摘要:

AbstractArrhenius parameters were measured for the methoxy‐lechlorination reactions of some chloroderivatives of isoxazolo[4,5‐c]‐ and [5,4‐b]pyridine. A comparison of these results with the kinetic data for the corresponding chloropyridines shows that fusion of the isoxazole ring with the pyridine ring strongly increases the reactivity of the 4‐ and 6‐positions toward nucleophilic s

ISSN:0022-152X    

DOI:10.1002/jhet.5570160111

出版商:Wiley‐Blackwell    

年代:1979

数据来源: WILEY

摘要:

AbstractThe main nmr parameters of 1,2,4‐triazino[4,5‐b]indazole derivatives were measured on the basis of their13C nmr spectral analysis compared to indazole models.1J C‐H coupling constants were studied and the correct structure of 1,2,4‐triazino[4,5‐b]indazoles was e

ISSN:0022-152X    

DOI:10.1002/jhet.5570160112

出版商:Wiley‐Blackwell    

年代:1979

数据来源: WILEY

摘要:

AbstractAs a continuation of recent study on the synthesis of abis[1,4]oxathiinodipyridine ring system, we would now like to report the preparation of 7‐chlorobenzo[1″,2″:5,6:3″,4″:5′,6′]‐bis[1,4]oxathiino[3,2‐b: 3′,2′‐b]dipyridine. Although a potentially complex reaction with several products possible, the title compound was formed exclusively, suggesting considerable mechanistic selectivity. The characterization of the product by FT‐1H‐nmr as well as its mass spectral fragmentation

ISSN:0022-152X    

DOI:10.1002/jhet.5570160113

出版商:Wiley‐Blackwell    

年代:1979

数据来源: WILEY

摘要:

AbstractThe behaviour of the aminopyrazole derivatives 1a‐c, 2‐amino‐4‐phenylthiazole (2) and 2‐amino‐5‐phenyl‐1,3,4‐thiadiazole (3) toward the action of ethoxycarbonyl and benzoyl iso‐thiocyanate is reported. The data clearly demonstrates the dependence of the nature of the products obtained from the reaction of isothiocyanates with cyclic amidines on the nature of the substituents on th

ISSN:0022-152X    

DOI:10.1002/jhet.5570160114

出版商:Wiley‐Blackwell    

年代:1979

数据来源: WILEY

摘要:

AbstractReaction of tertiary α‐substituted acetanilides with Vilsmeier reagent has been found to give 1,3‐disubstituted‐carbostyrils, 1. α‐Chloro‐N‐(1‐cyclohexen‐1‐yl) acetamides are similarly converted to tetrahydro carbostyrils 2 and 3. The method appears useful for the preparation of a variety of 1,3‐substituted 2(1H) quinolinones. The scope and mechanism of the reaction has been investigated, with evidence presented to indicate the ring‐closure proceedsviaelectrophilic attack of Vilsmeier reagent on in

ISSN:0022-152X    

DOI:10.1002/jhet.5570160115

出版商:Wiley‐Blackwell    

年代:1979

数据来源: WILEY

摘要:

AbstractThin layer chromatographic Rfdata on silica gel are reported for 64 compounds containing either a thiole sulfur atom, one or more azine nitrogen atoms, or both. Thiole adsorbates are compared with 28 aromatic hydrocarbons and non‐heterocyclic sulfur compounds. In general the orders of Rfvalues found are thioles>sulfides>sulfones>sulfoxides>azineN‐oxides and azines>azine‐N‐oxides. Results are interpreted in terms of hydrogen bonding from the silica gel to the adsorbate. The different orders of adsorbability found amongst four series of condensed thiophenes and their arene analogs for chromatography on silica gel and on alumina are rationalized in terms of planarity and acid‐base interactions. Correlations of the tlc data with separations on columns are

ISSN:0022-152X    

DOI:10.1002/jhet.5570160116

出版商:Wiley‐Blackwell    

年代:1979

数据来源: WILEY

摘要:

