Detail of "42059-81-4"

Reference

Enthalpies of combustion and formation of 3-formylchromones

All Rights Reserved. Enthalpies of combustion and formation of 3-formylchromones. Flores, Henoc; Lopez, Yessica I.; Amador, Patricia (Facultad de Ciencias Quimicas de la, Benemerita Universidad Autonoma de Puebla, Puebla Pue 72570, Mex.). Thermochimica Acta, 450(1-2), 35-37 (English) 2006 Elsevier B.V. CODEN: THACAS. ISSN: 0040-6031. DOCUMENT TYPE: Journal CA Section: 69 (Thermodynamics, Thermochemistry, and Thermal Properties) Section cross-reference(s): 27 The enthalpies of combustion of 3-formylchromone (3F), 3-formyl-6-methylchromone (3F6M), and 3-formyl-6-isopropylchromone (3F6I) were detd. by combustion calorimetry. The molar combustion energies (DcUm0(cr, 298.15 K)) of the 3F, 3F6M, and 3F6I are: -(4452.In this article, certain chemicals are used. Some of their cas registry numbers are 42059-81-4 and 17422-74-1 4 ± 1.8), -(5115.6 ± 2.7), and -(6411.4 ± 2.5) kJ mol-1, resp. The formation enthalpies in the cryst. state (DfHm°(cr, 298.15 K)) are: -(340.2 ± 2.2), -(355.1 ± 3.1), and -(415.5 ± 3.0) kJ mol-1, resp. .

Lithiation in flavones, chromones, coumarins, and benzofuran derivatives

Lithiation in flavones, chromones, coumarins, and benzofuran derivatives. Costa, Ana M. B. S. R. C. S.; Dean, Francis M.; Jones, Michael A.; Varma, Rajender S. (Robert Robinson Lab., Univ. Liverpool, Liverpool L69 3BX, UK). J. Chem. Soc., Perkin Trans. 1, (4), 799-808 (English) 1985. CODEN: JCPRB4. ISSN: 0300-922X. DOCUMENT TYPE: Journal CA Section: 26 (Biomolecules and Their Synthetic Analogs) Section cross-reference(s): 27 Flavones were lithiated in the 3-position by LiN(CHMe2)2 in THF at -78° to give stable derivs. which were readily converted to the corresponding carboxy, ethoxycarbonyl, mercapto, methylthio, trimethylsilyl, hydroxy, or other derivs. E.g., treatment of flavone with LiN(CHMe2)2 in THF at -78° gave 3-lithioflavone which reacted with CO2 to give 92% 3-flavonecarboxylic acid. Benzofurans were preferentially lithiated at the 2-position; where this was blocked lithiation occurred in the 3-position in the presence of an activating group. Ring-opening of benzofurans occurred in some cases giving acetylenic phenols directly. Chromenes were lithiated at positions 2 and 3, depending on substitution. Coumarins generally behaved as esters and gave the corresponding amides with LiN(CHMe2)2, except for 4-methoxycoumarin which underwent lithiation in the 3-position. Deprotonation in the 32-position in ethers occurs easily only when there is an ether link antiperiplanar to the proton removed.Except for chemicals metioned above, 42059-81-4 is also used. The lithiated species are really unstable intermediates in trans eliminations leading to alkyne derivs. .