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1.
The synthesis of O-nitrates of natural hydroxyamino acids serine and threonine was described for the first time. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 52–53, January–February, 2008.  相似文献   

2.
Synthesis of 3-Deoxy-3-(hydroxyamino)furanose Acetals Reduction of sugar ketoximes with NaBH3CN under acidic conditions constitutes a good synthetic pathway to deoxy(hydroxyamino)sugar derivatives. These compounds which are useful building blocks for the preparation of analogs of various classes of biologically important carbohydrates are reasonably stable.  相似文献   

3.
A series of bases containing X-azolopyridines (X = O, NH) and methylquinolines, assembled in different ways, was prepared by reaction of methylquinolinecarboxylic acids (or carboxamides) with diamino (or hydroxyamino) pyridines. The bases were quaternized with methyl iodide. The physical and spectroscopic data of both the bases and the salts were correlated and compared with those of [X-azolopyridine][pyridine] systems previously studied. The structure of the salts was markedly influenced by a balance of basicity-hindrance factors in the heteroaromatic substrates.  相似文献   

4.
Alkylation of the chiral glycine derivative 2 with “activated” organohalides under ultrasound-assisted phasetransfer catalysis or with activated and nonactivated organohalides in anhydrous medium provides (mostly crystalline) alkylation products 3 . Acidic hydrolysis of the pure products 3 gives (aminoacyl)sultams 4 which by mild saponification furnish pure α-amino acids 5 in good overall yields from 2 , along with recovered auxiliary 1 (Scheme 1). Pure ω-protected α,ω-diamino acids and α-amino-ω-(hydroxyamino)acids 12–16 are readily accessible from (ω-haloacyl)sultams 3 via reaction with N-nucleophiles followed by acidic and basic hydrolyses (Scheme 2). A reliable determination of the enantiomeric purity of α-amino acids using HPLC analysis of their N-(3,5-dinitrobenzoyl)prolyl derivatives 17 is presented.  相似文献   

5.
The acylation of 1-hydroxyamino-2-hydroxyiminoethanes with -halo acid chlorides has given the products of N- and O-acylation at the hydroxyamino group. The action of bases on the products of N-acylation — N-(2-hydroxyiminoalkyl)-2-halohydroxamic acids — has given, depending on the conditions, 1-hydroxy-2-oxo-1,2,3,6- or -1,2,5,6-tetrahydropyrazine 4-oxides and 1,2-oxazetidin-3-ones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 115–120, January, 1984.  相似文献   

6.
1-Hydroxy-9,9a-dihydro-1H-imidazo[1,2-a]indol-2(3H)-ones, as a new type of azaheterocyclic hydroxamic acids, have been synthesized regioselectively from 1-carbamoylmethyl- or 1-(methoxycarbonyl)methyl-2,3,3-trimethyl-3H-indolium salts by reaction with hydroxylamine in the presence of a strong base. The alkylation and reduction with sodium borohydride of these novel heterocycles have been investigated. When treated with protic acids 1-hydroxy- or 1-alkoxy-9,9a-dihydro-1H-imidazo[1,2-a]indol-2(3H)-ones underwent ring opening of the imidazolidine to afford 1-[2-(hydroxyamino)-2-oxoethyl]-2,3,3-trimethyl-3H-indolium salts. The structural assignments are based on extensive 1H, 13C and 15N NMR spectroscopic studies and single crystal X-ray analyses.  相似文献   

7.
The synthesis of nitronyl and imino nitroxides has been reexamined with the aim of both increasing yields and of offering opportunities for new structures. The conditions for the formation of 2,3-bis(hydroxyamino)-2,3-dimethylbutane, the key intermediate of Ullman's route, have been carefully studied, and a new procedure is proposed, which affords the free base in a very pure form and up to 60% yield. Full characterization of this intermediate including an X-ray crystal structure is presented. An alternative synthetic route through 2,3-diamino-2,3-dimethylbutane and the corresponding imidazolidines which bypasses the delicate synthesis of the bis(hydroxyamino) compound is described. It is shown that 3-chloroperbenzoic acid is an effective oxidant for the transformation of adequately substituted imidazolidines into nitronyl nitroxides, which are obtained in high yield. An illustration of the potentialities of this new route, a new nitronyl nitroxide with two ethyl substituents in positions 4 and 5 of the imidazoline ring, is reported. The scope and limitations of the two routes are discussed.  相似文献   

8.
Zonampanel monohydrate (YM872) has a potent and selective antagonistic effect on the glutamate receptor subtype, alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor. Metabolic fingerprinting in rat urine after a single intravenous administration of (14)C-labeled YM872 ((14)C-YM872) revealed the presence of two metabolites, R1 and R2. The two metabolites were semi-purified by preparative HPLC from rat urine after a single intravenous administration of non-labeled YM872, and their structures were elucidated by various instrumental analyses involving LC-NMR. The results showed that R1 and R2 have a hydroxyamino group and an amino group at the C-7 position of the quinoxalinedione skeleton, respectively. Therefore, the proposed metabolic pathway of YM872 in rats involves the reduction of the nitro group to a hydroxyamino group and then subsequent reduction to an amino group.  相似文献   

9.
2-Acyl-4-hydroxy-2-imidazoline 3-oxide derivatives were obtained by the reaction of 1,2-hydroxyamino oximes with a hydroxyamino group attached to a tertiary carbon atom with phenyl- and methylglyoxal.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1060–1064, August, 1986.  相似文献   

