The 9-decalyl and related cations. III. Generation of the 8-hydrindyl cation by solvolysis

1974 ◽  
Vol 27 (8) ◽  
pp. 1711 ◽  
Author(s):  
GE Gream ◽  
AK Serelis ◽  
TI Stoneman
Keyword(s):  
Ion Pairs ◽  
Cationic Species ◽  
Direct Route ◽  
Counter Ion ◽  
Product Composition ◽  
Cis And Trans

Acetolysis of 4-(cyclopent-1'-enyl)butyl and 3-(2'-methylenecyclopentyl)propyl derivatives, but not 3-(cyclohex-1'-enyl)propyl and 2-(2'-methylenecyclohexyl)ethyl derivatives, occurs with π-bond participation (95 and 92%, respectively) to give similar, including maybe identical, cationic species involving the 8-hydrindyl cation. On the basis of product composition, the 8-hydrindyl cations when generated from spiro[4,4]non-1-yl (σ-route) and cis- and trans-8-hydrindyl derivatives (direct route) are each different and are in turn different to those generated by the above π-routes. Reasons for the differences are discussed and the possible role of the counter-ion in ion-pairs is examined.

The 9-decalyl and related cations. V. Generation of cis- and trans-2-t-Butyl-9-decalyl cations through π-routes by acetolysis

1978 ◽  
Vol 31 (4) ◽  
pp. 863 ◽  
Author(s):  
GE Gream ◽  
AK Serelis
Keyword(s):  
Acetic Acid ◽  
Significant Role ◽  
Ion Pairs ◽  
Side Chain ◽  
Rate Enhancement ◽  
Cationic Species ◽  
Hydride Shift ◽  
Butyl Group ◽  
Counter Ion ◽  
Cis And Trans

The synthesis and solvolytic behaviour (in buffered acetic acid) of 4- (5?-t-butylcyclohex-1'-enyl)but-1-yl p-nitrobenzenesulfonate (6) and 3- (cyclohex-1'-enylmethyl)-4,4-dimethylpentyl p-nitrobenzene-sulfonate (7) are described. Kinetic and product studies have shown that π-bond participation occurs in the acetolysis of both compounds. The rate enhancements, compared with saturated analogues, are c. 46 and 8290 for (6) and (7). The considerably greater rate enhancement observed for (7) is a manifestation of the 'gem-dialkyl' effect and is explained in terms of the effect of the t-butyl group on the conformations that the side chain might adopt. ��� The acetolyses of (6) and (7) give rise to cyclized products (c. 97 and 100%) arising from both cis- and trans-2-t-butyl-9-decalyl cations (2) and (3). The compositions of the products, which also include compounds formed from the cis-cation (55) obtained by a 1,2-hydride shift in (2), show that (6) and (7) do not react via the same cationic species. ��� Ion-pairs of an undefined nature are implicated in the reactions. Entirely consistent evidence was not obtained for the hypothesis that the counter-ion, behaving as a base, probably plays a significant role in olefin formation from the cis- and trans-cations (2) and (3) in ion- pairs that might be formed initially from (6) and (7).

The 9-decalyl and related cations. IV. Generation of cis- and trans-2-t-Butyl-9-decalyl cations through σ-routes by acetolysis

1978 ◽  
Vol 31 (4) ◽  
pp. 835 ◽  
Author(s):  
GE Gream ◽  
MH Laffer ◽  
AK Serelis
Keyword(s):  
Ion Pairs ◽  
Ring Expansion ◽  
Ion Pair ◽  
Membered Ring ◽  
Boat Conformation ◽  
Proton Abstraction ◽  
Conformational Interconversion ◽  
Anchimeric Assistance ◽  
Cis And Trans

The synthesis and solvolytic behaviour (in buffered acetic acid) of cis- and trans-9-t-butylspiro[4,5]-dec-6-yl p-toluenesulfonate (5) and (6) are described. The two compounds solvolyse with anchimeric assistance and undergo ring expansion with complete stereospecificity; the cis- and trans-esters yield trans- and cis-2-t-butyl-9-decalyl cation (8) and (7), respectively. To account for the stereospecificity, it is proposed that (6) must solvolyse through a boat conformation of the six-membered ring. Ring contraction (c. 8%), with the formation of the 1-(3'-t-butylcyclopentyl)cyclopentyl cation (presumably trans (36)), also takes place in the acetolysis of (6). ��� The possible role of ion-pairs in the reactions of (5) and (6) is examined. It is concluded that the anion in an ion-pair might be involved in olefin formation only when it (the anion) is ideally located for proton abstraction in the initially formed ion-pair (or that formed by conformational interconversion of the cationic moiety).

The 9-decalyl and related cations. I. Generation of the 9-decalyl cation by solvolysis

1972 ◽  
Vol 25 (5) ◽  
pp. 1051 ◽  
Author(s):  
GE Gream
Keyword(s):  
Ion Pairs ◽  
Product Formation ◽  
Counter Ion ◽  
Quantitative Analyses ◽  
Cis And Trans

Kinetic and product studies have established that π-bond participation occurs in the acetolysis of 4-(cyclohex-1-enyl)but-1-yl derivatives to give a 9-decalyl cation. Quantitative analyses of the mixtures of products formed by the x-route (from 4-(cyclohex-1-enyl)but-1-yl derivatives), π-route (from spiro[4,5]dec-6-yl derivatives), and direct routes (from cis- and trans-9-decalyl derivatives) show that the intermediate 9-decalyl cations generated in each case must be different. Reasons for the differences are discussed; it is suggested that the counter-ion in ion-pairs involving cis-like and trans-like conformers of the 9-decalyl cation probably plays an important role in product formation.

ChemInform Abstract: THE ROLE OF SOLVENT IN CONJUGATE ADDITIONS LEADING TO CIS- AND TRANS-1-ALKYL-2-ARYL-3-CARBO(AROYL)AZIRIDINES

1977 ◽  
Vol 8 (40) ◽  
pp. no-no
Author(s):  
P. TARBURTON ◽  
P. B. WOLLER ◽  
R. C. BADGER ◽  
E. DOOMES ◽  
N. H. CROMWELL
Keyword(s):  
Conjugate Additions ◽  
Cis And Trans ◽  
Role Of Solvent

scholarly journals The Role of Two-Pore Channels in Norepinephrine-Induced [Ca2+]i Rise in Rat Aortic Smooth Muscle Cells and Aorta Contraction

Cells ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1144 ◽  
Author(s):  
Sergei K. Trufanov ◽  
Elena Yu. Rybakova ◽  
Piotr P. Avdonin ◽  
Alexandra A. Tsitrina ◽  
Irina L. Zharkikh ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Calcium Concentration ◽  
Muscle Cells ◽  
Rat Aorta ◽  
Structural Analogue ◽  
Aortic Smooth Muscle ◽  
Cis And Trans ◽  
High Degree

