摘要:

AbstractHydride abstraction of tricarbonyl[η4‐1‐(phenylsulfonyl)‐1,3‐cyclohexadiene]iron(0) complex 2 with Ph3C+PF6−regiospecifically provided the title compound 3 in excellent yield. Cationic complex 3 could react with a variety of nucleophiles in good yields. Soft nucleophiles prefer to attack at the C‐5 position, whereas hard nucleophiles such as methyllithium and the enolate of ethyl acetate gave the C‐5 as well as the C‐2 addition products. Some synthetic applications of the addition products w

ISSN:0009-4536    

DOI:10.1002/jccs.199700054

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThio‐substituted dienes bearing an enone moiety were readily prepared from 3‐sulfolenes, and their intramolecular Diels‐Alder (IMDA) reactions were studied. Octahydronaphthalenones were produced in good yield with high stereoselectivity. Hexahydroindenones were also obtained, but the stereoselectivity was

ISSN:0009-4536    

DOI:10.1002/jccs.199700055

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThe isolation and identification of twenty‐two components from the heartwood ofBauhinia purpureaare described. Their structures were determined on the basis of spectral evidence as well as direct comparison with authentic samples. Those components included six steroids, two triterpenoids, three fatty alcohol, acid and ester, two glycerols, five flavonoids, two phenols, one chromone, and one sugar. Among these, 6′‐(β‐sitosteryl‐3‐O‐β‐glucopyranosidyl)tetraeicosanoate

ISSN:0009-4536    

DOI:10.1002/jccs.199700056

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractSeven kaurane‐type diterpenoids were isolated from the Taiwanese liverwortsJungermannia truncata.Among them, three are new structures. They are:ent‐16‐kauren‐3, 15‐dione (6),ent‐16(S)‐kauran‐3,15‐dione (7), andent‐14α‐hydroxy‐16‐kauren‐15‐one (11). FromPlagiochila pulcherrima, three known kaurane alcohols were also isolated along with sesquiterpenoids plagiochilines A, B, C andent

ISSN:0009-4536    

DOI:10.1002/jccs.199700057

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractLead tetraacetate oxidation on caryachine, a pavine alkaloid possessing a phenolic group at the positionparato theN‐methine, in dichloromethane yielded four products — 10‐acetoxy‐O‐acetyl‐caryachine, 10‐acetoxycaryachine, 7‐acetoxy‐O‐acetylcaryachine and (6S, 11R, 12R)‐11‐acetoxy‐O‐acetyl‐caryachine. The reaction took place via adoption of an acetoxy group at a position majorlyorthoto the phenolic group, but very minorly at the desired benzylic posi

ISSN:0009-4536    

DOI:10.1002/jccs.199700058

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThe steroids were derivatised with aroyl chloride to yield the corresponding benzoates. Among them, their 4‐methoxybenzoates were obtained in greatest yield and were analyzed by HPLC with the smallest detection limit (10 ng) by means of a UV detector (254 nm). This method of derivatization can be applied for analysis of steroids and triterpenoids from crude products with the HPLC techniqu

ISSN:0009-4536    

DOI:10.1002/jccs.199700059

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThe hydrogens at 3‐position of diazepam, a frequently prescribed anxiolytic drug worldwide, undergo an efficient exchange with deuterium atoms in alkaline deuterated methanol. The position of deuterium exchange is confirmed by proton nuclear magnetic resonance and mass spectral analyses. A base‐catalyzed keto‐enol tautomerism is proposed to be responsible for the observed deuterium exchange. This finding has been applied to the preparation of tritium‐labeled diazepam in which only aromatic protons are labeled with tritium atoms. A tritium‐labeled diazepam lacking tritium atoms at 1 and 3 positions is valuable as a substrate for quantitative metabolis

ISSN:0009-4536    

DOI:10.1002/jccs.199700060

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractIn this study we prepared N,O‐bidentate ligands, sodium salt of 5‐(4′‐hydroxyphenylimino)quinolin‐8‐one, and sodium salt of 5,8‐quinolinequinone‐5‐(8‐hydroxy‐5‐quinolylimide) [indoöxine]. According to experimental results, formation of nickel complexes causes a large bathochromic shift of the absorption bands; in addition, these absorption bands appear in the near‐infrared region at 678‐812 nm. Also, EA,13C NMR, UV, and IR were performed to characterize these complexes. The above results suggest that coordination occurs via the oxygen atom of the quinoneimine moiety and the nitrogen

ISSN:0009-4536    

DOI:10.1002/jccs.199700061

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractChlorination of ribofuranose or 2‐deoxyribofuranose derivatives was carried out in a 1,4‐dioxane solution of hydrogen chloride. This improved procedure allowed the syntheses of 1‐chloro‐α‐D‐ribofuranose and 1‐chloro‐2‐deoxy‐α‐D‐ribofuranose derivatives and offered ease of handling, high yield, and the stereo‐contro

ISSN:0009-4536    

DOI:10.1002/jccs.199700062

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThe denaturation effect of urea and guanidine hydrochloride on (lie adenosine deaminase has been investigated spectrophotometrically at the two temperatures of 27 °C and 37 °C at pH = 7.50, phosphate buffer (55 mM). A simple, reversible two stale transition, N ⇔︁ D, was used to analyze the denaturation process from which conformational stability was estimated using three different methods, namely, the linear extrapolation method (LEM), Tanford's model (TM), and the denaturant binding method (DBM). A good agreement was observed among these methods. The results from free energy of denaturation at zero concentration of denaturant, ΔG°H2O, show the fragile conformation for adenosine deaminase m

ISSN:0009-4536    

DOI:10.1002/jccs.199700063

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY