3-(7,8,13,14-Tetra­hydrodi­benzo­[a,i]phen­an­thridin-5-yl)benzene-1,2-diol

In the title compound, C27H21NO2, the half-chair conformation of the alicyclic rings gives rise to a slightly folded structure of the central tricyclic tetra­hydrophenanthridine unit. Tandem intra­molecular O—H⋯N and O—H⋯O hydrogen bonds give rise to adjacent S(6) and S(5) rings, respectively, which dictate the conformation of the 5-aryl substituent. In the crystal structure, an inter­molecular C—H⋯O contact generates chains parallel to [101]. Short O—H⋯π and C—H⋯π contacts are also observed

(3E,5E)-1-Benzyl-3,5-bis­(2-fluoro­benzyl­idene)piperidin-4-one

The inversion-related mol­ecules of the title compound, C26H21F2NO, associate into closed dimeric subunits via co-operative C—H⋯π inter­actions. Two non-classical C—H⋯O and one C—H⋯N intra­molecular hydrogen bonds are also found in the crystal structure. The piperidin-4-one ring adopts a sofa conforamtion with the 1-benzyl group in the equatorial position, and the equiplanar fluoro­phenyl substituents in the 3- and 5-positions stretched out on either side. The 1-benzyl group is disposed towards the substituent in the 6th position of the piperidin-4-one ring. The 3,5-diene units possess E configurations

(7E)-5-Benzyl-7-(2-chloro­benzyl­idene)-3-(2-chloro­phen­yl)-2-phenyl-3,3a,4,5,6,7-hexa­hydro-2H-pyrazolo­[4,3-c]pyridine

In the title 2H-pyrazolo­[4,3-c]pyridine derivative, C32H27Cl2N3, the dihydro­pyrazole ring adopts an envelope conformation and the piperidine fused ring a twisted-chair conformation. Two short intra­molecular C—H⋯Cl contacts are observed. The crystal packing is characterized by dimeric C—Cl⋯π inter­actions involving the 5-benzyl ring, with Cl⋯centroid and closest atomic Cl⋯π distances of 3.778 (2) and 3.366 (4) Å, respectively

(3E,5E)-3,5-Bis(4-allyl­oxybenzyl­idene)-1-benzyl­piperidin-4-one

In the title compound C32H31NO3, the all­yloxy groups on either side of the piperidin-4-one ring are conformationally disordered. The contribution of major and minor components of the allyloxy group at the 3rd position of the ring are 0.576 (4) and 0.424 (4), respectively, and those at the 5th position are 0.885 (3) and 0.115 (3), respectively. The six-membered piperidin-4-one ring adopts a sofa conformation with the benzyl group occupying an equatorial position and the olefinic double bonds possessing an E configuration. Flanking phenyl substituents are stretched out on either side of the six-membered ring. π–π inter­actions with a centroid–centroid distance of 3.885 (1) Å give rise to mol­ecular dimers and short C—H⋯π contacts lead to chains along the c axis

(3E,5E)-1-Benzyl-3,5-dibenzyl­idenepiperidin-4-one

In the title compound, C26H23NO, C—H⋯O hydrogen bonds generate a ribbon structure along the a axis. These ribbons further assemble into a one-dimensional sheet parallel to the ac plane via C—H⋯π inter­actions. The piperidin-4-one ring adopts a sofa conformation with the 1-benzyl group in the equatorial position, and the 3- and 5-phenyl substituents stretched out on either side. The benzyl­idene units adopt E configurations and the 1-benzyl group is disposed towards the 3- substituent of the piperidin-4-one ring

An experimental study of cathodic protection for chloride contaminated reinforced concrete

Cathodic protection (CP) is being increasingly used on reinforced concrete structures to protect steel reinforcing bars from corrosion in aggressive conditions. Due to the complexity of environmental conditions, the design specifications in national and international standards are still open to discussion to achieve both sufficient and efficient protection for reinforced concrete structures in engineering practices. This paper reports an experimental research to investigate the influence of chloride content on concrete resistivity, rebar corrosion rate and the performance of CP operation using different current densities. It aims to understand the correlation between the chloride content and concrete resistivity together with the CP current requirement, and to investigate the precision of the CP design criteria in standards

Trapping of Intermediates with Substrate Analog HBOCaA in the Polymerizations Catalyzer by Class III Polyhydroxybutyrate (PHB) Synthase from Allochromatium Vinosum

Polyhydroxybutyrate (PHB) synthases (PhaCs) catalyze the formation of biodegradable PHB polymers that are considered as an ideal alternative to petroleum-based plastics. To provide strong evidence for the preferred mechanistic model involving covalent and noncovalent intermediates, a substrate analog HBOCoA was synthesized chemoenzymatically. Substitution of sulfur in the native substrate HBCoA with an oxygen in HBOCoA enabled detection of (HB)nOCoA (n = 2–6) intermediates when the polymerization was catalyzed by wild-type (wt-)PhaECAv at 5.84 hr−1. This extremely slow rate is due to thermodynamically unfavorable steps that involve formation of enzyme-bound PHB species (thioesters) from corresponding CoA oxoesters. Synthesized standards (HB)nOCoA (n = 2–3) were found to undergo both reacylation and hydrolysis catalyzed by the synthase. Distribution of the hydrolysis products highlights the importance of the penultimate ester group as previously suggested. Importantly, the reaction between primed synthase [3H]-sT-PhaECAv and HBOCoA yielded [3H]-sTet-O-CoA at a rate constant faster than 17.4 s−1, which represents the first example that a substrate analog undergoes PHB chain elongation at a rate close to that of the native substrate (65.0 s−1). Therefore, for the first time with a wt-synthase, strong evidence was obtained to support our favored PHB chain elongation model

Micropropagation and conservation of selected endangered anticancer medicinal plants from the Western Ghats of India

Globally, cancer is a constant battle which severely affects the human population. The major limitations of the anticancer drugs are the deleterious side effects on the quality of life. Plants play a vital role in curing many diseases with minimal or no side effects. Phytocompounds derived from various medicinal plants serve as the best source of drugs to treat cancer. The global demand for phytomedicines is mostly reached by the medicinal herbs from the tropical nations of the world even though many plant species are threatened with extinction. India is one of the mega diverse countries of the world due to its ecological habitats, latitudinal variation, and diverse climatic range. Western Ghats of India is one of the most important depositories of endemic herbs. It is found along the stretch of south western part of India and constitutes rain forest with more than 4000 diverse medicinal plant species. In recent times, many of these therapeutically valued herbs have become endangered and are being included under the red-listed plant category in this region. Due to a sharp rise in the demand for plant-based products, this rich collection is diminishing at an alarming rate that eventually triggered dangerous to biodiversity. Thus, conservation of the endangered medicinal plants has become a matter of importance. The conservation by using only in situ approaches may not be sufficient enough to safeguard such a huge bio-resource of endangered medicinal plants. Hence, the use of biotechnological methods would be vital to complement the ex vitro protection programs and help to reestablish endangered plant species. In this backdrop, the key tools of biotechnology that could assist plant conservation were developed in terms of in vitro regeneration, seed banking, DNA storage, pollen storage, germplasm storage, gene bank (field gene banking), tissue bank, and cryopreservation. In this chapter, an attempt has been made to critically review major endangered medicinal plants that possess anticancer compounds and their conservation aspects by integrating various biotechnological tool