A new highly versatile handle for chemistry on a solid support: the pipecolic linker

The versatility of the pipecolic linker (Pip-linker) is illustrated by the synthesis of modified amino acids, C-terminal-modified pseudopeptides, and cyclic peptides, through side-chain anchoring of a lysine residue. Introduction of the first residue was easily accomplished and the Pip-linker revealed to be robust enough to support various chemical modifications.     

A triazene-based new photolabile linker in solid phase chemistry

An extension of the T2 linker methodology by showing its applicability as a photocleavable linker is reported. Photocleavage was carried out with 355 nm UV laser irradiation (3ω Nd-YAG) in methanol/diethyl ether and is suitable for protected amino acid derivatives, as well as simple small organic molecules including resin-bound biotin. The linker is stable under a wide range of conditions with the exception of strongly acidic media.     

固相有机合成研究进展

组合化学技术给固相有机合成带来了新的发展契机,同时也提出了新的发展要求。目前这一研究领域发展迅速,应用范围不断扩大,技术日臻完善。本文综述了近期固相有机合成研究方面的最新进展。     

A universal strategy for preparing protected C-terminal peptides on the solid phase through an intramolecular click chemistry-based handle

A new universal strategy exploits DKP formation in a dipeptide moiety whose C-terminal residue is blocked by a leaving group. It enables both synthesis of C-terminal protected peptides that are useful for convergent synthesis of large peptides and use of a C-terminal permanent protecting group that can be cleaved by catalytic hydrogenation to release the peptide.     

A model for combinatorial organic chemistry

The set of coset representations, CR's, of a group G, [G(/G1), G(/G2), ..., G(/Gs)], where G1 = [I], Gs = G, the marks, m(ij) of subgroup Gj on a given G(/Gi), 1 < or = i < or = s, and the subduction of G(/Gi) by Gj, j < or = i, G(/Gi) precipitates to Gj, are essential tools for the enumeration of stereoisomers and their classification according to their subgroup symmetry (Fujita, S. Symmetry and Combinatorial Enumeration in Chemistry; Springer-Verlag: Berlin, 1991). In this paper, each G(/Gi) is modeled by a set of colored equivalent configurations (called homomers), H = h1, h2, ..., hr, r = G/Gi, such that a given homomer, h(k), remains invariant only under all g epsilon Gi, where g is an element of symmetry. The resulting homomers generate the corresponding set of marks almost by inspection. The symmetry relations among a set H can be conveniently stored in a Cayley-like diagram (Chartrand, G. Graphs as Mathematical Models; Prindle, Weber and Schmidt Incorporated: Boston, MA, 1977; Chapter 10), which is a complete digraph on r vertices so that an arc from vertex v(i) to vertex v(j) is colored with the set Sij of symmetry elements such that h(i)[g(if)]-->h(j),g(ij) epsilon Sij. In addition, each vertex, v(i), is associated with a loop that is colored with a set Sii so that g(ii) epsilon Sii stabilizes h(i). A Cayley-like diagram of a given CR, G[G(/Gi)], leads to graphical generation of G(/Gi) precipitates to Gj for all values of j and also to all m(ij)'s. Several group-theoretical results are rederived and/or became more envisagable through this modeling. The approach is examplified using C2, C3, D2, T, and D3 point groups and is applied to trishomocubane, a molecule that belongs to the D3 point group.     

Sodium persulfate in solid phase organic synthesis

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1930–1931, August, 1990.     

Selenol protecting groups in organic chemistry: special emphasis on selenocysteine Se-protection in solid phase peptide synthesis

The appearance of selenium in organic synthesis is relatively rare, and thus examples in the literature pertaining to the masking of its considerable reactivity are similarly uncommon. Greene's Protecting Groups in Organic Synthesis, the standard reference for the state of the art in this arena, offers no entries for selenium protective methodology, in stark comparison to its mention of the great variety of protecting groups germane to its chalcogen cousin sulfur. This scarcity of Se-protection methods makes it no less interesting and pertinent toward the construction of selenium-containing organic systems which do indeed require the iterative blocking and de-blocking of selenol functionalities. A selenium-containing system which is especially relevant is selenocysteine, as its use in Solid Phase Peptide Synthesis requires extensive protection of its selenol side chain. This review will attempt to summarize the current state of understanding with regard to selenium protection protocol in organic synthesis. Moreover, it will provide a special emphasis on selenocysteine side chain protection, comprising both the breadth of functionality used for this purpose as well as methods of deprotection.     

Fluorometric monitoring of organic reactions on solid phase

The direct monitoring of reaction progress on solid supports by fluorescence spectroscopy is described. An immobilized fluorescent tracer molecule (dansyl chloride) is used to monitor the reaction on OH resins (Argopore Wang, PS Wang, and Argogel Wang), both in batch and in parallel chemistry. Fluorescence measurements were obtained directly on solid phase. The method demonstrated to be a valuable tool for the quantitative determination of resin-bound hydroxyl groups, to study reaction kinetics and for continuously monitoring the progress of the conversion of the hydroxyl resins into the chlorinated ones. The procedure proposed is highly sensitive compared to the traditional ones. The system can be extended to monitor a variety of reactions on solid supports, and in conjunction with a well-established technique such as flow analysis, basic studies on solid-phase become possible.     

Direct mass spectrometric monitoring of solid phase organic syntheses

Direct on-bead monitoring of solid-phase reactions is possible with soft laser desorption time-of-flight mass spectrometry (SLD-TOF MS) without prior cleavage from the resin if photocleavable phenacyl ester or o-nitroveratryl linker groups are employed.     

