共查询到20条相似文献,搜索用时 687 毫秒
1.
Riku Shinohara Hidehisa Kawashima Narihito Ogawa Yuichi Kobayashi 《Tetrahedron》2019,75(18):2717-2725
Substitution of diethyl and diphenyl benzylic phosphates, Alk-CH(Ar1)OP(O)(OR)2 (R = Et, Ph; Alk = Me, Et, i-Pr; Ar1 = aryl), with the anions derived from Ar2CH2 (Ph2CH2,9H-xanthene and fluorene) and n-BuLi at –15 °C was studied. For phosphates with Me as an Alk, diethyl phosphates produced Me-CH(Ar1)CH(Ar2)2 (Ar1 = 4-halo-, 4-CN, 4-Me-, 2-Me, 2-Br-, 3-MeO-phenyl and 2-naphthyl). However, an unwanted substitution at the Et group competed with phosphates of Alk = Et- and i-Pr. Fortunately, the corresponding diphenyl phosphates cleanly underwent the desired substitution. Two enantioenriched phosphates, MeCH(Ph)OP(O)(OEt)2 and EtCH(Ph)OP(O)(OPh)2, proceeded with complete inversion of the stereochemistry. 相似文献
2.
Jean M. J. Tronchet Jean-Richard Neeser Etienne J. Charollais 《Helvetica chimica acta》1978,61(5):1942-1944
Some sugar phosphates, phosphonates and phosphine oxides, Preliminary communication Some new phosphates of 1, 2-O-isopropylidene-α-D-ribofuranose have been prepared. Reactions of 3-C-cyanomethylidene-3-deoxy-1, 2-O-isopropylidene-5-O-trityl-α-D -erythro-pentofuranose (9) have been studied. On treatment with phosphorus nucleophiles, 9 led to phosphorus bearing branched-chain sugar derivatives. Branched-chain cyanosugars as 15 and 16 prepared by cis-vic-dihydroxylation of 9 constitute interesting potential precursors of new types of cyclic sugar phosphates. 相似文献
3.
A new synthesis of the indole system has been achieved by chclodehydrogenation of amino phenylmalonate heterocycles. Thus, the 4-amino coumarins1 a,b or the 4-amino-2-quinolones1 c–g are converted to the indoles2 with palladium on charcoal in boiling diphenyl ether. The reaction of the aminocompounds1 with diphenyl carbonate yields the fused polycyclic isoquinolones4. 相似文献
4.
Fang Liu Gang Chen Li-hua Zhang Bing Liu Shaofei Chen Huiming Hua 《Natural product research》2018,32(1):30-35
A new diphenyl ether 3-methylpentyl-2, 4-dichloroasterrate (2), along with a known diphenyl ether butyl 2, 4-dichloroasterrate (1) were isolated from the metabolites of a wetland fungus Aspergillus flavipes. PJ03-11. The structures of 1 and 2 were determined by extensive NMR and HR–ESI–MS experiments. Compounds 1 and 2 showed weak cytotoxic activity, but both of them showed no antimicrobial activity. 相似文献
5.
《Green Chemistry Letters and Reviews》2013,6(1):1-2
Abstract Zinc dust serves as a reducing agent in the presence of ammonium formate and NaOH, and is highly effective for the hydrodebromination of decabromodiphenyl ether to give diphenyl ether and the less brominated diphenyl ethers. 相似文献
6.
Michel Maffei 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):1323-1328
The Diels-Alder reaction of diphenyl(1,2-propadienyl)phosphine oxide 1 and diphenyl(1-propynyl)phosphine oxide 2 with cyclopentadiene is reported. 1 reacts smoothly at room temperature in the presence of one equivalent of aluminum trichloride to give the corresponding adducts endo 3a and exo 3b (90:10 ratio) whose structure was attributed on the basis of their 13C NMR spectra, whereas 2 is a poor dienophile, affording the corresponding adduct in low yield even under harsh conditions. 相似文献
7.
Konstantin A. Popov Alexander M. Polozov 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract Diazo esters (la,b) react with trialkyl phosphates (2a–c) in the presence of BF3.OEt2 to give the corresponding phosphates (3a–e) in 42–58 % yields. The competed intra/intermolecular protonation in the reaction of la with dimethyl hydrogen phosphite leads to phosphonate. 4,and phosphite 5. 相似文献
8.
