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1.
Ganesabaskaran Sivaprasad Radhakrishnan Sridhar Paramasivan T. Perumal 《Journal of heterocyclic chemistry》2006,43(2):389-394
A selective and easy method is described for the synthesis of 4,5‐dihydro‐2H‐benzo[g]indazoles and 8,9‐dihydro‐2H‐benzo[e]indazoles by the Vilsmeier‐Haack reaction of various tetralone phenylhydrazones under thermal and microwave irradiation conditions. 相似文献
2.
Sergey M. Desenko Evgeny S. Gladkov Svetlana V. Shishkina Oleg V. Shishkin Sergey A. Komykhov Valery D. Orlov Herbert Meier 《Journal of heterocyclic chemistry》2006,43(6):1563-1567
The condensation of 5‐amino‐4‐phenyl‐1,2,3‐triazole ( 1 ) with chalcones 2a‐e or 3‐dimethylamino‐propiophenone ( 4f ) leads to the 6,7‐dihydro‐(1,2,3)‐triazolo[1,5‐a]pyrimidines 3a‐f. The equilibrium of 3 and the tautomeric 4,7‐dihydro‐(1,2,3)‐triazolo[1,5‐a]pyrimidines 3′ is described. 相似文献
3.
Braulio Insuasty Fabián Orozco Angélica Garcia Jairo Quiroga Rodrigo Abonia M. Nogueras Justo Cobo 《Journal of heterocyclic chemistry》2008,45(6):1659-1663
Novel 11‐amino‐6‐aryl‐6,7‐dihydroindeno[1,2‐e] pyrimido[4,5‐b][1,4]diazepin‐5(5aH)‐ones 4a‐f were prepared regioselectively by the tricomponent reaction of 4,5,6‐triaminopyrimidine 1, 1,3‐indandione 2 and aromatic aldehydes 3a‐f. The bicomponent approach, using 2,4,5,6‐tetraaminopyrimidine 5 and 2‐aryl‐ideneindandiones 6a‐f as reagents, afforded 9,11‐diamino‐6‐aryl‐6,7‐dihydroindeno[1,2‐e]pyrimido[4,5‐b]‐[1,4]diazepin‐5(5aH)‐ones 7a‐f in good yields and the regioisomeric 8,10‐diamino derivatives 8a‐c in lower yields. Both, bi‐ and tricomponent approaches were performed by microwave irradiation and all products were fully characterized by detailed NMR measurements. 相似文献
4.
Efficient syntheses of dibenz[b,f][1,4]oxazepin‐11(10H)‐one, 5,10‐dihydro‐11H‐dibenzo[b,e][1,4]‐diazepin‐11‐one and 5,11‐dihydro‐6H‐dibenz[b,e]azepin‐6‐one are described using a tandem reductionlactamization sequence. Precursors for these ring systems are available in 1‐3 steps using nucleophilic aromatic substitution and Ullmann coupling methodology. Direct reduction‐lactamization of these compounds using iron powder in acetic acid at 115° affords the target heterocycles in ≥90% yield. 相似文献
5.
H. D. Hollis Showalter 《Journal of heterocyclic chemistry》2006,43(5):1311-1317
Short pathways are described for the synthesis of a representative example of each of the 7,8‐dihydro‐and 1,2,3,4‐tetrahydro‐1,6‐naphthyridine‐5(6H)‐one ring systems from simple pyridine precursors. An attempted synthesis of the related 4,6‐dihydro‐1,6‐naphthyridin‐5(1H)‐one ring system from a common intermediate was unsuccessful. 相似文献
6.
An efficient two respectively three steps procedure for the synthesis of cycloalkyl[b]thieno[3,2‐e]‐pyridine amines was developed and in general good to very good yields were obtained. 相似文献
7.
Hiroshi Maruoka Kenji Yamagata Fumi Okabe Yukihiko Tomioka 《Journal of heterocyclic chemistry》2006,43(4):859-865
The unusual formation of 1‐acyl‐1,2‐dihydro‐3H‐pyrazol‐3‐ones starting from 3‐acyloxypyrazoles by Fries‐type rearrangement is described. Under normal conditions, acylation of 2,4‐dihydro‐3H‐pyrazol‐3‐ones 1 and 2 with acid chlorides or anhydrides in the presence of triethylamine gave the corresponding 3‐acyloxypyrazoles 3a‐f and 4a‐f . Treatment of 3a‐c and 4a‐f with Lewis acid, e.g. titanium(IV) chloride and tin(IV) chloride, caused migration of acyl groups to afford the corresponding 1‐acyl‐1,2‐dihydro‐3H‐pyrazol‐3‐ones 5a‐c and 6a‐f . Interestingly, the reactions of 3‐acyloxypyrazoles 3e and 3f with tin(IV) chloride provided the corresponding tin(IV) complexes 8e and 8f . 相似文献
8.
