An e.s.r. study shows that the initial reactions in alkali under nitrogen between an aromatic nitro-compound and hydroxylamine or a monosubstituted hydroxylamine are (i)–(iv). K,k1, and k2 have been evaluated by monitoring RNHOH + OH– [graphic omitted] RNHO–+ H2O (i), ArNO2+ RNHO– [graphic omitted] (ArNO2·)–+ RNHO·(ii), 2(ArNO2·) [graphic omitted] Products (iii), 2RNHO· [graphic omitted] Products (iv) the build-up and decay of (ArNO2·)– radical-anions by use of p-nitrobenzoic acid and N-methyl-, N-benzyl-, and N-diphenylmethyl-hydroxylamines.With hydroxylamine the kinetic measurements are much less accurate owing to a pseudo-unimolecular gas evolution which appears to come from reactions (v). Hydroxylamine is also destroyed by reaction (vi), the 2NH2O·→ H4N2O2→ N2+ 2H2O (v), ArNO + 2NH2OH → ArN3+ 3H2O (vi) nitroso-compound being formed by the disproportionation (iii).
{"title":"Reactions between aromatic nitro-compounds and hydroxylamines in alkaline solution. Part I. Kinetic studies","authors":"D. J. Cowley, M. H. Millen, W. Waters","doi":"10.1039/J29710002393","DOIUrl":"https://doi.org/10.1039/J29710002393","url":null,"abstract":"An e.s.r. study shows that the initial reactions in alkali under nitrogen between an aromatic nitro-compound and hydroxylamine or a monosubstituted hydroxylamine are (i)–(iv). K,k1, and k2 have been evaluated by monitoring RNHOH + OH– [graphic omitted] RNHO–+ H2O (i), ArNO2+ RNHO– [graphic omitted] (ArNO2·)–+ RNHO·(ii), 2(ArNO2·) [graphic omitted] Products (iii), 2RNHO· [graphic omitted] Products (iv) the build-up and decay of (ArNO2·)– radical-anions by use of p-nitrobenzoic acid and N-methyl-, N-benzyl-, and N-diphenylmethyl-hydroxylamines.With hydroxylamine the kinetic measurements are much less accurate owing to a pseudo-unimolecular gas evolution which appears to come from reactions (v). Hydroxylamine is also destroyed by reaction (vi), the 2NH2O·→ H4N2O2→ N2+ 2H2O (v), ArNO + 2NH2OH → ArN3+ 3H2O (vi) nitroso-compound being formed by the disproportionation (iii).","PeriodicalId":17268,"journal":{"name":"Journal of The Chemical Society B: Physical Organic","volume":"1 1","pages":"2393-2397"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91343615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The crystal and molecular structure of the p-iodobenzenesulphonate of fusicoccin A (C42H59IO14S) has been determined by three-dimensional X-ray analysis. The crystals are orthorhombic, space group P212121, with Z= 4 in a unit cell of dimensions: a= 10·32, b= 12·89, c= 35·14 A. The structure was solved by the heavy-atom technique and refined to a final R of 0·116, using 1706 observed reflections.Fusicoccin A, a phytotoxic metabolite of Fusicoccum amygdali, is a glycoside in which the sugar is D-glucose acetylated at C-3′ and etherified by 1,1-dimethylallyl alcohol at C-6′, and the aglycone is a tricyclic system formed by the fusion of one eight and two five membered rings. The absolute configuration is also given.
{"title":"Crystal structure of fusicoccin A p-iodobenzenesulphonate","authors":"M. Brufani, S. Cerrini, W. Fedeli, A. Vaciago","doi":"10.1039/J29710002021","DOIUrl":"https://doi.org/10.1039/J29710002021","url":null,"abstract":"The crystal and molecular structure of the p-iodobenzenesulphonate of fusicoccin A (C42H59IO14S) has been determined by three-dimensional X-ray analysis. The crystals are orthorhombic, space group P212121, with Z= 4 in a unit cell of dimensions: a= 10·32, b= 12·89, c= 35·14 A. The structure was solved by the heavy-atom technique and refined to a final R of 0·116, using 1706 observed reflections.Fusicoccin A, a phytotoxic metabolite of Fusicoccum amygdali, is a glycoside in which the sugar is D-glucose acetylated at C-3′ and etherified by 1,1-dimethylallyl alcohol at C-6′, and the aglycone is a tricyclic system formed by the fusion of one eight and two five membered rings. The absolute configuration is also given.","PeriodicalId":17268,"journal":{"name":"Journal of The Chemical Society B: Physical Organic","volume":"49 1","pages":"2021-2026"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90280915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Simple aliphatic aldehydes with a C4 or longer chain undergo ‘type 2’ photoelimination and photocyclisation as major reactions in solution. Both singlet and triplet nπ* states are direct precursors to products in these reactions. Quenching studies show that the triplet lifetime, governed largely by the rate constant for intramolecular hydrogen-abstraction, varies with the substituent at position 4 in the chain.