Peracetates of β-glycosyl dibenzyl phosphates are formed efficiently in the reaction of cesium dibenzyl phosphate with peracetyl-α-glycosyl
nitrates derived froml-fucopyranose,d-galactopyranose, and 2-azido-2-deoxy-d-galactopyranose or with tri-O-acetyl-α-l-fucopyranosyl bromide. On the contrary, the reaction of the above-mentioned glycosyl nitrates with cesium diphenyl phosphate
leads to thermodynamically more stable α-glycosyl diphenyl phosphatevia intermediate formation of the corresponding β-anomers.
Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1924–1928, November, 2000. 相似文献
9.
Three major methods have been elaborated in our laboratory for preparation of polymers with poly(alkylene phosphates) backbones: ring-opening polymerization, poly-condensation and transesterification, and polyaddition. The second method is based on the reaction of the commercially available compounds, namely dialkyl (or diaryl)-H-phosphonates and glycols. Reaction of the aliphatic H-phosphonates with aliphatic glycols is a reversible process, whereas polycondensation of diphenyl H-phosphonates with aliphatic and cycloaliphatic diols is practically irreversible. This latter method has recently been developed and is described in this paper. Poly H-phosphonates with M̄n up to 40–103 were prepared. Polymers are easily oxidized and quantitatively converted into the relatively stable poly(alkylene phosphates). Some physical properties of these polymers and kinetics of their hydrolysis is discussed. 相似文献
10.
Condensation of triethoxymethane and aniline with dimedone gives 2-anilinomethylene dimedone as the main product. An1H-NMR-spectroscopic investigation of the kinetics in chloroform-d
1 and methanol-d
4 shows different rate determining steps in these solvents. There are two predominant rate determining steps in a complicated multistep reaction sequence.The initial one involves condensation of aniline with triethoxymethane to form diphenyl formamidine via ethyl phenyl formimidate. The second step involves reaction of the intermediate diphenyl formamidine with dimedone. The rates are strongly dependent upon the nature of the solvent and the concentration of catalytic acid. In methanol the reaction of dimedone with the intermediate diphenyl formamidine is rate determining. For preparative purposes the isolation of the intermediate diphenyl formamidine and the subsequent use of less polar solvents offer an advantage, because the second step is found to be accelerated.
6. Mitt.:Wolfbeis, O. S., Mh. Chem.112, 369 (1981). 相似文献
11.
Ch. Subramanyam K. Venkata Ramana S. Rasheed S. Adam C. Naga Raju 《Phosphorus, sulfur, and silicon and the related elements》2013,188(9):1228-1235
Abstract An efficient synthesis of a series of novel diphenyl N-substituted carbamimidoyl phosphoramidate derivatives was accomplished in two steps. Diphenyl phosphorochloridate (1) was reacted with cyanamide (2) in the presence of 1,4–dimethylpiperazine as a base in THF at 50–55 °C to form an intermediate, diphenyl cyanophosphoramidate (3). Subsequently 3 was reacted with various aromatic/heterocyclic amines (4) in the presence of 1,4–dimethyl piperazine as a base at 55–60 °C to form the corresponding title compounds 5(a-k). The title compounds were tested for antiviral activity against Tobacco mosaic virus (TMV) in vitro, antibacterial and antifungal activities at two different concentrations of 50 and 100 μg/mL. The title compounds exhibited good antiviral and antimicrobial activities when compared to the standards. 相似文献
12.
Naomichi Furukawa Mitsuo Fukumura Takehiko Nishio Shigeru Oae 《Phosphorus, sulfur, and silicon and the related elements》2013,188(2):231-237
Abstract Various N-acyldiphenylsulfilimines (1a-k) were found to undergo photolysis in argon atmosphere, to afford the corresponding isocyanates, diphenyl sulfide and diphenyl disulfide. Attempts to trap intramolecularly the acylnitrene with olefinic linkage or sulfide afforded small amounts of the trapped products, whereas photolysis of N-mesitoyldiphenyl-sulfilimine (Ia) afforded a C–H inserted product of the nitrene in a substantial yield together with the isocyanate. Benzophenone-sensitized photolysis of Ia indicates that the nitrene generated is a singlet species. 相似文献
13.
