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1.
Thirteen new 2-alkylaminoimidazolones(4) wre rapidly synthesized by a new solution-phase parallel synthetic method,which includes aza-Wittig reaction of iminophosphorane(1) with aromatic isocyanate to give carbodi-imide(2) and subsequent reaction of 2 with various aliphatic primary amine in a parallel fashion.The products were confirmed by ^1H NMR,MS,IR and X-ray crystallographic analysis.The unusual selectivity of the cyclization was probably due to the deometry of the guanidine intermediate. 相似文献
2.
An efficient procedure for the synthesis of N‐alkyl‐2,5‐diaryl‐1,3‐dioxol‐4‐amines 3 via a one‐pot reaction of aromatic aldehydes 2 and alkyl isocyanides 1 at room temperature in good yields is described (Scheme 1, Table). 相似文献
3.
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
4.
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
5.
The 2‐hydroxy‐3,5,5‐trimethylcyclopent‐2‐en‐1‐one ( 1 ) was synthesized in 42% yield by rearrangement of epoxy ketone 10 on treatment with BF3⋅Et2O under anhydrous conditions. Intermediate 10 was available from the known enone 8 , either via direct epoxidation (60% H2O2, NaOH, MeOH; yield 50%), or via reduction to the corresponding allylic alcohol 14 (LiAlH4, THF), followed by epoxidation ([VO(acac)2], tBuOOH) and reoxidation under Swern conditions, in 37% total yield. 相似文献
6.
The title cyclohexenone 1d undergoes photodimerization selectively at the exocyclic C?C bond to give a 1 : 1 mixture of 1,2‐dialkynyl‐1,2‐dimethylcyclobutanes 6 and 7 . On irradiation in the presence of 2,3‐dimethylbuta‐1,3‐diene, 1d affords bicyclo[8.4.0]tetradeca‐1,2,3,7‐tetraen‐11‐one 9 . This – formal – (6+4)‐cycloadduct undergoes quantitative isomerization to 3‐cycloheptadienyl‐2,5,5‐trimethylcyclohex‐2‐enone 11 on treatment with basic silica gel. 相似文献
7.
Kazuhiro Kobayashi Hiroo Hashimoto Teruhiko Suzuki Hisatoshi Konishi 《Helvetica chimica acta》2011,94(11):2002-2009
An efficient method for the synthesis of 2‐aryl‐2,3‐dihydro‐3‐sulfanyl‐1H‐isoindol‐1‐ones 1 via Pummerer‐type cyclization of N‐aryl‐2‐(sulfinylmethyl)benzamides 2 is described. Thus, treatment of these sulfinyl‐benzamides 2 , easily prepared from 2‐(bromomethyl)benzoates 3 in three steps, with Ac2O at ca. 100° resulted in the formation of the desired isoindolones 1 in generally good yields. 相似文献
8.
Ttrans‐3,5‐dihydroperoxy‐3,5‐dimethyl‐1,2‐dioxalane has been used as new, effective, solid, inexpensive and nontoxic oxidant for in situ generation of Br+ from HBr. This system has been applied as catalyst for synthesis of 2‐aryl‐1H‐benzothiazoles and 2‐aryl‐1‐arylmethyl‐1H‐benzimidazoles at room temperature in excellent yields and high purity. 相似文献
9.
