共查询到20条相似文献,搜索用时 15 毫秒
1.
Tuba GÜNG
R 《Turkish Journal of Chemistry》2021,45(1):219
A series of novel imidazo[1,2- a ]pyrimidine containing tri/tetrasubstituted imidazole derivatives (1-10) has been synthesized via sequential two-step, one-pot, multicomponent reaction using imidazo[1,2- a ]pyrimidine-2-carbaldehyde, benzil, primary amines, and ammonium acetate catalyzed by p -toluenesulfonic acid under microwave-assisted conditions. The results showed that target compounds can be obtained from a wide range of primary amines bearing different functional groups with moderate to good yields (46%-80%) under optimum reaction conditions. This method provides a green protocol for imidazo[1,2- a ]pyrimidine containing tri/tetrasubstituted imidazole derivatives due to ethyl alcohol as a green solvent, microwave irradiation as a greener heating method and one-pot multicomponent reaction as a green technique. The synthesized compounds have been elucidated using various spectroscopic tools such as FT-IR, 1H NMR, 13 C NMR, and MS. 相似文献
2.
Tsukasa Furuya 《Journal of fluorine chemistry》2005,126(5):721-725
Synthesis of gem-difluorides from aldehydes was effectively achieved using DFMBA and Et3N-3HF under microwave irradiation or conventional thermal heating. Both aromatic and aliphatic aldehydes could be converted to the corresponding gem-difluorides in good yields. 相似文献
3.
María G. De los Santos Marcos Cua-Basulto Anallely Huepalcalco Wendy Delit Jesús Sandoval-Ramírez Adolfo Lpez-Torres Esaú Ruiz-Snchez María A. Fernndez-Herrera 《Molecules (Basel, Switzerland)》2022,27(23)
Herein, we describe the synthesis and characterization of fused pyrroles in cholestane and norcholestane side chains derived from kryptogenin and diosgenin, respectively. Both conventional and microwave heating techniques were used to synthesize the steroidal pyrroles from primary amines, with the microwave method producing the highest yields. In particular, the norcholestane pyrroles were tested as acaricides against the two-spotted spider mite (Tetranychus urticae Koch) under laboratory conditions and as plant growth promoters on habanero pepper (Capsicum chinense Jacq) under greenhouse conditions. 相似文献
4.
Ruifang Wang Wei Zhang Kathryn C. Golden John F. Quinn Peng Cui Dmytro O. Tymoshenko 《Tetrahedron letters》2009,50(50):7070-7073
A series of carbinamines (α,α,α-trisubstituted amines) have been prepared in a simple and efficient one-pot procedure by the addition of Grignard reagents to a series of aliphatic, aromatic and heteroaromatic nitriles. The resulting magnesium imines are subsequently converted to the desired amine after treatment with Ti(Oi-Pr)4 and additional microwave heating. Key to this procedure is the use of microwave heating for both steps of the reaction protocol, which significantly improves both reaction yields and reduces reaction times. In general, the Grignard addition reaction is complete within 5-10 min at 100 °C followed by conversion with Ti(Oi-Pr)4 and additional microwave heating to give the target amines in good yields. 相似文献
5.
Firouzeh Nemati Ali Ghorbani Gharjeh Ghiyaei Behrouz Notash Mojtaba Hajiloo Shayegan Vahid Amani 《Tetrahedron letters》2014
An efficient route for the synthesis of gem-bis(dithiocarbamate) derivatives is developed using dithiocarbamic acid salts generated from primary aliphatic amines and CS2. The method offers high yields, employs mild reaction conditions, and demonstrates excellent functional group compatibility. The structures of the products were confirmed spectroscopically and by X-ray analysis. 相似文献
6.
A.K. Mahalingam 《Tetrahedron letters》2006,47(18):3051-3053
Scandium triflate has been used as a convenient and efficient catalyst for removal of N-tert-butyl from amide groups. A variety of N-tert-butyl aryl and alkyl amides under these conditions gave the corresponding primary amide in high yields. With the use of microwave heating the deprotection reaction could be completed within 1 h. 相似文献
7.
