摘要:

AbstractThe novel didentate ligand 2‐(3,5‐dimethyl‐1‐pyrazolyl)ethylamine (Naed) and the tridentate ligand bis[2‐(3,5‐dimethyl‐1‐pyrazolyl)ethyl] amine (ddaH) were immobilized onto silica by two different methods. The first method involves the coupling of the ligand to silica, previously modified with (3‐glycidyloxypropyl)trimethoxysilane (GLYMO). The second method involves the coupling of the ligand to the oxirane ring of GLYMO in a homogeneous reaction, followed by grafting onto silica, yielding the highest ligand concentrations on the silica (about 0.3 mmol/g silica). With the first method, only part of the epoxy group reacts with the ligand. With Naed, tertiary amines are also formed through reaction of the primary amine group of the ligand with two epoxy groups.These new ion‐exchange materials selectively adsorb Cu2+(maximum capacity 0.11–0.26 mmol Cu2+per gram of ion exchange) at pH>2 from aqueous solutions containing a mixture of the bivalent metal ions, Cu2+, Cd2+, Zn2+, Ni2+and Co2+. For products containing the didentate ligand Naed as the chelating group, the metal‐ion capacity decreases rapidly with decreasing pH, while the Cu2+‐uptake capacity for the product containing the tridentate ligand ddaH is com

ISSN:0165-0513    

DOI:10.1002/recl.19921110901

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractThe sulfonation of [2.2]paracyclophane(1)with(i)sulfur trioxide in the presence of various amounts of dioxane as moderator in dichloromethane as solvent, and(ii)in sulfuric acid containing 98.5 wt‐% H2SO4acting both as reagent and solvent was studied. The introduction of the first sulfo group is rapid relative to the second one, which always enters only the non‐sulfo‐containing phenylene ring. The rate of sulfonation of1with SO3greatly exceeds that of the acyclic analogue 1,2‐di(p‐tolyl)ethane(2). With 98.5 wt‐% H2SO4, the main product is theps‐gemisomer,i.e., the 4,15‐disulfonic acid (83%) in addition to theps‐orthoisomer, and smaller amounts of theps‐metaandps‐paraisomers. With SO3as reagent, the sulfo products are 1–4,15‐disulfonic anhydride, and theps‐ortho, ps‐metaandps‐paradisulfonic acids. On using 4.0 equiv. of SO3, the main product is the 4,15‐disulfonic anhydride (87%). However, with increasing amounts of added dioxane, the yields of the three disulfonic acids increase at the expense of the 4,15‐disulfonic anhydride. Mechanisms for the formation of the sulfo products under the different reaction conditions are suggested and discussed. The relatively high degree of 4,15‐disulfonic anhydride formed in the sulfonation of 1–4‐sulfonic acid with SO3in the absence of dioxane is explained in terms of intramolecular sulfonation.X‐ray crystal structures for potassium 1–4‐sulfonate and 1–4,15‐disulfonic anhydride were obtained. The former compound suffers from steric strain due to the forced close proximity of the sulfonate group and the C(2)H(2,1), whereas the additional 4,15‐SO2‐O‐SO2‐ bridge of the latter one leads(i)to a very significant strain with the nearest,i.e., the C(3)C(14) ethylene bridge, and(ii)induces some rotation of the twop‐phenylene moieties around the C(3)C(6) and C(11)C(14) axes in opposite directions, the C(4)C(15)

