The Thermal Reaction of 3-Acetylguaiazulene with Sulfur

Kurokawa, Shinji

doi:10.1246/bcsj.43.509

Cited by 12 publications

(2 citation statements)

References 3 publications

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“…Workup by chromatography gave pure 3a and as a second, slower-moving component, the methyl or (7)); 4.75 (s, CH 2 ÀC(3)); 3.18 (s, MeO); 2.98 (s, MeÀC (8)); 2.74 (sept., J ¼ 6.9, Me 2 CHÀC(5)); 2.52 (s, MeCOÀC (1) (5)). (6aRS,13bSR)-3-Chloro-5-ethyl-10-isopropyl-12-methyl-2-oxo-2H-cyclohept [1,7]indeno [4,5-c] …”

Section: Experimental Partmentioning

confidence: 99%

Report on an Unusual Cascade Reaction between Azulenes and 2,3‐Dichloro‐5,6‐dicyano‐1,4‐benzoquinone (=4,5‐Dichloro‐3,6‐dioxocyclohexa‐1,4‐diene‐1,2‐dicarbonitrile; DDQ)

Sigrist

Hansen

2010

Helvetica Chimica Acta

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The oxidation of 1-(3,8-dimethylazulen-1-yl)alkan-1-ones 1 with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (¼ 4,5-dichloro-3,6-dioxocyclohexa-1,4-diene-1,2-dicarbonitrile; DDQ) in acetone/H 2 O mixtures at room temperature does not only lead to the corresponding azulene-1-carboxaldehydes 2 but also, in small amounts, to three further products (Tables 1 and 2). The structures of the additional products 3 -5 were solved spectroscopically, and that of 3a also by an X-ray crystal-structure analysis ( Fig. 1). It is demonstrated that the bis(azulenylmethyl)-substituted DDQ derivatives 5 yield on methanolysis or hydrolysis precursors, which in a cascade of reactions rearrange under loss of HCl into the pentacyclic compounds 3 (Schemes 4 and 7). The found 1,1'-[carbonylbis(8-methylazulene-3,1-diyl)]bis [ethanones] 4 are the result of further oxidation of the azulene-1-carboxaldehydes 2 to the corresponding azulene-1-carboxylic acids (Schemes 9 and 10).1. Introduction. -More then ten years ago, we applied a procedure of Okajima and Kurokawa [1], just published at that time, to the smooth oxidation of the Me group of 1-(3-methylazulen-1-yl)alkan-1-ones with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (¼ 4,5-dichloro-3,6-dioxocyclohexa-1,4-diene-1,2-dicarbonitrile; DDQ) in aqueous acetone to yield the corresponding azulenecarboxaldehydes. The authors reported for the oxidation of 3-acetylguaiazulene (¼ 1-(5-isopropyl-3,8-dimethylazulen-1-yl)-ethanone; 1a) an attractive yield of 91% for carboxaldehyde 2a (Scheme 1). In our hands, the reaction gave, in a ten times higher concentration of the reactants, also 2a as the main product, however, in yields ranging from 40 to 60%; and to our surprise, on TLC beside the dark red spot of 2a, at least two additional faint spots were present, a blue one, moving distinctly faster, and a red one, moving clearly slower than 2a, which stood for two additional products of unknown structure and in estimated yields of ca.

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Section: Experimental Partmentioning

confidence: 99%

Report on an Unusual Cascade Reaction between Azulenes and 2,3‐Dichloro‐5,6‐dicyano‐1,4‐benzoquinone (=4,5‐Dichloro‐3,6‐dioxocyclohexa‐1,4‐diene‐1,2‐dicarbonitrile; DDQ)

Sigrist

Hansen

2010

Helvetica Chimica Acta

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“…The NMR data of 6 and 7 are given in Table I along with the relevant data of guaiazulene (8), 30 3-acetylguaiazulene (9), 31 3-benzoylguaiazulene (10), 32 3-formylguaiazulene (11),33 and 3,3'-diguaiazulene ketone (12).33 A number of conclusions may be drawn. (1) In each of the guaiazulenyl derivatives under study, the seven-membered ring protons (H-5, H-6, H-8) give rise to an ABX system.…”

mentioning

confidence: 99%

Fulvenes and thermochromic ethylene. 88. Stabilization of cyclopropenium ion and cyclopropenone by guaiazulene

Agranat¹,

Aharon-Shalom²

1976

J. Org. Chem.

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Stabilization of Cyclopropenium Ion by Guaiazulene l-Methoxy-l,2-dichloro-2,3,3-trifluorocyclopropane (2). A solution of 24.8 g (0.2 mol) of la in 100 ml of methylene dichloride was protected from the light and treated slowly with 14.2 g (0.2 mol) of precondensed chlorine while keeping the reaction temperature below 0 °C. After stirring in the dark at room temperature overnight, the reaction mixture was distilled at atmospheric pressure to remove the solvent, and the residual oil was fractionated in vacuo to give 18.2 g (47%) of 2: bp 60-63 °C (190 mm); NMR (CC14)

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Gold(I)‐katalysierte Intramolekulare 7‐endo‐dig Zyklisierung von Trien‐In‐Systemen: Neuer Zugang zu Azulenothiophenen

Eshagh Saatlo,

Oczlon,

Wunsch

et al. 2024

Angewandte Chemie

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We report the direct synthesis of new azulene derivatives through gold‐catalyzed cyclization reactions. A five‐membered ring as backbone in the applied triene‐yne substrates turned out to be crucial to induce the 7‐endo‐dig cyclization mode necessary to trigger azulene formation. The obtained targets are of high interest due to their potential applications in different fields, like organic materials, medicine or cosmetics. UV/Vis spectra and cyclic voltammetry were measured, based on these the electronic properties were determined . Short two or three step sequences towards the applied starting materials make this approach synthetically highly attractive.

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The Thermal Reaction of 3-Acetylguaiazulene with Sulfur

Cited by 12 publications

References 3 publications

Report on an Unusual Cascade Reaction between Azulenes and 2,3‐Dichloro‐5,6‐dicyano‐1,4‐benzoquinone (=4,5‐Dichloro‐3,6‐dioxocyclohexa‐1,4‐diene‐1,2‐dicarbonitrile; DDQ)

Report on an Unusual Cascade Reaction between Azulenes and 2,3‐Dichloro‐5,6‐dicyano‐1,4‐benzoquinone (=4,5‐Dichloro‐3,6‐dioxocyclohexa‐1,4‐diene‐1,2‐dicarbonitrile; DDQ)

Fulvenes and thermochromic ethylene. 88. Stabilization of cyclopropenium ion and cyclopropenone by guaiazulene

Gold(I)‐katalysierte Intramolekulare 7‐endo‐dig Zyklisierung von Trien‐In‐Systemen: Neuer Zugang zu Azulenothiophenen

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