Nathalie Dubois Daniel Glynn Thomas McInally Barrie Rhodes Simon Woodward Derek J. Irvine Chris Dodds 《Tetrahedron》2013
The range and utility of DABAL-Me3 couplings of methyl esters and free carboxylic acids with primary and secondary amines under a variety of conditions (reflux, sealed tube, microwave) has been compared for a significant range of coupling partners of relevance to the preparation of amides of interest in pharmaceutical chemistry. Commercial microwave reactors promote the fastest couplings and allow the use of significantly sterically hindered amines (primary and secondary) and carboxylic acids derivatives. The influence of microwave energy on the reaction system was shown to be typically related to thermal effects (over-pressuring and superheating). 相似文献
8.
Significant base and temperature effects on the Wittig reactions of cyclohexanones with (carbethoxymethylene)triphenylphosphorane under microwave irradiation were observed. For the Wittig reactions carried out in a domestic microwave oven under solvent-free conditions, the initially formed exo-olefin products isomerized into the thermodynamically more stable endo-olefins due to uncontrolled high reaction temperature. In sharp contrast, under controlled microwave heating, both exo- and endo-olefins have been selectively synthesized by accurately regulating the reaction temperature with or without a base. 相似文献
9.
Dario MontebugnoliPierfrancesco Bravo Elisabetta BrennaCharles Mioskowski Walter PanzeriFiorenza Viani Alessandro VolonterioAlain Wagner Matteo Zanda 《Tetrahedron》2003,59(36):7147-7156
An effective traceless solid-phase synthesis of chloro-diaminopyrimidines via an amino-de-chlorination reaction of polymer-bound 4-alkoxycarbonylamino-2,6-dichloropyrimidines has been developed. After release from the polymer the target molecules were obtained in good to excellent purity, although with modest regiocontrol. Further reaction of solid-supported N-alkoxycarbonyl-chloro-diaminopyrimidines with secondary amines afforded triaminopyrimidines in good purity under mild conditions, whereas less nucleophilic primary amines did not perform well under the conditions explored so far. 相似文献
10.
Vinod Kumar 《Tetrahedron letters》2005,46(47):8121-8123
A new reagent for the efficient preparation of gem-chloronitroso compounds has been developed. The reaction of ketoximes with N-tert-butyl-N-chlorocyanamide takes place instantaneously in carbon tetrachloride at room temperature with excellent yields under mild conditions. 相似文献
11.
An O to N substitution in 4,4-difluorobutadiene-2,3-ol-1 has been accomplished in very satisfactory yields, and without compromising the gem-difluoroallenyl integrity, using modified Mitsunobu conditions. Recrystallization of the resulting tosyl-substituted amines furnished the first X-ray crystallographic analysis of difluoroallenes. 相似文献
12.
α-Aminonitriles have been synthesized by a Strecker synthesis from aldehydes and ketones under mild catalytic, metal-free conditions. Aromatic aldehydes (1 equiv) were reacted with aromatic and 1° or 2° aliphatic amines (1 equiv) in EtOH containing 3 mol % of NH4Cl to give high yields of α-aminonitriles. An alternative to adding NH4Cl as a catalyst involved the use of excess TMSCN (1 equiv) and to promote the process. The reaction was also successful under microwave conditions using excess TMSCN with no solvent. Ketones similarly reacted with aromatic amines and excess TMSCN under conventional and microwave heating, but 30 mol % of added NH4Cl was required for optimum conversion. 相似文献
13.
Formation of ketone acylals bearing trihaloacetoxy groups and their nucleophilic geminal disubstitution by fluoride ions were investigated. Cyclohexanone reacted with trifluoroacetic anhydride without catalyst to give gem-bistrifluoroacetates via a concerted bimolecular reaction. Treatment with hydrogen fluoride under mild conditions efficiently yielded the corresponding gem-difluorides. In this reaction process, trifluoroacetic acid was recovered and converted to trifluoroacetic anhydride using P2O5. Since gem-difluorides were derived from ketones, HF and P2O5, this constitutes a practical synthesis of gem-difluorides. 相似文献
14.
《Comptes Rendus Chimie》2007,10(7):652-657
Novel derivatives of β-amino alcohols have been prepared by reaction of primary amines with oxirane derivatives. The synthesis of epoxide by o-alkylation of substituted phenols with epibromhydrin under solvent-free solid–liquid phase-transfer catalysis conditions has been described. 相似文献
15.
