An eco-friendly benign catalyst-free synthesis of chromeno[2,3-c]pyrazoles and bis-pyrazolone derivatives has been reported using magnetized distilled water (MDW). Under the optimal condition, most chromeno[2,3-c]pyrazoles (5a-f) and bis-pyrazolone (7a-k) were obtained in 85-93% and 85-95% yields respectively. This process offers several advantages, including its environmentally friendly and cost-effective nature, along with a simplified workup procedure and a high yield of desired products. Additionally, the absence of catalysts minimizes the potential for undesirable side reactions and contamination, resulting in a cleaner and more efficient synthesis process.

Abstract. In this paper, we report the catalyst-free three-component synthesis of 1,8-dioxooctahydroxanthenes in magnetized water as a green solvent. The reaction of aldehydes and 1,3-cyclohexanedione/dimedone in magnetized water gives the 9-substituted 1,8-dioxooctahydroxanthene derivatives. This green method offers the advantages of short reaction times, low-cost, simple work-up procedure, quantitative reaction yields, and no need for an organic solvent.

Resumen. En este trabajo se describe la síntesis, sin catalizador, de 1,8-dioxooctahidroxantenos empleando agua magnetizada como disolvente ecológico. La reacción de aldehídos y 1,3-ciclohexanodiona/dimedona en agua magnetizada da lugar a derivados 9-sustituídos del 1,8-dioxooctahidroxanteno. Este método verde tiene la ventaja de tiempos cortos de reacción, bajo costo, trabajo de reacción simple, rendimientos cuantitativos y no necesita el empleo de un disolvente orgánico.

O complexo etilenodiamina paládio(II) suportado em polímero, [PS-en-Pd(II)], é um catalisador altamente ativo, usado para a reação de acoplamento de Sonogashira entre um iodeto de arila e brometo de 2-amino-3-(2-propinila)1,3-tiazólio, 3. Esse catalisador heterogêneo de paládio é eficiente, estável e reciclável. A reação do composto 3 com vários iodetos de arila, 4a-f, na presença do complexo [PS-en-Pd(II)] leva à produção dos 6-(benzil)imidazo[2,1-b][1,3]tiazóis, 5a-f.

The polymer-supported palladium(II) ethylenediamine complex, [PS-en-Pd(II)], is a highly active catalyst that could be used for the Sonogashira coupling reaction between an aryl iodide and 2-amino-3-(2-propynyl)-1,3-thiazolium bromide, 3. This heterogeneous palladium catalyst is efficient, stable, and recyclable. Reaction of compound 3 with various aryl iodides, 4a-f in the presence of the [PS-en-Pd(II)] complex leads to the production of the 6-(substituted benzyl)imidazo[2,1-b][1,3]thiazoles 5a-f.