Synthesis and characterization of 6-alkylcarbamato-2, 10-dichlorodibenzo [d,g] [1,3,6,2]dioxathiaphosphocin 6-oxides

Novel 6-alkylcarbamato/thiocarbamato-2,10-dichlorodibenzo [d,g][1,3,6,2]dioxathiaphosphocin 6-oxides were synthesized by cyclization of 5,5′-dichloro-2,2′-dihydroxydiphenyl sulfide with the corresponding dichlorophosphinyl carbamates/thiocarbamates that were obtained by the addition of alcohols/thiols to dichloroisocyanatophosphine oxide and were characterized by IR, ¹H, ¹³C, ³¹P NMR, and mass spectral studies. A ¹³C NMR analysis revealed ²J_POC and ³J_POCC couplings. © 1996 John Wiley & Sons, Inc.     

Photoelectric effect in some alloys in the region of absorption edges

Summary Photoelectric effect in alloys using the transmission method in the energy range (17.8÷138) keV, at energies in the region of absorption edges of the various elements in the alloys, have been measured and compared with the respective theoretical estimates.     

High spin states in102Ag

High spin states are populated in¹⁰²Ag using the reaction¹⁶O+⁸⁹Y with projectile energies in the energy range 60–80 MeV. Gamma multipolarities are inferred from DCO ratios and coincidence relationships are established among the gamma rays assigned to¹⁰²Ag. A comprehensive level scheme is constructed with four band systems, two of positive parity and the other two of negative parity. The present study extended spins upto 19^– in the main negative parity band. A new band is populated in the present work and is similar to the one observed in¹⁰⁶Ag.The authors wish to thank and record their appreciation to Dr. S.K. Parthasaradhi, VECC, Calcutta for preparing the target used in this experiment. The authors gratefully acknowledge useful discussions with Dr. Rakhesh Popli. The authors record their grateful thanks to Prof. A.P. Patro and Prof. G.K. Mehta, former and present directors of the Nuclear Science Centre, for their interest in this work, helpful discussions and providing excellent facilities. The authors also thank Dr. S.K. Datta of the Nuclear Science Centre for his continued interest and helpful discussions and accelerator staff of N.S.C. for their efficient services in delivering the beam. Grateful thanks are also due to the University Grants Commission for providing financial support.     

Mechanistic aspects of the reduction of ruthenium(III) catalyzed

The kinetics of Ru_III catalyzed reduction of hexacyanoferrate(III) [Fe(CN)₆]^3–, by atenolol in alkaline medium at constant ionic strength (0.80 mol dm^–3) has been studied spectrophotometrically, using a rapid kinetic accessory. The reaction between atenolol and [Fe(CN)₆]^3– in alkaline medium exhibits 1:2 stoichiometry [atenolol:Fe(CN)₆ ^3–]. The reaction showed first order kinetics in [Fe(CN)₆]^3– concentration and apparent less than unit order dependence, each in atenolol and alkali concentrations. Effect of added products, ionic strength and dielectric constant of the reaction medium have been investigated. A retarding effect was observed by one of the products i.e., hexacyanoferrate(II). The main products were identified by i.r., n.m.r., fluorimetric and mass spectral studies. A mechanism involving the formation of a complex between the atenolol and the hydroxylated species of ruthenium(III) has been proposed. The active species of oxidant and catalyst were [Fe(CN)₆]^3–and [Ru (H₂O)₅OH]²⁺, respectively. The reaction constants involved in the mechanism were evaluated. The activation parameters were computed with respect to the slow step of the mechanism, and discussed.     

Highly efficient Pd‐PEPPSI‐IPr catalyst for N‐(4‐pyridazinyl)‐bridged bicyclic sulfonamides via Suzuki–Miyaura coupling reaction

A protocol for the Suzuki–Miyaura coupling of novel 2‐(6‐chloropyridazin‐3‐yl)‐5‐(aryl/heteroarylsulfonyl)‐2,5‐diazabicyclo[2.2.1]heptanes and heteroarylboronic acids to afford variety of coupled products was realized. Pd‐PEPPSI‐IPr catalyst was found to be a powerful and reusable catalyst under relatively mild reaction conditions.     

