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1.
Cherukumalli Purna Koteswara Rao Tadiboina Bhaskara Rao Gulipalli Kali Charan Bodige Srinu Gangarapu Kiran Sridhar Gattu 《Russian Journal of General Chemistry》2020,90(10):1981-1989
Russian Journal of General Chemistry - A novel series of bis-isoxazole incorporated benzothiazole derivatives has been designed and synthesized. Molecular structures of the compounds have been... 相似文献
2.
Balasubramanian Sridhar Jagadeesh Babu Nanubolu Krishnan Ravikumar 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(2):128-135
A new polymorph of cytosine, C4H5N3O, is reported half a century after the report of its first known crystal structure [Barker & Marsh (1964). Acta Cryst. 17 , 1581–1587]. Cytosine thus provides the first polymorphic example in the category of parent nucleobases. The new form, denoted (Ib), was observed unexpectedly during an attempt to cocrystallize cytosine with catechol. Form (Ib) crystallizes in the orthorhombic centrosymmetric space group Pccn with two molecules in the asymmetric unit. The previously known form, denoted (Ia), crystallizes in the orthorhombic noncentrosymmetric space group P212121. The cytosine molecule is planar in both forms. Hydrogen‐bonding interactions are also similar for both forms. Infinite one‐dimensional ribbons composed of cytosine base‐pair dimers in R22(8) arrangements are observed in both (Ia) and (Ib). However, the way that the ribbons are packed differs in (Ia) and (Ib). This appears to guide the centrosymmetric versus noncentrosymmetric space‐group selection through the formation of an inversion‐related motif in polymorph (Ib) and a helical propagation in polymorph (Ia). A few selected polymorphic systems have been gathered from the Cambridge Structural Database to understand possible structural features responsible for achiral molecules adopting centro‐ and noncentrosymmetric space groups. 相似文献
3.
Krishnan Ravikumar Balasubramanian Sridhar Jagadeesh Babu Nanubolu Tamilselvan Rajasekaran Basi Venkata Subba Reddy 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(4):322-329
Four structures of oxoindolyl α‐hydroxy‐β‐amino acid derivatives, namely, methyl 2‐{3‐[(tert‐butoxycarbonyl)amino]‐1‐methyl‐2‐oxoindolin‐3‐yl}‐2‐methoxy‐2‐phenylacetate, C24H28N2O6, (I), methyl 2‐{3‐[(tert‐butoxycarbonyl)amino]‐1‐methyl‐2‐oxoindolin‐3‐yl}‐2‐ethoxy‐2‐phenylacetate, C25H30N2O6, (II), methyl 2‐{3‐[(tert‐butoxycarbonyl)amino]‐1‐methyl‐2‐oxoindolin‐3‐yl}‐2‐[(4‐methoxybenzyl)oxy]‐2‐phenylacetate, C31H34N2O7, (III), and methyl 2‐[(anthracen‐9‐yl)methoxy]‐2‐{3‐[(tert‐butoxycarbonyl)amino]‐1‐methyl‐2‐oxoindolin‐3‐yl}‐2‐phenylacetate, C38H36N2O6, (IV), have been determined. The diastereoselectivity of the chemical reaction involving α‐diazoesters and isatin imines in the presence of benzyl alcohol is confirmed through the relative configuration of the two stereogenic centres. In esters (I) and (III), the amide group adopts an anti conformation, whereas the conformation is syn in esters (II) and (IV). Nevertheless, the amide group forms intramolecular N—H...O hydrogen bonds with the ester and ether O atoms in all four structures. The ether‐linked substituents are in the extended conformation in all four structures. Ester (II) is dominated by intermolecular N—H...O hydrogen‐bond interactions. In contrast, the remaining three structures are sustained by C—H...O hydrogen‐bond interactions. 相似文献
4.
