Neue synthesen von Dialkylphtaliden

Kothe, Richard

doi:10.1002/jlac.18882480104

Cited by 7 publications

(2 citation statements)

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“….ch-ch2co2h 0 -CO Other reports of the interconversion of o-alkenylbenzoic acids and 3-substituted phthalides have appeared in several instances (37,38,102,174,344); the isomerism does not always proceed in both directions, however, and conditions necessary to effect the conversions are severe.…”

Section: Ach=chc02hmentioning

confidence: 99%

Ring-Chain Tautomerism.

Jones¹

1963

Chem. Rev.

108

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Section: Ach=chc02hmentioning

confidence: 99%

Ring-Chain Tautomerism.

Jones¹

1963

Chem. Rev.

108

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“…63-64°, was realized. 43 The acid was transformed into the ethyl ester in 60% yield, b.p. 95°( 3 mm.…”

Section: Experimental Partmentioning

confidence: 99%

Rates of Solvolysis of the Alkylphenyldimethylcarbinyl Chlorides. Evidence for the Importance of Carbon-to-Carbon Hyperconjugative Contributions in Alkyl Groups^1,2

Brown¹,

Brady²,

Grayson³

et al. 1957

J. Am. Chem. Soc.

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Phenyldimethylcarbinol and its o-, m-and ^-monoalkvl (methyl, ethyl, isopropyl and Z-butyl) derivatives were synthesized. With one exception, these carbinols were converted readily to the corresponding tertiary chlorides by treatment with hydrogen chloride. The failure of o-Z-butylphenyldimethylcarbinol to yield the expected tertiary chloride is attributed to the large strains to be expected in this molecule, a homomorph of the unknown y-di-Z-butylbenzene. The rates of hydrolysis of the various tertiary chlorides in 90% aqueous acetone were measured at several temperatures. The small increase in rate (25°) observed in the meta alkyl derivatives ( , 1.00; m-Me, 2.00; w-Et, 1.94; m-i-Pr, 1.87; m-Z-Bu, 1.85) is attributed primarily to the inductive effect of the substituent. The minor decrease in effect with increased branching is attributed to a small hyperconjugative contribution transmitted to the ortho position of the aromatic ring and relayed to the reaction center by induction. The much larger effect of the para alkyl groups (p-Me, 26.0; p-Et, 22.0; p-i-Pr, 18.8; p-t-Bu., 14.4) is attributed to hyperconjugation stabilization of the electron deficient center by the alkyl group. From the observation that both in the meta and para positions methyl and Z-butyl groups have similar effects, it is concluded that carbon-to-carbon hyperconjugation must be nearly as important as carbon-to-hydrogen hyperconjugation. A methyl group in the ortho position (o-Me, 3.63) is far less important than a methyl group in the ^-position (p-Me, 26.0). This is attributed to steric hindrance of resonance in the transition state. With increasing bulk of the ortho substituent, the effect increases (c-Et, 2.07; o-i'-Pr, 0.847). The rate data obey the empirical relationship, log p¡ = c log (pi!mi), previously developed for the substitution reactions of toluene.

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Ueber das o‐Isopropyltoluol

Sprinkmeyer¹

1901

Ber. Dtsch. Chem. Ges.

