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1.
An efficient one‐pot synthesis of 3‐[(4,5‐dihydro‐1H‐pyrrol‐3‐yl)carbonyl]‐2H‐chromen‐2‐one (=3‐[(4,5‐dihydro‐1H‐pyrrol‐3yl)carbonyl]‐2H‐1‐benzopyran‐2‐one) derivatives 4 by a four‐component reaction of a salicylaldehyde 1 , 4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one, a benzylamine 2 , and a diaroylacetylene (=1,4‐diarylbut‐2‐yne‐1,4‐dione) 3 in EtOH is reported. This new protocol has the advantages of high yields (Table), and convenient operation. The structures of these coumarin (=2H‐1‐benzopyran‐2‐one) derivatives, which are important compounds in organic chemistry, were confirmed spectroscopically (IR, 1H‐ and 13C‐NMR, and EI‐MS) and by elemental analyses. A plausible mechanism for this reaction is proposed (Scheme 2). 相似文献
2.
Efficient Solvent‐Free Synthesis of Benzothiazine‐Fused Pyrrolo[3,4‐c]coumarins: Cycloaddition Reactions between Coumarin‐Based Dihydrobenzothiazoles and Isocyanides 下载免费PDF全文
Mehdi Khoobi Ali Ramazani Mohammad Mahdavi Alireza Foroumadi Saeed Emami Sang Woo Joo Katarzyna Ślepokura Tadeusz Lis Abbas Shafiee 《Helvetica chimica acta》2014,97(6):847-853
A new and unusual synthesis of benzothiazine‐fused pyrrolo[3,4‐c]coumarins, involving the ring‐opening of coumarin‐based dihydrobenzothiazoles and subsequent [4+1] cycloaddition reaction with isocyanides, was described. Thus, simple heating of various 3‐(2,3‐dihydro‐2‐methylbenzo[d]thiazol‐2‐yl)coumarins with isocyanides produced the title compounds in good yields under solvent‐free conditions. 相似文献
3.
The reactions of the heterocyclic imines 5,6‐dihydro‐2H‐[1,3]oxazines and 2H‐1,4‐benzothiazines with different substituted acetyl chlorides in the presence of triethylamine forming β‐lactams were examined focusing on the stereochemistry of the Staudinger reaction. 相似文献
4.
Antonín Klásek Antonín Lyčka Michal Rouchal Ondřej Rudolf Aleš Růžička 《Helvetica chimica acta》2014,97(5):595-612
3‐Aminoquinoline‐2,4‐diones were stereoselectively reduced with NaBH4 to give cis‐3‐amino‐3,4‐dihydro‐4‐hydroxyquinolin‐2(1H)‐ones. Using triphosgene (=bis(trichloromethyl) carbonate), these compounds were converted to 3,3a‐dihydrooxazolo[4,5‐c]quinoline‐2,4(5H,9bH)‐diones. The deamination of the reduction products using HNO2 afforded mixtures of several compounds, from which 3‐alkyl/aryl‐2,3‐dihydro‐1H‐indol‐2‐ones and their 3‐hydroxy and 3‐nitro derivatives were isolated as the products of the molecular rearrangement. 相似文献
5.
Selective Synthesis of New Tetracyclic Coumarin‐fused Pyrazolo[3,4‐b]pyridines and Pyrazolo[3,4‐b]pyridin‐6(7H)‐ones 下载免费PDF全文
A three‐component reaction for the synthesis of new coumarin‐fused tetracyclic system from 4‐hydroxycoumarin, aldehydes, and 5‐aminopyrazoles/5‐aminoisoxazole is described. In the presence of acetic acid, 4,7‐dihydro‐1H‐pyrazolo[3,4‐b]pyridines ( 4 ) and pyrazolo[3,4‐b]pyridines ( 5 ) were obtained in acetonitrile and dimethylsulfoxide medium, respectively. The reaction gave rise to 4,5‐dihydro‐1H‐pyrazolo[3,4‐b]pyridin‐6(7H)‐ones ( 6 ) in acetic acid–ethanol combination system, which involved the C–O bond cleavage. 4‐Hydroxy‐6‐methyl‐2H‐pyran‐2‐one and acenaphthylene‐1,2‐dione were also examined, affording the corresponding C–O bond cleavage products. Mechanism indicates that the reaction is reversible in acetic acid–ethanol combination system. 相似文献
6.