A PASE-based approach towards 12-(1H-1,2,3-triazol-1-yl)-indolo[2,1-a]isoquinolines via the reaction of 3-(isoquinolin-1-yl)-1,2,4-triazines with benzyne

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Design and Synthesis of Some New Benzimidazole Containing Pyrazoles and Pyrazolyl Thiazoles as Potential Antimicrobial Agents

A new class of bis heterocycles‐benzimidazolyl pyrazoles were prepared from the Michael acceptor (E)‐3‐(1H‐benzimidazol‐2‐yl)‐1‐aryl‐prop‐2‐en‐1‐one. The thiamide group was exploited to develop thiazole ring on treatment with p‐fluorophenacyl bromide to get tris heterocycles. All the lead compounds were tested for antimicrobial activity. The compound 7d having nitro substituent on the aromatic ring showed greater antimicrobial activity particularly against Pseudomonas aeruginosa and Penicillium chrysogenum.     

Stereoselective Total Synthesis of Stagonolide C

A convergent and efficient total synthesis of stagonolide C ( 1 ), a phytotoxic metabolite, was achieved (Schemes 2 and 3) The synthesis exploited the high configuration control in the Prins cyclization along with alkene rearrangement and ring‐closing metathesis as key steps.     

Co-constructive development of a green chemistry-based model for the assessment of nanoparticles synthesis

Nanomaterials (materials at the nanoscale, ${10}^{?9}$ meters) are extensively used in several industry sectors due to the improved properties they empower commercial products with. There is a pressing need to produce these materials more sustainably. This paper proposes a Multiple Criteria Decision Aiding (MCDA) approach to assess the implementation of green chemistry principles as applied to the protocols for nanoparticles synthesis. In the presence of multiple green and environmentally oriented criteria, decision aiding is performed with a synergy of ordinal regression methods; preference information in the form of desired assignment for a subset of reference protocols is accepted. The classification models, indirectly derived from such information, are composed of an additive value function and a vector of thresholds separating the pre-defined and ordered classes. The method delivers a single representative model that is used to assess the relative importance of the criteria, identify the possible gains with improvement of the protocol’s evaluations and classify the non-reference protocols. Such precise recommendation is validated against the outcomes of robustness analysis exploiting the sets of all classification models compatible with all maximal subsets of consistent assignment examples. The introduced approach is used with real-world data concerning silver nanoparticles. It is proven to effectively resolve inconsistency in the assignment examples, tolerate ordinal and cardinal measurement scales, differentiate between inter- and intra-criteria attractiveness and deliver easily interpretable scores and class assignments. This work thoroughly discusses the learning insights that MCDA provided during the co-constructive development of the classification model.     

A facile synthesis and spectral (ir, 1H, 13C, 31P nmr) studies of 2,10-dichloro-6-aryloxy-12H-dibenzo[d,g][1,3,2]dioxaphosphocin 6-sulfides

The synthesis of new 2,10-dichloro-6-aryloxy-12H-dibenzo[d,g][1,3,2]dioxaphosphocin 6-sulfides 4 was achieved in two steps with high yields from the simple materials 5,5′-dichloro-2,2′-dihydroxydiphenyl-methane (1) and thiophosphoryl chloride (2) which produced the key intermediate 2,6,10-trichloro-12H-dibenzo[d,g][1,3,2]dioxaphosphocin 6-sulfide (3) . Treatment of 3 with substituted phenols under phase transfer catalytic (PTC) conditions led to members of 4 . Long range coupling [⁵J_(P,H) = 3.6 Hz] was observed between phosphorus and one of the bridged methylene protons in 4 . A ¹³C nmr analysis revealed ²J_(P,O,C), ³J_(P,O,C) ⁴J(P,O,C) and ⁵J(P,O,C) couplings. All ³¹P nmr chemical shifts for thirteen members of these new heterocycles are reported for the first time. The nmr data are not totally definitive to confirm a boat-chair as the major conformer for the central eight-membered dioxaphosphocin ring, but such a conformer is tentatively suggested as favored.