共查询到20条相似文献,搜索用时 562 毫秒
1.
Alonso-Cruz CR Kennedy AR Rodríguez MS Suárez E 《The Journal of organic chemistry》2008,73(11):4116-4122
The reaction of 3-azido-2,3-dideoxypyranose and 3-azido-2,3-dideoxy-2-halohexopyranose compounds with (diacetoxyiodo)benzene and iodine generated 2-azido-1,2-dideoxy-1-iodoalditols and 2-azido-1,2-dideoxy-1-halo-1-iodoalditols, respectively. These beta-iodo azides could be transformed by chemoselective dehydroiodination into 2-azido-1,2-dideoxy-4- O-formyl-pent-1-enitols and (Z, E)-2-azido-1,2-dideoxy-1-halo-4- O-formyl-pent-1-enitols in good yields. Thermolysis and photochemical studies of these vinyl azides and 1-halovinyl azides for the synthesis of polyhydroxylated 3-alkyl-2 H-azirines and the hitherto unknown 2-halo-3-alkyl-2 H-azirines have also been accomplished. 相似文献
2.
Len F. Lee Francis M. Schleppnik Robert K. Howe 《Journal of heterocyclic chemistry》1985,22(6):1621-1630
A variety of 2-halo-5-thiazolecarboxylates was prepared from substituted-3-aminoacrylates and 3-ketoes-ters. Selective reduction of 2-chloro-5-thiazolecarboxylates 4a, 4i and 4j with sodium borohydride in ethanol provided the corresponding 2-halo-5-thiazolemethanols 27-29 . Nucleophilic displacements on [2-chloro-4-(trifluoromethyl)-5-thiazolyl]methyl methanesulfonate ( 32c ) occurred selectively at the 5-substituent to provide 2-chloro-4-(trifluoromethyl)-5-(heteroatom-substituted-methyl)thiazoles 32d-f. 相似文献
3.
Teresa M.V.D Pinho e Melo Ana L CardosoAntónio M.d'A Rocha Gonsalves 《Tetrahedron》2003,59(13):2345-2351
The dehalogenation of 2-halo-3-phenyl-2H-azirine-2-carboxylates is described. Using sodium borohydride and tributyltin hydride 3-phenyl-2H-azirine-2-carboxylates were obtained in moderate yields. The synthesis of a new 2-bromo-2H-azirines with a chiral auxiliary, 10-phenylsulfonylisobornyl 2-bromo-3-phenyl-2H-azirine-2-carboxylate, is reported. Its dehalogenation led to 10-phenylsulfonylisobornyl 2H-azirine-2-carboxylate as single stereoisomer together with the formation of 10-phenylsulfonylisobornyl acetate. 相似文献
4.
A simple approach toward N(3)-substituted-2,3-diaminopyridines is presented, based on Pd-catalyzed C,N-cross coupling. The use of RuPhos- and BrettPhos-precatalysts in combination with LiHMDS allows for C,N-cross coupling reactions of unprotected 3-halo-2-aminopyridines with primary and secondary amines. 相似文献
5.
Boris A. Trofimov Lyubov N. Sobenina Zinaida V. Stepanova Olga V. Petrova Igor A. Ushakov Albina I. Mikhaleva 《Tetrahedron letters》2008,49(24):3946-3949
4,5,6,7-Tetrahydroindoles undergo a rapid, facile (rt, 60 min) ethynylation with ethyl 3-halo-2-propynoates upon grinding with solid K2CO3 (without solvent) at C-2 of the tetrahydroindole ring to afford ethyl 3-(4,5,6,7-tetrahydroindol-2-yl)-2-propynoates in 62–90% yield. 相似文献
6.
Treatment of acetonide protected 4,5-dihydroxy-2-chloroglycidic ester or its rearrangement product, the acetonide protected 4,5-dihydroxy-3-chloro-2-oxo ester, with magnesium halides gave 4-halo-3-hydroxy-2-pyrone in excellent to reasonable yields in one pot. The mechanism of this novel one pot rearrangement-cyclization reaction is also proposed. 相似文献
7.
