Reaction of β-oxodithioesters with propargylamine: a facile entry to novel 2-(acylalkylidene)-5-(methylene)thiazolidines

Reaction of β-oxodithioesters derived from acyclic and cyclic ketones with propargylamine affords novel 2-(acylalkylidene)-5-(methylene)-thiazolidines in high yields by intramolecular nucleophilic attack of thiocarbonyl sulfur on the triple bond of the β-oxo-N-propargylthioamide intermediates

Magnetic anomalies over the Andaman Islands and their geological significance

The Andaman Islands form part of the outer-arc accretionary sedimentary complex belonging to the Andaman–Sumatra active subduction zone. The islands are characterized by thick cover of Neogene sediments along with exposed ophiolite rocks at few places. A regional magnetic survey was carried out for the first time over the Andaman Islands with a view to understand the correlation of anomaly signatures with surface geology of the islands. The residual total field magnetic anomaly maps have revealed distinct magnetic anomalies having intermediate to high amplitude magnetic signatures and correlate with the areas over/close to the exposed ophiolite rocks along the east coast of north, middle and the south Andaman Islands. The 2D modelling of magnetic anomalies along selected E–W profiles across the islands indicate that the ophiolite bodies extend to a depth of about 5–8 km and spatially correlate with the mapped fault/thrust zones

Indian Academia-Industry Collaboration in Developing Novel Process for Hydrazine Hydrate

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Reformatsky reaction on thiocarbonyl compounds: new C-C bond forming reaction

Reformatsky regants are shown to undergo facile C-C bond formation on trithiocarbonates, xanthates, thione and dithioesters, through carbophilic additional yielding products formed by elimination of either sulphur or alkylthio group

Geochemistry of thermal springs around Lake Abhe, Western Djibouti

The Republic of Djibouti, occupying an area of 23,180 km2, falls within the arid zone of East Africa and is located above the 'Horn of Africa', adjacent to the Red Sea. This country has several thermal springs and fumaroles distributed over three regions - Lake Assal, Lake Hanle and Lake Abhe. The most characteristic feature of Lake Abhe is the presence of several linear chains of travertine chimneys. The thermal waters are typical of the Na-Cl type near neutral waters rich in CO2. These waters show an oxygen shift, indicating reservoir temperatures>200°C. The chemical signature of the thermal springs and the geology of the Lake Abhe region are very similar to the Tendaho geothermal area of Ethiopia. The geology, temperature gradient and its proximity to Damah Ale volcano make the Lake Abhe region a potential site for geothermal power development

Deprotection of thioacetals and 1,3-dithianes with dimethylsulphoxide

The dialkylthioacetals, cyclic ethanediylthioacetals and 1,3-dithianes are shown to undergo facile dethioacetalization on heating in dimethylsulphoxide under neutral conditions to afford the corresponding carbonyl compounds in good yields

On the distribution and speciation of arsenic in the soil-plant-system of a rice field in West-Bengal, India: A mu-synchrotron techniques based case study

Worldwide, West-Bengal is one of the areas most affected by elevated levels of arsenic in groundwater (50-3000 mu g/l). This groundwater does not only endanger humans owing to its use as drinking water. More and above that, irrigation of rice paddies consumes huge quantities of arsenic contaminated groundwater. Consequently, arsenic accumulates in soil and endangers the nutrition chain via arsenic uptake by plants. Rice is one of the staple foods in this region. Lately, there is a considerable intensification of research on the fate of arsenic in affected agricultural systems with most of them resorting to bulk analytical methods. However, so far, knowledge on the it-scale distribution of arsenic in soil and plants in such agricultural systems is rather limited. This case study combined mu-synchrotron studies on soil, rice root and rice grain from a rice paddy irrigated with groundwater containing about 519 mu g/L As. The investigation of a soil aggregate has shown that As is mainly associated with Fe and is not equally distributed over the whole aggregate but occurs in local enrichments of few tens mu m in size. In soil, As was mainly associated with Fe-(oxy)hydroxides. Rice root coatings consisted of a similar assemblage of arsenic bearing minerals. Furthermore the incorporation of soil matter in the coating could be shown. On mu m-scale, As concentrations in rice root coatings showed an inhomogeneous, patchy distribution (100-2400 mg/kg; median 500 mg/kg) and correlated with Fe Concentrations. Some small amounts of arsenic could also be detected in the interior of the root (3-60 mg/kg; median 21 mg/kg). In the rice grain, trace elements such as Zn and Cu were mainly enriched along the grain coating, while As in contrast showed the highest concentrations in the germ and some hot spots in the coating (up to 13 mg/kg). Thus, peeling of rice grain would remove some, but not all of the arsenic. (C) 2015 Elsevier Ltd. All rights reserved

Magnetic anomalies over the Andaman Islands and their geological significance

The Andaman Islands form part of the outer-arc accretionary sedimentary complex belonging to the Andaman-Sumatra active subduction zone. The islands are characterized by thick cover of Neogene sediments along with exposed ophiolite rocks at few places. A regional magnetic survey was carried out for the first time over the Andaman Islands with a view to understand the correlation of anomaly signatures with surface geology of the islands. The residual total field magnetic anomaly maps have revealed distinct magnetic anomalies having intermediate to high amplitude magnetic signatures and correlate with the areas over/close to the exposed ophiolite rocks along the east coast of north, middle and the south Andaman Islands. The 2D modelling of magnetic anomalies along selected E-W profiles across the islands indicate that the ophiolite bodies extend to a depth of about 5-8 km and spatially correlate with the mapped fault/thrust zones