p-Toluenesulphonic acid-promoted, I₂-catalysed sulphenylation of pyrazolones with aryl sulphonyl hydrazides

Abstract

Aryl pyrazolone thioethers were synthesized via the I2-catalysed cross-coupling of pyrazolones with aryl sulphonyl hydrazides in the presence of p-toluenesulphonic acid, which has been proposed to promote the reaction by facilitating the decomposition of sulphonyl hydrazides.

Metal-Free Iodine-Catalyzed Synthesis of Fully Substituted Pyrazoles and Its Sulphenylation

“…On the basis of previous reports [16][17][18][19] and from the observation of the experimental results, a mechanism analogous to the one recently proposed 18 was envisaged for this reaction (Scheme 6). Aryl 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 sulphenylated pyrazol-5-amines 4.…”

Theoretical insights into excited‐state process for the novel 2,3‐bis[(4‐diethylamino‐2‐hydroxybenzylidene)amino]but‐2‐enedinitrile system

“…In other words, these changes about chemical bond distances and bond angles indicate that the dual hydrogen bonds (O1 H2Á Á ÁN3 and O4 H5Á Á ÁN6) of BDABE should be strengthened in the S 1 state. [39][40][41][42][43][44][45][46][47] In addition, it is well known that the excited-state hydrogen bonding interactions could also be revealed by theoretical IR vibrational spectra. [48][49][50][51][52][53][54][55][56][57] Thus, we also simulated the IR vibrational spectra involved in hydrogen-bonding moieties, which is shown in Figure 4.…”

A theoretical investigation about the excited state behavior for 2‐(6'‐hydroxy‐2'‐pyridyl)benzimidazole: The water‐assisted excited state proton transfer process

“…It further indicates that these two intermolecular hydrogen bonds should be stronger in the S 1 state. [49][50][51][52][53][54][55][56][57][58][59][60][61][62][63] In view of the proton-transferred form 2HPB-H 2 O-PT, the lengths O1ÁÁÁH2 and O3ÁÁÁH4 became larger in the S 1 state than in the S 0 state (i.e., from 1.942 and 1.936 Å in the S 1 state to 1.918 and 1.894 Å in the S 0 state). The bond lengths H2-O3 and H4-N5 became shorter on going from the S 0 to the S 1 state.…”