Competitive Attack Research Articles

Organic Reactions upon Dimetalated Olefins. Reactions of the Olefinic Group in the Dirhenlum Complex (OC)4Re[E‐HCC(CO2Me)CS2]Re(CO)4 with Amines

AbstractThe reaction of (OC)4Re[μ‐E‐HCC(CO2Me)CS2]Re(CO)4, 1 with EtNH2 yielded two new complexes: Re(CO)4[C(H)C(CO2Me)C(NHEt)S], 2, (52%) and Re(CO)3(NH2Et)[C(H)C(CO2Me)C(NHEt)=S], 3a (24%) by competitive attack of the EtNH2 at the dithiocarboxylate grouping and at the hydrogen substituted olefinic carbon atom in 1. In both cases there is a loss of one of the rhenium groupings. The reaction of the sulfurized and oxygenated derivatives of 1, (OC)4Re[EC(H)C(CO2Me)CS2]Re(CO)4, 4a (E=S), 4b (E=O) with EtNH2 yielded Re(CO)4[C(H)=C(CO2Me)C(NHEt)=S], 5a, the parent carbonyl of 3a, by exclusive attack of the amine at the hydrogen substituted olefinic carbon atom. The reaction of (OC)4Re[μ‐SC(S)C(CO2Me)C(H)S]Re(CO)4,6a (an isomer of 4a) with EtNH2 produced a similar result. The reaction of 4a with Et2NH yielded Re(CO)4[μ‐S2C=C(CO2Me)C=NEt2], 5b an N‐ethyl substituted derivative of 5a. These results indicate that the addition of certain heteroatoms can have a directing effect upon the reactivity of these compounds with amines. Compounds 2 and 5a were characterized by single crystal x‐ray diffraction analyses. Crystal Data: For 2: space group = P1, a = 10.782(1) Å, b = 14.721(2) Å, c = 9.940(2) Å, a = 91.57(1)°, β = 93.61(1)°, γ = 70.774(9)°, Z = 4, 4516 reflections, R = 0.047 and for 5a: space group = P21/n, a = 11.389(2) Å, b = 9.660(2) Å, c = 14.756(3) Å, β = 103.36(2)°, Z = 4, 1601 reflections, R = 0.022.

Competitive attack, retaliation and performance: An expectancy‐valence framework

AbstractThis research examines how competitive attacks can best reduce the chances of retaliation. An expectancy–valence model is developed that views retaliation as a function of the subtlety of an attack: that is, its visibility, the difficulty rivals might have in responding to it in kind, and the importance or ‘centrality’ to rivals of the market under siege. Motivational theories suggest that all three of these independent variables need to be in place in order to elicit a response—or conversely, that low visibility, substantial response difficulty, or minimal centrality would each by itself be enough to prevent retaliation. This notion was not supported. Each one of the independent variables could serve as the ‘weak link of the chain,’ increasing the chances of retaliation. However, as predicted by expectancy theory, these variables selectively demonstrated some interactions that compound the threat of retaliation. In combination, high visibility and low levels of difficulty were especially likely to evoke responses from rivals. Finally, there appears to be a real incentive to avoid retaliation given its negative associations with performance.

One-Pot Selective Synthesis of Ethyl Esters from Aromatic Nitriles Using Acid Faujasites as Catalysts

Abstract In order to determine the potential of acidic zeolites as catalysts in the preparation of carboxylic esters from nitriles, faujasites, beta, and mordenite have been studied in a liquid ethanolic medium. From the results obtained, it can be concluded that the optimum zeolite for this reaction is the less acidic faujasite (Si/Al = 2.5). Competitive dehydration of ethanol takes place and, consequently, the two nucleophiles ethanol and water react with the nitrites. Zeolites with the strongest acid sites (beta, mordenite) show higher activity in a first step of the process, particularly towards amide formation. A linear relationship between activity and acidity is established in this step for a competitive attack of the nucleophiles. After the strong acid sites have been poisoned by the product, the reaction is performed over the remaining less acidic free sites. A consecutive reaction takes place leading to the ester with good selectivities (80%) over faujasites. The probable operating mechanism involves as the first step a fast protonation of the nitrile, the rate-determining step being, as in homogeneous conditions, the nucleophilic attack.

