نتایج جستجو برای: cyclo ketalization
تعداد نتایج: 4572 فیلتر نتایج به سال:
The title penta-cyclo-undecane cage derivative, C13H14OS2, was identified during a thio-ketalization reaction. The reaction selectively gave the title compound and the product corresponding to bis-ketal was not formed. The title compound exhibits unusual Csp (3)-Csp (3) single bond lengths ranging from 1.495 (3) to 1.581 (2) and strained bond angles as small as 89.29 (12) and as large as 115.11...
Second-generation biomass (BM) can be produced in amounts that meet worldwide fuel demands. However, BM favors parallel and undesirable reactions its transformation chain. We circumvent this problem by first modifying ketalization, giving a user-friendly liquid we named BP (bio-petroleum). This study converted representative compound of BP, DX (1,2:3,5-di-O-isopropylidene-α-D-xylofuranose), mix...
An efficient method for the synthesis of (+)-buergerinin F is established via the enantioselective aldol reaction of a tetra-substituted ketene silyl acetal with crotonaldehyde, followed by intramolecular Wacker-type ketalization.
A concise synthesis of a highly functionalized intermediate lacking only C10 of the mitomycin backbone is described. The key to this development is the Brønsted acid-catalyzed aza-Darzens reaction used to forge the cis-aziridine. Additionally an oxidative ketalization fortuitously occurs during the quinone-enamine coupling step, leading to an orthogonally protected hydroquinone.
A highly efficient method for the direct synthesis of α-iodoketals from methyl ketones has been developed via sustainable integration of orthogonal tandem catalytic reactions: copper(II) oxide catalyzed iodination reaction and the subsequent excess or regenerated iodine catalyzed regioselective ketalization reaction.
An inexpensive Fe doped aluminoborate consisted of 18% in PKU-1 material that exhibits high selectivity 4-hydroxymethy-2,2-dimethyl-1,3-dioxolane (Solketal, 98.3%), considerable activity (TOF 51.7 h−1), and recyclable ability the ketalization glycerol to Solketal with acetone at 318 K has been developed. Our study demonstrated structure (less agglomerated iron species vs. FeOx clusters) can be ...
Abstract Under different concentrations of the base potassium deuteroxide KOD, progress reactions, such as enolization, D‐substitution, isomerization, and conformational changes diketopiperazine cyclo(L‐Pro‐L‐Xxx) cyclo(D‐Pro‐L‐Xxx) (Xxx = Phe, Tyr) in D 2 O solution, was investigated by 1 H nuclear magnetic resonance (NMR). Cyclo(L‐Pro‐L‐Xxx) is mostly isomerized to whereas only slightly even ...
Synthetic efforts toward the chlorinated aza-propellane alkaloid acutumine (1) are described. The key vicinal quaternary centers were constructed by a photochemical [2 + 2] cycloaddition reaction of a furanyl-tetrahydroindolone. Dihydroxylation of the [2 + 2] product enabled a tandem retro-aldol/intramolecular ketalization reaction, which revealed the aza-propellane core of 1 while generating a...
The addition of an aqueous solution diketopiperazine cyclo(Pro-Xxx) (Xxx: amino acid residue) to (?)-epigallocatechin-3-O-gallate (EGCg) led precipitation the complex EGCg and cyclo(Pro-Xxx). molecular capture abilities using were evaluated by ratio amount included in precipitates with that total used. Stronger hydrophobicity side chain residue a higher ability. Furthermore, ability decreased w...
The title compound, C(13)H(24)O(7), is the product of the ketalization of methyl l-(+)-rhamnopyran-oside with 2,3-butane-dione. It crystallizes with two mol-ecules in the asymmetric unit, which are connected by O-H⋯O hydrogen bonds. The C-3,4 diequatorial hydroxy groups of the methyl l-(+)-rhamnopyran-oside were protected, leaving the C-2 hydroxy group free. The l-(+)-rhamnopyran-oside and 2',3...
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