Guangmin Liu Qingqing Shao Shujiang Tu Longji Cao Chunmei Li Dianxiang Zhou Baoping Han 《Journal of heterocyclic chemistry》2008,45(4):1127-1130
1,2‐dihydro‐pyrimido[1,2‐a]benzimidazole‐3‐carbonitrile derivatives were synthesized via the three‐component reaction of aldehyde, malonodinitrile and 2‐aminobenzimidazole in water under microwave irradiation. The new protocol has the advantages of excellent yield, low cost, reduced environment impact, wide scope and convenient procedure. 相似文献
9.
Pyrazolo[1,5‐a]pyrimidine and imidazo[1,2‐b]pyrazole derivatives were synthesized via intermolecular aza‐Wittig reaction of 5‐(triphenylphosphoranylideneamino)‐3‐phenylpyrazole 3 derived from 5‐amino‐3‐phenylpyrazole with some selected α‐chloroketones. 相似文献
10.
Anton V. Dolzhenko Wai‐Keung Chui Anna V. Dolzhenko 《Journal of heterocyclic chemistry》2006,43(6):1513-1521
The synthesis of ethyl 6‐aryl‐4‐oxo‐4,6‐dihdro‐1(12)(13)H‐pyrimido[2′,1′:4,5][1,3,5]triazino[1,2‐a]‐benzimidazole‐3‐carboxylates ( 4a‐p ) was described via pyrimidine ring annulation to 4‐aryl‐3,4‐dihydro[1,3,5]triazino[1,2‐a]benzimidazole‐2‐amines ( 2a‐p ) which were obtained from 2‐guanidinobenzimidazole ( 1 ). Tautomerism in the prepared compounds was investigated using nmr spectroscopy. Compounds 2a‐p were found to be present in dimethyl sulfoxide solution predominantly as 3,4‐dihyhydro tautomeric form. Compounds 4a‐p existed in dynamic equilibrium of 1‐, 12‐ and 13H‐forms. It was found that methylation of 4a‐d led to 13‐methyl substituted derivatives 9a‐d exclusively. 相似文献
11.
Carlos M. Martínez‐Viturro Domingo Domínguez 《Journal of heterocyclic chemistry》2007,44(5):1035-1043
The total synthesis of chromeno[4,3,2‐de]quinazolin‐2‐ones, ‐quinazolines and ‐pyrrolo[2,1‐b]quinazolines from easily prepared 4‐methoxy‐1‐nitro‐9H‐xanthen‐9‐one is reported. These compounds, in which a 1,3‐diazine ring is fused to the xanthene scaffold, were obtained with good overall yields in very few steps. 相似文献
12.
Yansong J. Lu Bin Hu Mahavir Prashad Shaum Kabadi Oljan Repi
Thomas J. Blacklock 《Journal of heterocyclic chemistry》2006,43(4):1125-1127
Lithiation of N‐protected‐2,3‐dihydro‐1,4‐benzoxazines is described. Lithiation of N‐(tert‐butoxycarbonyl)‐2,3‐dihydro‐1,4‐benzoxazine ( 1 ) with BuLi/TMEDA occurred in the α‐position to nitrogen on the heterocyclic ring, leading to the unexpected ring‐opened product 3 . On the other hand, lithiation of N‐methyl‐2,3‐dihydro‐1,4‐benzoxazine ( 4 ) took place at the oxygen‐adjacent ortho‐position of the aromatic ring. 相似文献
13.
The syntheses of 2‐amino‐s‐triazino[1,2‐a]benzimidazoles from 2‐guanidinobenzimidazoles were successfully carried out by a ring annelation reaction. The regiochemistry of the ring closure of 5‐methyl‐2‐guanidinobenzimidazole with diethyl azodicarboxylate, aldehydes, acetone, diethyl ethoxymethylenemalonate and orthoesters, leading to the formation of s‐triazine ring was studied. High regioselectivity was not observed in any of these reactions. However, the synthesis of s‐triazino[1,2‐a]benzimidazole system was found to be more regioselective than its 3,4‐dihydro analogue. NOESY experiment indicated that the compound, 2‐amino‐4,4‐dimethyl‐3,4‐dihydro‐s‐triazino[1,2‐a]benzimidazole existed predominantly as the 3,4‐dihydro tautomer in dimethyl sulfoxide. It was found to inhibit bovine dihydrofolate reductase with IC50 10.9 μM. 相似文献
14.
A. V. Karnik N. J. Malviya A. M. Kulkarni D. Jaimini B. L. Jadhav 《Journal of heterocyclic chemistry》2006,43(2):489-493
Chemoselective synthesis of novel hetero cyclopenta[b]chrysene derivatives, namely, 6‐Aryl‐2,2a‐dihydro‐naphtho[2′,1′‐5,6]pyrao[4,3‐e][1,2,4]triazolo[3,4‐b][1,3,4]thiadiazine ( 4a‐j ) under neutral condition has been described. These molecules exhibited good to excellent anti‐bacterial activities. 相似文献
15.