V. O. Koz'minykh E. N. Koz'minykh Yu. S. Andreichikov 《Chemistry of Heterocyclic Compounds》1989,25(8):862-865
Reaction of 5-aryl-4-halo-2,3-dihydrofuran-2,3-diones with alkoxycarbonylmethylenetriphenylphosphoranes has given 2-alkoxycarbonylmethylene-5-aryl-4-halo-2, 3-dihydrofuran-3-ones, which readily add halogens at the 2-exocyclic double bond, and on reaction with arylamines recyclize to give 2-hydroxy-2, 3-dihydropyrrol-3-ones.For Communication 1, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1034–1038, August, 1989. 相似文献
8.
Eremkin A. V. Ershov O. V. Lipin K. V. Kayukov Ya. S. Nasakin O. E. Tafeenko V. A. 《Russian Journal of Organic Chemistry》2009,45(10):1541-1545
5,5-Dialkyl-2-halo-6-hydroxy-5,6-dihydro-1H-pyridine-3,4,4-tricarbonitriles reacted with morpholine in aprotic solvent to give the corresponding 3,3-dialkyl-4,5-dicyano-6-halo-2-morpholino-1,2,3,4-tetrahydropyridine-4-carboxamides,
while analogous reaction in amphiprotic solvent resulted in the formation of 8,8-dialkyl-3-halo-6-oxo-2,7-diazabicyclo[3.2.1]oct-3-ene-4,5-dicarbonitriles. 相似文献
9.
A new general two-step methodology for the synthesis of chiral fluoro, chloro, bromo and iodo vinyl azides from carbohydrate-derived halohydrins has been developed. The anomeric alkoxyl radical fragmentation of 3-azido-2,3-dideoxy-2-halo-pyranoses under oxidative conditions with (diacetoxyiodo)benzene and iodine gave 2-azido-1,2-dideoxy-1-halo-1-iodo-alditols, which by chemoselective dehydroiodination afforded (Z,E)-2-azido-1,2-dideoxy-1-halo-4-O-formyl-pent-1-enitols in good overall yields. Preliminary thermolysis and photochemical studies of these compounds for the synthesis of hitherto unknown disubstituted 2-halo-3-alkyl-2H-azirines have also been accomplished. 相似文献
10.
Hikari Morita Kazuho Harada Yoshihisa Okamoto Kaname Takagi 《Journal of heterocyclic chemistry》1999,36(3):767-770
3-Chloro- and 3-bromo-4-methoxycoumarins 1a,b were readily transformed into 4-halo-5-(2-hydroxyphenyl)-3-oxo-2,3-dihydropyrazoles 2a,b with hydrazines. In the reaction of 1a,b with excess hydrazine and phenylhydrazine in boiling ethanol, unexpected 4-hydrazono-3-(2-hydroxyphenyl)-2-pyrazolin-5-ones 3 , 5 were obtained. The structure of 3 was determined by X-ray diffraction analysis. 相似文献
11.
An efficient three-step synthesis of 2-halo-3-aryl-4(3H)-quinazoliniminium halides from commercially available materials is described. Upon reaction with hydrogen halides, generated in situ from a Lewis acid (MX) and trace water, a variety of easily accessible heteroenyne-allenes underwent facile intramolecular cyclization to afford the title compounds in good yields. The method is highly versatile and provides a general way to construct quinazoliniminium ring systems with a variety of different substitutions. 相似文献
12.
Shuai Zhao 《Journal of fluorine chemistry》2010,131(5):597-605
A general procedure for the preparation of 4-substituted-3-halo-2-quinolones (halo = F, Cl, Br) utilizing 2-halo diethylphosphonoacetic acids (halo = F, Cl, Br) and o-aminophenylketones as the starting materials is described. The title compounds are obtained by an intramolecular Horner-Wadsworth-Emmons olefination of halogen-containing N-acyl-o-aminophenylketones. The transformation process is generally applicable under mild conditions. 相似文献
13.
Trifluoroacetylation of 3-halo-9-methylcarbazoles at 110C proceeds at 6-position. In the case of 3-bromo- and 3-iodo-derivatives, the reaction is complicated by competing processes of dehalogenation, followed by the halogenation of the substrate, leading to 3,6-dihalo derivatives.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1492–1495, November, 1987. 相似文献
14.
