- CELLULOSIC COMPLEX AND APPLICATIONS THEREOF
-
The present invention provides a polysaccharide supported fluorinating agents which can be used in fluorination reactions. The invention particularly describes a new bacterial cellulose supported tetra-n-butyl ammonium fluoride complex [NBu4(Bac-Cell-OH)F] which is stable and non-hygroscopic. The invention further relates to a process for fluorination using the [NBu4(Bac-Cell-OH)F] complex.
- -
-
Page/Page column 6-7; 11-12
(2020/10/20)
-
- Investigating the microwave-accelerated Claisen rearrangement of allyl aryl ethers: Scope of the catalysts, solvents, temperatures, and substrates
-
The microwave-accelerated Claisen rearrangement of allyl aryl ethers was investigated, in order to gain insight into the scope of the catalysts, solvents, temperatures, and substrates. Among the catalysts examined, phosphomolybdic acid (PMA) was found to greatly accelerate the reaction in NMP, at temperatures ranging from 220 to 300 °C. This method was found to be useful for preparing several intermediates previously reported in the literature using precious metal catalysts such as Au(I), Ag(I), and Pt(II). Additionally, substrates bearing bromo and nitro groups on the aryl portion required careful tailoring of the reaction conditions to avoid complex product profiles.
- Hui, Zi,Jiang, Songwei,Qi, Xiang,Ye, Xiang-Yang,Xie, Tian
-
supporting information
(2020/05/18)
-
- Total synthesis of (-)-Haouamine B pentaacetate and structural revision of haouamine B
-
The enantiocontrolled total synthesis of (-)-haouamine B pentaacetate was accomplished via an optically active indane-fused β-lactam, which was prepared by a newly developed Friedel-Crafts reaction. Subsequent cleavage of the β-lactam and an intramolecular McMurry coupling reaction provided the core indane-fused tetrahydropyridine, which led to the elucidation of the structure, as proposed by Trauner and Zuba.
- Momoi, Yuichi,Okuyama, Kei-Ichiro,Toya, Hiroki,Sugimoto, Kenji,Okano, Kentaro,Tokuyama, Hidetoshi
-
supporting information
p. 13215 - 13219
(2015/01/09)
-
- Ring-closing metathesis for the synthesis of 2H- and 4H-chromenes
-
Six 4H-chromenes were synthesized from substituted phenols using vinylstannylation and ring-closing metathesis (RCM) as key steps. In addition, a different approach involving amongst other steps, an aryl allyl isomerization and RCM afforded a set of seven 2H-chromenes from phenolic precursors.
- Van Otterlo, Willem A.L.,Ngidi, E. Lindani,Kuzvidza, Samuel,Morgans, Garreth L.,Moleele, Simon S.,De Koning, Charles B.
-
p. 9996 - 10006
(2007/10/03)
-
- Ring-closing metathesis for the synthesis of benzo-fused bicyclic compounds
-
Ring-closing metathesis (RCM) was used to synthesise five 4H-chromenes, a naphthol and an indenol. These are the first examples of RCM applied to the synthesis of such benzo-fused bicyclic compounds.
- Van Otterlo, Willem A.L.,Ngidi, E. Lindani,Coyanis, E. Mabel,De Koning, Charles B.
-
p. 311 - 313
(2007/10/03)
-
- A biomimetic approach to dihydrobenzofuran synthesis
-
A method for an acid-catalyzed construction of dihydrobenzofuran heterocycles (14) from 2-(2′-hydroxyethyl)quinone precursors 10 is presented. The putative oxonium ion intermediate 17 formed by an intramolecular hydroxyl cyclization followed by dehydration is reduced in situ by an added dihydroquinone source. Good to excellent yields of cyclized products are realized in all cases except for highly electron deficient systems, and these suffer reduction prior to oxonium ion formation. All products are monomeric and derived from a two-electron transfer except for 10g, which affords the dimeric dihydrobenzofuran. The amount of cyclization or reduction product is governed by the HOMO/LUMO gap between the quinone substrate and the dihydroquinone additive, and the product distribution can be adjusted by modifying the electronic properties of the added reducing agent.
- Benbow,Katoch-Rouse
-
p. 4965 - 4972
(2007/10/03)
-
- Thermodynamic, spectroscopic, and density functional theory studies of allyl aryl and prop-1-enyl aryl ethers. Part 1. Thermodynamic data of isomerization
-
A chemical equilibration study of the relative thermodynamic stabilities of seventy isomeric allyl aryl ethers (a) and (Z)-prop-1-enyl aryl ethers (b) in DMSO solution has been carried out. From the variation of the equilibrium constant with temperature the Gibbs energies, enthalpies, and entropies of isomerization at 298.15 K have been evaluated. Because of their low enthalpies, the (Z)-prop-1-enyl aryl ethers are strongly favored at equilibrium, the Gibbs energies of the a→b isomerization ranging from -12 to -23 kJ mol-1. The entropy contribution is negligible in most reactions, but occasionally small positive values less than +10 J K-1 mol-1 of the entropy of isomerization are found. The equilibration studies were also extended to involve two pairs of related isomeric ethers with a Me substituent on C(2) of the olefinic bond. The Me substituent was found to increase the relative thermodynamic stability of the allylic ethers by ca. 3.4 kJ mol-1.
- Taskinen, Esko
-
p. 1824 - 1834
(2007/10/03)
-
- The Synthesis of Megaphone
-
Condensation of 4,4,5-trimethoxy-2-propyl>-2,5-cyclohexadien-1-one (7) with 1,2,3-trimethoxy-5-(1-(Z)-propenyl)benzene in dichloromethane, in the presence of 1 equiv. of stannic chloride, gave (2β,3β,3aα)-3,3a-dihydro-5-methoxy-3-m
- Buechi, George,Chu, Ping-Sun
-
p. 2718 - 2721
(2007/10/02)
-