Reaction of 3H-1,2-benzodithiol-3-one 1-oxide with primary amines or anilines provides reasonable yields (40–70%) of the corresponding 1,2-benzisothiazolin-3(2H)-ones. These reactions may have relevance to the biological chemistry of 1,2-dithiolan-3-one 1-oxides and also offer a new method for ...
We have previously studied poly(ethylenimine) (PEI)-grafted Sepharose FF resins for ion-exchange chromatography of bovine serum albumin (BSA), and found the presence of a critical ionic capacity (cIC, 600 mmol/L for BSA), above which both BSA adsorption capacity and uptake rates increased drasti...
In this study, thiophilic cryogels were prepared by two different approaches and they were used in purification of IgG from aqueous solutions and human plasma. In the first approach, poly(2-hydoxyethyl methacrylate) [PHEMA] cryogel disks were prepared. The PHEMA cryogel disks were activated by d...
Publisher SummaryThis chapter discusses the racemization of N-protected active esters of phenylalanine under the influence of amines. The benzyloxycarbonyl group protects the adjacent asymmetric carbon atom from racemization. The p-nitrophenyl, 2,4,6-trichlorphenyl, phenyl and cyanomethyl esters...
N-Benzyloxycarbonylendothiodipeptide esters, 3, are synthesized without racemization from the corresponding N-benzyloxycarbonyldipeptide esters, 2, using 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide, 1, as thionation reagent. The benzyloxycarbonyl amino-protecting group (Z)...
Polymer catalysts, cross-linked with N,N′-ethylene (C2) {or butylene (C4)}-bisacrylamide containing l-histidine and quaternary trimethylammonium groups were imprinted with a racemic transition-state analogue of phenyl 1-benzyloxycarbonyl-3-methylpentylphosphonate for the hydrolysis of p-nitroph...
Multivalent 4-nitrophenyl (PNP)–carbonate esters were prepared from carbonate ester-containing core groups by a new divergent-growth process. The process doubles the number of PNP–carbonate esters with each round of growth, or branching, which occurs by reacting an N,N-dihydroxylalkyl amine wi...
Various cross-linked (with N,N′-ethylene (C2), butylene (C4), hexamethylene (C6), or decamethylene (C10)-bisacrylamide) polymer catalysts containing l-histidine and quaternary trimethylammonium groups were imprinted with a racemic transition-state analogue of phenyl 1-benzyloxycarbonyl-3-methyl...
Organogels of low molecular weight compounds,N-benzyloxycarbonyl-l-alanine 4-hexadecanoyl-2-nitrophenyl ester (BLAHN) and related compounds, in methanol and cyclohexane solvents were studied by FT-IR, circular dichroism (CD), transmission electron microscope (TEM), and scanning electron microsco...
A simple, one-pot preparation of monoprotected 1,4,7,10-tetraazacyclododecanes via an efficient acylation reaction with 4-nitrophenyl active esters has been developed.
The enantiospecific synthesis of unnatural unsaturated and saturated α-amino acids based on a Wittig type reaction is described. The versatile synthetic intermediates, l-glutamic and l-aspartic acid semialdehydes, are obtained from the corresponding N,N-di-Boc-diesters, by the selective reducti...
Based on a mechanism analogous to the serine/threonine ligation, the aspartic acid ligation, which is facilitated by the γ-amino alcohol based ligation and oxidation, is developed and applied to the synthesis of cyclic peptides. The γ-hydroxyl group triggers the ring-chain tautomerization via ...
A series of novel aryloxyphosphoramidate nucleoside prodrugs based on l-aspartic acid and l-glutamic acid as amino acid motif has been synthesized and evaluated for antitumoral activity. Depending on the cancer cell line studied and on the nature of the parent nucleoside compound (gemcitabine, 5...
The direct reaction between Te metal and methyl 2-(2-bromoacetamido)propanoate (27) at room temperature, yields the first example of organotellurium(IV) derivative (MeOC(O)CH(Me)NHCOCH2)2TeBr2 (31). Similarly, reaction of Te with methyl 2-(2-bromoacetamido)acetate (26) and methyl 2-(2-bromoaceta...
Biodiesel contains large methyl esters including methyl palmitate (MP), methyl oleate (MO), methyl linoleate (ML), etc. Long alkyl chains and asymmetric structures of these large methyl esters lead to complexity in development of kinetic models. In this paper, surrogate fuels for large methyl es...
The enantiomeric environmental behaviors, bioactivities and toxicities of isofenphos‑methyl enantiomers were characterized systematically in this study. (R)‑Isofenphos‑methyl was degraded preferentially in Yangtze River water and different types of vegetables with an enantiomeric fraction (EF) o...
A series of methylenealkanes RCH2CH2(R)C = CH2 (R = n-butyl, n-hexyl, isopropyl and isobutyl), which are products of selective zirconocene-catalyzed dimerization of α-olefins, were introduced into Pd-catalyzed methoxycarbonylation. With the use of 5-methyleneundecane (1-hexene dimer) as a subst...
In this study, the LLE data of ternary system (water + 1,6-diaminohexane + 2-methyl-1-propanol) and (water + 1,6-diaminohexane + 3-methyl-1-butanol) were measured at (293.15, 303.15 and 313.15) K under atmospheric pressure. Reliability of the experimental tie-line data was checked by empirical H...
A simple procedure for the synthesis of chiral 3,5-disubstituted piperazinones is described. The aza-Michael addition of α-amino esters to β-substituted nitroalkenes in an organic/aqueous biphasic solvent system followed by reduction of a nitro group with zinc nanopowder in acidic media and in...
Treatment of methyl 2,3-pentadlenoate, 3, with bromine in carbon tetrachloride affords a complex mixture, whose main products are methyl (E)- and (Z)-3,4-dlbromo-2-pentenoate, 9 and 10, and 4-bromo-5-methyl-5H-furan-2-one, 4. The mechanism of formation of these and other minor compounds is discu...
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