Raquel Andreu

Direct conversion of 4-amino-2-phenyl-2-oxazolines into either 2-arylimino-1,3-oxazolidine or 2-arylimino-1,3-thiazolidine hydrochlorides

Abstract A novel heterocycle–heterocycle inter-conversion is reported. It enables direct and efficient syntheses of either polysubstituted 2-arylimino-1,3-oxazolidine or 2-arylimino-1,3-thiazolidine hydrochlorides by a one-pot treatment of 4-amino-2-phenyl-2-oxazolines with arylisocyanates or arylisothiocyanates, respectively, followed by addition of hydrochloric acid.

Electrochemical generation of 4-amino-2-aryl-2-oxazolines

A convenient method for the synthesis of the title compounds has been established. Chloralbenzamides were efficiently converted to N-(1-amino-2,2-dichloroethyl)benzamides which were directly transformed to 4-amino-2-aryl-2-oxazolines in fair to good yields by electrochemical reduction in an aprotic medium under constant cathodic potential. The molecular structure of the electrolysis products has been corroborated by X-ray crystallographic analysis of 4-(1-benzyl-3-phenylureido)-2-phenyl-2-oxazoline.

Electrochemical generation of N-(2,2-dichlorovinyl)amides

Abstract A convenient method for the synthesis of N-(2,2-dichlorovinyl)amides has been established. Treatment of chloralamides with phosphorus pentachloride provides N-(1,2,2,2-tetrachloroethyl)amides in high yields whose electrochemical reduction leads to the title compounds in fair to quantitative yields. This approach exhibits superior efficiency and versatility than previously reported procedures.

A new synthetic route to 2-oxazolines. The electrochemical reduction of N-(2,2-dichloroethyl)amides as a key step

Abstract A convenient new method for the synthesis of 2-oxazolines has been established involving the preparation of N-(2,2-dichloroethyl)amides followed by electrochemical reductive cyclizations. It has been applied successfully in preparing previously unknown 4-alkylamino-2-phenyl-2-oxazolines in fair to good yields.

Direct conversion of 4-amino-2-oxazolines into 2-imidazolidinones

Abstract A convenient new method for the synthesis of polysubstituted 2-imidazolidinones has been established involving the reaction of 4-alkylamino-2-aryl-2-oxazolines with arylsulfonyl isocyanates. It has been applied successfully in preparing previously unknown 3-alkyl-4-aroylamino-1-arylsulfonyl-2-imidazolidinones in high yields.

A new synthetic route to 1-chlorophenazines. The electrochemical monodechlorination of 3,3,6,6-tetrachloro-1,2-cyclohexanedione as a key step

Abstract A convenient new method for the synthesis of 1-chlorophenazines has been established. The first step involves an almost quantitative electrochemical reduction of 3,3,6,6-tetrachloro-1,2-cyclohexanedione 1 to 3,6,6-trichloro-2-hydroxy-2-cyclohexen-1-one 2. The reaction of 2 with aromatic 1,2-diamines followed by aromatisation through treatment with 2,6-lutidine leads to the title compounds in high yields.

Synthesis and X-ray molecular structure of N-(1-amino-2,2-dichloroethyl)benzamides

Abstract Efficient procedures for the synthesis of N-(1-alkylamino-2,2-dichloroethyl)benzamides, N-(1-arylamino-2,2-dichloroethyl)benzamides and N-(1-amino-2,2-dichloroethyl)benzamides are reported. These compounds are of special interest as intermediates to access new heterocyclic series. N-(2,2-dichlorovinyl)amides react with primary or secondary alkylamines to yield the title compounds in high to quantitative yields. However, similar addition reactions with arylamines or ammonia are unsuccessful. In these cases the synthesis of the targeted products may be achieved by starting from N-(1,2,2,2-tetrachloroethyl)benzamides which are aminated via nucleophilic substitution yielding the corresponding N-(1-amino-2,2,2-trichloroethyl)benzamides. Finally, these compounds are selectively monodechlorinated by electrochemical reduction at constant cathodic potential. The crystallographic X-ray structure of N-(2,2-dichloro-1-isopentylaminoethyl)-4-methylbenzamide has been determined.

Electrochemical reduction of diheteroaryl-1,2-diketones in the presence of carbonimidoyl dichlorides. First synthesis of 2-arylimino-4,5-di-2-furyl-1,3-dioxoles and (E)-1,2-di-2-furylvinylene bis(N-arylchloroformimidates)

Abstract Selective cathodic reductions of 2,2′-furil in an aprotic medium, under constant potential, in the presence of equimolecular amounts of N -arylcarbonimidoyl dichlorides provide previously unknown 2-arylimino-4,5-di-2-furyl-1,3-dioxoles in high yields. These compounds were formed accompanied by minor products which were identified as ( E )-1,2-di-2-furylvinylene bis( N -arylchloroformimidates), a new class of compound. Similar reductions were applied to 2,2′-pyridil, 2,2′-thenil and bis(pyrrol-2-yl)-1,2-ethanedione. However, arylisocyanides were quantitatively generated by mediated electroreduction of arylcarbonimidoyl dichlorides.