Benzopyrans. Part 30. Synthesis of substituted xanthones from 3-acyl-2-methyl-1-benzopyran-4-ones
TL;DR: The xanthone as mentioned in this paper was derived from the base catalysed self-condensation of the chromone and showed that it can be obtained by refluxing with NaOMe in MeOH.
About: This article is published in Tetrahedron.The article was published on 1993-05-07. It has received 19 citations till now. The article focuses on the topics: Chromone & Pyran.
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Patent•
28 Aug 2001
TL;DR: In this article, compounds of Formula (I) that inhibit DNA-dependent protein kinase, compositions comprising the compounds, methods to inhibit the DNA-PK biological activity, and methods to sensitize cells the agents that cause DNA lesions are disclosed.
Abstract: Compounds of Formula (I) that inhibit DNA-dependent protein kinase, compositions comprising the compounds, methods to inhibit the DNA-PK biological activity, methods to sensitize cells the agents that cause DNA lesions, and methods to potentiate cancer treatment are disclosed.
66 citations
01 Jan 1996
45 citations
TL;DR: The chemistry and application of the title aldehyde and some simple derivatives thereof are reviewed in this paper, where the authors propose a simple derivative of the aldehydes, which they call simple aldeheeds.
42 citations
TL;DR: The Vilsmeier-Haack reagent can be used to form carbon-oxygen or carbon-nitrogen bonds, unless these are accompanied by formation of a carbon-carbon bond as mentioned in this paper.
Abstract: This chapter extends the discussion to reactions between the Vilsmeier-Haack reagent (subsequently referred to as the Vilsmeier reagent for brevity) and any other compounds in which a carbon-carbon bond is formed. The discussion thus excludes reactions in which the Vilsmeier reagent acts as a chlorinating agent (for example in the preparation of acid chlorides), or in which it forms carbon-oxygen or carbon-nitrogen bonds, unless these are accompanied by formation of a carbon-carbon bond. For a discussion of the nature of the reagent and of the mechanism of the reaction, the earlier chapter in vol. 49 should be consulted. There are also a number of reviews that deal at length with mechanisms of reactions involving the Vilsmeier reagent, notably those by Jutz and Marson, and hence this chapter will concentrate on applications, with brief mention of mechanisms when necessary.
Wizinger has pointed out that alkenes could react with the Vilsmeier reagent, but his only examples were styrenes where the intermediate carbocation has considerable stability.
Hydrolysis gives the cinnamaldehyde. In principle, any alkene which is not too sterically hindered can undergo this reaction, but the Vilsmeier reagent has low reactivity as an electrophile, and in practice activation is often necessary. The addition depends on the HOMO of the alkene, and anything increasing the HOMO energy will aid reaction, as for example further conjugation (dienes, trienes, etc.) or the presence of an electron-donating substituent. Hence aldehydes and ketones are active in their enol forms, and enol ethers and enamines are good substrates. Indeed, all additions covered by this chapter can be regarded as alkene additions, even those on active methyl groups attached to electron-deficient rings. As with any reaction involving carbocation intermediates, rearrangements are possible; the initial products are sometimes enamines, and this can give rise to polysubstitution. The substrates are grouped into eleven major subsections; references to reviews of particular relevance will be found in the appropriate subsection.
Keywords:
vilsmeier reaction;
non-aromatics;
alkenes;
dienes;
polyenes;
heteroatoms;
substituents;
enamines;
enamides;
alkynes;
aldehydes;
ketones;
imines;
hydrazones;
semicarbazones;
oximes;
carboxylic acids;
anhydrides;
acid chlorides;
esters;
lactones;
amides;
lactams;
imides;
nitriles;
methyl groups;
methylene groups;
adjacent rings;
comparison of methods;
experimental conditions;
experimental procedures;
tabular survey
36 citations
Patent•
Icos1
TL;DR: In this article, compositions comprising the compounds, methods of inhibiting the DNA-PK biological activity, and methods of sensitizing cells the agents that cause DNA lesions, and method of potentiating cancer treatment are disclosed.
Abstract: Compound that inhibit DNA-dependent protein kinase, compositions comprising the compounds, methods of inhibiting the DNA-PK biological activity, methods of sensitizing cells the agents that cause DNA lesions, and methods of potentiating cancer treatment are disclosed.
33 citations
References
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TL;DR: In this paper, the 13 C NMR chemical shifts of eleven hydroxy-, two hydroxymethoxy xanthones, and xanthone- C -glucoside, mangiferin, are presented and analyzed.
73 citations
TL;DR: The benzopyranones 1 and 3 reacted with 2,3-dimethyl-1,3butadiene in the presence of titanium (IV) chloride to give the corresponding (4 + 2) cycloadducts 8 and 11, the former undergoing facile deformylation to give 9 and 10.
56 citations
TL;DR: In 2-Stellung unsubstituierte 3-Acyl-chromone wurden aus 2-Hydroxy-ω-acyl-acetophenonen durch Reaktion with Orthoameisensaure-triathylester und Acetanhydrid oder aus 1-hydroxy-α-formylacetophenon and Acetanehydrid/Natriumacetat dargestellt as mentioned in this paper.
Abstract: In 2-Stellung unsubstituierte 3-Acyl-chromone wurden aus 2-Hydroxy-ω-acyl-acetophenonen durch Reaktion mit Orthoameisensaure-triathylester und Acetanhydrid oder aus 2-Hydroxy-ω-formyl-acetophenon und Acetanhydrid/Natriumacetat dargestellt. Strukturbeweise wurden mit Hilfe von UV-, IR- und NMR-Spektren gefuhrt.
37 citations
TL;DR: In this article, the 3-cyl-2-methylthio-chromone was shown to react with hydroxide or alkoxide ions or with amines to yield the substituted 3-acyl-4-hydroxycoumarins.
Abstract: Die 3-Acyl-2-methylthio-chromone 5a, 5c und 5d reagieren mit Hydroxid- und Alkoxidionen sowie Aminen unter Verdrangung der Methylthio-Gruppe zu den in 2-Stellung substituierten 3-Acyl-chromonen 8 und 10a–10p bzw. den 3-Acyl-4-hydroxy-cumarinen 6a und 6b. Mit Hydrazin, Hydroxylamin, o-Phenylendiamin, Guanidin und Amidin-Derivaten entstehen die anellierten Chromone 11a–11c, 12, 13 und 14a–14e..
Synthesis and Reactions of 3-Acyl-2-(methylthio)chromones
3-Acyl-2-(methylthio)chromones 5a, 5c and 5d react with hydroxide or alkoxide ions or with amines to yield the substituted 3-acylchromones 8, 10a–10p, or the 3-acyl-4-hydroxycoumarins 6a and 6b. With hydrazine, hydroxylamine, o-phenylenediamine, guanidine or amidine derivatives the fused chromones 11a–11c, 12, 13 and 14–14e are obtained.
27 citations
TL;DR: The 3-acyl-2-(methylthio)chromones 2a-2c and the 6-acetyl-7-methylthIO-furochromone 10 react with the CH-acidic compounds 5a-5f, 11 and potassium tert.-butylate to yield the 3acylchromones 4a-4d and 9, the xanthones 1 and 6a-6d and the furoxanthones 13a-13c and 20.
Abstract: Die 3-Acyl-2-methylthio-chromone 2a-2c und das 6-Acetyl-7-methylthio-furochromon 10 setzten sich mit den CH-aciden Verbindungen 5a-5f, 11 und Kalium-t-butylat zu den 2-substituierten 3-Acylchromonen 4a-4d und 9, den Xanthonen 1 und 6a-6d sowie den Furoxanthonen 13a-13c und 20 um. 4b und 4c reagierten mit Ammoniumacetat zu den Benzopyranopyridinonen (Azaxanthonen) 8a und 8b.
Xanthones from Chromone Derivatives
The 3-acyl-2-(methylthio)chromones 2a-2c and the 6-acetyl-7-(methylthio)furochromone 10 react with the CH-acidic compounds 5a-5f, 11 and potassium tert.-butylate to yield the 3-acylchromones 4a-4d and 9, the xanthones 1 und 6a-6d and the furoxanthones 13a-13c and 20. With ammonium acetate, 4b and 4c gave the benzopyranopyridinones (azaxanthones) 8a-8b.
17 citations