- A metal-free strategy for the cross-dehydrogenative coupling of 1,3-dicarbonyl compounds with 2-methoxyethanol
-
Here, we report a metal-free approach for the construction of methylene-bridged bis-1,3-dicarbonyl compounds via cross-dehydrogenative coupling of 1,3-dicarbonyl compounds with 2-methoxyethanol. In addition, we have extended this methodology to synthesize tetra-substituted pyridine derivatives using 1,3-dicarbonyl, 2-methoxyethanol and NH4OAc in one step. The key advantages include accepting a wide range of substrates, utilizing O2 as the sole oxidant, and synthesizing biologically active compounds such as 1,4-dihydropyridine and pyrazole. This journal is
- Chang, Yu-Lun,Huang, Sheng-Hua,Kudale, Vishal Suresh,Wang, Jeh-Jeng,Zheng, Sheng
-
p. 1226 - 1230
(2022/02/21)
-
- Template-free sol–gel synthesis of high surface area mesoporous silica based catalysts for esterification of di-carboxylic acids
-
High surface area mesoporous silica based catalysts have been prepared by a simple hydrolysis/sol–gel process without using any organic template and hydrothermal treatment. A controlled hydrolysis of ethyl silicate-40, an industrial bulk chemical, as a silica precursor, resulted in the formation of very high surface area (719?m2/g) mesoporous (pore size 67?? and pore volume 1.19?cc/g) silica. The formation of mesoporous silica has been correlated with the polymeric nature of the ethyl silicate-40 silica precursor which on hydrolysis and further condensation forms long chain silica species which hinders the formation of a close condensed structure thus creating larger pores resulting in the formation of high surface mesoporous silica. Ethyl silicate-40 was used further for preparing a solid acid catalyst by supporting molybdenum oxide nanoparticles on mesoporous silica by a simple hydrolysis sol–gel synthesis procedure. The catalysts showed very high acidity as determined by NH3-TPD with the presence of Lewis as well as Br?nsted acidity. These catalysts showed very high catalytic activity for esterification; a typical acid catalyzed organic transformation of various mono- and di-carboxylic acids with a range of alcohols. The in situ formed silicomolybdic acid heteropoly-anion species during the catalytic reactions were found to be catalytically active species for these reactions. Ethyl silicate-40, an industrial bulk silica precursor, has shown a good potential for its use as a silica precursor for the preparation of mesoporous silica based heterogeneous catalysts on a larger scale at a lower cost.
- More, Pavan M.,Umbarkar, Shubhangi B.,Dongare, Mohan K.
-
p. 1247 - 1253
(2016/10/13)
-
- Miniolins A-C, novel isomeric furanones induced by epigenetic manipulation of Penicillium minioluteum
-
Cultivation of Penicillium minioluteum with azacitidine, a DNA methyltransferase inhibitor, led to the isolation of a novel type of aspertetronin dimer, named miniolins A-C (1-3), along with their precursor aspertetronin A (4). The structures of 1-3 were elucidated by extensive spectroscopic methods, and the absolute configurations were assigned by the chiral HPLC analysis of chemical degradation products and electronic circular dichroism associated with the TDDFT computational method (CAM-B3LYP/TZVP). The miniolins showed moderate cytotoxic activity against Hela cell lines. This journal is
- Tang, Hao-Yu,Zhang, Qiang,Gao, Yu-Qi,Zhang, An-Ling,Gao, Jin-Ming
-
p. 2185 - 2190
(2015/02/05)
-
- The reaction between ethanedioyl (oxalyl) dihalides and Ag2C2O4: A route to Staudinger's elusive ethanedioic (oxalic) acid anhydride
-
Ethanedioic (oxalic) acid anhydride 1 was prepared for the first time and its dimeric cyclic nature established by spectroscopic and chemical evidence. The strong instability of 2-chloro-2-oxoethanoic acid 3 was incidentally observed. The chemical behaviour of 1 with MeOH and CH2N2 was investigated.
- Strazzolini, Paolo,Gambi, Alberto,Giumanini, Angelo G.,Vancik, Hrvoj
-
p. 2553 - 2557
(2007/10/03)
-
- Photosensitized Oxidation of Furans. Part 14. Nature of Intermediates in Thermal Rearrangement of Some endo-Peroxides of 2-Alkoxyfurans: New Rearrangement Pathway of Furan endo-Peroxides
-
2-Methoxy-5-phenylfurans (1a-c) substituted at C-4 with electron-withdrawing groups, by dye-sensitized photo-oxygenation in non-participating solvents, give the endo-peroxides (3a-c) which by thermal rearrangement partly yield the 3H-1,2-dioxoles (14a-c).The latter, which are the first examples of this ring system, are thermally very unstable.Their formation can be deduced only from the products obtained by thermal rearragement which are structurally related with the thermal rearrangement products of 3H-1,2,4-dioxazoles (10).The behavior of the furans (1a-c) contrasts with that of the 2-methoxy-5-phenylfurans unsubstituted at C-4 which under the same conditions give carbonyl oxides.
- Graziano, M. Liliana,Iesce, M. Rosaria,Cimminiello, Guido,Scarpati, Rachele
-
p. 241 - 245
(2007/10/02)
-