L. S. Zakharov G. N. Molchanova T. M. Shcherbina P. V. Petrovskii M. I. Kabachnik 《Russian Chemical Bulletin》1998,47(9):1718-1724
A number of trialkylsilylmethyl diphenyl phosphates MeRR′SiCH2OP(O)(OPh)2 (1a-e: R=Et (a), Pr (b), CF3CH2CH2 (c, e), Me3SiCH2 (d); R′=Me (a-d), Et (e)) were synthesized and their thermal rearrangement, of the 1,2-shift type, was studied. The rearrangement consists of the
migration of an alkyl group from Si atom to the methylene carbon atom and gives the corresponding silyl esters. The rate of
the rearrangement was found to increase in the order1d<1b<1a<1 (R=R′=Me)<1c corresponding to the enhancement of the total inductive effect (−I) of the substituents at the Si atom. The relative migration ability of the substituents at the Si atom, determined by GC/MS
analysis of the disiloxane fraction resulting from hydrolysis of pyrolyzed phosphates1a-e, increases in the order R=Pr<Et<CF3CH2CH2<Me≪Me3SiCH2, which differs substantially from the order in which the rate of the rearrangement of phosphates1a-d changes. The electronegativity of the migrating group affects noticeably the relative ability to migrate.
For Part 4, see Ref. 1.
Deceased.
Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 9, pp. 1767–1772, September, 1998. 相似文献
14.
Petr Melnikov Ana Maria Massabni Oscar Malta 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract Luminescent properties of scandium and yttrium phosphates are discussed and mechanisms involving their emissions proposed. 相似文献
15.
Kosuke Kakita Toshifumi Tsuda Noritoshi Suzuki Seiichi Nakamura Hisanori Nambu Shunichi Hashimoto 《Tetrahedron》2012,68(25):5005-5017
TMSOTf-promoted glycosidation of 2-azido-4,6-O-benzylidene-2-deoxygalactosyl diphenyl phosphates with fluorenylmethoxycarbonyl (Fmoc)-protected serine and threonine derivatives in THF/Et2O (1:1) gave glycosyl amino acids in high yields and with excellent levels of α-selectivity (α/β=94:6–95:5). The synthetic utility of the present glycosidation method was demonstrated by a stereoselective synthesis of mucin-type glycopeptide core 5 and core 7 building blocks, which are suitable for Fmoc-based solid-phase synthesis of O-glycopeptides. 相似文献
16.
Ester exchange reaction of oxyphosphorane (1) with thymidine (2) afforded diastereomeric spirooxyphosphoranes 3 under mild conditions in good yield. After hydrolysis, thymidine phosphates monomers (5, 6) and dimer (7) were obtained. 相似文献
17.
DIHALOCARBENE ADDITION TO ARYLSUBSTTTUTED VINYL PHOSPHATES UNDER PHASE TRANSFER CATALYTIC CONDITIONS
Imre Petneházy György Keglevich László Tőke 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-2):77-82
Abstract Dihalocarbene addition to aryl-substituted vinyl phosphates was carried out both in solid-liquid and in liquid-liquid two phase systems. The dihalocyclopropane adducts of vinyl phosphates could be obtained in better yield using dihalocarbenes generated by the latter method and no hydrolysis of the vinyl phosphate and of the adduct occurred under these circumstances. Eighteen new vinyl phosphate-dihalocarbene adducts were synthetized and characterized. 相似文献
18.
Abstract The present work reports some applications of microwave processing in the synthesis of inorganic condensed phosphates. 相似文献
19.
α-L-Rhamnopyranosyl phosphates 8a-b~12a-b were obtained in high yield and high stereoselectivity from α-L-rhamnopyranosyl trifluoroacetate 2a-b and phosphoric acid diesters in the presence of a Lewis acid. 相似文献
20.
M. T. Averbuch-pouchot A. Durif 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4)
Abstract Up to now a dozen of inorganic condensed phosphates containing two anions with different degrees of condensation have been reported. 相似文献