Vethathiri Pakkirisamy Sridhar Mahadevan Surianarayanan Suthangathan Paramashivan Sivapirakasam Asit Baran Mandal 《Journal of Thermal Analysis and Calorimetry》2013,112(3):1335-1341
The objective of this article is to generate thermal decomposition data on fireworks tip mixture, a mixture used to coat the tip of fireworks, for easy ignition. This mixture has reportedly involved in triggering many accidents in fireworks industry. Different quantities of water were added to the mixture and its thermal characteristics were studied. Differential scanning calorimeter was used for screening tests and accelerating rate calorimeter was used for detailed studies in adiabatic and isothermal modes. The self-heat rate data obtained showed onset temperature for different quantity of water, at a range of 80–170 °C. The mixture with 40 % water wt/wt had onset at 80 °C in adiabatic mode. The same mixture on isoaging at 40 °C exhibited exothermic characteristics with a substantial rise in system pressure (57 bar). The heats of exothermic decomposition and Arrhenius kinetics were also computed. 相似文献
5.
Prathama S. Mainkar Chirumarry Sridhar Ambadi Sudhakar Srivari Chandrasekhar 《Helvetica chimica acta》2013,96(1):99-108
The synthesis of bolaamphiphiles from unusual β‐amino acids or an alcohol and C12 or C20 spacers is described. Unusual β‐amino acids such as a sugar amino acid, an AZT‐derived amino acid, a norbornene amino acid, and an AZT‐derived amino alcohol were coupled with spacers under standard conditions to get the novel bolaamphiphiles 5 – 8 (Scheme 1), 12 and 13 (Scheme 2), and 17 and 20 (Scheme 3). Some of these compounds, on precipitation from MeOH/H2O, self‐assembled into organized molecular structures. 相似文献
6.
Krishnaiah Atmakur Narender Reddy Emmadi Sridhar Balasubramanian 《Journal of heterocyclic chemistry》2013,50(3):513-518
A series of novel fluorinated 11H‐azaindolo[3,2‐c]isoquinolines ( 7 ) have been synthesized starting from 2(1H)pyridones ( 1 ) via azaindoles ( 5 ). Initially, compound 1 was treated with POCl3/DMF, and the resulting compound 2 was reacted with benzylamine to obtain compounds 3 that were subjected to cyclization after protecting the secondary amine to get azaindoles ( 5 ). Further, compounds 5 were subjected to cyclization as per Pictet–Spengler reaction condition. However, it was not successful. Subsequently, the azaindoles ( 5 ) were acetylated and then cyclized to give title compounds 7 . These compounds are new and well characterized by spectral data. 相似文献
7.
M. A. Sridhar N. K. Lokanath J. Shashidhara Prasad C. V. Yelammagad S. K. Varshney 《Liquid crystals》2013,40(1):45-49
The title compound, cholesteryl 6[4-(4-pentyloxyphenylethynyl)phenoxy]hexanoate (DMT5), a cholesterol-based dimesogen, crystallizes in the monoclinic space group P21 with the parameters a = 9.812(3) Å, b = 9.713(2) Å, c = 24.179(2) Å, β = 92.48(1)° V = 2302.2(9) Å3, Z = 2, F000 = 836, λ(MoKα) = 0.71069 Å, μ = 0.067 cm 1, final R = 0.0772. The structure has intermolecular hydrogen bonds; it is stabilized by the presence of intermolecular contacts whose spacings are less than van der Waals' radii. 相似文献
8.
9.
B. H. Doreswamy Chandra K. Mantelingu M. A. Sridhar M. Mahendra 《Research on Chemical Intermediates》2014,40(8):2659-2665
The isolation of stable carbenes of the Arduengo and Wanzlick type has prompted us to look for stable nitrenium ions of the related structural type 1-Hydroxy-3-methyl benzotriazolium trifluromethane sulfonate. Nitrenium ions are azocations with structure and survive long enough under in vitro conditions to bind with biological nucleophiles, i.e. DNA bases, and play an important role in carcinogenic processes involving the metabolism of aromatic amines. The title compound (C15H16F3N6O5S) was isolated and crystallized in the monoclinic space group Cc with cell parameters a = 19.866(1) Å, b = 13.128(9) Å, c = 7.673(5) Å, and Z = 4. The structure has both intra- and intermolecular hydrogen bonds. 相似文献
10.