摘要:

AbstractThe synthesis of some pyrrolo[1,2,3‐de]‐1,4‐benzothiazine derivatives by using a modified Bischler type cyclization ofN‐(2,2‐diethoxyethyl)‐2H‐1,4‐benzothiazines as a crucial step is described. The alternative approach based on Friedel‐Crafts alkylation of theN‐(2‐chloroethyl)‐2H‐1,4‐benzothiazines is shown to be impractical du

ISSN:0022-152X    

DOI:10.1002/jhet.5570270601

出版商:Wiley‐Blackwell    

年代:1990

数据来源: WILEY

摘要:

Abstract2,6‐Dichloro‐3‐(trifluoromethyl)pyridine3was used to develop a six‐step preparation of 7‐amino‐4‐oxo‐6‐(trifluoromethyl)naphthyridines. The CF3group deactivated the pyridine ring towards both nucleophiles and electrophiles. A new reagent for pyridone annulation, the aminomethylidenemalonate anion, is described, along with several strategies to manipulate the electron density of subs

ISSN:0022-152X    

DOI:10.1002/jhet.5570270602

出版商:Wiley‐Blackwell    

年代:1990

数据来源: WILEY

摘要:

Abstract4‐Aminocyclopenta‐, 4‐aminocyclohexa‐, and 4‐aminocycloheptathieno[2,3‐b]pyridines were synthesized in very low overall yield by four‐step procedures starting from bis(2‐thienylammonium) hexachlorostannate(IV) and 2‐hydroxymethylenecyclopentanone, 2‐methoxymethylenecyclohexanone, and 2‐hydroxymethylenecyclohe

ISSN:0022-152X    

DOI:10.1002/jhet.5570270603

出版商:Wiley‐Blackwell    

年代:1990

数据来源: WILEY

摘要:

AbstractA variety of novel 1,2‐disubstituted‐1,2‐di(benzotriazol‐1‐yl)ethane and 1,2‐di(benzotriazol‐1‐yl)ethylene derivatives were prepared from the adduct of benzotriaz

ISSN:0022-152X    

DOI:10.1002/jhet.5570270604

出版商:Wiley‐Blackwell    

年代:1990

数据来源: WILEY

摘要:

AbstractAn efficient synthesis of the novel triazoloquinazoline adenosine antagonist, CGS 15943, is reported in five steps in approximately 50% overall yield. A key reaction in the synthetic sequence is the double cyclization of anN‐(substituted‐2‐cyanophenyl)carbamate with a carboxylic acid hydrazide to afford a [1,2,4]triazolo‐[1,5‐c]quinazolin‐5(6H)‐one in high yield without either a Dimroth or “translocative” rearrangement occurring. Another key reaction is the condensation of a 2‐(1H‐1,2,4‐triazol‐5‐yl)benzenamine with cyanamide under acidic condit

ISSN:0022-152X    

DOI:10.1002/jhet.5570270605

出版商:Wiley‐Blackwell    

年代:1990

数据来源: WILEY

摘要:

AbstractTreatment of certain diaminomethylenehydrazones1of aromatic carbonyl compounds with ethylN‐cyanoimidate (2) in acetonitrile in the presence of a tertiary amine at room temperature gives the corresponding amino(N‐cyanoiminomethyl)aminomethylenehydrazones3in high yields. The intermediate3can readily be cyclized to the corresponding 5‐amino‐2,3‐dihydro[1,2,4]triazolo[1,5‐a][1,3,5]triazines4in moderate to good yields by brief heating in acetonitrile. When the reaction of diaminomethylenehydrazones1with ethylN‐cyanoimidate (2) is performed at reflux temperature in the presence of a tertiary amine, 5‐amino‐2,3‐dihydro[1,2,4]triazolo[1,5‐a]1,3,5]triazines4can be directly obtained in moderate yields. The yields of triazolotriazine produced by the one‐step synthesis are generally comparable or even higher than the overall yields from

ISSN:0022-152X    

DOI:10.1002/jhet.5570270606

出版商:Wiley‐Blackwell    

年代:1990

数据来源: WILEY

摘要:

AbstractTricyclic analogs of piperazinylthiopyrano[3,2‐d]pyrimidine hypoglycemic agents were prepared. The angular tricyclic systems, 8,9‐dihydro‐7H‐thiopyrano[2,3‐e][1,2,4]triazolo[4,3‐a]pyrimidine and 8,9‐dihydro‐7H‐tetrazolo[1,5‐a]thiopyrano[2,3‐e]pyrimidine derivatives were synthesized from 2,4‐dichloro‐7,8‐dihydro‐6H‐thiopyrano[3,2‐d]pyrimidine in three step sequences. Derivatives of the linear tricyclic system, 5,6‐dihydro‐7H‐thiopyrano[3,2‐d][1,2,4]triazolo[2,3‐a]pyrimidine, were prepared by condensation of 3‐amino‐1,2,4‐triazole with ethyl 3‐oxo‐tetrahydropyran‐2‐carboxylate. The tricyclic hetero

ISSN:0022-152X    

DOI:10.1002/jhet.5570270607

出版商:Wiley‐Blackwell    

年代:1990

数据来源: WILEY

摘要:

AbstractTriacetylmethane (1) reacts with amidinohydrazines in acidic medium to afford 4‐acetyl‐3,5‐dimethylpyrazole amidinohydrazone derivatives2,4. However, a similar reaction of1with thiosemicarbazide or semicarbazide led mainly to 3,5‐dimethylpyrazole (6). The great propensity of1to hydrolysis accounts for this last transformation, as well as for the fact that with guanidine it led to 2‐amino‐4,6‐dimethylpyrimidine (10) and withS‐methylisothiourea it provided the unexpected 2‐amino‐4‐methyl‐6‐methy

ISSN:0022-152X    

DOI:10.1002/jhet.5570270608

出版商:Wiley‐Blackwell    

年代:1990

数据来源: WILEY

摘要:

Abstract5‐Benzyl and 5‐benzyloxybenzyl‐substituted 3′‐azido‐2′,3′‐dideoxyuridine, (8aand8b), 3′‐halogeno‐2′,3′‐dideoxyuridine,9a, 9b, 10a, 10b, 11aand11b, and 2′,3′‐dideoxyuridine,12aand12b, of Scheme I were synthesized as potential anti AIDS agents. Synthesis of epimers of8aand8b, 5‐benzyl‐ and 5‐benzyloxybenzyl‐1‐(3′‐azido‐2′,3′‐dideoxy‐β‐D‐threo‐pentafuranosyl)uracil,15aand15b, and 5‐benzyl‐ and 5‐benzyloxy‐5′

ISSN:0022-152X    

DOI:10.1002/jhet.5570270609

出版商:Wiley‐Blackwell    

年代:1990

数据来源: WILEY

摘要:

AbstractCarbazoledioxazines with linear type structure (5,15‐dialkyl‐8,18‐dichloro‐5,15‐dihydrodiindolo[3,2‐b:‐3′,2′‐m]triphenodioxazine) were selectively synthesized by demethanolation ring closure of 2,5‐bis(2‐methoxy‐9‐alkyl‐3‐carbazolylamino)‐3,6‐dichloro‐1,4‐benzoquinone in a high boiling solvent. The structure has been confi

ISSN:0022-152X    

DOI:10.1002/jhet.5570270610

出版商:Wiley‐Blackwell    

年代:1990

数据来源: WILEY