Selective cathodic cleavage of unsymmetrical imidodicarbonates, acylcarbamates and diacylamides

A study of the selective cathodic cleavage of one of the alkoxycarbonyl or acyl groups from various imidodicarbonates, acylamides, and diacylamides is reported. The compounds investigated include all 15 possible combinations of the following groups in unsymmetrical N,N-diprotected derivatives, of benzylamine: p-nitrobenzyloxycarbonyl, trichloroethyloxycarbonyl, toluene-p-sulfonyl, benzoyl, benzyloxycarbonyl, and tert-butyloxycarbonyl which can all be electrochemically cleavaged, except the last one. Initially the compounds were examined by cyclic voltammetry in order to measure the potentials associated with the cleavage of each group and afterwards they were electrolysed at constant potential in the presence of a proton donor. The following ranges in negative potential were recorded: 1.03–1.13 V [Z(NO2)], 1.8–2.14 V (Troc), 1.75–2.41 V (Tos), 1.88–2.52 V (Bz), and 2.83–2.9 V (Z), thus occasionally revealing a drastic effect of the auxiliary group. In the electrolytic experiments competitive attack by base occasionally led to mixtures of monoacylamides. However, all compounds apart from some of the trichloroethyloxycarbonyl derivatives could be selectively cleaved in 89–100% yields when an appropriate proton donor was used. Tentative explanations are given for the behaviour of the compounds studied and some conclusions are drawn.

Quaternary ammonium salts as useful cationic initiators. 6. Synthesis, activity, and thermal latency of N-benzylpyridinium salts and the role of the pyridine moiety

N-Benzyl-, N-(1-phenethyl)-, and N-(p-methoxybenzyl)-o-cyanopyridinium hexafluoroantimonate (2a, 2b, and 2c, respectively). N-(p-Methoxybenzyl)-m-(methoxycarbonyl) pyridinium, N-benzyl-p-methylpyridinium, and N-benzyl-o-methylpyridinium hexafluoroantimonate were prepared, and their initiator activities were evaluated similarly. The o-cyanopyridinium salts 2 showed much higher activity than the corresponding p-cyanopyridium salts in the cationic polymerization of glycidyl phenyl ether. The activity change was attributed to the electronic and steric effect of the o-cyano group of pyridine. A plausible mechanism is discussed, which involved competitive attack of monomer and liberated free pyridine group on the cationic propagating end

Site selectivity and competitive CO attack in Co4(CO)10(μ4-PPh)2 using methanolic [Et4N][OH

The reaction between the tetracobalt cluster Co4(CO)10(μ4-PPh)2 (1) and [Et4N][OH] (1.1 equivalents of a 1.3 M solution in MeOH) has been examined in THF at -78°C. Low-temperature IR analysis reveals the presence of both the hydroxycarbonyl cluster [Co4(CO)9(μ4-PPh)2(CO2H)-] [2-] and the methoxycarbonyl cluster [Co4(CO)9(μ4-PPh)2(CO2Me)-] [3-] as a result of hydroxide and methoxide attack, respectively, on a terminal carbonyl group in 1. IR band-shape analysis indicates that [2-] and [3-] exist in a 77:23 ratio at -72°C. Addition of excess [Li+] (as [CF3SO3][Li]) to solutions of [2-] and [3-] affords [3-] in quantitative yield at -72°C. The thermal stability and reactivity of these anionic clusters are discussed and comparisons made to the structural similar formyl and acetyl clusters derived from 1.

Defensive industrial marketing strategies

This study provides a framework for industrial product managers to select defensive marketing strategies for products facing competitive attack. The proposed model is based on Hauser and Shugan's Defender model. It can be used by marketing decision makers to assess the impact of competitive attack on the firm's shares and contributions, as well as the effects of a range of possible defensive maneuvers. It therefore can serve as an effective model for planning response strategies. An actual (disguised) real-life application of the model to an industrial-product situation is presented and discussed.

