A novel three‐component reaction involving 2‐methylbenzothiazole or 2,5‐dimethylbenzothiazole, acetylenic esters and 1,3‐dicarbonyl compounds such as (1,3‐dimethylbarbituric acid or 1,3‐indanedione) leading to the synthesis of spiro pyrrolobenzothiazole derivatives. The reactions proceeded smoothly at room temperature without using any catalyst. This method is very useful to functionalize benzothiazole derivatives in a one‐pot operation. The structures of the synthesized compounds have been characterized by spectral studies.

Stable crystalline phosphorus ylides were obtained in excellent yields from the 1:1:1 addition reactions between triphenylphosphine and dialkyl acetylenedicarboxylates, in the presence of an NH-acid, such as 6-chlorobenzoxazolinone. These stable ylides exist in solution as a mixture of two geometrical isomers as a result of restricted rotation around the carbon-carbon partial double bond resulting from conjugation of the ylide moiety with the adjacent carbonyl group. To determine the kinetic parameters of the reactions, they were monitored by UV spectrophotometry. The second order fits were drawn and the values of the second order rate constant (k2) were calculated automatically using standard equations within the program. Over the temperature range studied, the dependence of the second order rate constant (Ln k2) on reciprocal temperature was in a good agreement with the Arrhenius equation, leading to the activation energies of all reactions. Furthermore, useful information was obtained from studies of the effect of solvent, the structure of reactants (different alkyl groups within the dialkyl acetylenedicarboxylates) and also the concentration of reactants on the rate of reactions. The proposed mechanism is consistent with the results obtained and the steady state approximation, and the first step (k2) of reaction was recognized as the rate-determining step on the basis of experimental data.

A new class of enamino esters has been isolated in excellent yields from the 1:1:1 addition reaction between phenanthridine or isoquinoline and activated acetylenic esters in the presence of heterocyclic NH compounds (succinimide, 5-nitroindazole, benzoxazolinone, 6-chlorobenzoxazolinone, carbazole and 3,6-dibromocabazole) or 1,3-dicarbonyl compounds such as 1,3-dimethylbarbituric acid and 1,3-diethyl-2-thiobar-bituric acid.

Reduktion des Keto ‐ esters (I) mit NaBH4 ergibt den Alkohol (11), der mit Hydrazin (III) das Pyrrolidon (IV) liefert.

Phenanthridine or Isoquinoline Are Good Reagents for the Synthesis of Enamino Esters. -A new method to synthesize a novel class of heterocyclic derivatives, e.g. (IV), (VI), and (IX) is presented. Nucleophiles, e.g. 5-nitroindazole, benzoxazole or carbazole can also be used for the reaction. -(NASSIRI, M.; HEYDARI, R.; HAZERI, N.; HABIBI-KHORASSANI, S. M.; MAGHSOODLOU*, M. T.; MILANI, F. J.; J. Chem. Res. 34 (2010) 7, 365-369, http://dx.