{"title":"Photochemical reactions of aliphatic aldehydes in solution","authors":"J. Coyle","doi":"10.1039/J29710002254","DOIUrl":"https://doi.org/10.1039/J29710002254","url":null,"abstract":"Simple aliphatic aldehydes with a C4 or longer chain undergo ‘type 2’ photoelimination and photocyclisation as major reactions in solution. Both singlet and triplet nπ* states are direct precursors to products in these reactions. Quenching studies show that the triplet lifetime, governed largely by the rate constant for intramolecular hydrogen-abstraction, varies with the substituent at position 4 in the chain.","PeriodicalId":17268,"journal":{"name":"Journal of The Chemical Society B: Physical Organic","volume":"51 1","pages":"2254-2256"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75279768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The acid-catalysed hydrolyses of some para-substituted benzohydroxamic acids have been studied in perchloric, sulphuric, and hydrochloric acids. Plots of the first-order rate-coefficients, k1, against [H+] show maxima which are caused by extensive protonation of the substrate. The mechanism of hydrolysis is found to be similar to that of amides. The protonation behaviour of these compounds correlates better with the amide acidity function HA than with H0.
{"title":"The acid-catalysed hydrolysis and protonation behaviour of hydroxamic acids","authors":"A. J. Buglass, K. Hudson, J. Tillett","doi":"10.1039/J29710000123","DOIUrl":"https://doi.org/10.1039/J29710000123","url":null,"abstract":"The acid-catalysed hydrolyses of some para-substituted benzohydroxamic acids have been studied in perchloric, sulphuric, and hydrochloric acids. Plots of the first-order rate-coefficients, k1, against [H+] show maxima which are caused by extensive protonation of the substrate. The mechanism of hydrolysis is found to be similar to that of amides. The protonation behaviour of these compounds correlates better with the amide acidity function HA than with H0.","PeriodicalId":17268,"journal":{"name":"Journal of The Chemical Society B: Physical Organic","volume":"10 1","pages":"123-126"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74721769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The i.r. and Raman spectra of a number of thioacetals containing aromatic rings have been measured in the range of 1650–1000 cm–1. Assignments for some frequencies are suggested by comparison with reference compounds and with deuteriated products. The influence of one or two sulphur atoms on adjacent group vibrations are demonstrated; methods of differentiation between benzaldehyde and benzophenone thioacetals and of characterization of the phenylthio-group are suggested. Comparison is made between some sulphur compounds and the corresponding oxy- or chloro-analogues.
{"title":"The infrared and Raman spectra of some thioacetals","authors":"B. Wladislaw, P. Olivato, O. Sala","doi":"10.1039/J29710002037","DOIUrl":"https://doi.org/10.1039/J29710002037","url":null,"abstract":"The i.r. and Raman spectra of a number of thioacetals containing aromatic rings have been measured in the range of 1650–1000 cm–1. Assignments for some frequencies are suggested by comparison with reference compounds and with deuteriated products. The influence of one or two sulphur atoms on adjacent group vibrations are demonstrated; methods of differentiation between benzaldehyde and benzophenone thioacetals and of characterization of the phenylthio-group are suggested. Comparison is made between some sulphur compounds and the corresponding oxy- or chloro-analogues.","PeriodicalId":17268,"journal":{"name":"Journal of The Chemical Society B: Physical Organic","volume":"50 1","pages":"2037-2040"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74804099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Expressions, based on simple reaction models, for the effects of substituents on the equilibrium constants and rate constants of the reactions mentioned in the title are derived. Conditions under which ρσ relationships should be valid are established. Various theoretical σ and ρ scales are evaluated and are shown to be in good agreement with empirical scales when they ought to be. The calculations of all of the theoretical scales involve only one measured value of a substituent effect on a reaction.
{"title":"Field and charge-transfer theory for the quantitative correlation of substituent effects in aromatic molecules. Part III. Thermal heterolytic addition and elimination reactions of substituted benzenes","authors":"M. Godfrey","doi":"10.1039/J29710001540","DOIUrl":"https://doi.org/10.1039/J29710001540","url":null,"abstract":"Expressions, based on simple reaction models, for the effects of substituents on the equilibrium constants and rate constants of the reactions mentioned in the title are derived. Conditions under which ρσ relationships should be valid are established. Various theoretical σ and ρ scales are evaluated and are shown to be in good agreement with empirical scales when they ought to be. The calculations of all of the theoretical scales involve only one measured value of a substituent effect on a reaction.","PeriodicalId":17268,"journal":{"name":"Journal of The Chemical Society B: Physical Organic","volume":"32 1","pages":"1540-1544"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72908924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rate profiles are reported for the title reactions. Exchanges are shown to proceed on the conjugate acid species at various positions in the carbocyclic rings. Exchange in the heterocyclic rings occurs by deprotonation α to nitrogen, and probably via covalent hydrated species β to nitrogen.