E. K. Kurbankulieva A. N. Kazakova L. V. Spirikhin S. S. Zlotskii 《Russian Journal of General Chemistry》2013,83(6):1060-1063
The alkylation of aromatic hydrocarbons with 2-bromo-2-phenyl-gem-dichlorocyclopropane in the presence of catalytic quantities of aluminum chloride was found to afford the corresponding 2-aryl-3-phenyl-1,1-dichloroprop-1-enes. It was shown that the yield of the alkylation products depended on the nature of substituents in the aromatic ring. Compared with the thermal heating, microwave irradiation allows reducing the reaction time and increasing the yield of the corresponding 2-aryl-3-phenyl-1,1-di-chloroprop-1-enes, wherein the ortho-/para-isomers ratio changes. 相似文献
16.
H. Loghmani-Khouzani M. M. Sadeghi M. H. Ghorbani 《Journal of the Iranian Chemical Society》2006,3(4):360-366
Some α-oxoketene-N,S- and N,N-acetals were selectively synthesized in good to excellent yields by the reaction of 1,1-dimethoxy-4,4-di(methylthio)-3-buten-2-one with primary and secondary amines under moderate conditions. Secondary amines in reaction with α-oxoketene dithioacetal yielded double-substitution products exclusively, whereas primary amines under the same conditions yielded the mono-substituted products as exclusive or main products. 相似文献
17.
Dr. Aurélie Claraz Dr. Clémence Allain Dr. Géraldine Masson 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(2):e202103337
An electroreductive access to gem-difluoroalkenes has been developed through the decarboxylative/defluorinative coupling of N-hydroxyphtalimides esters and α-trifluoromethyl alkenes. The electrolysis is performed under very simple reaction conditions in an undivided cell using cheap carbon graphite electrodes. This metal-free transformation features broad scope with good to excellent yields. Tertiary, secondary as well as primary alkyl radicals could be easily introduced. α-aminoacids L-aspartic and L-glutamic acid-derived redox active esters were good reactive partners furnishing potentially relevant gem-difluoroalkenes. In addition, it has been demonstrated that our electrosynthetic approach toward the synthesis of gem-difluoroalkenes could use an easily prepared Kratitsky salt as alkyl radical precursor via a deaminative/defluorinative carbofunctionalization of trifluoromethylstyrene. 相似文献
18.
Amination of a variety of functionalized aryl bromides with imidazole and primary and secondary amines was accomplished using
a CuI/amino acid catalyst system under microwave heating. Application of microwave irradiation shortened the reaction time
from 25–40 h to 6–20 min. Good to very good yields of the corresponding coupling products were obtained when imidazole and
secondary amines were used as starting materials. In case of primary amines, the outcome of the reaction was dependent on
the character of the substituent on aryl bromide. 相似文献
19.
The debromination of α-bromoketones with an easily accessible ionic liquid, 1-methyl-3-pentylimidazolium tetrafluoroborate, [pmIm]BF4 under microwave irradiation has been investigated. By controlling the reaction time gem-α-dibromoketones are selectively debrominated to either monobromo or debromoketones. The α-monobromo- and α-monoiodoketones are dehalogenated while the corresponding chloroketones remain inert. The activated vic-bromoacetates are converted to the corresponding (E)-alkenes by the same procedure. These reactions do not require any organic solvent, any metal or any conventional reducing agent. The ionic liquid works here as catalyst as well as reaction medium and is recycled without any appreciable loss of its catalytic efficiency. 相似文献
20.
Mohamed A. Mohamed Teleb Ahmed E. M. Mekky Sherif M. H. Sanad 《Journal of heterocyclic chemistry》2021,58(9):1825-1835
In this study, ethyl 3-aminothieno[2,3-b]pyridine-2-carboxylate was taken as a versatile precursor for the one-pot three-component synthesis of related fused pyrimidine hybrids. The tandem protocol involved the reaction of 3-aminothieno[2,3-b]pyridine, dimethylformamide-dimethylacetal, and amines. The reaction afforded a new series of the target pyrimidine hybrids, linked to different arene units, in good to excellent yields. The prior reaction was evaluated in different solvents under traditional heating or microwave irradiation. Moreover, the influence of reaction temperature was also examined. The optimal conditions were obtained under microwave irradiation in dioxane at 110°C for 40 to 60 min. Additionally, by repeating the previous tandem reaction using the appropriate amines at reaction times of 20 to 60 min, a new series of pyrimidine hybrids linked to alkyl, arylthiazole, and benzo[d]thiazole units has been prepared in good to excellent yields. Furthermore, the utility of bis(amines) was examined to conduct the synthesis of new bis(pyrimidine) hybrids linked to aliphatic cores, in excellent yields, using the same protocol at 30 min reaction time. 相似文献