Lucija Juki Sorak Gorazd Sorak Renata Toplak David Bevk Jurij Svete Branko Stanovnik 《Journal of heterocyclic chemistry》2006,43(5):1205-1215
In this paper the regiospecific transformations of methyl 2‐(benzyloxycarbonyl)amino‐3‐dimethylaminopropenoate ( 1 ) with hydrazine, alkyl‐, aryl‐ and heteroaryl‐substituted hydrazines via the corresponding hydrazones 12‐16 into pyrazoles 17‐25 are described. Heteroaryl‐substitued hydrazones 13‐16 afforded by oxidation with bromine or lead tetraacetate the corresponding substituted (1,2,4‐triazolo[4,3‐b]pyridazin‐3‐yl)glycinates 27‐30 . Alkyl 2‐(2,2‐disubstituted‐1‐ethenyl)amino‐3‐dimethylaminopropenoates 31‐33 gave with hydrazines alkyl 2‐[2,2‐(disubstituted)ethenyl]amino‐3‐heteroarylhydrazonopropanoates 40‐48 and 2‐alkyl 2,3‐bis((hetero)arylhydrazono)propanoates 51‐55 . 相似文献
16.
Shujiang Tu Qingqing Shao Dianxiang Zhou Longji Cao Feng Shi Chunmei Li 《Journal of heterocyclic chemistry》2007,44(6):1401-1406
Benzo[4,5]imidazo[1,2‐a]pyrimidine derivatives were synthesized via the three‐component reaction of aldehyde, β‐dicarbonyl compound and 2‐aminobenzimidazole in water under microwave irradiation and without catalyst conditions. The new protocol has the advantages of higher yield, lower cost, reduced environment impact, wider scope and convenient procedure. 相似文献
17.
A facile approach was developed on assembly of the 2‐pyridone nucleus by ferric chloride promoted [3+3] cycloaddition in propionic acid. The tandem process involves cyclization of Michael adduct followed by aromatization. Thus, different substituted 1,2‐dihydro‐2‐oxo‐3‐pyridinecarboxylate and 1,2‐dihydro‐2‐oxo‐3‐pyridinecarboxamide derivatives were prepared in good yields from various enones with malonamic ester and malonamide, respectively 相似文献
18.
Alaa A. Hassan Aboul‐Fetouh E. Mourad Kamal M. El‐Shaieb Ashraf H. Abou‐Zied 《Journal of heterocyclic chemistry》2006,43(2):471-475
Reactions of N,N′‐disubstituted hydrazine‐1,2‐carbothioamides 8a‐c and substituted N,N″‐ethane‐1,2‐diylbis(thioureas) 9a‐c with 2,3,5,6‐tetrachloro‐1,4‐benzoquinone (chloranil, 10a ) and 2,3,5,6‐tetrabromo‐1,4‐benzoquinone (bromanil, 10b ) to form N,N′‐disubstituted 1,3,4‐thiadiazole‐2,5‐diamines 11a‐c , substituted 3‐amino‐6,7‐dichloro‐2,3‐dihydro‐1H‐4,2,1‐benzothiadiazine‐5,8‐diones 12a‐c , 2,3,7,8‐tetrahalothianthrene‐1,4,6,9‐tetrones 13a,b , substituted 5,6,8‐trihalo‐7‐oxo‐3,7‐dihydroquinoxaline‐2H‐carbothioamides 14a‐c, 15a‐c and 7‐substituted imino‐1,3,6‐thiadiazepane‐2‐thiones 16a‐c are reported. 相似文献
19.
Thermal decomposition of 5‐azidopyrido[2,3‐d]pyrimidines 2 and 7 having reactive ortho‐substituents such as a formyl or a nitro group yielded isoxazolo[3′,4′:4,5]pyrido[2,3‐d]pyrimidines 3 or oxadiazolo‐[3′,4′:4,5]pyrido[2,3‐d]pyrimidines 9. The reaction conditions of the azide decomposition were studied by differential scanning calorimetry (DSC). In addition, desoxygenation of N‐oxides 9 to oxadiazoles 10 and regioselective reduction of azides 7 to amines 8 were studied. 相似文献
20.
Jií Hanusek Pavel Drabina Milo Sedlk Pavel Rosa 《Journal of heterocyclic chemistry》2006,43(5):1281-1285
Acylation of 2‐amino‐N‐methyl‐thiobenzamide with substituted benzoyl chlorides has been used to synthesize the corresponding 2‐benzoylamino‐N‐methylthiobenzamides. Subsequent sodium methoxide‐catalyzed ring closure gives the corresponding 3‐methyl‐2‐phenylquinazoline‐4‐thiones. These compounds were characterized by means of their 1H‐ and 12C‐NMR spectra. The kinetics of the cyclization reaction has been followed with UV‐VIS spectroscopy at 100 °C in methanolic solutions of sodium methoxide. 相似文献