Syntheses of .alpha.- and .beta.-sorigenin methyl ethers

Hauser, Frank M.; Rhee, Richard P.

doi:10.1021/jo00445a041

Cited by 20 publications

(15 citation statements)

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“…[42] In order to circumvent the formation of decomposition products, it was reasoned that use of the dianion from an ortho-toluic acid instead of the ester-derived monoanion might be preferable, since such dianions have been successfully used in synthesis previously. [43][44][45][46] Thus the corresponding toluic acid 12 [47] was treated with 2.2 equivalents of sec-butyllithium. Quenching the resulting dilithiated toluate with the Weinreb amide 9 resulted in a mixture of starting acid 12 and acylated material after The PMB-protecting group could be removed oxidatively from macrocycle 14 using cerium(IV) ammonium nitrate (CAN) to give allyl alcohol 15 in reasonable yield (Scheme 4), ready for conversion into other substituents.…”

Section: Resultsmentioning

confidence: 99%

“…Previous studies with toluate anions have shown that by‐products such as those resulting from self condensation are common in such reactions 42. In order to circumvent the formation of decomposition products, it was reasoned that use of the dianion from an ortho‐ toluic acid instead of the ester‐derived monoanion might be preferable, since such dianions have been successfully used in synthesis previously 43–46. Thus the corresponding toluic acid 12 47 was treated with 2.2 equivalents of sec ‐butyllithium.…”

Section: Resultsmentioning

confidence: 99%

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Inhibition of Hsp90 with Resorcylic Acid Macrolactones: Synthesis and Binding Studies

Day

Sharp

Rowlands

et al. 2010

Chemistry A European J

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A series of resorcylic acid macrolactones, analogues of the natural product radicicol has been prepared by chemical synthesis, and evaluated as inhibitors of heat shock protein 90 (Hsp90), an emerging attractive target for novel cancer therapeutic agents. The synthesis involves acylation of an ortho-toluic acid dianion, esterification, followed by a ring-closing metathesis to form the macrocycle. Subsequent manipulation of the protected hydroxymethyl side chain allows access to a range of new analogues following deprotection of the two phenolic groups. Co-crystallization of one of the new macrolactones with the N-terminal domain of yeast Hsp90 confirms that it binds in a similar way to the natural product radicicol and to our previous synthetic analogues, but that the introduction of the additional hydroxymethyl substituent appears to result in an unexpected change in conformation of the macrocyclic ring. As a result of this conformational change, the compounds bound less favorably to Hsp90.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Inhibition of Hsp90 with Resorcylic Acid Macrolactones: Synthesis and Binding Studies

Day

Sharp

Rowlands

et al. 2010

Chemistry A European J

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“…4 In addition, these hydroxynaphthoates have been used as precursors for the synthesis of taiwanin C, 5 a epipodophyllotoxin analog, 6 α,β-sorigenin methyl ethers 7 and olivine trimethyl ether. 8 1-Hydroxy-2-naphthoates can be synthesized by: a) reaction of isocumarins with the Reformatsky reagent, 7 b) annulations of 2-formylbenzoate thioacetals with α,β-unsaturated esters followed by hydrolysis of the thioacetals with N-chlorosuccinimide or with mercury(II) perchlorate, 9 c) a three-component reaction of an aryne precursor, β-keto sulfones and α,β-unsaturated esters, 10 d) lithiation-carbonylation of α-methoxynaphthalenes, 6 e) condensation of phthalides with α,β-unsaturated esters, 8 and f) intramolecular cyclization of aryl substituted alkenyl β-keto esters by means of phenylselenyl chloride in the presence of FeCl 3 11 or by palladium. 12 Although, the most direct way for the preparation of these 1-hydroxy-2-naphthoates is the brominationdehydrobromination of 2-substituted α-tetralones 5 bearing an ester group at the 2-position.…”

