Stereoselektive synthese des 4-desmethoxydaunomycinons

Krohn, Karsten; Tolkiehn, Klaus

doi:10.1016/s0040-4039(01)95128-7

Cited by 31 publications

(5 citation statements)

References 12 publications

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“…This latter reaction may be regarded as the silicon analogue of the Kornblum oxidation which would proceed as illustrated in Scheme IV. While the chemistry reported here has been used to prepare only 6 and 21, it would appear to offer a general route not only to benzocyclobutenedione monoketals but also to the diones30 themselves via hydrolysis.…”

Section: Synthesis Of the Ab-ring Systemmentioning

confidence: 99%

1,4-Dipole-metalated quinone strategy to (.+-.)-4-demethoxydaunomycinone and (.+-.)-daunomycinone. Annelation of benzocyclobutenedione monoketals with lithioquinone bisketals

Swenton¹,

Anderson²,

Jackson³

et al. 1981

J. Org. Chem.

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882 cm'1 (m); UV 268 nm (e 9.6 X 103); mass spectrum, m/z = 148.0887 (M+, caled for C10H12O 148.0889).3-(3-Butenyl)cyclopent-2-enone (32). Following the procedure described above for the preparation of 11, the alcohol obtained from 3-butenylmagnesium bromide and cyclopent-2-enone (5.0 g, 61 mmol), after treatment with acidic Cr03, gave 32 (1.403 g, 17% overall), bp 110-115 °C (10 mm); further purification was achieved by preparative VPC on column D (175 °C): NMR (60 MHz) 6.13-5.47 (m, 1 H), 5.83 (dd, J = 1,1 Hz, 1 H), 5.22-4.8 (m, 2 ), 2.72-2.10 (m, 8 H); IR 3070 (w), 2955 (m), 1715 (s), 1672 (w), 1643 (m), 1617 (s), 1435 (m), 981 (m), 910 cm"1 (m); mass spectrum, m/z 136.0887 (M+, caled for C9H120 136.0887).Photolysis of 32. A solution of 32 (176 mg) in CeH6 (67 mL) was irradiated at 25 °C through an uranium glass filter for 10 days.VPC analysis on column G (178 °C) indicated two components and a considerable amount (~40%) of 32 remaining. After preparative VPC, a NMR spectrum of the first component indicated it was a mixture. Further separation was achieved on column H (150 °C); the first eluted component was identified as 14b: NMR (220 MHz) 2.

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Section: Synthesis Of the Ab-ring Systemmentioning

confidence: 99%

1,4-Dipole-metalated quinone strategy to (.+-.)-4-demethoxydaunomycinone and (.+-.)-daunomycinone. Annelation of benzocyclobutenedione monoketals with lithioquinone bisketals

Swenton¹,

Anderson²,

Jackson³

et al. 1981

J. Org. Chem.

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“…53 Acid-catalysed dehydration of 3-alkynyl-1,2,3,4-tetrahydro-1,3,5,8-tetrahydroxyanthraquinones, in which the acetylenic group is not directly bound to either the quinoid or aromatic ring, afforded 6-alkynyl-1,4-dihydroxyanthraquinones. 54,55…”

Section: Other Methodsmentioning

confidence: 99%

Acetylenic derivatives of quinones

Shvartsberg¹,

Barabanov²,

Fedenok³

2004

Russ. Chem. Rev.

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“…It has now been established that simple l,3-bis(trimethylsiloxy)-1,3-butadienes (1,2) give analogous results with 2,5-and 2,6-dichlorobenzoquinones (5, 6), providing chloronaphthoquinones as convenient intermediates for a second regiospecific annulation with other dienes such as vinylketene acetals (23,26). They also react directly…”

Section: Methodsmentioning

confidence: 99%

Studies toward practical thioxanthene-derived protective groups. 9,10-Propanothioxanthylium salts

Kemp¹,

Vellaccio²

1981

J. Org. Chem.

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1807of 156.5-159.5 "C upon mixture with salicylic acid.The pH 10.5 extract after evaporation yielded 191 mg (75%) of a solid that exhibited an intense blue-green fluorescence.Recrystallization from chloroform-petroleum ether afforded 100 mg of crystals, mp 153.5-155.5 "C.For analysis the substance was recrystallized twice from chloroform-petroleum ether and dried in vacuo a t 60 "C for 3 h; mp 157-157.5 "C. Anal. Calcd for C11H110N3: C, 65.64; H, 5.52; N, 20.88; 0,7.95. Found: C, 65.76; H, 5.61; N, 20.88.This product (CllHllONB; 100 mg, 4.7 mmol) was dissolved in 6 N HCl(20 mL) and refluxed for 48 h. The solution was then brought to pH 14 with 6 N NaOH and extracted twice with 10-mL portions of ethyl acetate. Evaporation of the ethyl acetate layer yielded 35 mg (35%) of a solid identical with 3 prepared by the reaction of 2-hydroxybenzamidine and ethyl acetoacetic ester as described in this paper. Acidification of the base layer to pH 10 and extraction with ethyl acetate followed by evaporation yielded 50 mg of the starting material.2-Phenyl-4H-1,3-benzoxazin-4-one (1). The procedure described by Titherley2 was followed: decoupled C13 NMR (CDC13) 6 117.0, 118.3, 127.1, 128.0, 129.0, 129.9, 134.2, 135.4, 154.9,164.0, 166.9; 'H NMR (CDC13) 6 7.27-7.80 (m, 5 H), 8.20 (td, 1 H), 8.38 (dd, 1 H), 8.41 (dd, 2 H). Benzo[ 1,3]oxazin-2,4-dione 12. The procedure described by Kemp and Woodward* was followed: decoupled C13 NMR (CDClJ 6 1.32 (t, 3 H), 4.13 (4, 2 H), 7.30 (dd, 1 H), 7.34 (td, 1 H), 7.70 (td, 1 H), 8.08 (dd, 1 H).The preparation of 9,lO-propanothioxanthylium salts 1 is described. The novel bridged ring system of these salts is readily cleaved by nucleophiles to yield the open-chain derivatives 2. These readily undergo rapid solvolysis when substituted in the 9-position with an electronegative group. The potential use of a 9-oxygenated-9,lOpropanothioxanthylium salt as a protective group is discussed. (6) Muren, J. F.; Bloom, B. M.

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Stereoselektive synthese des 4-desmethoxydaunomycinons

Cited by 31 publications

References 12 publications

1,4-Dipole-metalated quinone strategy to (.+-.)-4-demethoxydaunomycinone and (.+-.)-daunomycinone. Annelation of benzocyclobutenedione monoketals with lithioquinone bisketals

1,4-Dipole-metalated quinone strategy to (.+-.)-4-demethoxydaunomycinone and (.+-.)-daunomycinone. Annelation of benzocyclobutenedione monoketals with lithioquinone bisketals

Acetylenic derivatives of quinones

Studies toward practical thioxanthene-derived protective groups. 9,10-Propanothioxanthylium salts

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