Marine Polysaccharides in Medicine

About 70% of the Earth\u27s surface is covered with seawater and 90% biosphere wraps maximum biodiversity that offers resourceful novel bio‐molecules. Marine species are enriched with organic compounds viz. terpenoids, polyethers/ketides, lipo‐glycoproteins, peptides and polysaccharides that act as cell surface receptors and involve in cell development/differentiation, besides being antimicrobial agents. Algae, sponge and fish have various defense mechanisms developed via specific/potent natural molecules to survive under hostile, extreme conditions such as various degrees of salinity, pressure, temperature, darkness, besides microbial and viral attacks. Marine seaweeds and algae enriched with polysaccharides such as glycosaminoglycans, agar, alginate and chitin/chitosan owing to their diversified significance have received growing attention among researchers. Currently, marine‐derived biomolecules cater 20% market drug load while other natural products bear 30% share. Chitins exhibit various biological and physicochemical properties that can be exploited in biotechnology and medicine/drug, cosmetic, food and textile industries. This chapter focuses on chitin/chitosan production, its physicochemical characterization and biological activities and relationship between its chemical structure and bio‐activity, including chemical modification reactions such as acylation, substitution, sulfonation and other cross‐linking strategies applied to skeletal modification with the recently updated literature

Rationally Fabricated Nanomaterials for Desalination and Water Purification

Rationally designed nanomaterials from synthetic/biopolymers like chitosan, zeolites, graphene, nanometal/oxides, zerovalent metal/magnetic iron, OMS and nanocarbon/carbon nanotube (CNT) utilized in desalination/purification are thoroughly discussed. Conventional desalination membrane/materials own inherent limitations; nevertheless, designed nanocomposite/hybrid/films address the new challenges/constraints and consequently aid the remediation of environmental/water pollution, thus denoting prospective nanotechnology/science. The morphology and chemical functionality of certain natural/synthetic polymers are altered/controlled rationally yielding advanced membranes/materials, for example, aquaporin, nanochannels, graphene and smart self-assemble block copolymer blends to cater futuristic desalination needs besides superseded conventional membrane limitations too. In a nut shell, advance nanotechnology via electrospinning, track-etching, phase inversion and interfacial polymerization yields structured composites/matrixes that conquer traditional barriers of conventional desalination and supplies treated/purified water. This review confers synthetic strategy and utility of nanomaterials that are procured via ordered/rational designing/self-assembly to be used in separation techniques including RO/FO antifouling membrane, superwet surface, oil-water/emulsion separation and multifunctional desalination nanodevices

Potent Antibacterial Profile of 5-Oxo-Imidazolines in the New Millennium

Pharmaceutics and therapeutics industries enforced chemists to seek/discover antibacterial novel heterocycles owing specific bioactivity and innate characteristics significance. This chapter summarized potent antibacterial profile of 5-oxo-imidazolines in the new millennium as an antibacterial against Gram-positive and Gram-negative bacteria viz. B. thuringiensis, S. aureus, E. coli, and E. aerogenes is presented in this chapter. 5-(H/Br benzofuran-2-yl)-1-phenyl 1H-pyrazole-3-carbohydrazides are condensed with 4-(arylidene)-2 phenyloxazol-5(4H)-one in acetic acid at elevated temperature to yield product 5-(H/Br benzofuran-2-yl)-N-(4-arylidene-5-oxo-2-phenyl-4,5-dihydroimidazol-1-yl)-1-phenyl-1H-pyrazole-3-carboxamides. Different substrates like 4-(arylidene)-2-phenyloxazol-5(4H)-one allowed to react with benzaldehyde hippuric acid to yield 5-oxo-imidazolines/5-oxo-4,5-dihydroimidazole. All synthesized 5-oxo-imidazolines were characterized via elemental analysis and FT-IR, 1H-NMR and mass spectra techniques. All 5-oxo-imidazolines assayed in vitro for inherent antimicrobial activity at different concentration against stated bacterial strains and compared with standard chloramphenicol. 5-Oxo-imidazolines (3a and 3c) with 125 μg/mL concentration showed excellent antibacterial profile against Gram-positive bacteria, B. thuringiensis, while other derivatives at different concentrations showed moderate antibacterial activity against Gram-positive bacteria, S. aureus and B. thuringiensis. Gram-negative bacteria like E. coli and E. aerogenes are tested at higher concentration (1000, 500, and 125 μg/mL) and found good-to-moderate antibacterial activity. Tested products found non-active against E. aerogenes for 125, 61, and 31 μg/mL concentration also inactive at conc. 31 μg/mL against E. coli

Synthesis of new annulated pyrano[2,3-d]pyrimidine derivatives using organo catalyst (DABCO) in aqueous media

A selective method for the synthesis of annulated pyrano[2,3-d]pyrimidines has been developed. It was shown that base catalysis is more efficient in this reaction, rather than acid catalysis as it is believed that 1,4-diazabicyclo[2.2.2]octane (DABCO) is N-type base catalyst used for the synthesis of pyrano[2,3-d]pyramidine derivatives via one-pot three component condensation reactions of various aromatic aldehydes, active methylene compounds and barbituric acid in aqueous ethanol carried at normal temperature. The potential application of DABCO in organic synthesis increasing rapidly because of its reaction simplicity, less pollution, and minimum reaction time, high yields of the biological active products, uses less toxic solvents and low cost chemicals

Microwave assisted one-pot catalyst free green synthesis of new methyl-7-amino-4-oxo-5-phenyl-2-thioxo-2,3,4,5-tetrahydro-1H-pyrano[2,3-d]pyrimidine-6-carboxylates as potent in vitro antibacterial and antifungal activity

An efficiently simple protocol for the synthesis of methyl 7 amino-4-oxo-5-phenyl-2-thioxo-2, 3, 4,5-tetrahydro-1H-pyrano[2,3-d]pyrimidine-6-carboxylates via one-pot three component condensation pathway is established via microwave irradiation using varied benzaldehyde derivatives, methylcyanoacetate and thio-barbituric acid in water as a green solvent. A variety of functionalized substrates were found to react under this methodology due to its easy operability and offers several advantages like, high yields (78–94%), short reaction time (3–6 min), safety and environment friendly without used any catalyst. The synthesized compounds (4a–4k) showed comparatively good in vitro antimicrobial and antifungal activities against different strains. The Compounds 4a, 4b, 4c, 4d 4e and 4f showed maximum antimicrobial activity against Staphylococcus aureus, Bacillus cereus (gram-positive bacteria), Escherichia coli, Klebshiella pneumonia, Pseudomonas aeruginosa (gram-negative bacteria). The synthesized compound 4f showed maximum antifungal activity against Aspergillus Niger and Penicillium chrysogenum strains. Streptomycin is used as standard for bacterial studies and Mycostatin as standards for fungal studies. Structure of all newly synthesized products was characterized on the basis of IR, 1H NMR, 13C NMR and mass spectral analysis

A short and faster entrée to N-oxides: Transition metal acetylacetonates promoted aerobic oxidative transformation of tertiary nitrogen compounds to N-oxides

374-379Transition metal acetylacetonates promoted aerobic oxidation methodology involving molecular oxygen as an oxidant with co-oxidant like isobutyraldehyde have been used for oxidative transformation of variety of tertiary nitrogen compounds to its N-oxides. The system of O2-aldehyde metal acetylacetonates needs shorter reaction time than simple molecular O2-aldehyde system without catalyst for oxidative conversion of tertiary nitrogen to corresponding N-oxides. The corresponding N-oxides have been obtained in near quantitative yield using transition metal acetylacetonates of Fe (II), Ni (II), VO (V) and Mn (II)

Proficient synthesis of bioactive annulated pyrimidine derivatives: A review

Syntheses of bioactive annulated pyrimidine derivatives are the most significant tasks in N-heterocyclic chemistry because these compounds have proved to be very attractive and useful for the design of new molecular frameworks of potential drugs with varying pharmacological activities. This review paper summarizes the one-pot multicomponent synthesis of annulated nitrogen- and oxygen-containing heterocycles, such as pyrano[2,3-d]pyrimidines, pyrido[2,3-d]pyrimidines and pyrido[2,3-d;5-6-d]dipyrimidines. The synthetic procedure is based on the chemistry of the domino Knoevenagel-Michael addition mechanism. Keywords: Pyrano[2,3-d]pyrimidines, Pyrido[2,3-d]pyrimidines, Pyrido[2,3-d;5-6-d]dipyrimidines, Barbituric acid/Thio-barbituric acid, Aromatic aldehydes, 6-aminouraci

Computational analysis for antimicrobial active pyrano[2,3-d]pyrimidine derivatives on the basis of theoretical and experimental ground

Annulated pyrano[2,3-d]pyrimidine derivatives were synthesized with methoxy, hydroxyl, nitrile and bromine substituents in its skeleton and correlated by electronic effect of substituents on the magnitude of antimicrobial activity. The different electron donating and electron withdrawing substituents of the pyrano[2,3-d]pyrimidine derivatives exerted positive influence on its antimicrobial activity against some Gram positive and Gram negative bacteria such as, Bacillus cereus, Staphylococcus aureus, Klebsiella pneumonia, Pseudomonas aureus and Escherichia coli, respectively. Antibacterial screening revealed that the presence of heteroaryl, cyano and amino groups on pyrano[2,3-d]pyrimidine skeleton increases its penetrating power on bacterial cell wall and becomes more biologically active. All the pyrano[2,3-d]pyrimidine derivatives were characterized by IR, 1H NMR, 13C NMR and mass spectra