ISSN:0165-0513    

DOI:10.1002/recl.19921110902

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractReactions of ω‐phenylalkenes1a‐31awith sulfur trioxide were studied in the temperature range −60 to 25°C using dichloromethane as solvent and 1.5 mol equiv. of dioxane as reactivity moderator. ω‐Phenylalkenes1a‐7areact just like simple alkenes: at low temperature, they yield the (thermally unstable) β‐sultones1b‐7band4c‐7c, which at 25°C are converted into the corresponding carbyl sulfates. Reactions of ω‐phenylalkenes8a‐10a, which have a ‐(CH2)3‐ linkage between the Ph and the C = C moieties, with 1.1 equiv. of SO3at −60°C yield very rapidly and quantitatively the 1‐(1‐sulfoalkyl)‐1,2,3,4‐tetrahydronaphthalenes8fand9f (= 10f). Reaction of ω‐phenylalkenes11aand12a, having a ‐(CH2)2‐ linkage between Ph and C = C, with 1.1 mol equiv. of SO3at − 60°C leads to quantitative and stereospecific formation of 1‐methyl‐1,2,3,4‐tetrahydronaphthalene ‐2‐sulfonic acids11hand12h, respectively. The 5‐(chlorophenyl)‐2‐pentenes13a‐16aclearly demonstrate the presence of β‐sultones13b‐16band13c‐16cas the sole initial products leading to the Friedel‐Crafts cyclization products13h‐16h. Reaction of 1,3‐diphenyl‐1‐propenes26aand27awith 1.5 equiv. of SO3at − 60°C quantitatively yields β‐sultones26cand27c, which upon raising the temperature to − 20°C, are slowly converted intotrans‐1‐phenylindane‐2‐sulfonic acid (34).Attempted intermolecular Friedel‐Crafts type of sulfoalkylation of arenes using β‐sultones as reagent failed. Reaction of, for example,trans‐4,5‐octanesultone with anisole instead led only to transfer sulfodeprotonation, to yield(E)

ISSN:0165-0513    

DOI:10.1002/recl.19921110903

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractA new route for the construction of the mitosene skeleton was developed using 2‐(diphenylphosphinyl)pyrrolidine(2)and 2‐methoxy‐3‐methyl‐1,4‐benzoquinone(3)as starting materials. Regioselective oxidative addition of2to3gave 5‐substituted pyrrolidinylbenzoquinone4. Protection of the quinone function by reduction, followed byin‐situreaction with benzyl bromide, gave the bis‐benzylated product5. Using a recently developed route to pyrrolo[1,2‐a]indoles,5was converted into the protected mitosenes8. Debenzylation and subsequent oxidation of8produced the mitos

ISSN:0165-0513    

DOI:10.1002/recl.19921110904

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractCrystals of cyclopropanecarboxylic acid, C4H6O2, grown from the liquid are triclinic, space groupP1, a =8.6992(6),b= 8.8017(4),c= 6.6930(3) Å, α = 103.71(1), β = 103.93(1), γ = 66.49(1)° (171 K); Z = 4. The finalRfor 1649 independent observed reflexions [I>3σ(I)] is 0.037. Crystals of cyclopropanecarbonyl chloride, C4H5OCl, grown from the liquid are monoclinic, space groupP21/m. a= 6.287(2),b= 7.092(2),c= 5.647(3) Å, β = 101.84(3)° (151 K); Z = 2. The finalRfor 446 independent observed reflexions is 0.042.The C=O groups in the molecules of both compounds are in the bisectings‐cisconformation. The distal bonds in the cyclopropyl rings have (average) lengths of 1.463(2) and 1.467(2) Å, the average vicinal bond lengths are 1.514(2) and 1.516(2) Å for the acid and the carbonyl chloride respectively (corrected fo

ISSN:0165-0513    

DOI:10.1002/recl.19921110905

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractThe acid catalyzed heterolytic cleavage of the CoC bond in coenzyme B12(1) was studied using the ‘excess acidity’ functions of Cox and Yates. The results are compared to the acid induced decomposition of (methyl‐5‐deoxy‐ribofuranosyl)‐(2) and (2‐ethoxyethyl)cobalamin (3). Evidence is presented to view the CoC bond cleavage in the compounds (1) and (2) as an A2mechanism with water as the nucleophile or as an Iasubstitution at Co3+, and in (3) as an A1mechanism. Volumes of activation are consistent with the p

ISSN:0165-0513    

DOI:10.1002/recl.19921110906

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19921110908

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19921110910

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY