摘要:

AbstractThe structure of C‐alkaloid‐O (1=his HCL‐salt) was established on the basis of spectral data and comparison with the analogous compound2, synthesized from a natural product of known absolute configuration. Internally consistent13C‐NMR. assignments are given for1, 2, huntrabrine methochloride(4)and its diacetate deri

ISSN:0018-019X    

DOI:10.1002/hlca.19830660202

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

The Dicyanation of 1,4‐Diaminoanthraquinones and the Reactivity of 1,4‐Diamino‐9,10‐dioxo‐9,10‐dihydroanthracene‐2,3‐dicarbonitriles towards Nucleophilic ReagentsThe reaction of 1‐amino‐9, 10‐dioxo‐4‐phenylamino‐9,10‐dihydroanthracene‐2‐sulfonic acid (1, RC6H5) with cyanide in water yields a mixture of 1‐amino‐9,10‐dioxo‐4‐phenylamino‐9,10‐dihydroanthracene‐2‐carbonitrile (3, R  C6H5) and 1‐amino‐4‐(phenylamino)anthraquinone (4, R  C6H5) under the usual reaction conditions(Scheme 1). In dimethylsulfoxide, however, a second cyano group is introduced, and 1‐amino‐9,10‐dioxo‐4‐phenylamino‐9,10‐dihydroanthracene‐2,3‐dicarbonitrile(7)is formed(Scheme 2). The cyano groups are very reactive towards nucleophiles. The cyano group in 2‐position can be substituted by hydroxide and aliphatic amines(Schemes 5and6). The cyano group in 3‐position can be eliminated by aliphatic amines and hydrazine(Scheme 7). Nucleophilic attack at the cyano C‐atom of the 2‐cyano group by suitable reagents leads to ring formation, yieldinge.g.2‐(Δ2‐1, 3‐ox

ISSN:0018-019X    

DOI:10.1002/hlca.19830660203

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

AbstractEight triterpenoid saponins(1–8)have been isolated from the berries ofLonicera nigraL.(Caprifoliaceae)by combination of droplet counter‐current chromatography and column chromatography on silica. The structures have been established by1H‐NMR.,13C‐NMR. spectroscopy, FD.‐MS., FAB.‐MS. and D./CI.‐MS., and on the basis of acidic and basic hydrolyses. The monodesmosidic saponins1–5possess strong molluscicidal activity against the schistosomiasis‐transmitting snailBiomphalaria glabrata, whereas the bidesmosidic saponi

ISSN:0018-019X    

DOI:10.1002/hlca.19830660204

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

Spirocoleons: Synthesis and Characterization of Four Diastereomeric Spiro (methylcyclopropane) Substructures; Revision of the Configuration at C(12) and C(15) of Coleon P and Derivatives and Coleon‐Z Derivatives; X‐Ray Analysis of Lanugon J and of Further SpirocoleonsX‐ray analyses show the correctness of the previously published structure of coleon Q(1), establish the structure of lanugon J(4a), and necessitate a revision of the configuration at C(12) and C(15) in coleon P(3a)and its derivatives3band3c, and furthermore of the coleon Z derivatives11a–11d. Two further diastereomeric spiro (methylcyclopropane) substructures have been generated by photoisomerization of lanugon J(4a)and 12‐O‐desacetylcoleon N(8); they represent the novelcis‐typeBwith (12R, 13R, 15S)‐ and the noveltrans‐typeDwith (12R, 13R, 15R)‐configuration(Scheme 1). The structures of the photoproducts5a((12R, 13R, 15R)‐lanugon J) and7a((12R, 13R, 15S)‐lanugon J) were established by X‐ray analysis. So far, only two of the eight possible diastereomers of the spiro‐(methylcyclopropane) substructureIhave been detected in nature,i.e.thetrans‐typeAwith (12R, 13S, 15S)‐ and thecis‐typeCwith (12R, 13S, 15R)‐configuration. The four diastereomersA‐D, all possessing (12R)‐configuration, show very similar properties. However, careful comparison of spectral and chiroptical data allow a differentiation, even in the case of functionalization of H3C(17). The (12S)

ISSN:0018-019X    

DOI:10.1002/hlca.19830660205

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

AbstractA general scheme for the synthesis of the tetrahydroisoindolinone moiety of naturally occurring cytochalasans and unnatural analogs was developed. The key‐step consists of theintermolecular [2+4]cycloaddition of 4‐methylsorbinol (7) to an alkylidene malonic ester derivative such as6, 9or10, obtained from the corresponding amino acids. The products obtained,4a, 17, and18were converted to the desired lactams5, 21, and22.Cycloaddition of the diene alcohol7to the optically active alkylidene malonic ester derivative9b(s. Footnote 5) prepared fromL‐leucine gave compound17bwith 98% enantiomeric excess. The optical activity was retained during the conversion of17bto the lactam21b. The latter is a subunit for the synthesis of the aspochal

