- Silica gel an efficient catalyst for one-pot synthesis of pyrazines from ethylenediamine and 1, 2-diketones and their analogs
-
A straightforward one-pot synthesis of pyrazines from ethylenediamine and 1, 2-diketones/ α-hydroxy ketone/α-bromo ketone under solvent-free conditions at room temperature is described. This environmentally benign process has the edge on previous methods in respect of workup procedure, ease and cost of reaction, and use and generation of hazardous substances. The catalyst is recovered, characterized, and proved to be recyclable for successive four runs examined with appreciable conversions.
- Chakraborty, Rakesh Ranjan,Singha, Rabindranath,Ghosh, Pranab
-
p. 373 - 378
(2018/09/29)
-
- Clean and green approach for one-pot synthesis of pyrazines from Eth-ylenediamine and 1,2-diketone or its analogues under neat reaction condition
-
Background: Compounds having N-heterocyclic moieties are of huge importance in the field of agrochemical, pharmaceutical, biological, fragrances, etc. Due to a lot of applications associated with pyrazine moieties, their synthesis has always been important for organic chemists. Method: Surfeit synthetic methodologies are documented in literature. Most of the methodologies used expensive solvents, harmful metal catalyst and all suffer from rigorous work-up procedures. An efficient, environmentally benign methodology, needs to be developed. We mixed ethylenediamine (2mmol) with 1, 2-diketone(1mmol), later, α-hydroxy ketone and α-bromo ketone on magnetic stirrer at room temperature under neat reaction condition for 5 to 10 hrs. Results: After purification by column chromatography using silica gel(60-120 mesh) and pet-ether, et-hylacetate mixture as eluent, we achieved pyrazine derivatives from moderate to high yield. Conclusio n: Efficient and clean procedure for one-pot preparation of pyrazines from ethylenediamine and 1, 2-diketones or with α-hydroxy ketone or with α-bromo ketone has been carried out under neat reaction condition at room temperature. Environmentally benign process furnishing moderate to excellent yields of the product and simple work-up giving pure products are special features of this reaction.
- Ghosh, Pranab,Chakraborty, Rakesh Ranjan
-
p. 566 - 570
(2017/09/29)
-
- γ-Maghemite-silica nanocomposite: A green catalyst for diverse aromatic N-heterocycles
-
γ-Maghemite-silica nanocomposite has been applied as a green catalyst to synthesize variety of aromatic N-heterocycles under solvent free conditions. Characterization was done by modern analytical tools (UV, IR, AAS, DSC, EDXRF, powdered XRD, EPR, Mo?ssbauer and TEM). Mild reaction conditions and recyclability have made the present protocol both environmentally and economically viable.
- Ghosh, Pranab,Mandal, Amitava,Subba, Raju
-
p. 146 - 152
(2013/09/02)
-
- 3-SUBSTITUTED 5,6-DIARYL-PYRAZINE-2-CARBOXAMIDE AND -2-SULFONAMIDE DERIVATIVES AS CB1 MODULATORS
-
The present invention relates to 3-substituted-5,6-diarylpyrazine-2-carboxamide and -2-sulfonamide derivatives and processes for preparing such compounds, their use in the treatment of obesity, psychiatric and neurological disorders, to methods for their therapeutic use and to pharmaceutical compositions containing them. The compounds are cannabinoid receptor 1 (CB1) modulators.
- -
-
-