摘要:

Efficient cleavage of the C(1)—C(2) bond in 9,10-dibromocamphor (3) provides a chiral intermediate (5) that can be used in a new enantiospecific synthesis of estrone.

ISSN:0008-4042    

DOI:10.1139/v87-001

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

The fungusArmillariamellea(Vahl ex. Fr.) Kummer is responsible for severe losses in timber and fruit production. The metabolites isolated when certain strains of this fungus are grown in liquid culture have been identified as diterpenoid acids possessing the abietane (1) and pimarane (2) skeletons. These compounds, known collectively as resin acids, have not been reported previously from a fungal source. In addition to the resin acids dehydroabietic acid (3), pimaric acid (4), isopimaric acid (5), and sandaracopimaric acid (6), three additional acids, levopimaric acidendo-peroxide (7), 7-oxodehydroabietic acid (9), and 7-oxo-15-hydroxydehydroabietic acid (10) were obtained. On one occasion three orange pigments, austocystin F (11), averufin (12), and averufanin (13), all previously known fungal metabolites, were isolated.

ISSN:0008-4042    

DOI:10.1139/v87-002

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

The structure of bullerone (3), a minor metabolite of the bird's nest fungusCyathusbulleriBrodie, has been determined by a combination of chemical and spectroscopic methods. The possible biogenesis of bullerone, a new skeletal class of sesquiterpenoid, is discussed.

ISSN:0008-4042    

DOI:10.1139/v87-003

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Treatment of 3-aryl-2-carbomethoxy-4,5-dihydro-1,4-benzothiazepines withN-chlorosuccinimide in ether gave 3-aryl-4-carbomethoxyisoquinolines in a reaction in which the sulfur atom was extruded from the seven-membered thiazepin ring.

ISSN:0008-4042    

DOI:10.1139/v87-004

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

To test the feasibility of a biogenetically inspired synthesis of edulone A1, podocarpic acid3ahas been transformed into a substituted hexahydrophenalene16b. The critical steps involve introduction of a double bond into the A ring, cleavage by ozone, and, after suitable manipulation, an epoxy-arene cyclization. A second product from this cyclization is an octahydrophenaleno[1,9-bc]furan17.

ISSN:0008-4042    

DOI:10.1139/v87-005

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Methyl penicillanate has been synthesized by condensation ofD-penicillamine with three different variations of the synthon RO2CCH2CHO, followed by esterification of the resulting 4-carboxythiazolidine-2-acetic acid ester, removal of R, and Mukaiyama ring closure. The conditions for the synthesis of an analogous 4-carboxyoxazolidine-2-acetic acid ester, containing anN-benzoyl protecting group, have been worked out. The condensation of threonine with diethinylketone does not lead directly to a vinylogous oxapenam.

ISSN:0008-4042    

DOI:10.1139/v87-006

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

The formal synthesis of aklavinone and the first synthesis of 4,11-dideoxy-α-rhodomycinone are described. Oxidative decyanation of the tetracyclic nitrile to the corresponding ketone using a strong base (LDA) constitutes an important strategy in the synthesis of both these compounds.

ISSN:0008-4042    

DOI:10.1139/v87-007

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Two new tetranortriterpenoids, trijuginsA(1) andB(3), isolated from the leaves ofHeyneatrijuga(Meliaceae), have been shown to be derivatives of methyl angolensate but with a novel carbon skeleton having a contracted ring C. The structures were assigned on the basis of detailed1H and13C nuclear magnetic resonance spectroscopic examination including 2D long-range δC/δHcorrelation and homonuclear1H nuclear Overhauser effect difference experiments.

ISSN:0008-4042    

DOI:10.1139/v87-008

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

The oxidation of sulfonhydrazides with benzeneseleninic acid provides an efficient and convenient preparation of selenosulfonates. Se-Phenylp-tolueneselenosulfonate was also produced in good to excellent yield from the reaction ofp-toluenesulfonhydrazide with PhSeCl, PhSeBr3, or PhSeCl3. Sulfonhydrazides react with sulfenyl halides or with PhSBr3to produce thiosulfonates in generally high yield. The treatment ofp-toluenesulfonhydrazide with benzenetellurinic acid, PhTeCl3, or PhTeBr3afforded only diphenyl ditelluride and not the corresponding tellurosulfonate.

ISSN:0008-4042    

DOI:10.1139/v87-009

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

The malonate anion intramolecular displacement of propargylic or allylic chlorides, and of primary bromide, in eleven- and twelve-carbon chains containing either two, one, or no unsaturation centers leads to the corresponding 11- and 12-membered ring compounds in good yield under conditions of medium dilution.

ISSN:0008-4042    

DOI:10.1139/v87-010

出版商:NRC Research Press    

年代:1987

数据来源: NRC