Sulfonation of <i>trans</i>‐10b,10c‐dimethyl‐10b,10c‐dihydropyrene and its 2,7‐di‐<i>tert</i>‐butyl derivative with sulfur trioxide

Cerfontain, H.; Koeberg-Telder, Ankie; Mitchell, Reginald H.; Khalifa, Nasr; Tashiro, Masashi

doi:10.1002/recl.19961150506

Cited by 4 publications

(2 citation statements)

References 34 publications

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“…When the solution of 1 in dioxane was purged with argon for 15 min prior to the irradiation in order to remove the dissolved oxygen, only the [2.2]metacyclophane-1,9-diene 2 was obtained. This observation is important, as it rules out the possibility that the secondary photoproduct would be the Dewar benzene isomer of unti-8,16-dimethyl[2.2]metacyclophane-1,9-diene (9). Upon irradiation of an oxygen-containing solution of 2,7-di-tertbutyl-tmrzs-lob, 10c-dimethyl-lob, 1 Oc-dihydropyrene (5) in [D8]dioxane, the corresponding [2,2]metacyclophane-1,9-diene 6 and 5,13-di-tevt-butyl-5,8-epidioxy-anti-8,16-dimethyl[2.2]metacyclophane-1,9-diene (8) were obtained.…”

Section: Photoreaction Of the Dimethyldihydropyrenes 1 Andmentioning

confidence: 99%

“…Irradiation of the 50: 8:42 mixture of 2,7-di-tert-butyltrans-lob, l0c-dimethyl-1 Ob, 1 Oc-dihydropyrene-4-sulfonic acid (=5-4-S), 5-4,9-S2, and 5-4, 10-S, [9] in (acidic) [D,]dioxane as solvent at either h = 436 or 2495 nm did not lead to any photoconversion, whereas irradiation of the corresponding mixture of the analogous potassium sulfonate salts in D 2 0 only yielded undefinable products.…”

Section: Photoreaction Of the Dimethyldihydropyrenes 1 Andmentioning

confidence: 99%

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Photoreactions of trans‐10b,10c‐Dimethyl‐10b,10c‐dihydropyrenes

et al. 1997

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The photoisomerization of translob, 10c-dimethyl-lob, 1Ocdihydropyrene (l), its 2,?-di-tert-butyl derivative 5 and a series of potassium sulfonate derivatives of 1, in both [D8]1,4dioxane and [D,]dichloromethane as solvent, has been studied using h = 420-570 nm irradiation. Irradiation of a deoxygenated solution of 1 in dioxane leads to the exclusive formation of anti-8,16-dimethyl[2.2]metacyclophane-l,9-diene (2), whereas the photoconversion of 1 in a non-degassed solution leads to the successive formation of 2 and 5,8-epidioxy-anti-8,16 -dime t hyl [ 2.21 met ac y clophane -1,9diene (7). Similarly, irradiation of the 2,7-di-tert-butyl derivative 5 in oxygen containing [D,]dioxane as solvent leads to the consecutive formation of the corresponding 5,13-di-tert-butyl derivatives 6 and 8. Irradiation of mixtures of potassium sulfonate derivatives of 1 (1-S,) in D 2 0 as solvent leads to photoisomerization with formation of the correspondingly substituted sulfonate derivatives of 2. Only with the dipotassium 2,4-and 2,5-di-sulfonates of 1 eventually small amounts of the corresponding epidioxy-bridged products 7 were formed. The photoisomerization 1-s, + 2-s,, appeared to be most effective for 1-2-S and 1-2,5-S2 and least effective for 1-2,4,7-S3 and 1-2,4,7,10-S4. In the dark, the epidioxy products 7 and 8 reverted to give initially the corresponding metacyclophanes 2 and 6, and subsequently the respective dihydropyrenes 1 and 5, and the dark reactions of the potassium sulfonate derivatives 2-S, yielded the correspondingly substituted 1-S,. A quantitative study showed that the dark reactions steps 7 + 2, 8 + 6, and 2-S, + 1-S, (n = 1-4) exhibit first-order kinetics. For the deoxygenation of 5,8-epidioxy-anti-8,16-dimethyl[2.2]metacyclophane-l,9-diene (7) the rate coefficient is ca. 2.7 times that of its 5,13-di-tert-butyl derivative (8), and the rate coefficient for the isomerization 2 3 , + 1-S, follows the order 2-5-S = 2-5,13-S2 > 2-1,5,10-S3.

