Convenient Synthesis of 7,8‐Dimethoxytetralin‐2‐one

Gorka, Álmos; Czuczai, B.; Szoleczky, P.; Hazai, László; Szántay, Cs.; Háda, Viktor

doi:10.1080/00397910500187753

Cited by 10 publications

(10 citation statements)

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“…The threebond proton-carbon coupling constants were measured from the E.COSY multiplets of the gradient-and sensitivity-enhanced HETLOC 32 and/or HECADE 33 spectra with 60.4 Hz accuracy. All the types of coupling constants, 3 J H(i)OH(i) and 3 …”

Section: Resultsmentioning

confidence: 99%

“…A Karplus relationship 45 has been reported and was applied to interpret 3 J H(i)OHi couplings. [46][47][48] Till the recent year, 9 longrange heteronuclear couplings involving the exchangeable OHgroups, 3 J C(i21)OHi and 3 J C(i11)OHi , have been mostly used qualitatively to describe the conformational preference of OHgroups.…”

Section: Resultsmentioning

confidence: 99%

“…[46][47][48] Till the recent year, 9 longrange heteronuclear couplings involving the exchangeable OHgroups, 3 J C(i21)OHi and 3 J C(i11)OHi , have been mostly used qualitatively to describe the conformational preference of OHgroups. 19,24,49 In this study for quantitative assessment of rotamer populations, a Karplus-type equation with Tvaroska parameters proposed for the CÀ ÀOÀ ÀCÀ ÀH interglycosidic segment [50][51][52] was used for the interpretation of heteronuclear vicinal 3 J C,OH couplings.…”

Section: Resultsmentioning

confidence: 99%

“…8 populations) together with the Karplus parameters (A, B, C) 38 describing the angular dependence of 3 J C(i11)OH(i) couplings. As a result of an iterative procedure when the 11 parameters were simultaneously varied, the best fit between the 12 experimental and calculated coupling constants was obtained with the Karplus equation as follows: 3 to prefer the gauche1 (exp. $72 6 8% and comp.…”

Section: Experimentally Determined and Qm Calculated Scalar Coupling mentioning

confidence: 99%

“…Compounds with multiple hydroxyl groups, such as vicinal diols and their derivatives, play an important role as synthetic building blocks or intermediates [1][2][3] for a large number of biologically active natural 4 or synthetic products, e.g., vinca alkaloids 5 or commercially available medicines (Enoxaparin, Docetaxel, Topiramate, etc.). Because stereoselective synthesis of such compounds sometimes requires special steric orientation of functional groups, there is a general interest in describing the solution state conformers of vicinal polyalcohols and saccharides.…”

Section: Introductionmentioning

confidence: 99%

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Combined NMR three‐bond scalar coupling measurements and QM calculations to calculate OH‐rotamer equilibrium of polyalcohols

et al. 2008

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A combined but independently applied NMR and QM procedure has been used to investigate the conformational properties of the exchangeable hydroxyl protons of polyalcohols. In this study, to demonstrate the applicability of such a strategy, we investigated a simple monosaccharide, i.e. alpha- and beta-anomers of a D-glucopyranoside derivative. The redundant set of experimental vicinal homonuclear and heteronuclear scalar couplings involving the OH-protons obtained for both anomers of our model compound were simultaneously analyzed to yield the preferred OH-rotamer populations and moreover to parametrize a new Karplus-type equation for (3)J(C(i-1)OH(i)) coupling. The populations of the lowest energy conformers and the conformational-averaged coupling constants were independently calculated using the QM approach in both vacuum and chloroform. The similarity of the estimated rotamer populations obtained by two very different techniques and the similarity of the experimental and calculated coupling constants suggest that these approaches can be used in conjunction and in a fully integrated way to determine a more accurate atomic level description of molecular conformers.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Experimentally Determined and Qm Calculated Scalar Coupling mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Combined NMR three‐bond scalar coupling measurements and QM calculations to calculate OH‐rotamer equilibrium of polyalcohols

et al. 2008

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The Krapcho Dealkoxycarbonylation Reaction of Esters with α‐Electron‐Withdrawing Substituents

Krapcho

Ciganek

2013

Organic Reactions

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The Krapcho reaction involves esters with α‐electron‐withdrawing substituents such as malonates, β‐keto esters, and α‐cyano esters, which undergo dealkoxycarbonylation on being heated in polar aprotic solvents (such as DMSO, DMF, or HMPT) in the presence of water, or in polar aprotic solvents with water in the presence of added salts (such as NaCN, NaCl, LiCl, LiI, or MgCl 2 ). This procedure avoids the use of strongly aqueous acidic and alkaline conditions and tolerates many functional and protecting groups. The chapter presents the mechanistic aspects of this procedure, which include reaction parameters such as solvents, salts, other additives, and the use of microwave irradiation. The diastereoselectivity of protonation of the enolate intermediate leading to the dealkoxycarbonylated products is discussed. Trapping of the intermediate enolate by electrophiles other than a proton is illustrated. Potential side reactions and same‐pot subsequent reactions of substrates are discussed along with functional‐group compatibility for halogens and nitrogen, oxygen, sulfur, selenium, and carbon functional groups. Several examples of applications of this methodology for the synthesis of natural products along with experimental conditions and procedures are presented. Closely related methods are discussed in the Comparison with Other Methods section. The tables, which consist of 371 pages, are grouped according to substrate structure. Selective entries for other methods (excluding classical aqueous acidic or basic methods) are included in the tabular survey for comparative purposes.

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