Section: Introductionmentioning

confidence: 99%

Copper- versus palladium-catalyzed aromatization of 2-(methoxycarbonyl) tetralones: synthesis of methyl 1-hydroxy-2-naphthoates

et al. 2016

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“…Isocoumarins can be used as precursors of carbocycles as shown in Scheme 4.2. The lithium enolate of ethyl acetate reacts smoothly with benzopyran-1-ones 252 to give naphthoates 253 in high yield [21,22]. Larock and co-workers described the synthesis of the 3,4-disubstituted isocoumarins 256 in good yields by treating the 2-halobenzoate esters 254 with internal alkynes 255 in the presence of a palladium catalyst (Scheme 4.3) [23].…”

Section: Regiospecific Synthesis Of Benzopyran-1-onesmentioning

confidence: 99%

Synthesis of Isocoumarins and Dihydroisocoumarins

Shahzad

2012

Springer Theses

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This chapter initially reviews methods for the preparation of isocoumarin derivatives and describes some previous synthetic methods. A new selenium-catalysed synthesis of isocoumarins is discussed and its application for preparation of a range of isocoumarins by reaction of stilbene carboxylic acids with diphenyl diselenide and a hypervalent iodine reagent is described. It was also discovered that dimethyl diselenide and diphenyl disulfide can be used in place of diphenyl diselenide. Using this modification the method was extended to prepare more challenging dihydroisocoumarins. Applications of Isocoumarins and DihydroisocoumarinsThe isocoumarin skeleton is part of many naturally occurring lactones which display a wide range of biological and pharmacological activities [1][2][3][4][5][6]. 3,4-Dihydroisocoumarins and their derivatives are compounds that widely exist in nature and serve as key intermediates in the synthesis of biologically active molecules. As these compounds are known to have a wide range of interesting activities such as antifungal, antiallergenic, antiulcer, and antimalarial activities, they are regarded as highly attractive molecules in organic chemistry [3][4][5][6]. 3-Aryl-isocoumarin derivatives constitute a pharmacologically important chemical entity which occurs in several natural products. These include thunberginol C, D, and E and hydrangenol [7,8]. Pharmacological activities of these natural products include the promotion of the adipogenesis of murine 3T3-L1 cells [7] and antiproliferative activity against mouse splenocytes [8]. Previous Synthesis of Isocoumarins and Dihydroisocoumarins Regiospecific Synthesis of Benzopyran-1-onesIn 1988, Hauser and co-workers [20] reported the synthesis of benzopyran-1-ones 248 from phthalaldehydic acids 244 and nitroalkanes (Scheme 4.1). The sequence permits a straightforward variation of both the 3-substituent and the pattern of functionalisation on the aromatic ring of the benzopyran ring system. The nitroalkyl isobenzofuranones 245 (obtained from condensation of 244 and nitroalkanes with triethylamine in DMSO) are treated with sodium borohydride in dimethyl sulfoxide providing the (nitroalkyl) benzoic acids 246 in 70-95 % yield. The benzopyran-1-ones 248 were obtained by the Nef reaction of 246 followed by intramolecular cyclisation of the resulting 247 and subsequent dehydration (Scheme 4.1). Stobbe condensations of homophthalates 249 with aldehydes have also been widely employed for the synthesis of benzopyran-1-ones 252 as shown in Scheme 4.2. Reactions of the homophthalate 249 with aromatic aldehydes gave good yields of the styryl half esters 250; however, the corresponding reaction with aliphatic aldehydes gave low yields. The additional steps necessary to convert 250 to 251 are harsh, and the overall yields of products using this approach are rather modest, especially for benzopyranones containing a 3-alkyl group 252.

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Syntheses of .alpha.- and .beta.-sorigenin methyl ethers

Cited by 20 publications

References 3 publications

Inhibition of Hsp90 with Resorcylic Acid Macrolactones: Synthesis and Binding Studies

Inhibition of Hsp90 with Resorcylic Acid Macrolactones: Synthesis and Binding Studies

Copper- versus palladium-catalyzed aromatization of 2-(methoxycarbonyl) tetralones: synthesis of methyl 1-hydroxy-2-naphthoates

Synthesis of Isocoumarins and Dihydroisocoumarins

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