Ahmad Shaabani Fatemeh Hajishaabanha Hamid Mofakham Mojtaba Mahyari Bagher Lali 《Helvetica chimica acta》2012,95(2):246-254
A novel and efficient isocyanide‐based multicomponent reaction between alkyl or aryl isocyanides 1 , 2,3‐diaminomaleonitrile ( 2 ), naphthalene‐2,3‐diamines ( 6 ) or benzene‐1,2‐diamine ( 9 ), and 3‐oxopentanedioic acid ( 3 ) or Meldrum's acid ( 4 ) or ketones 7 was developed for the ecologic synthesis, at room temperature under mild conditions, of 1,6‐dihydropyrazine‐2,3‐dicarbonitriles 5a – 5f in H2O without using any catalyst, and of 3,4‐dihydrobenzo[g]quinoxalin‐2‐amine and 3,4‐dihydro‐3,3‐dimethyl‐quinoxalin‐2‐amine derivatives 8a – 8g and 10a – 10e , respectively, in the presence of a catalytic amount of p‐toluenesulfonic acid (TsOH) in EtOH, in good to excellent yields (Scheme 1). 相似文献
7.
Keng‐Shiang Huang Sie‐Rong Li You‐Feng Wang Yu‐Li Lin Yung‐Hua Chen Tzu‐Wei Tsai Chih‐Hui Yang Eng‐Chi Wang 《中国化学会会志》2005,52(1):159-167
Synthesis of some benzoheterocyclic compounds like substituted benzofurans, 4‐methyl‐2H‐chromenes and 3,4‐dihydro‐2H‐benzo[b]oxepin‐5‐ones from 2‐hydroxyacetophenone via base induced cyclization and ring‐closing metathesis (RCM) is described. 相似文献
8.
A Facile Synthesis of Aryl‐Substituted Hydrazono‐Pyrazolyl[1,2,4]triazolo[3,4‐b][1,3,4][thiadiazol]‐coumarin Derivatives 下载免费PDF全文
Some inimitable and therapeutic coumarin‐substituted fused[1,2,4]triazolo‐[3,4‐b][1,3,4]thiadizole derivatives were synthesized by the cyclocondensation reaction of 2‐oxo‐2H‐chromene‐3‐carboxylic acid ( 1 ) and 4‐amino‐5‐hydrazinyl‐4H‐[1,2,4]‐triazole‐3‐thiol ( 2 ) by using phosphorous oxychloride as a cyclizing agent. This cyclized intermediate 3‐(3‐hydrazino‐[1,2,4]triazolo[3,4‐b][1,3,4]thiadiazol‐6‐yl)‐chromen‐2‐one ( 3 ) later condensation with various ethyl 2‐(2‐arylhydrazono)‐3‐oxobutanoates ( 4 ) in NaOAc/MeOH under reflux conditions afforded the corresponding new series of aryl‐substituted hydrazono‐pyrazolyl‐[1,2,4]triazolo[3,4‐b][1,3,4][thiadiazol]‐coumarin derivatives ( 5 ) in good to excellent yields. The structures of newly synthesized compounds were established on the basis of elemental analysis, IR, 1H NMR and mass spectroscopic studies. 相似文献
9.
Stanislas Mayer Axelle Arrault GRald Guillaumet Jean‐Yves Mrour 《Journal of heterocyclic chemistry》2001,38(1):221-225
Ethyl 3,4‐dihydro‐2H‐1,4‐benzoxazine‐3‐carboxylate derivatives 2 were obtained and isolated in low yields from the condensation of 2‐aminophenol and ethyl 2,3‐dibromopropanoate. They can be obtained by hydrogenation of ethyl 2H‐1,4‐benzoxazine‐3‐carboxylate in satisfactory yield. Using 2‐iminophenol did not direct the condensation with ethyl 2,3‐dibromopropanoate towards 2 but was fruitfull for the preparation of ethyl 2‐(4‐benzyl‐3,4‐dihydro‐2H‐1,4‐benzoxazin‐3‐yl)acetate from ethyl bromocrotonate. 相似文献
10.
The chemoselectivity in the palladium‐catalyzed intramolecular cyclization of 2‐(o‐bromoaryl)‐alkenenitriles depends on the nature of α‐substitutents. 2‐(o‐Bromoanilino)alkenenitriles attacked the cyano group, followed by the cyano group transposition and hydrolysis, to give o‐(methylamino)benzonitrile. 2‐(o‐Bromobenzyl)alkenenitriles, 2‐(o‐bromophenylthio)alkenenitriles and 2‐(o‐bromophenoxy)‐alkenenitriles attacked the olefinic double bonds and led to l‐vinyl‐2‐indancecarbonitrile, 1,2,3,4‐tetrahydronaphthalene‐2‐carbonitriles, 3,4‐dihydro‐2H‐benzo[b]thiine‐2‐carbonitriles, and 3,4‐dihydro‐2H‐benzo[b]oxine‐2‐carbonitriles. A general mechanism for the palladium‐catalyzed arylations is proposed. 相似文献
11.