A novel porous carbon and its perspectives for the solid phase extraction of volatile organic compounds

A porous carbon sorbent prepared by controlled pyrolysis of saccharose in a matrix of silica gel was tested for the preconcentration of a variety of compounds differing in polarity and volatility (hydrocarbons, halocarbons, oxygenated compounds) in simulated and real air samples. The trapped components were desorbed off-line by liquid-(carbon disulphide and carbon disulphide with 1% methanol) and on-line by thermo-desorption in combination with HRCGC. Adsorption-desorption properties of the sorbent were evaluated according to the determined recovery values, whereby physicochemical interactions of both the sorbent and solute were taken into consideration. With oxygenated compounds recovery data indicate the presence of active sites on the surface of the sorbent.Dedicated to Professor Dr. Dr. h.c. mult. J. F. K. Huber on the occasion of his 70th birthday     

A two-step synthesis of medicinally-important 1,8-naphthalimide peptidyls by solid phase organic synthesis

A new approach for a short synthesis of novel medicinally-important mono-, bis- and tris-1,8-naphthalimide peptidyl derivatives is described. The method generates efficiently 1,8-naphthalimides with variable spacer lengths and charged, polar or hydrophobic residues at desired positions, which can increase binding affinity, conformational stability, intracellular transport and/or biological activity. The synthetic routes reported in this work are both general and applicable, and significantly expand the scope of potential 1,8-naphthalimide anticancer candidates.     

A magnetizable solid phase for enzyme extraction

A method for the convenient and reliable preparation of magnetizable agarose beads containing iron particles is described. The beads were treated with the triazine dye, Reactive Red 120, and the matrix was examined for the ability to extract proteins from crude preparations using lactate dehydrogenase from porcine muscle as a model. The recovery and specific activity values of enzyme obtained using this matrix and magnetic field separation were significantly greater than those for enzyme purified by centrifugation and conventional dye ligand chromatography.     

固体碱对油品中有机硫化物的脱除性能及分析

预碱洗（电精制）是轻质油品精制中的重要环节,通过氢氧化钠水溶液预碱洗可除去油品中的硫化氢、低分子硫醇等酸性物质,但大量含硫废碱液的排放给环保造成很大压力。以固体碱代替液体碱预碱洗,是减少甚至消除废碱液产生和排放的最有效措施。近十几年来,许多学者致力于固体碱对轻质油品中硫醇、硫化氢的脱除研究。     

Quantum chemistry study on internal conversion of diphenyldibenzofulvene in solid phase

We investigate the nonradiative decay process of diphenyldibenzofulvene (DPDBF) in solid phase by using the quantum chemistry methods. To carry out the nonradiative rate constant calculation, we construct a solid phase model based on the ONIOM method. The geometry of the DPDBF molecule is optimized for the ground state by DFT and the first excited state by TD-DFT, and the corresponding vibrational frequencies and normal coordinates are computed. Under displaced-distorted harmonic oscillator potential approximation, Huang-Rhys factors are obtained. Vibronic coupling constants are calculated as a function of the normal mode based on Domcke's scheme. We find that vibronic coupling constants of 12 modes with large reorganization energies are of similar order, and if this result is still valid for other modes, the internal conversion rate would be determined by high frequency modes because they have a significant nuclear factor that is related to Franck-Condon overlap intergrals. We also find that geometrical changes are suppressed due to the stacking effect, which yields small Huang-Rhys values in the solid phase.     

Calibration procedure for solid phase microextraction-gas chromatographic analysis of organic vapours in air

A calibration procedure for solid phase microextraction-gas chromatographic (SPME-GC) analysis of organic vapours in air was described in which GC detector (MS in this case) signal is directly related to concentration of analytes of interest sampled by SPME. Gaseous standard mixtures used for the calibration were generated by means of a home-made permeation-type apparatus described elsewhere, W. Janicki et al., Chem. Anal., 38 (1993) 423 and modified to permit easy sampling of analytes on an SPME fibre. To establish sampling parameters, times for equilibrium partitioning of five selected organic compounds (carbon tetrachloride, toluene, chlorobenzene, p-xylene, n-decane) between gaseous mixtures and the fibre (fused silica fibre coated with 100 mum polydimethylsiloxane) were determined. For 10 min sampling time, the detector response and hence amount sampled on the fibre were linear functions of analytes concentration in a gaseous sample.     

共价有机骨架材料在固相微萃取中的研究进展

共价有机骨架(COFs)作为一类新颖的、结晶性的、通过共价键构建而成的多孔聚合物材料.由于其稳定的化学性质、巨大的比表面积及可调控的孔道结构,还兼有易于功能化和快速的载流子迁移率等特点,已被成功应用于样品前处理中.然而,很少有关于COFs在固相微萃取(SPME)方面的研究进展.本文主要综述了制备方法、萃取机理及在环境污...     

Silyl nitronates and nitrile oxides in organic synthesis. A novel route to d,l-deoxysugars. Use of aluminum oxide as solid phase base for generation of

Novel methodology is developed for a three step synthesis of deoxyaldoses and deoxyketoses: 1. Regioselective addition of silyl nitronate or nitrile oxide to a diene. 2. Stereospecific hydroxylation of the double bond. 3. Unmasking of the aldol moiety by catalytic reduction of the 2-isoxazoline. The syntheses of D,L-deoxyribose, D,L-oleose, D,L-digitoxose, D,L-2-deoxygalactose, 1,3-dideoxyfructose, 3-deoxyfructose etc. are described. Basic aluminum oxide is introduced as a solid phase base for the one step synthesis of 2-isoxazolines from aldoximes and olefins. An X-ray diffraction study of compound $\text{13c}$ verifies the stereochemical assignments.