Abstract1‐Deoxy‐1‐diazo‐3,6‐anhydro‐4,5,7‐tri‐O‐benzoyl‐D‐allo‐heptulosc (III) has been prepared from 2,5‐anhydro‐3,4,6‐tri‐O‐benzoyl‐D‐allonic acid. 1,3‐Dipolar cycloaddition of III to benzyne afforded the indazole C‐nucleoside analog V. Cycloaddition of methyl 6‐deoxy‐6‐diazo‐2,3‐O‐isopropylidene‐β‐D‐ribohexofuranosid‐5‐ulose (IV) to the benzyne generated from 5‐methyl‐anthranilic acid gave a mixture of the β‐isomericC‐glycosylindazoles VI and VII along with traces of the corresponding α‐anomers VIa and VIIa. Finally, a multistep transformation of the acyclic carbohydrate moiety of 2,3,4,5‐tetra‐O‐acetyl‐1‐(indazol‐3‐yl)‐keto‐D‐ribopentulose (I, R = H, n =3, D‐ribo) led to theC

ISSN:0022-152X    

DOI:10.1002/jhet.5570160117

出版商:Wiley‐Blackwell    

年代:1979

数据来源: WILEY

摘要:

AbstractThe synthesis of three new racemic aporphine alkaloids (1b, 1cand2) is reported and these alkaloids are fully characterized. The method of synthesis involved either a Bischler‐Napieralski‐Psehorr sequence or a Reissert alkylation‐Pschorr cyclization route. The Pschorr cyclization also gave the morphinandienones7aand7b, respect

ISSN:0022-152X    

DOI:10.1002/jhet.5570160118

出版商:Wiley‐Blackwell    

年代:1979

数据来源: WILEY

摘要:

AbstractThe dipolar 1,4‐cycloaddition of dichloroketene toN,N‐disubstituted 3‐amino‐1‐phenyl‐2‐propene‐1‐onesled directly toN,N‐disubstituted 4‐amino‐3‐chloro‐6‐phenyl‐2H‐pyran‐2‐ones only in the case of an usual aliphaticN,N‐disubstitution. In the case of partial or full aromaticN‐substitution,N,N‐disubstituted 4‐amino‐3,3‐dichloro‐3,4‐dihydro‐6‐phenyl‐2H‐pyran‐2‐ones were instead obtained, which were dehydrochlorinated with D

ISSN:0022-152X    

DOI:10.1002/jhet.5570160119

出版商:Wiley‐Blackwell    

年代:1979

数据来源: WILEY

摘要:

AbstractThe homolytic arylation (substituents in the phenyl radical: none, p‐methyl, p‐fluoro, p‐chloro, p‐bromo, o‐chloro, 2,4‐dichloro, 3,5‐dichloro, 2,3,4‐trichloro, 2,3,5‐trichloro, o‐carbomethoxy, p‐carboethoxy, and o‐phenyl) and heteroarylation (2‐thiazolyl, 2‐benzothiazolyl, 3‐pyridyl) of coumarin and benzo[b] furan has been studied. The radicals were generated by thermal decomposition of the corresponding 1,3‐diaryltriazenes in the presenceof isoamyl nitrite. Homolytic substitution of coumarin takes place exclusively in the position3, in agreement with the prediction based on SCF‐MO free valences. In the case of benzo[b]furan, all the reactivity indices (F, Sr, and Ar) predict the position 2 to be most reactive, in agreement with the experimental results. Comparison of the mass spectra of the products indicates similarities between the spectra of arylcoumarins and arylbenzo[b]furans and the existence of a common intermediate in their fragmentation pattern,viz., the benzo[b]furan cation radical.One of the authors (G.V.) wishes to thank Prof. A. Maquestiau (Mons, Belgium) for useful suggestions concerning mass spectrometry. One of the authors (CP.) should like to thank the Ministere de l'Education Nationale, le Secretariat d Etat aux Universités, Paris, for a visiting professorship, and the National Science Foundation, Washington, D. C. for a travel grant. Also, the authors wish to express thanks to Mrs. G. Vernin fo

ISSN:0022-152X    

DOI:10.1002/jhet.5570160120

出版商:Wiley‐Blackwell    

年代:1979

数据来源: WILEY