Second messenger nicotinic acid adenine dinucleotide phosphate (NAADP) triggers Ca2+ release via two-pore channels (TPCs) localized in endolysosomal vesicles. The aim of the present work is to evaluate the role of TPCs in the action of norepinephrine (NE), angiotensin II (AngII), vasopressin (AVP), and 5-hydroxytriptamine (5-HT) on free cytoplasmic calcium concentration ([Ca2+]i) in smooth muscle cells (SMCs) isolated from rat aorta and on aorta contraction. To address this issue, the NAADP structural analogue and inhibitor of TPCs, NED 19, was applied. We have demonstrated a high degree of colocalization of the fluorescent signals of cis-NED 19 and endolysosmal probe LysoTracker in SMCs. Both cis- or trans-NED 19 inhibited the rise of [Ca2+]i in SMCs induced by 100 μM NE by 50–60%. IC50 for cis- and trans-NED 19 were 2.7 and 8.9 μM, respectively. The inhibition by NED 19 stereoisomers of the effects of AngII, AVP, and 5-HT was much weaker. Both forms of NED 19 caused relaxation of aortic rings preconstricted by NE, with relative potency of cis-NED 19 several times higher than that of trans-NED 19. Inhibition by cis-NED 19 of NE-induced contraction was maintained after intensive washing and slowly reversed within an hour of incubation. Cis- and trans-NED 19 did not cause decrease in the force of aorta contraction in response to Ang II and AVP, and only slightly relaxed aorta preconstricted by 5-HT and by KCl. Suppression of TPC1 in SMCs with siRNA caused a 40% decrease in [Ca2+]i in response to NE, whereas siRNA against TPC2 did not change NE calcium signaling. These data suggest that TPC1 is involved in the NE-stimulated [Ca2+]i rise in SMCs. Inhibition of TPC1 activity by NED 19 could be the reason for partial inhibition of aortic rings contraction in response to NE.

Octahedral cobalt(III) complexes in dipolar aprotic solvents. II. Association between cis- and trans-dichlorobisethylenediamine cobalt(III) cations,[Co en2 Cl2]+, and chloride and bromide ions in the solvents NN-dimethylformamide, dimethyl sulphoxide, and LVN-dimethylacetamide

1966 ◽  
Vol 19 (1) ◽  
pp. 43 ◽  
Author(s):  
WA Millen ◽  
DW Watts
Keyword(s):  
Spectrophotometric Method ◽  
Ion Pairs ◽  
Ion Association ◽  
Ion Pair ◽  
Association Constants ◽  
Dimethyl Sulphoxide ◽  
Aprotic Solvents ◽  
Ion Association Constants ◽  
Cis And Trans ◽  
Dipolar Aprotic Solvents

Ion association constants at 30� have been determined for the cis-[Co en, Cl2]+Cl- ion pair in NN-dimethylformamide (DMF), NN-dimethylacetamide (DMA), and at 20.0�, 25.0�, and 30.0� in dimethyl sulphoxide (DMSO), by a spectrophotometric method. Association constants for the cis-[Co en2 Cl2]+Br- and the trans- [Co en2 Cl2]+Cl- ion pairs have also been determined in DMF at 30�.

The effect of the trisulfur radical ion on molybdenum transport by hydrothermal fluids

2021 ◽  
Author(s):  
Maria A. Kokh ◽  
Clement Laskar ◽  
Gleb S. Pokrovski
Keyword(s):  
Composition Range ◽  
Ion Pairs ◽  
Primary Source ◽  
Econ Geol ◽  
Hydrothermal Conditions ◽  
Earth Planet ◽  
Porphyry Deposits ◽  
Experimental And Theoretical Studies ◽  
Partitioning Behavior