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Section: Photoreaction Of the Dimethyldihydropyrenes 1 Andmentioning

confidence: 99%

Section: Photoreaction Of the Dimethyldihydropyrenes 1 Andmentioning

confidence: 99%

Photoreactions of trans‐10b,10c‐Dimethyl‐10b,10c‐dihydropyrenes

et al. 1997

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Aromatic Sulfonation, 131. Formation of Sulfonic Acids and Sulfonic Anhydrides in the Sulfur Trioxide Sulfonation of Some Dialkylbenzenes and 1,ω‐Diarylalkanes

et al. 1997

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An exploratory study has been made on the SO, sulfonation of a number of alkylarenes in [D,]dichloromethane as an aprotic solvent, mostly in the presence of [D8]1,4-dioxane as a reactivity moderator, in order to obtain information on sulfonic acid and sulfonic anhydride formation. 1,2-Dimethylbenzene (1) with 1.0 mol-equiv. of SO3 yields predominantly the 4-sulfonic acid (1-4-S), whereas with 4.0 mol-equiv. of SO3, 18 mol-Yo of the corresponding (intermolecular) sulfonic anhydride ( 1-4-S02)20 is additionally formed. 1,4-Dimethylbenzene (2) with 0.8 mol-equiv. of SO3 yields predominantly 2-2-S, whereas with 4.0 mol-equiv. of SO, the sulfonic anhydride (2-2-S02)20 and its 6-S and 6,6'-S2 derivatives are formed, the eventual main product being (6-S-2-2-S02),0. Reaction of 1-ethyl-4-methylbenzene (3) with 2.0 mol-equiv. of SO3-[D,]dioxane at -78 + -40 "C leads to the predominant formation of the 2-and 3-S derivatives in a molar ratio of 26:74, with small amounts of the three corresponding intermolecular anhydrides. Upon performing the sulfonation of 3 at 0 + 22 "C, the relative amounts of the anhydrides are larger, and in addition the 3,5-s2 derivatives of the intermolecular anhydrides are formed. The absence of the isomeric 2,6-S2 derivative is ascribed to the buttressing effect of the 2-sulfo on the 1-ethyl group, hampering the sulfonation at C(6). Reaction of diphenylmethane (4) with 4.2 mol-equiv. of SO3 at -20 + 25 "C yields initially 4-4'-S and subsequently 4-4',4"-S2. Sulfonation of 1,2-diphenylethane (5) with 4.0 mol-equiv. of SO, at -78 + 22 "C for 4.5 h leads mainly to the cyclic dimeric disulfonic anhydride [5-4',4"(-S02)20]2, which upon hydrolysis affords 9% of 5-2',4"-and 91% of 5-4',4"-s2. However, sulfonation of 5 at 0 + 22 "C for ca. 0.8 h was found to lead to the formation of the intermolecular sulf onic anhydride (4 ' -S -5 -4 ' '-SOz)zO. On sulfonation of 1,2 -di-p-tolylethane ( 6 ) with 1.0 mol-equiv. of SO3, only ca. 20% of the substrate was sulfonated to give, after hydrolysis, 3% of the 2'-and 12% of the 3'-sulfonate, whereas with 4.0 molequiv. of SO3 the initial monosulfonic acids are almost completely converted to yield the 2',3",5"-s3, 3',3",5"-S3, and 3',3 ",5' ,5"-S,.

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