2-Fluoro and 2-chloro aryl thioureas, which are usually inert toward heteroarylation forms intramolecular C−S linkage by Cu(I) and Pd(II) catalyst. A regioselective intramolecular C−S bond formation is observed during the formation of 2-aminobenzothiazoles from 2-halothioureas using both these transition metal catalysts. While Cu prefers a dehalogenative path, Pd favors predominantly C−H activation strategy during the formation of 2-aminobenzothiazoles. In the absence of 2-halo (−F, −Cl) groups, Pd favors C−H activation, while Cu is unproductive. However, identical selectivities were observed both for Cu-and Pd-catalyzed reactions for 2-bromo and 2-iodo aryl thioureas.

DNA is rapidly cleaved under mild alkaline conditions at apyrimidinic/apurinic sites, but the half-life is several weeks in phosphate buffer (pH 7.5). However, abasic sites are ~100-fold more reactive within nucleosome core particles (NCPs). Histone proteins catalyze the strand scission, and at superhelical location 1.5, the histone H4 tail is largely responsible for the accelerated cleavage. The rate constant for strand scission at an abasic site is enhanced further in a nucleosome core particle when it is part of a bistranded lesion containing a proximal strand break. Cleavage of this form results in a highly deleterious double-strand break. This acceleration is dependent upon the position of the abasic lesion in the NCP and its structure. The enhancement in cleavage rate at an apurinic/apyrimidinic site rapidly drops off as the distance between the strand break and abasic site increases and is negligible once the two forms of damage are separated by 7 bp. However, the enhancement of the rate of double-strand break formation increases when the size of the gap is increased from one to two nucleotides. In contrast, the cleavage rate enhancement at 2-deoxyribonolactone within bistranded lesions is more modest, and it is similar in free DNA and nucleosome core particles. We postulate that the enhanced rate of double-strand break formation at bistranded lesions containing apurinic/apyrimidinic sites within nucleosome core particles is a general phenomenon and is due to increased DNA flexibility.

Surface water is widely adulterated by hazardous pollutants such as dyes, pharmaceutical wastes, surfactants, heavy metals, hormones, etc. Hence, there is a necessity to develop a water treatment technology that can overcome all the major waterrelated problems. The conventional methods for water disinfection are very specific and expensive. The challenge is to devise a purification protocol without forming harmful byproducts, which opens up the opportunity for new technologies with efficient materials toward water treatment. The present work demonstrates a sustainable strategy for robust water purification through a powder based membrane fabricated from a highly oxygenated and Al-functionalized solvothermal carbon (Al-STC) composite. AlOOH/Al(OH) 3 functionalized Al-STCs with improved surface acidity were prepared by a low temperature solvothermal process from a eutectic system (ES) comprising ethylene glycol (EG), choline chloride (ChoCl), glucose (Glu), and aluminum salt. The ES acts as both carbon precursor and catalyst. Attributed to the unique properties such as high surface functionality, moderately high surface area, and caterpillar-like morphology, Al-STCs were employed for the fabrication of a powder based membrane to purify water in a dead-end filtration mode. Various pollutants, for instance, dyes such as malachite green (with rejection of >99.9% and flux 1522 LMH) and methylene blue (with rejection of >99.9% and flux 885 LMH), pharmaceutical drugs such as ciprofloxacin and (with rejection of >99.9% and flux 1011 LMH) and paracetamol (with rejection of 53% and flux 1010 LMH), oxytocin hormone (with rejection of 88.6% and flux 955 LMH), surfactant CTAB (with rejection of 94.9% and flux 1436 LMH), and heavy metal [Cr(VI) with rejection of >99.9% and flux 932 LMH] were successfully removed from aqueous solution using an Al-STCs based membrane. Moreover, a membrane active surface was regenerated by simple ethanol washing and reused for five consecutive cycles without compromising the flux and rejection, thus demonstrating the utility of an Al-STC based membrane as an easy-to-use and ecofriendly membrane toward all kinds of water purification in a sustainable and affordable manner.

Metallized DNA is an exciting functional material having widespread utility toward multifunctional applications. However, conventional DNA metallization processes are time-consuming and multistep and, most importantly, the helicity of DNA is destroyed during the metallization process. Herein, an ecofriendly and rapid approach has been demonstrated to metallize salmon milt DNA with Pd and Fe3O4 in deep eutectic solvent (DES; ChoCl–EG 1:2 mol ratio) without disturbing the structural integrity of the biopolymer. Besides maintaining the stability of DNA at high temperature, DES played the dual role of (i) a solvent for DNA metallization and (ii) a reducing agent for reduction of Pd­(II) to Pd(0) during the metallization process. Microscopic studies confirmed the stepwise formation of aggregated coil type morphology in metallized DNA (Pd–DNA–Fe3O4). Whereas, the interactions between Pd and Fe3O4 with DNA in Pd–DNA–Fe3O4 were probed by different analytical tools, which suggested that Pd interacted with phosphate groups and Fe3O4 interacted with the base pairs of DNA. Circular dichroism spectroscopy analysis established that the B-form of DNA was maintained before and after the metallization process. After successful metallization, Pd–DNA–Fe3O4 was utilized as a nanobiocatalyst for Suzuki coupling reaction and reduction of nitrobenzene to aniline. The metallized DNA showed remarkable catalytic activity and efficiency for sustainable Suzuki coupling reaction in DES. Under optimized conditions, 100% conversion of the substrates was recorded with 100% selectivity of the desired C–C coupled product. Taking advantage of the high temperature stability of DNA in DES, the recyclability (up to 6 cycles) potential of both metallized DNA and DES toward C–C coupling was explored without significant loss in the catalytic activity, thus demonstrating the green aspects of the process. When utilized as a catalyst for the reduction of nitrobenzene to aniline, ∼90% conversion of nitrobenzene was achieved with 66% selectivity of aniline which suggested that the overall assembly of metallized DNA is a very efficient system to carry out facile nitrobenzene reduction. Overall, the present study demonstrates a general process for metallization of DNA in DES and the applications of the metallized DNA as a catalyst in different organic reactions.

It has been reported by us recently that p-nitrobenzyl bromide (PNBBr) can be synthesized from p-nitrotoluene (PNT) in high isolated yield with respect to available bromine in 2:1 Br(-)-BrO3(-) employed as brominating reagent. The reaction was conducted in ethylene dichloride (EDC) and the substrate was taken in excess to suppress dibromo impurity formation. The product was "cold crystallized" from the reaction mass and the mother liquor was recycled in the subsequent batch thereby eliminating organic discharge. The present work attempts to further advance the synthesis of this commercially important molecule employed in protection-deprotection strategies. Herein its successful synthesis employing neat substrate and solar radiation as the sole energy source to drive this photothermochemical reaction is reported. Further, 100% pure PNBBr could be isolated from the solid reaction mass in 87% yield by leaching out the excess substrate through supercritical CO2 (Sc-CO2) extraction. The reaction was therefore accomplished cleanly in all respects and with low carbon footprint.