1(4H)-Naphthalenones in anthracyclinone synthesis: a new route for the total synthesis of (.+-.)-aklavinone

Hauser, Frank M.; Hewawasam, Piyasena; Rho, Young S.

doi:10.1021/jo00282a028

Cited by 22 publications

(3 citation statements)

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“…Thus a new more efficient procedure was proposed 232 for the preparation of racemic aklavinone [(AE)-212] starting from readily available compounds, viz., phthalide sulfone 193b and enone 214b (the total yield was * 17% with respect to 2-ethylacrolein used as the starting compound for the preparation of the enone 214b). The first regio-and enantiospecific synthesis of a compound of the anthracyclinone series, viz., the preparation of ( 7)-(R)-7,11dideoxy-13-deoxydaunomycinone (216) from the anion of phthalide sulfone 193d and enantiomerically pure enone 215, was performed.…”

Section: Reactions Of Amentioning

confidence: 99%

Sulfones and sulfoxides in the total synthesis of biologically active natural compounds

Prilezhaeva¹

2000

Russ. Chem. Rev.

185

103

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A graphical treatment of the tone reproduction problem in television systems satisfactorily answered by extensive experimental work, using the techniques of subjective appraisal which have been increasingly developed in recent years. Direct comparison of a reproduction and an original, with all the parameters of the system accurately known, calls, of course, for a considerable experimental effort. Such limited observations as have been made, however, suggest that the shape of the curves at least gives a good impression of the relative effects of viewing cathode-ray tubes with different values of A, and operating under, different conditions. It is not intended to draw any conclusions or express any as to what form of reproduction characteristic is most desirable. There can, however, be little doubt that there are instances where faithful reproduction is not desirable -where, in fact, the television system can improve on the eye and convey the maximum of information or enhance the asthetic value of a scene by emphasizing certain luminosity differences at the expense of others. To a large extent the value of such distortions must be a matter of personal preference.What constitutes the most desirable form of characteristic is, again, a question which calls for large-scale experiment on a subjective basis; factors such as signal-to-noise ratio and the effect of the characteristic on apparent definition have to be taken into account.Reference may be made in passing to the results of Jones's investigation into the preferences of a large number of observers in the matter of photographic prints.Q) This investigation tends to show that preferred prints are those in which the gradient of the logL,/logL, curve is approximately unity for the medium tones, and that a greater fall in the gradient is acceptable towards black. It would be unwise to assume, however, that the results obtained are necessarily applicable to television practice, where the form of the transfer characteristics and the viewing conditions are different. One general principle which does not seem to be in dispute is that, whereas a considerable tolerance exists when the reproduction is in monochrome, colour calls for a much closer approach to fidelity in luminosity reproduction.Large-area luminance range in modern aluminized cathoderay tubes, in the absence of external light, appears to offer little scope for worth-while improvement. It is worth noting, however, that the importance of good detail luminance range in determining the subjective quality of television pictures has been stressed by Law@) and other writers.Assuming that an optimum characteristic, or range of characteristics, can be defined, practical realization of the optimum raises a number of issues, e.g. the relative contributions of the transmitting and receiving apparatus to the overall result, and whether the desired objective can best be arrived at by selection of the camera or cathode-ray tube characteristic or by suitable circuit design.It is hoped that the present communication may help...

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Section: Reactions Of Amentioning

confidence: 99%

Sulfones and sulfoxides in the total synthesis of biologically active natural compounds

Prilezhaeva¹

2000

Russ. Chem. Rev.

185

103

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“…In the case of benzylic α-oxy sulfones, Bu t OLi has been widely used. [209][210][211][212][213][214][215][216] Deprotonation with Bu t OK in liquid ammonia has also been reported. 217 For α-oxy β-keto sulfones, a tertiary amine can be used, 218,219 as well as inorganic bases (caesium carbonate) in the case of α-oxy disulfones.…”

Section: Deprotonation Of -Oxy Sulfonesmentioning

confidence: 92%

α-Oxy sulfones and sulfoximines: versatile intermediates

Chemla

2002

J. Chem. Soc., Perkin Trans. 1

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“…In the precedent publications, we frequently used Michael-type condensation [13][14][15][16] or Friedel-Crafts acylation [17,18] for the total synthesis of anthracyclinone derivatives. Here, we report the successful preparation of a new aglycon containing an ester linkage at C-14 through a nucleophilic displacement esterification method.…”

mentioning

confidence: 99%

SYNTHESIS OF NEW ANTHRACYCLINE DERIVATIVES CONTAINING PYRUVIC, ASPARTIC, ORN-ACETYLASPARTIC ACID MOLECULE

Rho

Park

Kim

et al. 2002

Synthetic Communications

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1(4H)-Naphthalenones in anthracyclinone synthesis: a new route for the total synthesis of (.+-.)-aklavinone

Cited by 22 publications

References 0 publications

Sulfones and sulfoxides in the total synthesis of biologically active natural compounds

Sulfones and sulfoxides in the total synthesis of biologically active natural compounds

α-Oxy sulfones and sulfoximines: versatile intermediates

SYNTHESIS OF NEW ANTHRACYCLINE DERIVATIVES CONTAINING PYRUVIC, ASPARTIC, ORN-ACETYLASPARTIC ACID MOLECULE

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