Solvent-controlled self-assembly of Fmoc protected aliphatic amino acids.

Self-assembly of modified amino acids facilitate the formation of various structures that have unique properties and therefore serve as excellent bio-organic scaffolds for diverse applications. Self-assembly of Fmoc protected single amino acids has attracted great interest owing to their ease of synthesis and applications as functional materials. Smaller assembly units enable synthetic convenience and potentially broader adoption. Herein, we demonstrate the ability to control the morphologies resulting from self-assembly of Fmoc modified aliphatic single amino acids (Fmoc-SAAs) namely, Alanine, Valine, Leucine, Isoleucine, and Proline. Controlled morphological transitions were observed through solvent variation and the mechanism that allows this control was investigated using coarse-grained molecular dynamics simulations. These show that FmocA can form well defined crystalline structures through uniform parallel Fmoc stacking and the optimization of ion concentrations, which is not observed for the other Fmoc-SAAs. We demonstrate that Fmoc protected aliphatic single amino acids are novel scaffolds for the design of distinct micro/nanostructures through a bottom-up approach that can be tuned by control of the environmental parameters.

Unraveling the access to the regioselective synthesis of highly functionalized pyranopyrazoles using an ionic liquid catalyst.

An efficient and green strategy for the regioselective synthesis of highly functionalized pyranopyrazole via one-pot condensation of 3-methyl-1-phenyl-5-pyrazolone or EAA and hydrazine hydrate, substituted aromatic aldehydes with NMSM [(E)-N-Methyl-1-(methylthio)-2-nitro-ethenamine] in the existence of IL [(EMIM)Ac] as catalyst with solvent-free condition (SFC) is described. This domino protocol produces biologically substantial heterocycles through Knoevenagel condensation proceeded by Michael addition and O-cyclization with an eradication of methanethiol group, which create the one stereo-center and creation of "C-C, C-N, C-O, C=C, C=N, bonds." The final product is produced by exceptionally easy filtering after the reaction mass was triturated with ethanol. The strategy's noteworthy features include the use of biodegradable IL catalyst, excellent to exceptional yield with rapid reaction times, applicability to a wide range of substrate, clear reaction profile, and straightforward workup process.

Enhanced production of violacein by Chromobacterium violaceum using agro-industrial waste soybean meal.

AIMS: The research is aimed at developing an economic and sustainable growth medium using abundantly available and highly nutritive agro-industrial waste soybean meal as the substrate for the production of violacein by Chromobacterium violaceum. METHODS AND RESULTS: Violacein produced using soybean meal medium was compared with the commercial complex growth media. Upon utilization of 2% w/v soybean meal (SM2 ) medium, 496 mg/L crude violacein was achieved after 48-hr incubation time, which was 1.62-fold higher than the crude violacein produced in Luria-Bertani (LB) broth. Additionally, supplementation of 100 mg/L L-tryptophan to 1% and 2% w/v soybean meal (SMT1 and SMT2 ) medium yielded 1217 mg/L (3.96-fold higher as compared to LB) and 1198 mg/L (3.90-fold higher as compared to LB) crude violacein respectively. Optimization of culture conditions and concentration of L-tryptophan using Box-Behnken design (BBD) model produced as high as 1504.5 mg/L crude violacein. To the best of our knowledge, this is the highest crude violacein produced to date using agro-industrial-based waste as a substrate with minimal supplementation in a shake flask. CONCLUSIONS: The study signifies the potentiality of soybean meal as a cost-effective growth medium for the production of violacein. Optimization of the fermentation parameters clearly demonstrated a surge in violacein production. SIGNIFICANCE AND IMPACT OF THE STUDY: Utilization of soybean meal as an alternative to the expensive commercial media would surely promote the large-scale synthesis of this multifaceted compound.

Stereoselective total synthesis of arachnid harvestmen natural product: (4S,5S)­4-hydroxy-γ-decalactone.

Herein, we described the novel synthetic strategy for the total synthesis of harvestmen natural product (4S,5S)­4-hydroxy-γ-decalactone (minor) from an inexpensive precursor ((R)-2,2-dimethyl-1,3-dioxolane-4-carbaldehyde) with 31% overall yield. Hydroxy-γ-lactones represent a special class of harvestmen exocrine defense compounds. The present convergent synthesis utilizes classical reactions like the Barbier reaction, the Grignard reaction, and the employment of an olefin as a masked carboxylic acid functionality followed by lactone formation as key steps.

Synthetic Approaches toward the Synthesis of Brivaracetam: An Antiepileptic Drug.

Epilepsy is a chronic neurological disorder in the brain, affecting individuals of all age groups. Nearly 1% of the world population is affected by seizure disorder, of which 80% of the patients are observed in underdeveloped and developing countries. The predominant treatment option for epilepsy includes an antiepileptic drug named brivaracetam. This drug emerged as an unusual success of rational drug discovery in clinical development by exhibiting magnificent affinity toward synaptic vesicle glycoprotein as compared to conventional drug levetiracetam and piracetam. Given its efficiency in limiting the progression of epilepsy, this drug has drawn considerable attention of researchers to devise novel routes of its synthesis. The present review encapsulates the reported literature on synthetic strategies for brivaracetam, which will assist medicinal chemists in the further progress of its synthesis.

Zinc Chloride-Catalyzed Synthesis of Carbamates: An Application for the Synthesis of the Anti-Alzheimer's Drug Rivastigmine.

Herein, we report a synthetic protocol for the synthesis of carbamates by employing zinc chloride as a catalyst from carbamoyl chlorides and aromatic/aliphatic alcohols. The developed protocol successfully utilizes the gram-scale synthesis of the FDA-approved rivastigmine drug and its derivative. The utility of zinc chloride over other catalysts such as zinc dust and zinc acetate exhibits a 49-87% yield of carbamates.