4849-59-6Relevant articles and documents
A facile and convenient synthesis of 3-alkylamino-5-arylthiophenes with a variety of substituents at C-2 and studies of reaction mechanisms
Kim, Bo Sung,Kim, Kyongtae
, p. 3690 - 3699 (2007/10/03)
Thioaroylketene S,N-acetals were treated with active methylene compounds including β-keto ester, nitromethane, cyanoacetic acid, p- toluenesulfonylacetone, 4-nitrophenylacetic acid, and diethyl (2- oxopropyl)phosphonate in the presence of mercury(II) acetate in CH2Cl2 at room temperature. These reactions gave 3-alkylamino-5-arylthiophenes containing various substituents, which comprised, respectively, alkoxycarbonyl, nitro, cyano, p-toluenesulfonyl, 4-nitrophenyl, and diethylphosphono groups at C-2 in good yields. The reaction of 3-methylamino- 3-methylthio-1-phenylthioxopropene with malonic acid or Meldrum's acid under the same conditions gave 3-methylamino-5-phenylthiophene. Similarly, treatment of 3-methylamino-3-methylthio-1-phenylthioxopropene with various enolizable cyclic ketones such as 4-hydroxy-6-methyl-2-pyrone, homophthalic anhydride, 2-hydroxy1,4-benzoquinone, and 1,3-diethyl-2-thiobarbituric acid gave thieno[3,2-b]pyridin-4-one, thieno[3,2c]isoquinolin-5-one, thieno[3,2- c]benzazepine-1,6-dione, and thieno[3,2-d]pyrimidine-2,4-dione, respectively.
Specific Molecular Orbital Contributions to Nucleophilicity. The Thiocarbonyl Group as Privileged Monitor To Pinpoint Active and Less Active Molecular Orbitals in Reactions with Methylating Agents
Arbelot, M.,Allouche, A.,Purcell, K. F.,Chanon, M.
, p. 2330 - 2343 (2007/10/02)
The rate constants for 41 compounds bearing a C=S function reacting with MeX (X = I, Tos) span 7 orders of magnitude.The PES spectra of these compounds display two very low energy peaks, which stand clearly apart from the other peaks.These two peaks correspond to the ? orbitals of the C-S group; one is its CS ? bonding orbital oriented out of the molecular plane (?CS) and the other its p-type in-plane lone pair orbital (?S).For some of the compounds, the HOMO is the ?CS orbital and for others the HOMO is the ?S lone pair orbital.The best correlation (R = 0.96) between rate constants k and PES data is obtained when ln(k) is plotted against the inverse of PES energy of the ?S lone pair orbital.Whether this lone pair orbital is the HOMO or the next lower HOMO has no importance.A modest correlation (R = 0.78) is obtained when ln(k) is plotted against the inverse of PES energy of the ?CS bonding orbital.An attempt to correlate the calculated energy of the third highest occupied orbital (from AM1 calculations) with ln(k) provides a complete scattering of data (R S (ca. 90 kcal mol-1 deeper than the HOMO) correlates reasonably with ln(k) (R = 0.88).The energies of the S 2s and 2p core orbitals (calculated for 13 cyclic compounds with the HF/3-21G technique to be 4000 to 5500 kcal mol-1 deeper than HOMO) correlate with ln(k) (R = 0.86) as well as does that of the second lone pair orbital ?S.These results are the first where both frontier orbitals and core orbitals display correlation with overall reactivity.They are discussed in terms of direct (perturbational) versus indirect (nonperturbational) concepts.
