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81.
R. Venkateswarlu C. Kamakshi S.G.A. Moinuddin D. Rama Sekhara Reddy A. Pelter M.B. Hursthouse M.E. Light 《Tetrahedron》2006,62(18):4463-4473
Treatment of diphyllin 4 with phenyliodonium diacetate (PIDA) in methanol affords a 1-methoxy-1-aryl-4-oxonaphthalene lactone 6. Reduction of 6 with lithium aluminium hydride yields, inter alia, 3,4-dihydrodiphyllin 13, while reaction with sodium in ethanol yields 8 as a major product. These reactions illustrate that selective oxidation followed by reduction provides a facile route for the conversion of a 1-arylnaphthalene lactone to novel functionalised naphthalene and dihydronaphthalene derivatives. Of particular interest is that the oxidation indirectly activates the methylene position (C-10) of the γ-lactone, which may then potentially be substituted to give a new series of lignans. Reaction of 6 with hydroxylamine and benzyloxyamine also proceeds by way of initial attack at C-10. 相似文献
82.
Basir Md. Faisal Md. Mabood Fazle Satya Narayana P. V. Venkateswarlu B. Ismail Ahmad Izani Md. 《Journal of Thermal Analysis and Calorimetry》2022,147(1):661-674
Journal of Thermal Analysis and Calorimetry - The enhancement of heat transfer in a new kind of hybrid nanofluid is more than that of a single nanoparticle. Also, the thermal conductivity of... 相似文献
83.
Venkateswarlu Chimaladenne Ramesh Manda Ashok Reddy Gudipally Krishna Reddy Valluru Pradeep Kumar Brahman 《合成通讯》2020,50(19):2941-2949
Abstract A mild and efficient base promoted, microwave assisted, green synthesis of 2-amino-2-ene-1,4-diones has been described by the decomposition of phenacyl azides followed by treatment with pyridinium salts of phenacyl bromides in aqueous media. A diverse range of substrates bearing electron-releasing and electron-withdrawing substituents were well tolerated and delivered corresponding 2-amino-2-ene-1,4-diones in good yields. Synthesized 2-amino-2-ene-1,4-diones have been further explored in the synthesis of various substituted 4-hydroxypyrrolidin-2-ones. 相似文献
84.
A simple and rapid gradient elution high-performance liquid chromatographic method using photodiode array and electrospray ionization mass spectrometric detectors was developed for separation and determination of the process-related substances and photodegradation products of stilbenesulfonic acids, viz. 4,4'-dinitrostilbene-2,2'-disulfonic acid (DNSDA), 4-amino-4'-nitrostilbene-2,2'-disulfonic acid (ANSDA), and 4,4'-diaminostilbene-2,2'-disulfonic acid (DASDA) in industrial waste waters. Gradient elution was carried out using ammonium acetate and acetonitrile as mobile phase and an Inertsil-ODS 3V column for separation. The negative-ion electrospray ionization mass spectra containing [M-H]- ions of sulfonic acids allowed molecular mass determination of unknowns and the structures were proposed on the basis of the fragment ions in the MS/MS spectra. 相似文献
85.
Non-static plane symmetric cosmological solutions are studied with zero mass scalar fields in the context of cosmic strings
in general relativity. Some physical and geometrical features of these models are discussed. 相似文献
86.
Lakshmi Niranjan Reddy V Ravinder K Srinivasulu M Venkateshwar Goud T Malla Reddy S Srujankumar D Prabhakar Rao T Suryanarayana Murty U Venkateswarlu Y 《Chemical & pharmaceutical bulletin》2003,51(9):1081-1084
The stems of Boswellia ovalifoliolata BAL. & HENRY (Burseraceae) afforded two new macrocyclic diaryl ether heptanoids, ovalifoliolatin A (1) and B (2) together with three known compounds; acerogenin C (3), 3 alpha-hydroxyurs-12-ene (4), and sitost-4-en-3-one (5). The structures were established by means of spectroscopic analysis and compounds 1, 3-5 were evaluated for their antibacterial activity. 相似文献
87.
A.S.R. Anjaneyulu P.Atchuta Ramaiah L.Ramachandra Row R. Venkateswarlu A. Pelter R.S. Ward 《Tetrahedron》1981,37(21):3641-3652
The isolation and characterisation of five new compounds and nine known compounds from the heartwood of Cleistanthus collinus are reported. The new compounds are wodeshiol 16,3,4-dihydrotaiwanin C 20, and three new glycosides 24, 25 and 26 of diphyllin and taiwanin E The 1H and 13C NMR spectra of these compounds are also reported. 相似文献
88.
Karuturi Rajesh Vangaru Suresh Jondoss Jon Paul Selvam Chitturi Bhujanga Rao Yenamandra Venkateswarlu 《Helvetica chimica acta》2009,92(9):1866-1872
A simple and highly efficient stereoselective total synthesis of xestodecalactone C ( IIb ), a polyketide natural product, was achieved (Scheme 2). The synthesis involved Keck's asymmetric allylation, a iodine‐induced electrophilic cyclization, and an intramolecular Friedel–Crafts acylation as key steps. 相似文献
89.
B. V. R. Chowdari Putcha Venkateswarlu F.A.Sc. 《Proceedings Mathematical Sciences》1968,67(3):130-137
Electron paramagnetic resonance investigation of Mn2+ in (NH4)2SO4 single crystal is discussed both in paraelectric and ferroelectric phases of the crystal. Mn2+ is found to substitute one of the two possible types (α andβ) of NH 4 + ions and get associated with the second type of NH 4 + vacancy, the vacancy being the second distant neighbour in thebc-plane. As The line joining Mn2+ substituted NH 4 + site and NH 4 + vacancy lies at an angle of 18° from the crystallographicb-axis in thebc-plane. As the temperature is lowered to ? 56° C the crystal becomes ferroelectric and the spectrum in the paraelectric phase splits into two from which it appears that two sets of Mn2+ sites which are magnetically equivalent in the paraelectric phase become inequivalent in the ferroelectric phase. The spin Hamiltonian analysis is presented for the spectrum in the paraelectric phase. 相似文献
90.
Bromine was excited by an uncondensed transformer discharge in the presence of argon. The spectrum obtained was found to be different from what one gets without the presence of a foreign gas and consists of (1) a short discrete band system in the region 3150–2970 Å, (2) an extensive discrete band system in the region 2950–2670 Å, (3) a short and weak discrete system in the region 2660–2590 Å and a set of diffuse bands in the region 3340–3190 Å. The wavelengths and wave numbers of the band heads of the system 2950–2670 Å, as obtained from the measurements of the plates taken on the first order 21-ft. grating spectrograph, are given along with the vibrational analysis. This system is shown to be due to a transition from an upper electronic state at 51802 cm.-1 with ω′e = 150·5 cm.-1 and ω′e X′e = 1·15 cm.-1 to the well known3 II α (O2 +) state at 15918 cm.-1 相似文献