Kazuhiro Kobayashi Toshihide Komatsu Yuki Yokoi Hisatoshi Konishi 《Helvetica chimica acta》2011,94(1):67-72
An efficient synthesis of 3‐alkyl‐3,4‐dihydro‐4‐thioxobenzoquinazolin‐2(1H)‐ones 3 has been accomplished in two steps and in satisfactory yields from 1‐bromo‐2‐fluorobenzenes 1 . Thus, the reaction of 1‐fluoro‐2‐lithiobenzenes, generated by the Br/Li exchange between 1 and BuLi, with alkyl isothiocyanates, gives N‐alkyl‐2‐fluorobenzothioamides 2 , which, in turn, react with a series of isocyanates in the presence of NaH to give the desired products 3 . 相似文献
12.
Cherng‐Chyi Tzeng I.‐Li Chen Yeh‐Long Chen Tai‐Chi Wang Ya‐Ling Chang Che‐Ming Teng 《Helvetica chimica acta》2000,83(2):349-358
In continuation of our search for potent antiplatelet agents, we have synthesized and evaluated several α‐methylidene‐γ‐butyrolactones bearing 3,4‐dihydroquinolin‐2(1H)‐one moieties. O‐Alkylation of 3,4‐dihydro‐8‐hydroxyquinolin‐2(1H)‐one ( 1 ) with chloroacetone under basic conditions afforded 3,4‐dihydro‐8‐(2‐oxopropoxy)quinolin‐2(1H)‐one ( 2a ) and tricyclic 2,3,6,7‐tetrahydro‐3‐hydroxy‐3‐methyl‐5H‐pyrido[1,2,3‐de][1,4]benzoxazin‐5‐one ( 3a ) in a ratio of 1 : 2.84. Their Reformatsky‐type condensation with ethyl 2‐(bromomethyl)prop‐2‐enoate furnished 3,4‐dihydro‐8‐[(2,3,4,5‐tetrahydro‐2‐methyl‐4‐methylidene‐5‐oxofuran‐2‐yl)methoxy]quinolin‐2(1H)‐one ( 4a ), which shows antiplatelet activity, in 70% yield. Its 2′‐Ph derivatives, and 6‐ and 7‐substituted analogs were also obtained from the corresponding 3,4‐dihydroquinolin‐2(1H)‐ones via alkylation and the Reformatsky‐type condensation. Of these compounds, 3,4‐dihydro‐7‐[(2,3,4,5‐tetrahydro‐4‐methylidene‐5‐oxo‐2‐phenylfuran‐2‐yl)methoxy]quinolin‐2(1H)‐one ( 10b ) was the most active against arachidonic acid (AA) induced platelet aggregation with an IC50 of 0.23 μM . For the inhibition of platelet‐activating factor (PAF) induced aggregation, 6‐{[2‐(4‐fluorophenyl)‐2,3,4,5‐tetrahydro‐4‐methylidene‐5‐oxofuran‐2‐yl]methoxy}‐3,4‐dihydroquinolin‐2(1H)‐one ( 9c ) was the most potent with an IC50 value of 1.83 μM . 相似文献
13.
One‐Pot Synthesis of 3‐Alkoxy‐2,3‐dihydro‐1H‐isoindol‐1‐ones by the Reactions of 2‐(Azidomethyl)benzoates with NaH 下载免费PDF全文
A new and facile method for the general preparation of 3‐alkoxy‐2,3‐dihydro‐1H‐isoindol‐1‐ones has been developed. Thus, the reaction of 2‐(azidomethyl)benzoates with NaH affords, after workup with H2O, 3‐alkoxy‐2,3‐dihydro‐1H‐isoindol‐1‐ones 2 . 2‐Substituted 3‐alkoxy‐2,3‐dihydro‐1H‐isoindol‐1‐ones 4 can be obtained by adding alkyl halides prior to workup with H2O. 相似文献
14.
Yoshihisa Kurasawa Ayaka Kawase Jun Takizawa Yuka Maesaki Eisuke Kaji Yoshihisa Okamoto Ho Sik Kim 《Journal of heterocyclic chemistry》2005,42(4):551-556
The 3‐amino‐1‐methylpyridazino[3,4‐b]quinoxalin‐4(1H)‐one 6 and N‐(1,4‐dihydro‐1‐methyl‐4‐oxopyridazino[3,4‐b]quinoxalin‐3‐yl)carbamates 17a,b were synthesized from the 1,4‐dihydro‐1‐methyl‐4‐oxopyridazino[3,4‐b]quinoxa‐line‐3‐carboxylate 1b via the 1,5‐dihydro‐4‐hydroxy‐1‐methylpyridazino[3,4‐b]quinoxaline‐3‐carbohydrazide 13b and then 1,4‐dihydro‐1‐methyl‐4‐oxopyridazino[3,4‐b]quinoxaline‐3‐carboxazide 8 . Heating of compound 13b and arylalde‐hydes afforded the 1,4‐dihydro‐1‐methyl‐4‐oxopyridazino[3,4‐b]quinoxaline‐3‐carbo(2‐arylmethylene)hydrazides 14a‐d. 相似文献
15.
Yun‐Mei Bi Xu‐Bin Bi Qian‐Rong Zhao Yuan‐Teng Chen Jin‐Lun Xie 《Helvetica chimica acta》2004,87(11):2890-2895
Four novel dihydroisocoumarin (=3,4‐dihydro‐1H‐2‐benzopyran‐1‐one) glucosides were isolated from a culture broth of a strain of the fungus Cephalosporium sp. AL031. Their structures were elucidated as (2E,4E)‐5‐[(3S)‐5‐acetyl‐8‐(β‐D ‐glucopyranosyloxy)‐3,4‐dihydro‐6‐hydroxy‐1‐oxo‐1H‐2‐benzopyran‐3‐yl]penta‐2,4‐dienal ( 1 ), (2E,4E)‐5‐[(3S)‐5‐acetyl‐8‐(β‐D ‐glucopyranosyloxy)‐3,4‐dihydro‐6‐methoxy‐1‐oxo‐1H‐2‐benzopyran‐3‐yl]penta‐2,4‐dienal ( 2 ), (3S)‐8‐(β‐D ‐glucopyranosyloxy)‐3‐[(1E,3E,5E)‐hepta‐1,3,5‐trienyl]‐3,4‐dihydro‐6‐hydroxy‐5‐methyl‐1H‐2‐benzopyran‐1‐one ( 3 ), and (3S)‐8‐[(6‐O‐acetyl‐β‐D ‐glucopyranosyl)oxy]‐3‐[(1E,3E,5E)‐hepta‐1,3,5‐trienyl]‐3,4‐dihydro‐6‐methoxy‐5‐methyl‐1H‐2‐benzopyran‐1‐one ( 4 ) by spectroscopic methods, including 2D‐NMR techniques and chemical methods. 相似文献
16.
N,N′‐Dioxide/Nickel(II)‐Catalyzed Asymmetric Inverse‐Electron‐Demand Hetero‐Diels–Alder Reaction of β,γ‐Unsaturated α‐Ketoesters with Enecarbamates 下载免费PDF全文
Yuhang Zhou Yin Zhu Dr. Lili Lin Yulong Zhang Jianfeng Zheng Prof. Dr. Xiaohua Liu Prof. Dr. Xiaoming Feng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(50):16753-16758
N,N′‐Dioxide/nickel(II) complexes have been developed to catalyze the inverse‐electron‐demand hetero‐Diels–Alder reaction of β,γ‐unsaturated α‐ketoesters with acyclic enecarbamates. After detailed screening of the reaction parameters, mild optimized reaction conditions were established, affording 3,4‐dihydro‐2H‐pyranamines in up to 99 % yield, 99 % ee and more than 95:5 d.r. The catalytic system was also efficient for β‐substituted acyclic enecarbamates, affording more challenging 2,3,4‐trisubstituted 3,4‐dihydro‐2H‐pyranamine with three contiguous stereogenic centers in excellent yields, diastereoselectivities, and enantioselectivities. The reaction could be scaled up to a gram scale with no deterioration of either enantioselectivity or yield. Based on these experiments and on previous reports, a possible transition state was proposed. 相似文献
17.
Kazuhiro Kobayashi Toshiyuki Nagaoka Yuu Shirai Wataru Miyatani Yuki Yokoi Hisatoshi Konishi 《Helvetica chimica acta》2012,95(2):191-196
A new type of isocoumarins (=1H‐isochromen‐1‐ones=1H‐2‐benzopyran‐1‐ones), 4‐substituted 3,4‐dihydro‐3‐methoxyisocoumarins 2 , can be obtained by a one‐pot process from α‐substituted 2‐bromo‐β‐methoxystyrenes 1 . Thus, lithium 2‐(1‐aryl(or methyl)‐2‐methoxyethenyl)benzoates are conveniently generated via the Br/Li exchange between 1 and BuLi, followed by the action of CO2 on the resulting α‐substituted 2‐lithio‐β‐methoxystyrenes. Upon treating with concentrated HCl at room temperature, these lithium benzoates undergo lactonization to provide the desired 3,4‐dihydroisocoumarins 2 in relatively good yields. 相似文献
18.
H. D. Hollis Showalter Anthony D. Sercel Michael A. Stier William R. Turner 《Journal of heterocyclic chemistry》2001,38(4):961-964
Approaches toward the preparative‐scale synthesis of target 3,4‐dihydro‐1(2H)‐isoquinolinones 1–3 are presented. Compounds 1 and 2 were prepared via a Schmidt rearrangement on easily obtained indanone precursors, but in low overall yield. A better method to make this class of compounds is exemplified by the large‐scale synthesis of 2 via a Curtius rearrangement sequence. Thus, high‐temperature thermal cyclization of an in situ formed styryl isocyanate from precursor 8 in the presence of tributylamine gave the corresponding 1(2H)‐isoquinolinone ( 9 ). Catalytic hydrogenation of 9 provided the desired 3,4‐dihydro‐5‐methyl‐1(2H)‐isoquinolinone ( 2 ) in 65 % overall yield. Similar reduction of a commercially available 5‐hydroxy‐1(2H)‐isoquinolinone precursor 10 followed by an O ‐alkylation/amination sequence gave target 3 in good overall yield. The route proceeding via the Curtius rearrangement is recommended for large scale synthesis of other 3,4‐dihydro‐1(2H)‐isoquinolinones. Only when deactivating substituents or sensitive functionality within the benzenoid ring render the high temperature ring closure of the intermediate isocyanate inefficient might a Schmidt rearrangement protocol be the method of choice. 相似文献
19.
Regioselective Synthesis of Amino Substituted Indazolo[2,1‐b]phthalazine‐triones and Pyrazolo[1,2‐b]phthalazine‐2‐carbonitriles Catalyzed by 2‐1′‐Methylimidazolium‐3‐yl‐1‐ethyl Sulfate 下载免费PDF全文
Yu Wan Chao Wang Xiao‐xiao Zhang Jingjing Shi Shu‐ying Huang Gui‐Xiang Liu Liang‐feng Chen Ling‐ling Zhao Hai‐ying Wang Hui Wu 《Journal of heterocyclic chemistry》2014,51(Z1):E77-E83
The regioselective reactions of luminol with 1,3‐cyclohexanedione (or malononitrile) and aromatic aldehydes catalyzed by 2‐1′‐methylimidazolium‐3‐yl‐1‐ethyl sulfate were developed to synthesize 7‐amino‐3,4‐dihydro‐2H‐indazolo[2,1‐b]phthalazine‐1,6,11(13H)‐triones and 3,9‐diamino‐5,10‐dihydro‐5,10‐dioxo‐1H‐pyrazolo[1,2‐b]phthalazine‐2‐carbonitriles in good to excellent yields in short times. 相似文献
20.
Sheng‐Cai Zheng Qian Wang Jieping Zhu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(27):9313-9317
Racemic 3,4‐dihydro‐2H‐pyrroles, hypothetical intermediates of the Barton–Zard reaction, were synthesized in a highly diastereoselective manner and fully characterized for the first time. Kinetic resolution of the dihydropyrroles with a quinine‐derived thiourea afforded the (+)‐3‐arylpyrrole products and recovered (+)‐3,4‐dihydro‐2H‐pyrroles with high efficiency (s‐factor up to 153). The resolved (+)‐3,4‐dihydro‐2H‐pyrroles underwent subsequent aromatization with a quinidine‐derived thiourea catalyst to afford (?)‐3‐arylpyrroles with excellent central‐to‐axial chirality transfer. In contrast to the well‐accepted Barton–Zard mechanism, the aromatization of the 3,4‐dihydro‐2H‐pyrroles in the presence of a bifunctional catalyst is believed to proceed by an unprecedented sequence involving syn elimination of HNO2 and aromatization. 相似文献