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Part I : = Total synthesis of the macrolide antitumor antibiotic lankacidin C. Part II : Total synthesis of the acaricidal antitumor alkaloid altemicidin.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Part I :/
Reminder of title:	Total synthesis of the macrolide antitumor antibiotic lankacidin C. Part II : Total synthesis of the acaricidal antitumor alkaloid altemicidin.
Author:	Liu, Kun.
Description:	1 online resource (247 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 57-07, Section: B.
Contained By:	Dissertations Abstracts International57-07B.
Subject:	Organic chemistry. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9603755click for full text (PQDT)
ISBN:	9798641561417

Part I : = Total synthesis of the macrolide antitumor antibiotic lankacidin C. Part II : Total synthesis of the acaricidal antitumor alkaloid altemicidin.
Liu, Kun.

Part I :Total synthesis of the macrolide antitumor antibiotic lankacidin C. Part II : Total synthesis of the acaricidal antitumor alkaloid altemicidin. - 1 online resource (247 pages)

Source: Dissertations Abstracts International, Volume: 57-07, Section: B.

Thesis (Ph.D.)--University of Rochester, 1995.

Includes bibliographical references

Part I. The first total synthesis of natural (-)-Lankacidin C (1) has been achieved by a convergent, enantioselective sequence starting from D-arabinose and L-aspartic acid, proceeding through the tricyclic carbamate 47 as an advanced relay intermediate. Specifically, the β-lactam diene intermediate 72 is acylated by the thiopyridyl ester 65c. The resulting β-ketolactam 73 is stereospecifically reduced by KEt3BH to carbinol 74, which on desilylation undergoes acid-catalyzed N→O acyl migration to yield the δ-lactone 75. The derived iodo aldehyde 77 undergoes Stille coupling to give tetraene 97, which upon Stork-Takahashi cyclization to ketone 100 and CBS reduction gives the key relay 47. N-acylation of the latter, then regioselective carbamate scission followed by Dess-Martin oxidation, produces the target antibiotic, (-)-Lankacidin C (1). Part II. The first total synthesis of the structurally novel 6-azaindene alkaloid (-)-altemicidin (1) has been achieved in a stereocontrolled fashion. Enantioselection began by using the chiral dienophile 6, which was derived from L-serine (12). Stereospecific Diels-Alder cycloaddition of 6 and cyclopentadiene according to the Reetz protocol afforded the optically pure adduct 5, thereby establishing the stereocenters at C(1), C(3a) and C(7a) in one synthetic operation. Highly regioselective Rh(I)-mediated hydroboration of the double bond in 5 produced carbinol 19 as a single isomer. Although the Baeyer-Villiger oxidation of ketone 20 gave only the undesired methylene migrating lactone 21, the oxazolidinone derivative 34 produced on oxidation by pertrifluoroacetic acid a 5:4 mixture of the expected bridgehead migrating lactone 4 and the methylene migrating product 35. Selective debenzylation of the BOC derivative 49, followed by sequential acidic removal of the BOC group and transannular lactam formation afforded 51. The enantio-directing CH2OBn group was then removed after hydroxyl protection to give piperidone derivative 77, which was reduced to piperidine 78 by lithium diethoxyaluminum hydride. N-debenzylation and N-methylation was achieved through an one-pot process to produce 71. Modified Potier-Polonovski reaction on N-oxide 79 afforded the vinylogous trifluoromethylamide 80, which was further elaborated to give the amino alcohol 84. Coupling of 84 and sulfamoyl acid 85 generated amide 86. Nucleophilic cleavage of the methyl ester by n-PrSLi followed by Haller-Bauer fragmentation produced the target alkaloid, (-)-altemicidin (1).

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2023

Mode of access: World Wide Web

ISBN: 9798641561417Subjects--Topical Terms:

523952
Organic chemistry.
Index Terms--Genre/Form:

542853
Electronic books.

Part I : = Total synthesis of the macrolide antitumor antibiotic lankacidin C. Part II : Total synthesis of the acaricidal antitumor alkaloid altemicidin.
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035 $a AAI9603755
040 $a MiAaPQ $b eng $c MiAaPQ $d NTU
100 1 $a Liu, Kun. $3 3451383
245 1 0 $a Part I : $b Total synthesis of the macrolide antitumor antibiotic lankacidin C. Part II : Total synthesis of the acaricidal antitumor alkaloid altemicidin.
264 0 $c 1995
300 $a 1 online resource (247 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertations Abstracts International, Volume: 57-07, Section: B.
500 $a Publisher info.: Dissertation/Thesis.
500 $a Advisor: Kende, Andrew S.
502 $a Thesis (Ph.D.)--University of Rochester, 1995.
504 $a Includes bibliographical references
520 $a Part I. The first total synthesis of natural (-)-Lankacidin C (1) has been achieved by a convergent, enantioselective sequence starting from D-arabinose and L-aspartic acid, proceeding through the tricyclic carbamate 47 as an advanced relay intermediate. Specifically, the β-lactam diene intermediate 72 is acylated by the thiopyridyl ester 65c. The resulting β-ketolactam 73 is stereospecifically reduced by KEt3BH to carbinol 74, which on desilylation undergoes acid-catalyzed N→O acyl migration to yield the δ-lactone 75. The derived iodo aldehyde 77 undergoes Stille coupling to give tetraene 97, which upon Stork-Takahashi cyclization to ketone 100 and CBS reduction gives the key relay 47. N-acylation of the latter, then regioselective carbamate scission followed by Dess-Martin oxidation, produces the target antibiotic, (-)-Lankacidin C (1). Part II. The first total synthesis of the structurally novel 6-azaindene alkaloid (-)-altemicidin (1) has been achieved in a stereocontrolled fashion. Enantioselection began by using the chiral dienophile 6, which was derived from L-serine (12). Stereospecific Diels-Alder cycloaddition of 6 and cyclopentadiene according to the Reetz protocol afforded the optically pure adduct 5, thereby establishing the stereocenters at C(1), C(3a) and C(7a) in one synthetic operation. Highly regioselective Rh(I)-mediated hydroboration of the double bond in 5 produced carbinol 19 as a single isomer. Although the Baeyer-Villiger oxidation of ketone 20 gave only the undesired methylene migrating lactone 21, the oxazolidinone derivative 34 produced on oxidation by pertrifluoroacetic acid a 5:4 mixture of the expected bridgehead migrating lactone 4 and the methylene migrating product 35. Selective debenzylation of the BOC derivative 49, followed by sequential acidic removal of the BOC group and transannular lactam formation afforded 51. The enantio-directing CH2OBn group was then removed after hydroxyl protection to give piperidone derivative 77, which was reduced to piperidine 78 by lithium diethoxyaluminum hydride. N-debenzylation and N-methylation was achieved through an one-pot process to produce 71. Modified Potier-Polonovski reaction on N-oxide 79 afforded the vinylogous trifluoromethylamide 80, which was further elaborated to give the amino alcohol 84. Coupling of 84 and sulfamoyl acid 85 generated amide 86. Nucleophilic cleavage of the methyl ester by n-PrSLi followed by Haller-Bauer fragmentation produced the target alkaloid, (-)-altemicidin (1).
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2023
538 $a Mode of access: World Wide Web
650 4 $a Organic chemistry. $3 523952
655 7 $a Electronic books. $2 lcsh $3 542853
690 $a 0490
710 2 $a ProQuest Information and Learning Co. $3 783688
710 2 $a University of Rochester. $3 515736
773 0 $t Dissertations Abstracts International $g 57-07B.
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9603755 $z click for full text (PQDT)