N-nitroso compounds. Part 1. Structure and decomposition of N-nitroso-2-arylimidazolines in aqueous acidic media

Kinetic measurements for the acid-catalysed decomposition of N-nitroso-2-arylimidazolines are reported. Reactions are first-order in both [substrate] and [H+]. Two products are formed; an oxazoline, which is the product of hydrolysis of the amidine moiety, and the parent imidazoline formed by denitrosation of the substrate. These products arise from two competing pathways both of which are acid catalysed. The solvent isotope effects for the denitrosation, kNOD+/kNOH+, and amidine hydrolysis, kAD+/kAH+, are 3.1 and 3.5, respectively. The denitrosation pathway, but not amidine hydrolysis, is catalysed by nucleophilic anions, and a value of 1.7 for the Swain–Scott constant, s, is obtained. In the absence of nucleophilic anions, amidine hydrolysis is preferred over denitrosation, kAH+ being twice as large as kNOH+ at 25 °C. Substitutents in the 2-aryl ring affect the rate of decomposition giving Hammett ρ values of 0.7 for denitrosation and 1.0 for amidine hydrolysis, which reflect the proximity of the reacting centres to the substituents. Values of the activation parameters are ΔHNO‡ 74 kJ mol–1, ΔHA‡ 74 kJ mol–1, ΔSNO‡–48 J K–1 mol–1 and ΔSA‡–43 J K–1 mol–1. The data are interpreted in terms of a fast equilibrium protonation of the substrate, followed by competitive attack at the protonated substrate, either of water or nucleophilic anions at the nitroso nitrogen atom, or of water at the amidine carbon atom. Protonation is required to activate the substrate, the substrate being recovered from neutral or alkaline solutions unchanged. The mechanism is discussed with reference to the analogous reactions of N-nitrosoamines and N-nitrosoamides.

Sources of Economic Rent in the Deregulated Airline Industry

THE airline industry has always captured the imagination, but never more so than during the current deregulatory period. To understand the sources of economic rents that are the driving forces for change in this industry, we employ an interdisciplinary analysis drawn from the economics and strategy literature. This analysis allows us to identify sources of rent that are geographically based (local monopoly sources) and others that stem from economies of scale-based advantages in providing nationwide service (oligopoly sources). We examine the economic and strategic characteristics of these diverse sources of rent and suggest some policy concerns about the emerging airline market structure. An interdisciplinary approach is taken because economic models normally assume that firms have identical factor costs and similar production opportunities. Yet much of our ability to frame the forces for change in the airline industry begins with the recognition that firms came into the deregulatory period with differing factor costs and differing locational endowments and, hence, differing production opportunities. Building on Porter'sl concept of strategic groups, we offer evidence that air carriers

Criteria distinguishing successful from unsuccessful ventures in the venture screening process

Venture Capitalists responded to a questionnaire in which they rated a highly successful and a highly unsuccessful venture on 25 screening criteria and on several performance criteria. In all, 150 ventures were rated by 67 venture capital firms. Cluster analysis revealed three broad classes of unsuccessful ventures. The first type is the bane of all venture capitalists—the venture in which the venture team is lacking in experience or staying power, the product has no prototype, and there is no clear market demand for the product, yet the venture somehow slips through the screens and gets funded. The second type is one in which the venture team is very well credentialed, but the venture faces early competition and the team has no staying power and runs out of steam. The third major class of venture is one in which the team has exceptional staying power, so much so that by perserverance it demonstrates that a market exists, only to lose that market to competition because of a lack of protection for the product. Cluster analysis also showed that there are four broad classes of successful ventures. First is the high-tech venture with a well-qualified venture team that has the staying power needed to face competitive attack. Second is the class of venture where the venture team does not have much in the way of credentials, but the product has a very high level of protection and turns out to be highly successful. Third is a class of “market makers”—a venture team with exceptional perseverance that demonstrates that there is in fact a market for the product, but also has some form of product protection once that market has been demonstrated. It can be seen that each of these classes of successes has a look-alike class of failures that is very similar except for some flaw in the venture team. A final class of successful venture is a small group of low-tech products in which distribution skills are critical. We suspect that these ventures tend to be for consumer goods. An important finding is the identification of two major criteria that are predictors of venture success. These are 1) the extent to which the venture is initially insulated from competition and 2) the degree to which there is demonstrated market acceptance of the product. Regression analyses indicate that only these two screening criteria correlate pervasively across several performance criteria. Interestingly, neither of these criteria were rated as essential in an earlier study. Much more importance needs to be attached to these criteria in screening venture proposals. The final analysis was a factor analysis, which indicates that the 150 ventures were screened according to five major classes of criteria, each class corresponding to some facet of risk management of the venture. These were as follows: 1. 1. Criteria that screen out ventures where there is a risk of failure due to unqualified management; 2. 2. Criteria that screen out management that may well be qualified but lack experience; 3. 3. Criteria that screen out ventures where basic viability of the project is in doubt; 4. 4. Criteria that screen out ventures where there is high exposure to competitive attack and profit erosion before the investment can be recouped; 5. 5. Finally, criteria that avoid ventures that lock up the investment so that it cannot be cashed out for long periods of time.

