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1.
A single fully automated generic microbore liquid chromatography electrospray time-of-flight protocol has been developed for the analysis of single beads, single beads with analytical constructs, and isotopically labelled dialkylamine hard tags. The protocol relies upon the incorporation of an isotopic signature into the linker and/or derivatising molecule to give a specific isotopic ratio together with an accurate isotopic difference. These properties facilitate highly specific and sensitive analysis of beads and hard tags using accurate isotopic difference analysis (AIDA) without prior knowledge of the molecular weight. Three open access methods with automated processing have been developed around a core generic approach. 相似文献
2.
A double elimination protocol has been established for access to unsymmetrically substituted aromatic polyynes by use of dialdehyde and substituted benzylic or propargylic sulfones as starting compounds. For this protocol, various substituted sulfones and phthalaldehydes were usable giving rise to the formation of the desired substituted aromatic polyynes. 相似文献
3.
Mohammad Salim Akira AkutsuTakao Kimura Masahiro MinabeMichinori Karikomi 《Tetrahedron letters》2011,52(35):4518-4520
New oxa[9]helicenes which possess one furan ring have been readily prepared by reactive helical quinone with Lawesson’s reagent or phosphorus pentasulfide in good yields. The versatility of this protocol has been demonstrated with various substituted helical quinones. 相似文献
4.
An operationally simple process has been developed for the synthesis of unsymmetrical amines and α-amino carbonyl derivatives in the absence of a catalyst, ligand, oxidant, or any additives. Contrary to known reductive amination methods, this protocol is amenable to substrates containing other reducible groups. This process effectively results in consecutive cleavage and formation of C−N bonds. DFT studies and Hammett analysis provide useful insight into the mechanism. The role of noncovalent interactions as a stabilizing factor have been examined in the protocol. A wide range of alkyl-bromides have been coupled efficiently with a variety of dimethyl anilines to get unsymmetric tertiary amines with yields up to 90%. This methodology was further extended to the synthesis of α-amino carbonyl derivatives with yields up to 93%. 相似文献
5.
Shyamasankar Mandal Jeet Banerjee Sougata Maity Shital K. Chattopadhyay 《Helvetica chimica acta》2021,104(3):e2000216
A synthetic protocol involving sequential use of three atom-economic processes viz. Claisen rearrangement, ring-closing metathesis and cross metathesis has been developed to access 7-substituted benzo[b]azepine and benzo[b]oxepine derivatives starting from appropriate aniline or phenol in good overall yield. A one-pot RCM-CM protocol has also been developed for the synthesis of benzazepine and benzoxepine derivatives. 相似文献
6.
A rapid, efficient, and ecofriendly protocol has been developed for the Knoevenagel condensation of active methylene compounds such as malononitrile or ethyl cyanoacetate with aldehydes in the presence of melamine with good to excellent yields at room temperature without solvent. 相似文献
7.
A facile two-step synthesis of 2-arylbenzofurans based on the selective cross McMurry couplings 总被引:1,自引:0,他引:1
A novel two-step synthesis of 2-arylbenzofurans has been developed. It involves a selective cross McMurry coupling of a salicylaldehyde or substituted salicylaldehyde with an aromatic aldehyde and a sequential oxidative cyclization of the resulting ortho-vinylphenols. Utilizing this synthetic protocol, a variety of 2-arylbenzofurans including cicerfuran have been efficiently synthesized. 相似文献
8.
An efficient and mild protocol has been developed for the Minisci acylation reactions of nitrogen-containing heteroarenes with α-keto acids. Distinct from the conventional Minisci acylation conditions, the chemistry was performed using non-noble metal Fe(II), instead of expensive Ag(I) salt, as catalyst. A wide range of substrates, including aliphatic or aromatic α-keto acids, as well as various N-heteroarenes, proved to be compatible with the protocol. Scale-up experiment also demonstrates the practicality of the approach. 相似文献
9.
Py M Barnes JP Lafond D Hartmann JM 《Rapid communications in mass spectrometry : RCM》2011,25(5):629-638
The abundance of work on SiGe-based devices demonstrates the importance of the compositional characterization of such materials. However, Secondary Ion Mass Spectrometry (SIMS) characterization of SiGe layers often suffers from matrix effects due to the non-linear variation of ionization yields with Ge content. Several solutions have been proposed in order to overcome this problem, each having its own limitations such as a restricted germanium concentration range, or a weak sensitivity to dopants or impurities. Here, we studied the improvements brought by an alternative protocol: the extended Full Spectrum protocol, which states proportionality between the composition of the secondary ion beam and that of the actual material. Previous studies on this protocol showed that it was extremely precise and reproducible for Ge quantification in a permanent regime, because of minimized matrix effects. In this study we thus investigated its accuracy for the simultaneous quantitative depth profiling of both matrix elements (Si, Ge) and impurities (B, C or P) in strained SiGe/Si superlattices by comparing results with those from more classic protocols. The profiles provided by the extended Full Spectrum protocol were found to be accurate, and to exhibit better properties than classic protocols in terms of signal/noise ratio and signal stability, along with a slight enhancement in depth resolution. 相似文献
10.
A TMG catalyzed, practical and efficient hydrophosphorylation of 4-oxo-enoates by diethyl or diphenyl phosphite has been described. This protocol allows a convenient access to a variety of enol phosphates under mild conditions in good yield with excellent stereoselectivity. 相似文献
11.
Anwar M Bailey JH Dickinson LC Edwards HJ Goswami R Moloney MG 《Organic & biomolecular chemistry》2003,1(13):2364-2376
Alkylation reactions using alpha-halolactams or lactam enolates derived from bicyclic lactam templates can proceed with high endo- or exo- diastereoselectivity respectively. In the latter case, stereochemical correction by means of enolate generation and hindered phenol quench is possible with moderate efficiency. This protocol has been applied to the synthesis of protected penmacric acid and its analogues. 相似文献
12.
