corresponding reaction with aryl isocyanates affords benzothiadiazinones.