<p>Knowledge of molybdenum (Mo) speciation under hydrothermal conditions is a key for understanding the formation of porphyry deposits which are the primary source of Mo. Existing experimental and theoretical studies have revealed a complex speciation, solubility and partitioning behavior of Mo in fluid-vapor-melt systems, depending on conditions, with the (hydrogen)molybdate (HMoO<sub>4</sub><sup>-</sup>, MoO<sub>4</sub><sup>2-</sup>) ions and their ion pairs with alkalis in S and Cl-poor fluids [1-3], mixed oxy-chloride species in strongly acidic saline fluids [4, 5], and (hydrogen)sulfide complexes (especially, MoS<sub>4</sub><sup>2-</sup>) in reduced H<sub>2</sub>S-bearing fluids and vapors [6-8]. However, these available data yet remain discrepant and are unable to account for the observed massive transport of Mo in porphyry-related fluids revealed by fluid inclusion analyses demonstrating 100s ppm of Mo (e.g., [9]). A potential missing ligand for Mo may be the recently discovered trisulfur radical ion (S<sub>3</sub><sup>•-</sup>), which is predicted to be abundant in sulfate-sulfide rich acidic-to-neutral porphyry-like fluids [10]. We performed exploratory experiments of MoS<sub>2</sub> solubility in model sulfate-sulfide-S<sub>3</sub><sup>•-</sup>-bearing aqueous solutions at 300°C and 450 bar. We demonstrate that Mo can be efficiently transported by S<sub>3</sub><sup>•-</sup>-bearing fluids at concentrations ranging from several 10s ppm to 100s ppm, depending on the fluid pH and redox, whereas the available data on OH-Cl-S complexes cited above predict negligibly small (<100 ppb) Mo concentrations at our conditions. Work is in progress to extend the experiments to wider T-P-composition range of porphyry fluids and to quantitatively assess the role of S<sub>3</sub><sup>•-</sup> in Mo transport by geological fluids.</p><ul><li>1. Kudrin A.V. (1989) <em>Geochem. Int. </em><strong>26</strong>, 87–99.</li> <li>2. Minubayeva Z. and Seward T.M. (2010) <em>Geochim. Cosmochim. Acta</em> <strong>74</strong>, 4365–4374.</li> <li>3. Shang L.B. et al. (2020) <em>Econ. Geol. </em><strong>115</strong>, 661–669.</li> <li>4. Ulrich T. and Mavrogenes J. (2008) <em>Geochim. Cosmochim. Acta </em><strong>72</strong>, 2316-2330.</li> <li>5. Borg S. et al. (2012) <em>Geochim. Cosmochim. Acta</em> <strong>92</strong>, 292–307.</li> <li>6. Zhang L. et al. (2012) <em>Geochim. Cosmochim. Acta</em> <strong>77</strong>, 175–185.</li> <li>7. Kokh M.A. et al. (2016) <em>Geochim. Cosmochim. Acta </em><strong>187</strong>, 311–333.</li> <li>8. Liu W. et al. (2020) <em>Geochim. Cosmochim. Acta</em> <strong>290</strong>, 162–179.</li> <li>9. Kouzmanov K. and Pokrovski G.S. (2012) <em>Soc. Econ. Geol. Spec. Pub.</em> <strong>16</strong>, 573–618.</li> <li>10. Pokrovski G.S. and Dubessy J. (2015) <em>Earth Planet. Sci. Lett. </em><strong>411</strong>, 298–309.</li> </ul>

scholarly journals Intrinsic Regulatory Role of RNA Structural Arrangement in Alternative Splicing Control

2020 ◽  
Vol 21 (14) ◽  
pp. 5161 ◽  
Author(s):  
Katarzyna Taylor ◽  
Krzysztof Sobczak
Keyword(s):  
Alternative Splicing ◽  
Rna Structure ◽  
The Other ◽  
Splicing Regulation ◽  
Rna Structures ◽  
Structural Arrangement ◽  
Biological Functionality ◽  
Cis And Trans ◽  
Structural Aspects

Alternative splicing is a highly sophisticated process, playing a significant role in posttranscriptional gene expression and underlying the diversity and complexity of organisms. Its regulation is multilayered, including an intrinsic role of RNA structural arrangement which undergoes time- and tissue-specific alterations. In this review, we describe the principles of RNA structural arrangement and briefly decipher its cis- and trans-acting cellular modulators which serve as crucial determinants of biological functionality of the RNA structure. Subsequently, we engage in a discussion about the RNA structure-mediated mechanisms of alternative splicing regulation. On one hand, the impairment of formation of optimal RNA structures may have critical consequences for the splicing outcome and further contribute to understanding the pathomechanism of severe disorders. On the other hand, the structural aspects of RNA became significant features taken into consideration in the endeavor of finding potential therapeutic treatments. Both aspects have been addressed by us emphasizing the importance of ongoing studies in both fields.

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