The reaction of 1H‐imidazole‐4‐carbohydrazides 1 , which are conveniently accessible by treatment of the corresponding esters with NH2NH2?H2O, with isothiocyanates in refluxing EtOH led to thiosemicarbazides (=hydrazinecarbothioamides) 4 in high yields (Scheme 2). Whereas 4 in boiling aqueous NaOH yielded 2,4‐dihydro‐3H‐1,2,4‐triazole‐3‐thiones 5 , the reaction in concentrated H2SO4 at room temperature gave 1,3,4‐thiadiazol‐2‐amines 6 . Similarly, the reaction of 1 with butyl isocyanate led to semicarbazides 7 , which, under basic conditions, undergo cyclization to give 2,4‐dihydro‐3H‐1,2,4‐triazol‐3‐ones 8 (Scheme 3). Treatment of 1 with Ac2O yielded the diacylhydrazine derivatives 9 exclusively, and the alternative isomerization of 1 to imidazol‐2‐ones was not observed (Scheme 4). It is important to note that, in all these transformations, the imidazole N‐oxide residue is retained. Furthermore, it was shown that imidazole N‐oxides bearing a 1,2,4‐triazole‐3‐thione or 1,3,4‐thiadiazol‐2‐amine moiety undergo the S‐transfer reaction to give bis‐heterocyclic 1H‐imidazole‐2‐thiones 11 by treatment with 2,2,4,4‐tetramethylcyclobutane‐1,3‐dithione (Scheme 5). 相似文献
10.
An effective route to novel 4‐(alkylamino)‐1‐(arylsulfonyl)‐3‐benzoyl‐1,5‐dihydro‐5‐hydroxy‐5‐phenyl‐2H‐pyrrol‐2‐ones 10 is described (Scheme 2). This involves the reaction of an enamine, derived from the addition of a primary amine 5 to 1,4‐diphenylbut‐2‐yne‐1,4‐dione, with an arenesulfonyl isocyanate 7 . Some of these pyrrolones 10 exhibit a dynamic NMR behavior in solution because of restricted rotation around the C? N bond resulting from conjugation of the side‐chain N‐atom with the adjacent α,β‐unsaturated ketone group, and two rotamers are in equilibrium with each other in solution ( 10 ? 11 ; Scheme 3). The structures of the highly functionalized compounds 10 were corroborated spectroscopically (IR, 1H‐ and 13C‐NMR, and EI‐MS), by elemental analyses, and, in the case of 10a , by X‐ray crystallography. A plausible mechanism for the reaction is proposed (Scheme 4). 相似文献
11.
2‐Formylchromones and 3‐formylchromones as the first materials singly reacted with 2‐amino‐5‐mercapto‐1,3,4‐thiadiazole to give the corresponding Schiff bases, which on cyclocondensation with mercapto‐acetic acid in 1,4‐dioxane yielded target compounds named 4‐oxo‐thiazolidines. The structures of all the synthetic compounds were confirmed by elemental analysis and IR, 1H NMR, LC‐MS (ESI) spectral data. 相似文献
12.
5‐Methylene‐2‐oxazolidinone (1) and 5‐methylene‐1,3‐thiazolidine‐2‐thione (4) react with various isocyanates to give the corresponding urethanes 3 and 5 in high yields in the presence of palladium(0) or palladium(II) catalyst under mild reaction conditions. A mechanism is proposed. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
13.
The oxidation of 1‐(3,8‐dimethylazulen‐1‐yl)alkan‐1‐ones 1 with 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (=4,5‐dichloro‐3,6‐dioxocyclohexa‐1,4‐diene‐1,2‐dicarbonitrile; DDQ) in acetone/H2O mixtures at room temperature does not only lead to the corresponding azulene‐1‐carboxaldehydes 2 but also, in small amounts, to three further products (Tables 1 and 2). The structures of the additional products 3 – 5 were solved spectroscopically, and that of 3a also by an X‐ray crystal‐structure analysis (Fig. 1). It is demonstrated that the bis(azulenylmethyl)‐substituted DDQ derivatives 5 yield on methanolysis or hydrolysis precursors, which in a cascade of reactions rearrange under loss of HCl into the pentacyclic compounds 3 (Schemes 4 and 7). The found 1,1′‐[carbonylbis(8‐methylazulene‐3,1‐diyl)]bis[ethanones] 4 are the result of further oxidation of the azulene‐1‐carboxaldehydes 2 to the corresponding azulene‐1‐carboxylic acids (Schemes 9 and 10). 相似文献
14.
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
15.