ISSN:0018-019X    

DOI:10.1002/hlca.19830660206

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

Multifidene1is a chemical messenger for male gametes of the brown algaCutleria multifida. The synthesis of messenger analogues with a tetrahydrofurane ring will be reported. The general synthetic approach offers the possibility to prepare a great variety of stereospecific 2,3‐ and 3,4‐cis/trans‐disubstituted tetrahydrof

ISSN:0018-019X    

DOI:10.1002/hlca.19830660207

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

AbstractThe biosynthesis of the benzo[c]phenanthridine alkaloids was investigated in a cell suspension culture ofMacleaya cordata (papaveraceae). Feeding experiments define the biosynthetic pathway (–)‐7,8,13,13a‐tetrahydrocoptisine →(–)‐cis‐N‐methyl‐7,8,13,13a‐tetrahydrocoptisinium salt15→ protopine(5)→ sanguinarine(1)→ che

ISSN:0018-019X    

DOI:10.1002/hlca.19830660208

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

AbstractThe production of (S)‐ethyl 3‐hydroxybutyrate(2)from ethyl acetoacetate(1)in higher yields and with higher optical purity than with the usual procedures was achieved by continuous addition of the substrate1and sucrose to an aerated suspension of bakers' yeast. The microbial reduction of1by the fungusGeotrichum candidumLINKyields ‐ for the first time ‐ the an

ISSN:0018-019X    

DOI:10.1002/hlca.19830660209

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

A Rapid Purification ofD‐Oxynitrilase from Almond Meal by Affinity ChromatographyOxynitrilase from almond meal is capable of catalyzing the stereospecific addition of cyanide to a variety of aldehydes. Thus, the enzyme is potentially useful in the synthesis of optically active cyanohydrins on a preparative scale [1]. As the currently available purification procedures for this enzyme [2]are rather tedious, we have elaborated a simple and rapid procedure based on affinity chromatography. An inhibitor for the enzyme, methylp‐(3‐aminopropoxy)benzoate(4), has been synthesized and attached covalently toSepharose 4Bas a solid matrix(5). With this affinity gel it was possible to prepare theD‐oxynitrilase in a simple procedure with high

ISSN:0018-019X    

DOI:10.1002/hlca.19830660210

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY

摘要:

Carotenoids from Hips ofRosa pomifera: Discovery of (5Z)‐Neurosporene; Synthesis of (3R, 15Z)‐RubixanthinExtensive chromatographic separations of the mixture of carotenoids from ripe hips ofR. pomiferahave led to the identification of 43 individual compounds, namely(Scheme 2): (15Z)‐phytoene(1), (15Z)‐phytofluene(2), all‐(E)‐phytofluene(2a), ξ‐carotene(3), two mono‐(Z)‐ξ‐carotenes (3aand3b), (6R)‐ϵ, ψ‐carotene(4), a mono‐(Z)‐ϵ, ψ‐carotene(4a), β, ψ‐carotene(5), a mono‐(Z)‐β, ψ‐carotene(5a), neurosporene(6), (5Z)‐neurosporene(6a), a mono‐(Z)‐neurosporene(6b), lycopene(7), five (Z)‐lycopenes(7a–7e), β, β‐carotene(8), two mono‐(Z)‐β, β‐carotenes (probably (9Z)‐β, β‐carotene(8a)and (13Z)‐β, β‐carotene(8b)), β‐cryptoxanthin(9), three (Z)‐β‐cryptoxanthins(9a–9c), rubixanthin(10), (5′Z)‐rubixanthin (=gazaniaxanthin;10a), (9′Z)‐rubixanthin(10b), (13′Z)‐ and (13Z)‐rubixanthin(10cand10d, resp.), (5′Z, 13′Z)‐ or (5′Z, 13Z)‐rubixanthin(10e), lutein(11), zeaxanthin(12), (13Z)‐zeaxanthin(12b), a mono‐(Z)‐zeaxanthin (probably (9Z)‐zeaxanthin(12a)), (8R)‐mutatoxanthin(13), (8S)‐mutatoxanthin(14), neoxanthin(15), (8′R)‐neochrome(16), (8′S)‐neochrome(17), a tetrahydroxycarotenoid(18?), a tetrahydroxy‐epoxy‐carotenoid(19?), and a trihydroxycarotenoid of unknown structure.Rubixanthin(10)and (5′Z)‐rubixanthin(10a)can easily be distinguished by HPLC. separation and CD. spectra at low temperature. The synthesis of (3R, 15Z)‐rubixanthin(29)is described.The isolation of (5Z)

ISSN:0018-019X    

DOI:10.1002/hlca.19830660211

出版商:WILEY‐VCH Verlag GmbH    

年代:1983

数据来源: WILEY