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M y l i u s und F u n k fiir die beiden anderen Hydrate gegebeneo Curven eingetragen (fiir das Tetrahydrat nur bis 40O). Wenngleich eich die Curven dee Hexahydrate und Tetrahydrats i u ihrem Verlauf nur wenig unterecheiden, so sieht man doch, dase sie sich zwiechen 26O und 270 schneiden, wodurch der oben g$fundene Uebergangepunkt beetgtigt wird. Etwas achsrfer tritt die wendong der Cnrre nach meinen drei Liislichkeitebeedmmungen am Tetrahydrat hervor, jedoch will ich diesen vereinzelten Beetimmungeu keinen bemnderen Werth beimeesen und habe sie deshalb aue der Tafel weggelaesen. Wenn also M y l i o e imd F u n k eagen (a. a. 0. S. 452): sbei dem Chromat wird der C'ebergang (aus dem Dekahydrat) iu das Anhydrid durch dae intermeditire Hydrat Na2Cr04 + 4 H s 0 vermiltelt, welchee von 20-650 stabil ieta, 80 mum dies nunnrehr dahin er weitert werden, daee eich zwiechen dae Dekahydrat und Tetrahydrat noch daa nur innerhtrlb weniger Grade stabile Hexahydrat einschiebt. 901. H. S p r i n k m e y e r : Ueber des o-Isopropyltoluol~). [Mittheilaog aus dem cbem. Institut der K. Akademie zu Miinster i. W.] Bingegangen am 30. Mai 1901.) Bis zum Jahre 1880 waren von den seche theoretisch miiglichen Propyltoluolen met zwei bekannt, n&mlich das p-Normalpropylund dae p-leopropyl-Toluol. 1880 erhielt aledam Ad. CI nu 8') aus o-ind m-Bromtoluol und normulem Propyljodid mittele der Fi t t ig'scheo Reaotioo zwei weitere Propyltoluole, das o-und m-Normalpropyltolool. sodme nur noch zwei unbekannt blieben. Eius yon diesen, dns la-Ieopropyholuol , fnnd R e 1 b e 5) unter den Producten d e r trocknen Deetillatiea dea Colophnniums auf, f a d zu deraelben Zeit, als C l a u s die beiden normalen Kohlenwaesersloffe daretellte. Aucb iet es K e l b e gelungen. dieeen Kohlenwaeeeretnff syntbetiech nacb der eogenannten ,Reaction von F r i e d e l uod C r a f t s 4 darzustellen. Es blieb eomit voii den aechs Ieomereii nur nocb dae o-Ieopropylto-11101 unbekannt. Von Interesee echien es deehalb zu eein, festzuetellen, ob uicht anch dieeer Kohletiwsseeratoff synthetisch dsrgestellt werden k6nnle. Scbon im Jahre 1880 hat Claus, wie er selbat berichtet'), die Vorarbeiten fiir die Darstellang diesee Kiirpere in An-, grid genommen; do& eind bie hente keinle weiteren Angnben dariiber , 1) Ausfiihrlich: Inauguraldissertation, Minster i, W., 1901. ?) Ditse Beriohb 18, 896 [1880).4) Diese Berichte 13, 896 [lSSO]. 3) Ann. d. Chem. 210, 1 [ISSlJ immer noch rnit dem Oel, das eich zum grossen Tbeil im siedenden Wlrseer geliist und rnit den Krystallen wieder abgescbieden hatte, verunreinigt waren. Derselbe liiste das krystallisirende Sulfamid beim Kochen eebr leicht, das Oel dagegen echwer. Aus dieser Liisnng krystallisirte beim Erkalten das Sulfamid d l i g rein aus. Es stellt, wenn es ganz rein ist, grosse, gllinzende Bliitter dar, die bei 1030 schmelzen. Aus dieser Verlegrnheit half schliesslich der Petroleumfither. I

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Neue synthesen von Dialkylphtaliden

Cited by 7 publications

References 2 publications

Ring-Chain Tautomerism.

Ring-Chain Tautomerism.

Rates of Solvolysis of the Alkylphenyldimethylcarbinyl Chlorides. Evidence for the Importance of Carbon-to-Carbon Hyperconjugative Contributions in Alkyl Groups^1,2

Ueber das o‐Isopropyltoluol

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Neue synthesen von Dialkylphtaliden

Cited by 7 publications

References 2 publications

Ring-Chain Tautomerism.

Ring-Chain Tautomerism.

Rates of Solvolysis of the Alkylphenyldimethylcarbinyl Chlorides. Evidence for the Importance of Carbon-to-Carbon Hyperconjugative Contributions in Alkyl Groups1,2

Ueber das o‐Isopropyltoluol

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Rates of Solvolysis of the Alkylphenyldimethylcarbinyl Chlorides. Evidence for the Importance of Carbon-to-Carbon Hyperconjugative Contributions in Alkyl Groups^1,2