Preparation of Newtert-Butyl Substituted Coumarins, Thiocoumarins and Dithiocoumarins

EPR Studies on Carboxylic Esters. Part 17.1 EPR Spectra and Spin Densities in the Radical Anions of Thio and Dithiocoumarins

“…The compounds 1, 16 2, 17 3, 16 4, 16,18 5, 16 6 19 and 7 16 were prepared as described in the cited literature.…”

Thiocoumarins: From the Synthesis to the Biological Applications

“…Thiocoumarins can also be converted to dithiocoumarins using Lawesson’s reagent, in a reaction with ~30–40% yield ( Figure 4 ) [ 9 , 11 , 42 ]. This reaction may contribute to deeply exploring these analogues, which are less studied due to the scarcity and rarity of starting materials.…”

“…Few reports on new synthetic routes to achieve this scaffold have been recently reported [ 50 ]. Thiocoumarins, presenting a variety of functional groups, were prepared from the corresponding thiophenols and diketene via cyclocondensation [ 42 ]. Thionation of the obtained products with Lawesson’s or Davy’s reagent led to the corresponding thiono- or dithiocoumarins.…”

The effect of chalcogen substitution on the structure and spectroscopy of 4,7-dimethyl-2H-chromen-2-one/thione analogues

“…The analysis of the Raman spectra allows for a clear assignment of the C-C stretching modes in the benzopyrone ring, with signals at 1559, 1512 and 1412 cm -1 . 14,45 (14) a' / ν as CH 3 -Ph (82) 3079 (9) a''/ν as CH 3 -Py (100) 3076 (13) a''/ν as CH 3 -Ph (100) 3030 (11) a'/ ν s CH 3 -Py (99) 3027 (25) a'/ ν s CH 3 247(<1) a'' / γ C 4 C 10 C 5 C 9 (56); γ C 3 C 4 C 10 C 12 (16); τ C 5 C 6 C 7 C 8 (27) 220(1) a' / δCC (43); δ O-C 9 -C 8 (16) 204 m 205(2) a'' / τ H-C 12 -C 4 -C 10 (68); τ C 3 -C 4 -C 10 -C 9 (32) 171 w 167(<1) a'' / τ C3-C4-C10-C9 (51); γ C-CH3 Py(29) 117 w 100(<1) a'' / τ C 2 -O-C 9 -C 8 (43); τ C 6 -C 7 -C 8 -C 9 (24); γ OC 10 -C 8 -C 9 (23) 89(2) a'' / τ C 2 -O-C 9 -C 10 (46); τ C 7 -C 8 -C 9 -C 10 (35); τ C 5 -C 6 -C 7 -C 8 (18) 43(<1) a'' / τ C-CH 3 Ph (84); γ C 13 -C 6 -C 8 -C 7 (11) a Band intensities and shape: vs = very strong; s = strong; m = medium; w = weak; vw = very weak, sh: shoulder, br: broad. b In parenthesis computed IR intensities in Km/mol are given.…”

“…In particular, 2-thiocoumarins are accessible from the corresponding coumarine by using an equimolar amount of p-methoxyphenylthionophosphine sulfide dimer (Lawesson's Reagent) as sulfur-transfer reagent. [13][14][15] The simplest 2-thiocoumarin derivative have an essentially planar structure in the solid phase and crystallizes in a non-centrosymmetric space group, being promising candidate for non-linear optical applications, as crystals may display second harmonic generation (SHG) effects. 16 Moreover, analytical applications of thiocoumarins were reported, with significant chromogenic and fluorogenic signaling toward Hg(II) and Au (III) ions, which induce the selective desulfuration of thiocoumarin to coumarin.…”