10.
A reaction of calix[4]arene tetraaldehyde with 2,3-bis(hydroxyamino)-2,3-dimethylbutane in DMF resulted in the corresponding 1,3-dihydroxyimidazolidine tetraadduct, whose oxidation gave a calix[4]arene (1,3-alternate) bearing four nitronyl nitroxyl-containing substituents at the upper rim.  相似文献   

11.
Bis-(hydroxyamino)triazines (BHTs) constitute a new, general and highly versatile group of tridentate iron(III) chelating agents exhibiting higher affinity to iron(III) than other tridentate iron(III) chelators and superior iron(III) over iron(II) selectivity compared to desferrioxamine-B (DFO), EDTA as well as other tridentate ligands.  相似文献   

12.
不对称氨羟化反应   总被引:2,自引:0,他引:2  
徐一鸣  周维善 《有机化学》1999,19(6):565-573
介绍了Sharpless等人新近发现的不对称氨羟化反应,该反应可将烯烃直接转化成为手性β-氨基醇类化合物。对于有些烯烃,Sharpless不对称氨羟化反应具有高的区域选择性(20:1)和高的对映选择性(>98%e.e.)。  相似文献   

13.
Reaction of 2-(hydroxyamino)-1-R-propan-1-one oximes with furfural in methanol afforded the corresponding α-furylnitrones. The cyclization of α-furylnitrones in alkaline medium results in the formation of 5-aryl(hetaryl)-2-(furan-2-yl)-1H-imidazol-1-oles.  相似文献   

14.
A synthetic procedure for optically active and racemic alpha-nitronyl nitroxides (alpha-NNs) having a stereogenic center at the 4-position of the imidazolyl ring is described. This procedure consists of (1) the synthesis of a dissymmetric vic-dinitro compound by Kornblum reaction, (2) the enantiomeric resolution of the racemate by a diastereomer method for obtaining the optically active sample, (3) the quick reduction of the optically active or racemic vic-dinitro compound to the bis(hydroxyamino) derivative with Al/Hg, (4) the solvent-free condensation of the bis(hydroxyamino) compound with an aldehyde to give the 1,3-dihydroxyimidazolidine, and (5) the final oxidation of the alpha-NN precursor with aqueous NaIO(4). The absolute configuration of the optically active alpha-NNs was assigned by correlating with the X-ray crystal structure of the (-)-(1S,4R)-camphanic acid ester derivative of the optically active vic-dinitro compound. The molecular conformation of the optically active alpha-NNs was found to be folded both in solution and in the solid state by CD spectroscopy and energy minimization with the Monte Carlo method. The magnetic properties of both optically active and racemic alpha-NNs in solution and in the solid state were characterized by EPR spectroscopy and magnetic susceptibility measurement, respectively.  相似文献   

15.
《合成通讯》2013,43(11):1455-1459
Abstract

The reaction of phenylglycidyl ether with hydroxylamine was evaluated, and the prepared 1‐hydroxyamino‐3‐phenoxypropan‐2‐ol was used for the 1‐arylideneamino‐ and 1‐alkylideneamino‐3‐phenoxypropan‐2‐ol N‐oxides syntheses. The title nitrones were tested as antioxidants in biological systems.  相似文献   

16.
[1,2,3]Triazolo[4,5-d]pyrimidine 3-oxides were synthesized by replacement of the amino group in 6-aminouracil by hydroxyamino, coupling of the resulting 6-hydroxyaminopyrimidine with benzenediazonium salts, and oxidation of 6-hydroxyamino-5-phenylazouracils with a solution of K3[Fe(CN)6] in water.  相似文献   

17.
A solid-phase synthesis of benzimidazole N-oxides was developed while attempting to synthesize 1,5-benzodiazepine-2,4-diones. The key step of the synthesis involves the reduction of an arylnitro to a hydroxyamino intermediate which subsequently condenses with an internal carbonyl group to give a benzimidazole N-oxide. A library of nine benzimidazole N-oxides was prepared on SynPhase™ Lanterns using this reduction-cyclization methodology.  相似文献   

18.
Selective N-protection of hydroxyamino esters has been readily achieved using 1-alkoxycarbonyl- or 1-acyl-v-triazolo[4,5-b]pyridines. The amide-type triazolides reacted with alcohols in the presence of DBU at room temperature to afford in high yields the corresponding esters. The different reactivity of 1- and 3-alkoxycarbonyl derivatives of the title bicyclic system toward primary amines has been further investigated.  相似文献   

19.
Derivatives of 1,4-dihydroxypiperazine-2,3-dione were obtained by reaction of cis-1,2-bis(hydroxyamino)cycloalkanes with diethyl oxalate. Their alkylation with CH2N2 or Mel afforded 1,4-dimethoxypiperazine-2,3-diones. Hydrolysis of the latter gave 1,2-bis(methoxyamino)cycloalkanes.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 925–929, April, 1996.  相似文献   

20.
Treatment of 2-ethylamino-2-methylpropanol oxime with aryl isocyanates leads to 4-[N-(arylcarbamoyl) hydroxyamino [-1-ethyl-3-aryl-5,5-dimenthyl-2-imidazolidionones, which are acylated by acid chlorides and methyl isocyanate to give the corresponding O-acyl derivatives and are converted to 2-(2-oxo-1-ethyl-3-aryl-5,5-dimethyl-4-imidazolidinyl)-4-aryl-1,2,4-oxadiazolidine-3,5-diones by the action of methyl chlorocarbonate.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 980–983, July, 1980.  相似文献   

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