{"title":"Kinetics and mechanism of electrophilic substitution of heteroaromatic compounds. Part XXIII. Acid-catalysed hydrogen exchange of quinoline, isoquinoline, and their N-oxides","authors":"U. Bressel, A. Katritzky, J. Lea","doi":"10.1039/J29710000004","DOIUrl":"https://doi.org/10.1039/J29710000004","url":null,"abstract":"Rate profiles are reported for the title reactions. Exchanges are shown to proceed on the conjugate acid species at various positions in the carbocyclic rings. Exchange in the heterocyclic rings occurs by deprotonation α to nitrogen, and probably via covalent hydrated species β to nitrogen.","PeriodicalId":17268,"journal":{"name":"Journal of The Chemical Society B: Physical Organic","volume":"89 S1","pages":"4-10"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72560144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. G. Bonner, E. J. Bourne, P. J. V. Cleare, R. Cole, D. Lewis
Acid-catalysed condensation of n-butyraldehyde with (a) 1-deoxy-D-glucitol yields a 2,3-acetal as a kinetically controlled product and the 2,4-acetal as the thermodynamically controlled product, (b) 2-deoxy-D-glucitol yields the 1,3-acetal as the kinetically controlled product and the 3,4-acetal(s) as the thermodynamically controlled product, and (c) 3-O-methyl-D-glucitol yields the 2,4-acetal as the predominant product throughout the reaction.In aqueous acid there is no evidence that 1,3-O-butylidene-2-deoxy-D-glucitol undergoes intramolecular conversion; instead substantial hydrolysis to the polyol and aldehyde occurs before the synthesis of the 3,4-acetal(s).
正丁醛与(a) 1-脱氧-d -葡萄糖醇的酸催化缩合反应生成2,3-缩醛作为动力学控制产物和2,4-缩醛作为热力学控制产物，(b) 2-脱氧-d -葡萄糖醇生成1,3-缩醛作为动力学控制产物和3,4-缩醛(s)作为热力学控制产物，(c) 3- o -甲基-d -葡萄糖醇生成2,4-缩醛作为整个反应的主要产物。在酸性水溶液中，没有证据表明1,3- o -丁基-2-脱氧-d -葡萄糖醇发生分子内转化;相反，在合成3,4-缩醛之前，多元醇和醛发生了实质性的水解。
{"title":"Acid-catalysed formation of monoacetals from n-butyraldehyde and certain D-glucitol derivatives","authors":"T. G. Bonner, E. J. Bourne, P. J. V. Cleare, R. Cole, D. Lewis","doi":"10.1039/J29710000957","DOIUrl":"https://doi.org/10.1039/J29710000957","url":null,"abstract":"Acid-catalysed condensation of n-butyraldehyde with (a) 1-deoxy-D-glucitol yields a 2,3-acetal as a kinetically controlled product and the 2,4-acetal as the thermodynamically controlled product, (b) 2-deoxy-D-glucitol yields the 1,3-acetal as the kinetically controlled product and the 3,4-acetal(s) as the thermodynamically controlled product, and (c) 3-O-methyl-D-glucitol yields the 2,4-acetal as the predominant product throughout the reaction.In aqueous acid there is no evidence that 1,3-O-butylidene-2-deoxy-D-glucitol undergoes intramolecular conversion; instead substantial hydrolysis to the polyol and aldehyde occurs before the synthesis of the 3,4-acetal(s).","PeriodicalId":17268,"journal":{"name":"Journal of The Chemical Society B: Physical Organic","volume":"09 1","pages":"957-962"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84255822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The rate of racemisation of optically active 4,4′-biquinolyl varies only slightly from one solvent to another but drops about tenfold in strong acid. The effect is attributed mainly to alteration of the molecular dimensions on protonation.
{"title":"The effect of pH on the racemisation rate of 4,4′-biquinolyl","authors":"M. Crawford, R. Ingle","doi":"10.1039/J29710001907","DOIUrl":"https://doi.org/10.1039/J29710001907","url":null,"abstract":"The rate of racemisation of optically active 4,4′-biquinolyl varies only slightly from one solvent to another but drops about tenfold in strong acid. The effect is attributed mainly to alteration of the molecular dimensions on protonation.","PeriodicalId":17268,"journal":{"name":"Journal of The Chemical Society B: Physical Organic","volume":"72 1","pages":"1907-1912"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84343632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tetrahydro-1,3-oxazine and its N-methyl, ethyl, isopropyl, and t-butyl derivatives have been prepared, and the dipole moments of the four last compounds measured. Provisional conclusions regarding the conformations of these compounds are presented.
{"title":"The conformational analysis of saturated heterocycles. Part XXX. 3-Alkyl tetrahydro-1,3-oxazines","authors":"Richard A. Jones, A. Katritzky, D. L. Trepanier","doi":"10.1039/J29710001300","DOIUrl":"https://doi.org/10.1039/J29710001300","url":null,"abstract":"Tetrahydro-1,3-oxazine and its N-methyl, ethyl, isopropyl, and t-butyl derivatives have been prepared, and the dipole moments of the four last compounds measured. Provisional conclusions regarding the conformations of these compounds are presented.","PeriodicalId":17268,"journal":{"name":"Journal of The Chemical Society B: Physical Organic","volume":"46 1","pages":"1300-1302"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84576002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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