Reactions of aromatic and heteroaromatic compounds containing electron-acceptor substituents

(1R,2R,4R)-N-((4-((4-(2-Carboxyethyl)phenoxy)methyl)thiophen-2-yl)methyl)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-aminium Chloride

“…The attached proton test (APT) modification of the J-modulated spin-echo (JMOD) experiment was performed. The structure of the products was determined by means of 1 H and 13 C NMR spectra (Figures S1-S6). High-resolution mass spectrometry (HRMS) was conducted using a DFS Thermo Scientific spectrometer in full scan mode (m/z 15-500, 70 eV electron impact ionization, and direct sample injection).…”

Photochemical Synthesis of 4H-Thieno[3,2-c]chromene and Their Optical Properties

“…The cyclization was performed under the same conditions as those used for compound 6a, and the reaction progress was monitored by TLC. Complete cyclization of compounds 6b-o required irradiation for 4-30 hours and the yields of thienochromenes 7bp were in the range 33-90% (Table 1, entries [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17].…”

“…The yields of compounds 7b and 7f with electrondonor substituents in the benzene ring obtained by palladium-catalyzed cyclization of 6b and 6f, respectively, were slightly higher than those of the photochemical reaction (Table 1, entries 3 and 7), whereas photochemical cyclization of compounds 6h and 6i bearing electron-withdrawing substituents proceeds with significantly higher yields of thienochromenes 7h and 7i, respectively (entries 9 and 10). The photochemical cyclization of 6m-o gave compounds 7m-o, respectively, as the sole reaction products (entries [14][15][16]. Only in the case of 6e were the isomeric 4H-thieno [3,2-c]chromene-2-carbaldehydes 7e (entry 6) and 7p (entry 17) obtained in a 2:5 ratio according to NMR data.…”

“…The starting compounds 5a-c were synthesized by treating 14 o-iodophenols 3a-c with 4-(chloromethyl)thiophene-2-carbaldehyde (1), prepared by chloromethylation of thiophene-2-carbaldehyde. 15 Compounds 6a-o were synthesized by the reaction of the appropriate phenol 4a-o with 5-iodo-4-(chloromethyl)thiophene-2-carbaldehyde (2), obtained by iodination of aldehyde 1. 12 Note that the latter approach is preferable because of the ready availability of phenols 4a-o.…”

EFFECT OF LEWIS ACID CATALYSTS ON THE POSITIONAL SELECTIVITY OF THE ELECTROPHILIC AROMATIC SUBSTITUTION ON Α-Substituted THIOPHENES: A CONCEPTUAL DFT INVESTIGATION

“…Similarly, the local nucleophilicity index predicts that the EAS attack on the α position is preferred for both non-substituted and α-substituted five-membered heterocycles as found experimentally. On the other hand, experiments [35][36][37][38][39] carried out for the EAS on some thiophene derivatives α-subsituted by electron-withdrawing groups, namely, 2-CHO-thiophene 1, 2-COMe-thiophene 2, and 2-CO 2 Me-thiophene 3, show that the orientation of the electrophilic substitution at the α position may be changed to the β position by strengthening the ability of such substituents by forming complexes with LA, AlCl 3 (see Fig. 1).…”