The stabilities of Meisenheimer complexes. Part 42. Kinetic studies of the reactions of methyl 3,5-dinitrobenzoate and of methyl 4-chloro-3,5-dinitrobenzoate with hydroxide ions in dimethyl sulphoxide–water mixtures. Competitive nucleophilic attack at aryl and carbonyl carbon atoms

Kinetic and equilibrium data, obtained by stopped-flow spectrophotometry, are reported for the reactions of methyl 3,5-dinitrobenzoate (1) and methyl 4-chloro-3,5-dinitrobenzoate (5) with hydroxide ions in dimethyl sulphoxide–water mixtures. There is evidence for competition between attack at carbonyl and aryl carbon atoms, the latter becoming relatively favoured as the proportion of dimethyl sulphoxide in the solvent is increased. It is shown that the major pathway in the formation of 4-hydroxy-3,5-dinitrobenzoate from (5) involves hydroxide attack at the carbonyl function followed by slow attack at the ring carbon atom carrying chlorine.

Époxydes α-éthyléniques et phénate de sodium: accès à des éthers phénoliques et phénols ortho-allyliques

The ring cleavage reactions of α-ethylenic epoxides by sodium phenoxide afforded a mixture of products. Problems of competitive attack by this nucleophile, at the less substituted carbon (compounds A) or at the β-ethylenic carbon atom (compounds B and C), were encountered and could be resolved by judicious choice of reaction conditions (solvents, stereochemistry of the oxiranes). The regioselectivity of the attack was dependent on the transition states, implying weak steric hindrance and a conjugation oxirane – double bond.

The Net Present Value of Market Share

This article evaluates the dynamic interaction of market share and profit. The determinants of market share are compared with published empirical research and illustrated in a consumer product industry. The effects of market growth, maturity and decline, competitive attack, price leadership, and heavy user strategies on market share and profit are analyzed theoretically and simulated over a 10-year period.

Kinetics and mechanism of the oxidative addition of cyanogen to [Ni(CO)2(PPh3)2

The complex [Ni(CO)2(PPh3)2], (1), reacts with C2N2 in toluene, at 30.0–44.5 °C, to give trans-[Ni(CN)2(PPh3)2], (2), which crystallizes as a clathrate containing 1 mol of C2N2. The reaction mechanism postulated involves preliminary carbon monoxide dissociation from complex (1), followed by competitive cyanogen attack on the three-co-ordinate [Ni(CO)(PPh3)2] intermediate and subsequent oxidative addition.

Substituent effect on the electrochemical reduction of tricarbonylchromium-tropylium tetrafluoroborate in acetonitrile

The electrochemical reduction of the tricarbonylchromium alkyl-tropylium tetrafluoroborates (TCC-R−C7H6+BF4−; R=Me, Et, Pri and But) and of the tricarbonylmolybdenum and tungsten tetrafluoroborates (TCM-C7H7+BF4−; M=metal) was investigated in MeCN andMeCN+MeCOOH 50:50 V:V. The voltammetric and coulometric results suggest that the process involves the reversible transfer of two electrons to form the complexed cycloheptatrienyl anion. In MeCN, this intermediate couples with the unreduced cation to produce the bis-complexed bitropyl and the rate of dimerization is strongly affected by the steric size of the alkyl group. On the other hand, in MeCN MeCOOH the TCM-cycloheptatrienyl anion undergoes a competitive attack from H+ and the starting cation toform TCM-cycloheptatriene and (TCM)2-bitropyl respectively. The ratio monomer: dimer depends upon both the alkyl group and the nature of the metal.