Frederik Rombouts Dennis Franken Mirielle Braeken Jinsheng Chen 《Tetrahedron letters》2010,51(37):4815-2879
A new and facile microwave-assisted protocol for the debenzylation of N-benzylamides with triflic acid has been developed. Both secondary and tertiary aliphatic or aromatic amides are obtained in moderate to good yields. 相似文献
13.
Iain A.S. Walters 《Tetrahedron letters》2006,47(3):341-344
A simple Ni-catalysed cross-coupling protocol for amino-heteroaryl chlorides with alkylzinc reagents has been developed. The alkylzinc reagents can be commercially available dialkylzincs or alkylzinc halides, or can be conveniently generated in situ from diethylzinc and primary alkyl bromides in the presence of the same inexpensive Ni catalyst used to effect the subsequent coupling reaction. 相似文献
14.
Peruncheralathan S Yadav AK Ila H Junjappa H 《The Journal of organic chemistry》2005,70(23):9644-9647
[Reaction: see text]. An efficient highly regioselective protocol for the synthesis of isomeric 1,3-diaryl (or 1-aryl-3-alkyl) and 1,5-diaryl (or 1-aryl-5-alkyl)-5 (or 3)-(N-cycloamino)pyrazoles has been reported by cyclocondensation of common alpha-oxoketene N,S-acetal precursors with arylhydrazines by variation of reaction conditions. 相似文献
15.
New (S)-pyrrolidinylmethylimidazole ligands (4a-c) have been readily synthesized in a straightforward fashion from least expensive starting materials in short steps in high yields. Relatively mild and highly efficient CuI-catalyzed N-arylation procedures for imidazoles with aryl and heteroaryl bromides or chlorides have been developed in the presence of 4a and Cs2CO3. It is important to note that the protocol could tolerate functional groups such as ester, nitrile, nitro, ketone, free hydroxyl, and free primary amine on the aryl halide. The protocol could also be applicable to other pi-electron-rich nitrogen heterocycles (pyrrole, pyrazole, indole, benzimidazole, and triazole), affording the N-arylazoles in good to excellent yields. 相似文献
16.
A protocol is described for monitoring the heterogeneity of end products of organic syntheses yielding amphoteric molecules containing two or more amino groups. This protocol was found to be a valuable aid in synthesis of carrier ampholytes for specific isoelectric focusing applications. This method does not depend on the ampholytes themselves to dictate the conditions under which they are analyzed. Carrier ampholytes have been found previously to be insoluble in picric acid and the insolubility property was not dependent upon the pI of individual ampholyte species. This insolubility property was exploited in the protocol. Immobilized pH gradients were used to focus the carrier ampholytes. Ampholytes were then visualized in situ by picric acid precipitation. The data shows that the protocol is useful for analyzing the results of chemical manipulations for enhancing the resolution of carrier ampholytes. A direct relationship was shown between carrier ampholyte heterogeneity as demonstrated by this protocol and the resolution of complex protein mixtures in isoelectric focusing gels. Picric acid formed visible precipitates with a variety of organic compounds which contained more than one amino group. 相似文献
17.
Goutam Brahmachari Sujay Laskar 《Phosphorus, sulfur, and silicon and the related elements》2014,189(7-8):873-888
AbstractA facile and efficient protocol for one-pot three-component synthesis of structurally diverse (2-amino-3-cyano-4H-chromen-4-yl)phosphonic acid diethyl esters from the reaction of salicylaldehydes, malononitrile (or ethyl cyanoacetate), and triethylphosphite using basic nanocrystalline MgO as catalyst in aqueous ethanolic medium at room temperature has been developed. Nano-MgO has been prepared using a simple sol-gel approach. Clean reaction profile, easy reusability of MgO nano-catalyst, mild reaction condition, good yields, and practical applicability are the major advantages of the present protocol. 相似文献
18.
Condensation of maleic anhydride or dimethyl maleate with benzylaldehydes controlled by tris(4‐anisyl)‐phosphine to synthesize dimethyl (E)‐2‐benzylidenesuccinates has been systematically investigated. The protocol gives the product with high stereoselectivity in moderate to good yields under mild conditions. A plausible mechanism has been proposed. 相似文献
19.
González Cabrera D Koivisto BD Leigh DA 《Chemical communications (Cambridge, England)》2007,(41):4218-4220
A series of mono- and bis-metallated [2]rotaxanes has been prepared using a CuAAC 'click' protocol that is compatible with metal-coordinated building blocks and ligands; the methodology provides a general means for appending a metal ion or complex to an organic scaffold via Cu(I)-catalysed 'click' chemistry, even when the molecule contains redox-active or kinetically labile metals or vacant ligand sites. 相似文献
20.
Hydroboration of 1-bromo-1-alkynes with dibromoborane followed by addition of 3 or 4 equiv of Me2Zn provides an efficient and selective route to (Z)-2-alkenyldimethylboranes (3) or (Z)-2-alkenylmethylzincs (4), respectively, which have been successfully applied to one-pot Suzuki (B-I) or Negishi (Zn-I) coupling in some less demanding cases. However, in more demanding cross-coupling reactions, only the use of either (Z)-2-alkenyliodides (5) or the alkenylzincs prepared from lithiation and then zincation of 5 proves to be highly satisfactory (Zn-II or Zn-III protocol). On the contrary, the corresponding organoboron coupling under B-II or B-III protocol appears to be less satisfactory. Preliminary studies indicate that certain substituents proximal to trisubstituted alkenes seriously affect the course of the desired alkenylboron cross-coupling. 相似文献