Ethyl 3-halo-2-propynoates undergo facile (no heating, no base, no solvent) palladium- and copper-free cross-coupling with 4,5,6,7-tetrahydroindoles on alumina to afford the corresponding 4,5,6,7-tetrahydroindole-2-propynoates in 46% and 71% yields. The yield of the by-products [ethyl 3,3-di(4,5,6,7-tetrahydro-1H-indol-2-yl)acrylates] under appropriate conditions can reach 79%. 相似文献
15.
E. A. Bocharova L. M. Gornostaev N. P. Gritsan T. N. Gurova 《Russian Journal of Organic Chemistry》2010,46(11):1639-1644
Reactions of 3,5-dibromo-4-nitrosoanilines with arylamines and 3-halo-4-nitroso-phenols with alkyland arylamines result in the nucleophilic substitution of the halogen atoms. 相似文献
16.
Teresa M V D Pinho e Melo Cláudia S J Lopes António M d'A Rocha Gonsalves Ana M Beja José A Paix?o Manuela R Silva Luiz Alte da Veiga 《The Journal of organic chemistry》2002,67(1):66-71
Nucleophilic substitution reactions of 2-halo-2H-azirines 1a, 1b, 1d, and 1e with potassium phthalimide and aniline allowed the preparation of new substituted 2H-azirines 2-5. The reactions of 2-bromo-2H-azirine 1a with methylamine led to the synthesis of alpha-diimines 7 and 8. 2-Halo-2H-azirines were also established as building blocks for the synthesis of a range of heterocyclic compounds, namely, quinoxalines 10a-10d, 3-oxazoline 14, and 2H-[1,4]oxazines 18 and 20. X-ray crystal structures of alpha-diimine 7, 3-oxazoline 14, and 2H-[1,4]oxazine 18 are reported. 相似文献
17.
Shyam Krishnan 《Tetrahedron letters》2007,48(43):7571-7573
A method for the synthesis of 3,3-disubstituted oxindole derivatives is described. This involves the base-mediated addition of malonate esters to 3-halo-3-alkyloxindoles. The addition is tolerant of a range of alkyl substituents at position 3 of the oxindole. Addition to an aryl chloro-oxindole is also described. 相似文献
18.
Arife YaziciStephen G. Pyne 《Tetrahedron letters》2011,52(12):1398-1400
The Cu(I) halide (X = I, Br, Cl) mediated reactions of Cbz-protected cis-2-phenylethenyl-3-hydroxypyrrolidine gave novel 3-halo-2,5-trisubstituted furans in good yields, via a cyclization-halogenation, ring-opening reaction sequence. In contrast, the reactions with CuCN gave mainly the corresponding 3-cyanofuro[3,2-b]pyrrole formed from a cyclization-cyanation reaction. 相似文献
19.
V. I. Tyvorskii I. G. Tishchenko A. S. Kukharev E. V. Yushkevich S. F. Vlasov 《Chemistry of Heterocyclic Compounds》1985,21(11):1210-1213
The reaction of esters of alkyl-substituted (E)-5-amino-4-hydroxy-2,3,epoxyvaleric acids with some hydrohalic acids gave the corresponding 2-halo-4-amino-methyl-2-buten-4-olides, the hydrochlorides of which have diuretic activity.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1471–1474, November, 1985. 相似文献
20.
Galina G. LevkovskayaValentina A. Kobelevskaya Elena V. RudyakovaKhanh Q. Ha Dmitrii O. SamultsevIgor B. Rozentsveig 《Tetrahedron》2011,67(10):1844-1851
Synthesis of hard-to-reach 5-chloro-3-alkenylpyrazoles was developed via heterocyclization of alkyl-, benzyl- or dialkylhydrazines with 1,1-dichloro-4-halo-1-alken-3-ones obtained from haloacyl chlorides and vinylidene chloride. The reaction process includes the formation of intermediate 5-chloro-3-(1-haloalkyl)pyrazoles followed by dehydrohalogenation. 相似文献