Substituent effect on the electrochemical reduction of tricarbonylchromium-tropylium tetrafluoroborate in acetonitrile

The electrochemical reduction of the tricarbonylchromium alkyl-tropylium tetrafluoroborates (TCC-R−C 7H 6 +BF 4 −; R=Me, Et, Pr i and Bu t) and of the tricarbonylmolybdenum and tungsten tetrafluoroborates (TCM-C 7H 7 +BF 4 −; M=metal) was investigated in MeCN andMeCN+MeCOOH 50:50 V:V. The voltammetric and coulometric results suggest that the process involves the reversible transfer of two electrons to form the complexed cycloheptatrienyl anion. In MeCN, this intermediate couples with the unreduced cation to produce the bis-complexed bitropyl and the rate of dimerization is strongly affected by the steric size of the alkyl group. On the other hand, in MeCN MeCOOH the TCM-cycloheptatrienyl anion undergoes a competitive attack from H + and the starting cation toform TCM-cycloheptatriene and (TCM) 2-bitropyl respectively. The ratio monomer: dimer depends upon both the alkyl group and the nature of the metal.

Participation of 19-substituents in acid cleavage of steroidal 5α,6α-epoxides

Participation of the 19-methoxy and 19-acetoxy group in 5α,6α-epoxides IIIa and IVa on treatment with aqueous perchloric acid is investigated and compared with acid cleavage of previously studied 3β-acetoxy epoxides IIIb and IVb. The methoxy group in IIIa participates by a 5(O)n process. The participation is predominant on treatment with perchloric acid but is completely suppressed by the attack of an external nucleophile on treatment with hydrobromic acid. The acetoxy group in IVa participates by a 6(O)π,n process. Participation is predominant on treatment with perchloric acid and is only partially suppressed by a competitive external nucleophile attack on the action of hydrobromic acid. This behavior constitutes a difference to the 3β-acetoxy derivative IVb where hydrobromic acid completely suppresses the participation in favor of an external attack.

Conjugate addition of Grignard reagents to p-nitrotoluene. Competitive attack of entering alkyl group to ortho and para positions

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConjugate addition of Grignard reagents to p-nitrotoluene. Competitive attack of entering alkyl group to ortho and para positionsGiuseppe Bartoli, Marcella Bosco, and Germana PezziCite this: J. Org. Chem. 1978, 43, 14, 2932–2933Publication Date (Print):July 1, 1978Publication History Published online1 May 2002Published inissue 1 July 1978https://doi.org/10.1021/jo00408a046RIGHTS & PERMISSIONSArticle Views144Altmetric-Citations10LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (313 KB) Get e-Alerts Get e-Alerts

Exchange Reaction of Tetrahydrofuran to Pyrrolidine with NH<sub>3</sub> over Supported Transition Metal Chloride Catalysts

The exchange reaction of THF to pyrrolidine (with NH3) was studied using the LiCl-KCl supported catalyst containing transition metal chloride (MnCl2, CoCl2 and NiCl2). The excellent selectivities to produce pyrrolidine were observed over MnCl2-LiCl-KCl and CoCl2-LiCl-KCl supported catalysts. The primary by-products were confirmed to be 1-pyrrolidino-2-butene and 4-pyrrolidino-1-butene which are believed to be produced by means of the competitive attack of pyrrolidine (together with the attack of NH3, yielding the expected pyrrolidine) toward an intermediate or protonated THF to yield _??_N+HCH2CH2CH2CH2OH followed by the subsequent dehydration. When the conversion (%) and selectivity (%) were plotted as a function of wt% loadings of metal chlorides on a support, it was found that higher loadings (more than 10wt%) markedly suppressed the conversion of THF compared with that over alumina catalyst alone. This indicates that the exchange reaction using higher loadings of support proceeds via a different mechanism from that over alumina alone. This finding and the adsorption experiment of NH3 on catalysts suggest that this exchange reaction over supported catalysts saturated with loadings proceeds through the formation of an ammine complex of transition metal chlorides (CoCl2, MnCl2) with NH3 as an intermediate and the superior selectivity attained by means of these catalysts was also rationalized based on the above proposed mechanism.

Pyridazines. LXXXIV. Studies on borohydride reduction of pyridazine compounds

AbstractImidazo[1,2‐b]pyridazine, s‐triazolo[4,3‐b]pyridazine and tetrazolo[1,5‐b]pyridazine and some derivatives thereof were reduced with sodium borohydride to give the corresponding 5,6,7,8‐tetrahydro derivatives. A mechanism for these reductions is proposed and reduction at the C7‐C8 bond occurs before the reduction of the C6N5 bond. Substituents at position 7 and/or 8 cause a significant decrease in the extent of reduction or lead to a 5,6‐dihydro derivative by competitive attack at the 6 position.