Condensed 4-Thiazolidinones

Stereocontrolled Synthesis of New Tetrahydrofuro[2,3‐d]thiazole Derivatives via Activated Vinylogous Iminium Ions.

“…Despite the considerable amounts of other products being formed (vide infra), this result prompted us to further explore whether the thiazolidines 9a-d can be employed for the synthesis of not easily obtainable bicyclic products 13a-d 12 via a reduction-alkylation-ring closure sequence, involving the C(5) and C(4) positions of the starting derivatives. 13 Figure 1. Perspective view of the crystal structure of (Z)-(5-ethoxycarbonylmethyl-3-methyl-4-oxothiazolidin-2-ylidene)-1-phenylethanone (10a), showing the crystallographic numbering scheme.…”

“…The NMR spectra were obtained using a Varian Gemini 2000 instrument ( 1 H at 200 MHz, 13 C at 50.3 MHz). 13 C NMR resonance assignments were aided by the use of the DEPT technique to determine numbers of attached hydrogens. ROESY have been performed..... Chemical shifts are reported in parts per million (ppm) on the δ scale from TMS as an internal standard in the solvents specified.…”

“…Crystal data for 13a: C 14 H 15 NO 2 S, MW 261.33, monoclinic, P2 1 /c, a = 21.7289 (13), b = 7.7567 (4), c = 15.5614(9) Å, β = 110.413(1) o , V = 2458.1(2) Å 3 , Z = 8, T = -183 o C, F(000) = 1104, μ (MoKα) = 0.256 mm -1 , D calcd = 1.412 g.cm -3 , 2θ max 53 o (CCD area detector, 99.5 % completeness), wR(F 2 ) = 0.0828 (all 5018 data), R = 0.0311 (4543 data with I > 2σI).…”

“…protons cannot be determined as signals are of higher order), 3.27 (3H, s, NCH 3 ), 3.59 (2H, m, CH 2 OH), 4.12 (1H, dd, J AX =4.8 Hz, J BX =4.2 Hz, CH A H B CH X S), 4.80 (1H, broad t, OH), 6.92 (1H, s, =CH), 7.47-7.63 (3H, m, p-Ph and m-Ph), 7.83 (2H, dd, J o,m =7.8 Hz; J o,p =1.8 Hz, o-Ph);13 C NMR (DMSO-d 6 ): δ 30.4 (NCH 3 ), 35.9 (CH A H B ), 42.8 (CH X ), 58.5 (CH 2 OH), 95.4…”

“…cm -1 ; 1 H NMR (DMSO-d 6 ): δ 1.78-1.96 (1H, m, CH A H B CH X S), 2.17-2.32 (1H, m, CH A H B CH X S; the coupling constants of H A and H B protons cannot be determined as signals are of higher order), 3.04 (3H, s, NCH 3 ) 3.50-3.60 (2H, m, CH 2 OH), 4.41 (1H, dd, J AX =9.8 Hz and J BX =3.8 Hz, CH A H B CH X S), 4.82 (1H, t, J=5.0 Hz, OH), 5.27 (1H, s, =CH);13 C NMR (DMSO-d 6 ): δ 29.7 (NCH 3 ), 35.7 (CH A H B ), 45.7 (CH X ), 58.5 (CH 2 OH), 67.…”