Background:
Amide bond plays a key role in medicinal chemistry, and the analysis of bioactive
molecular database revealed that the carboxamide group appears in more than 25% of the existing
database drugs. Typically amide bonds are formed from the union of carboxylic acid and
amine; however, the product formation does not occur spontaneously. Several synthetic methods
have been reported for amide bond formation in literature. Present work demonstrated simple and
eco-friendly amide bond formation using carboxylic acid and primary amines through in situ generation
of O-acylurea. The reaction was found to be more efficient, faster reaction rate; simple work-up
gave pure compound isolation in moderate to excellent yield using microwave irradiation as compared
to conventional heating.
Methods:
Developed one-pot synthesis of amide compounds using agro-waste derived greener catalyst
under microwave irradiation.
Results:
Twenty amide bond containing organic compounds are synthesized from carboxylic acid
with primary amine catalyzed by agro-waste derived medium under microwave irradiation. First, the
reaction involved carboxylic acid activation using EDC.HCl, which is the required base for the neutralization
and coupling. The method employed natural agro-waste derived from banana peel ash
(WEB) for the coupling gave target amide product without the use of an external organic or inorganic
base.
Conclusion:
In the present work, we demonstrated that agro-waste extract is an alternative greener
catalytic medium for the condensation of organic carboxylic acid and primary amine under microwave
irradiation. The method found several advantages compared to reported methods like solventfree,
non-toxic, cheaper catalyst, and simple reaction condition. The final isolated product achieved
chromatographically pure by simple recrystallization and did not require further purification.
3′-Methyl-2-oxo-1′,5′-diphenyl-1′,7′-dihydrospiro[indoline-3,4′-pyrazolo[3,4-b]pyridine]-6′-carboxylic Acid