Rajendra Singh

BrettPhos Ligand Supported Palladium‐Catalyzed CO Bond Formation through an Electronic Pathway of Reductive Elimination: Fluoroalkoxylation of Activated Aryl Halides

We report an unprecedented BrettPhos ligand supported Pd-catalyzed Cuf8ffO bond-forming reaction of activated aryl halides with primary fluoroalkyl alcohols. We demonstrate that the Phosphine ligand (BrettPhos) possesses the property of altering the mechanistic pathway of reductive elimination from nucleophile to nucleophile. The Pd/BrettPhos catalyst system facilitates the reductive elimination of the oxygen nucleophile through an electronic pathway.

Nano copper ferrite: A reusable catalyst for the synthesis of β , γ -unsaturated ketones

AbstractCopper ferrite nano material as reusable heterogeneous initiator in the synthesis of β, γ-unsaturated ketones and allylation to acid chlorides are presented. The reaction of allylichalides with various acid chlorides is achieved in the presence of copper ferrite nano powders at room temperature in tetrahydrofuran (THF). The present method is first of its kind in the synthesis of title compounds without any additive/ co-catalyst. The nano catalyst is easily recovered and its reusability is recorded.n Graphical AbstractAn efficient protocol for the synthesis of β, γ -unsaturated ketones using copper ferrite nano material was achieved. The compounds were characterized by spectroscopic techniques.

Effect of acyl chain length on selective biocatalytic deacylation on O-aryl glycosides and separation of anomers

It has been demonstrated that Lipozyme® TL IM (Thermomyces lanuginosus lipase immobilised on silica) can selectively deacylate the ester function involving the C-5 hydroxyl group of α-anomers over the other acyl functions of anomeric mixture of peracylated O-aryl α,β-D-ribofuranoside. The analysis of results of biocatalytic deacylation reaction revealed that the reaction time decreases with the increase in the acyl chain length from C1 to C4. The unique selectivity of Lipozyme® TL IM has been harnessed for the separation of anomeric mixture of peracylated O-aryl α,β-D-ribofuranosides, The lipase mediated selective deacylation methodology has been used for the synthesis of O-aryl α-D-ribofuranosides and O-aryl β-D-ribofuranosides in pure forms, which can be used as chromogenic substrate for the detection of pathogenic microbial parasites containing glycosidases.

Synthesis of some 6-arylamino-3-amino-1,2,4,5-dithiadiazines

Synthese par condensation de S-benzyl thiocarbazimidate et disothiocyanates daryle suivie doxydation des aryl-4 benzylthioformimidoyl-1 thiosemicarbazides (A) obtenus. Reduction des dithiadiazines et des composes A en amides, arylamides dacide hydrazothioformique

Long-term rainfall trend and drought analysis for Bundelkhand region of India

In this study, an effort has been made to characterise the spatial and temporal variability of precipitation in 13 districts of the Bundelkhand region spreading in Uttar Pradesh and Madhya Pradesh of India in the during 1901–2002. The Bundelkhand region receives an average annual rainfall of 1,071.7 mm. The highest annual rainfall of 1,190.6 mm has been recorded in Sagar district, whereas the lowest annual rainfall of 902 mm has been recorded in Jalaun district. On the basis of rainfall records, the Bundelkhand region can be classified into two groups, namely, districts with high rainfall, namely, Panna, Tikamgarh, Lalitpur and Sagar receiving an average annual rainfall of 1,138 mm and low rainfall districts, namely, Jhansi, Jalaun, Hamirpur, Banda, Mahoba, Chitrakut, Datia, Chhatarpur and Damoh receiving an annual average rainfall of 1,011 mm. Standardized Precipitation Index indicates that 5 drought years were observed during 1901–1950 and 12 drought years were noticed during 1951–2000. This indicated a rising trend in the occurrence of drought in the region. Also indicates that the first half of the century was slightly wetter that the second half.

Lower bounds of correlation measure for time hopping codes in UWB communication systems

Correlation measure is an important indicator of the performance any code sequence family used for communication system. Frequency Hopping (FH) codes are similar in construction of Time Hopping (TH) codes used in Ultra Wide Band (UWB) communication systems. Since the development of TH codes is not yet fully established, in this paper an effort has been made to utilize FH code families as TH codes as the former are widely available in large numbers and have been dealt with in literature. This paper investigates the similarity between correlation properties of FH and TH codes. Lower bounds of auto correlation and cross correlation functions of TH codes have been derived and compared those with FH codes. It is found that the values of correlation functions for TH codes are higher than those for FH codes. This conclusion has been established through a case study using three well-established FH code sequence families.

10,21-Dimethyl-2,7,13,18-tetraphenyl-3,6,14,17-tetraazatricyclo[17.3.1.18,12]tetracosa-1(23),2,6,8(24),9,11,13,17,19,21-decaene-23,24-diol cyclohexane 0.33-solvate

The title compound, C46H40N4O2·0.33C6H12, was obtained unintentionally as a product of an attempted synthesis of a cadmium(II) complex of the [2,6-{PhSe(CH2)2N=CPh}2C6H2(4-Me)(OH)] ligand. The full tetraiminodiphenol macrocyclic ligand is generated by the application of an inversion centre. The macrocyclic ligand features strong intramolecular O—H⋯N hydrogen bonds. The dihedral angles formed between the phenyl ring incorporated within the macrocycle and the peripheral phenyl rings are 82.99u2005(8) and 88.20u2005(8)°. The cyclohexane solvent molecule lies about a site of symmetry. Other solvent within the lattice was disordered and was treated with the SQUEEZE routine [Spek (2009). Acta Cryst. D65, 148–155].