摘要:

AbstractThe tricyclic nucleoside 8‐amino‐4‐methylthio‐6‐methyl‐2‐(β‐D‐ribofuranosyl)‐1,2,3,5,6,7‐hexaazaacenaphthylene (3) was synthesized from 3‐cyano‐4,6‐bis(methylthio)‐1‐(β‐D‐ribofuranosyl)pyrazolo[3,4‐d]pyrimidine (1). Attempts to synthesize 8‐amino‐6‐methyl‐2‐(β‐D‐ribofuranosyl)‐1H‐2,6‐dihydro‐1,2,3,5,6,7‐hexaazaacenaphthylene (5) ([an aza analog of 6‐amino‐4‐methyl‐8‐(β‐D‐ribofuranosyl)‐1,3,4,5,8‐pentaazaacenaphthylene (TCN)], which is a potent antitumor agent), by the treatment of3with Raney nickel did not afford the desired aza analog of TCN. Instead, it was established that a reductive cleavage of the pyridazine moiety of3had occurred to give 4‐methylamino‐6‐methylthio‐1‐(β‐D‐ribofuranosyl)‐1H‐pyrazolo[3,4‐d]pyrimidine‐3‐carboxamidine (6). Assuming that solubility was a problem in the reductive step, the isopropylidene derivative of3, 8‐amino‐6‐methyl‐4‐methylthio‐2‐(2,3‐O‐isopropylidene‐β‐D‐ribofuranosyl)‐2,6‐dihydro‐1,2,3,5,6,7‐hexaazaacenaphthylene (8), was treated with Raney nickel, only to observe that a similar reductive ring cleavage of8had occurred to afford 4‐methylamino‐6‐methylthio‐1‐(2,3‐O‐isopropylidene‐β‐D‐ribofuranosyl)‐1H‐pyrazolo[3,4‐d]pyrimidine‐3‐carboxamidine (10) and 4‐methylamino‐1‐(

ISSN:0022-152X    

DOI:10.1002/jhet.5570280101

出版商:Wiley‐Blackwell    

年代:1991

数据来源: WILEY

摘要:

AbstractThe title derivatives were synthesized containing two meso‐tri‐p‐tolylpheneleneporphyrin units attachedviaamide bridges to 4,7‐and 4,4′ positions of the respective heteroaromati

ISSN:0022-152X    

DOI:10.1002/jhet.5570280102

出版商:Wiley‐Blackwell    

年代:1991

数据来源: WILEY

摘要:

AbstractThe first regiospecific synthesis of the 2,3‐dihydrothieno[2,3‐b]thiophene ring system was achieved using an intramolecular Michael addition in the key cyclization step. This strategy represents a novel and potentially general method for dihydrothiophene and dihydrothiopheneS,S‐dioxide annell

ISSN:0022-152X    

DOI:10.1002/jhet.5570280103

出版商:Wiley‐Blackwell    

年代:1991

数据来源: WILEY

摘要:

AbstractThe synthesis of novel thiophene‐2‐carboxylic acids bearing alkyl and aryl‐substituted oxazole and oxadiazole rings is reported. Sequential functionalization of the key precursor, 5‐formyl‐2‐thiophenecarboxylic acid furnished the intermediate carboxylic acid esters which were converted into desired acids by bas

ISSN:0022-152X    

DOI:10.1002/jhet.5570280104

出版商:Wiley‐Blackwell    

年代:1991

数据来源: WILEY

摘要:

AbstractThe suspected environmental contaminants phenanthro[2,3‐h]isoquinoline12and phenanthro[3,2‐h]isoquinoline11were synthesized in four steps from a common intermediate 1,4‐phenanthroquinone3, using a Diels‐Alder r

ISSN:0022-152X    

DOI:10.1002/jhet.5570280105

出版商:Wiley‐Blackwell    

年代:1991

数据来源: WILEY

摘要:

AbstractStarting from 2,3‐dichloro‐1,4‐naphthaquinone a series of 2‐hydroxy‐1‐methylbenz[f]indolequinones bearing benzyl‐, amino‐ and hydroxy substituents in position3, and benz[f]isatinquinone have been synthesised and their reactions ha

ISSN:0022-152X    

DOI:10.1002/jhet.5570280106

出版商:Wiley‐Blackwell    

年代:1991

数据来源: WILEY

摘要:

AbstractHydrazidoyl halides were condensed with 2‐mercaptobenzimidazole yielding4a‐cand7a,bwhich were cyclized to the corresponding 2‐arylhydrazonothiazolo[3,2‐a]benzimidazol‐3‐ones5a,band 3‐substituted 2‐arylazo thiazolo[3,2‐a]benzimidazoles8a,brespectively. Imidazo[2,1‐b]thiazoles were obtained by the reaction of hydrazidoyl halides with 2‐mercapto‐4,5‐dihydroimidazole. Also, hydrazidoyl halides6a,bwere reacted with 3‐amino‐4‐mercapto‐5‐phenylpyrazole to give pyrazolo[4,3‐b]thiazines15a,b. The structures of the products were assigned on the basis of their

ISSN:0022-152X    

DOI:10.1002/jhet.5570280107

出版商:Wiley‐Blackwell    

年代:1991

数据来源: WILEY

摘要:

AbstractTreatment of 1‐(α‐hydroxybenzyl)‐ and 3‐(α‐hydroxybenzyl)indolizines with trifluoroacetic acid in dichloromethane gave phenylbis(α‐indolizinyl)methanes, bis[α‐(indolizinyl)benzyl] ethers and indolizines, depending upon the presence or absence of the substituent at the 2‐ or 5‐position and the rea

ISSN:0022-152X    

DOI:10.1002/jhet.5570280108

出版商:Wiley‐Blackwell    

年代:1991

数据来源: WILEY

摘要:

Abstract1‐Aroyl‐4,5‐dihydro‐5‐methylene‐1H‐pyrazoles1are converted upon oxidation withm‐chloroperbenzoic acid to the pyrazolones2. The same aroyl enamides1are also oxidized with LTA to form the acetoxy derivatives7and8. The reaction mechanism

ISSN:0022-152X    

DOI:10.1002/jhet.5570280109

出版商:Wiley‐Blackwell    

年代:1991

数据来源: WILEY

摘要:

AbstractThe effect of the [2.2.2]cyclophane ring structure on the reduction of 1,2,5‐thiadiazole ring incorporated in cyclophanes1a‐cand2a‐cwas investigated. When reduced by sodium metal in ethanol followed by acetylation, para[23]cyclophane1gave a mixture of the expectedcis‐andtrans‐diamides,3and4, in which4was the major product. On the other hand, reduction of1with lithium aluminum hydride proceeded in acis‐selective manner and gave3as a major product after a treatment of the reduced products with acetic anhydride. The reduction of metacyclophane2, which is less strained than1, proceeded exclusively incis‐fashion and a subsequent treatment of the reduction product with acetic anhydride gave onl

ISSN:0022-152X    

DOI:10.1002/jhet.5570280110

出版商:Wiley‐Blackwell    

年代:1991

数据来源: WILEY