曾佳吕岫华曾程初胡利明钟儒刚 《中国化学》2009,27(5):953-962
一价铜催化端炔与叠氮化物的1, 3-环加成反应是一种快速构建小分子库并筛选其可能性质的的主要方法。本文报道了1,2,3-三唑取代的1,4-二氢-4-氧代-1,5-二氮杂萘-3-羧酸衍生物的设计与合成。在该类化合物中,疏水性与亲水性片段通过Click反应有效地连接。所设计化合物8和12的结构通过光谱手段进行了表征;其可能的HIV整合酶抑制活性也进行了筛选。 相似文献
16.
4‐(5‐oxo‐1,2,4‐triazol‐3‐yl)‐sydnones 11 and 4‐(4‐arylamino‐5‐oxo‐1,2,4‐triazol‐3‐yl)‐sydnones 13 have been obtained from a‐chloroformylarylhydrazine hydrochloride 2 . Moreover, the intermediates, including 3, 4 , 9 and 10 , in this study are synthetically informative and valuable. It is also noteworthy that three reactants, 1, 2 and sydnonecarbaldehydes, were prepared from sydnone derivatives and their fragments. The oxidative cyclizations of sydnonecarbaldehyde semicarbazones 9 and carbazones 10 with two different oxidizing agents (Cu(ClO4)2 and Fe(ClO4)3) have been extensively examined. The reaction time and the yields of cyclizations were affected by the substituents of semicarbazones 9 and carbazones 10. 相似文献
17.
The hitherto unreported, highly functionalized 1H‐pyrazole‐3‐carboxylates 3 have been synthesized in good yields via a one‐pot three‐component domino reaction of phenylhydrazines, dialkyl acetylenedicarboxylates, and ninhydrin under mild conditions for the first time. No co‐catalyst or activator is required for this multicomponent reaction, and the reaction is, from an experimental point of view, simple to perform (Scheme 1). The structures of compounds 3 were corroborated spectroscopically (IR, 1H‐ and 13C‐NMR, and EI‐MS) and by elemental analyses. A plausible mechanism for this type of cyclization/addition reaction is proposed (Scheme 2). 相似文献
18.
2‐(1‐Aryl‐2‐methoxyethenyl)benzaldehydes 2 , obtained by successive treatment of 1‐(1‐aryl‐2‐methoxyethenyl)‐2‐bromobenzenes 1 with BuLi and 1‐formylpiperidine, were transformed to the corresponding phenylhydrazones 3 on treatment with PhNHNH2. When these hydrazones were allowed to react with conc. HBr, cyclization, followed by dehydrogenation with air occurred, furnished 3‐aryl‐2‐methoxyinden‐1‐one (Z)‐phenylhydrazones 4 . 相似文献
19.
The newly synthesized 2‐(alk‐3‐en‐1‐ynyl)cyclohex‐2‐enones 4 undergo photodimerization (chemo‐ and regio‐)selectively at the exocyclic C?C bond to give diastereoisomeric mixtures of 1,2‐dialkynyl‐1,2‐dimethylcyclobutanes. On irradiation of 4 in the presence of 2‐chloroacrylonitrile, cyclobutane formation occurs again (chemo‐ and regio‐)selectively at the exocyclic C?C bond to afford diastereoisomeric mixtures of 2‐alkynyl‐1‐chloro‐2‐methylcyclobutanecarbonitriles. Similarly, compounds 4 undergo photoaddition to 2,3‐dimethylbuta‐1,3‐diene exclusively at the exocyclic C?C bond to afford mixtures of [2+2] and [4+2] cycloadducts. 相似文献
20.
By the treatment of N‐3‐bromo‐3‐alkenylthioamides with sodium hydroxide in DMF‐H2O in the presence of tetra‐butylammonium bromide, series of 6‐alkylidene‐5,6‐dihydro‐4H‐1,3‐thiazine derivatives were prepared in moderate to good yields. The cyclization is supposed to proceed via both the intramolecular vinylic nucleophilic substitution and the elimination‐addition mechanisms (formation of acetylenic intermediates) in a competitive manner. 相似文献