The addition reaction of diamides to 1,2,5‐thiadiazole 1,1‐dioxide derivatives

Abstract

The reactions of several derivatives of 1,2,5‐thiadiazole 1,1‐dioxide [3,4‐diphenyl‐(1a), 3,4‐bis(p‐methoxyphenyl)‐(1b), phenanthro[9,10‐c]‐(1c) and acenaphtho[1,2‐c]‐1,2,5‐thiadiazole 1,1‐dioxide (1d), 3,4‐diphenyl‐1,2,5‐thiadiazoline 1,1‐dioxide (2a) and 4‐ethoxy‐5‐methyl‐3,4‐diphenyl‐1,2,5‐thiadiazoline 1,1‐dioxide (2b)], with reagents possessing two nucleophilic nitrogen atoms (urea, N,N′‐dimethylurea, thiourea, N‐methylthiourea, N‐ethylthiourea, N‐allylthiourea, N,N′‐diethylthiourea, N,N′‐diphenylthiourea, dithioxamide and sulfamide), were followed by cyclic voltammetry (CV) and UV–visible spectrophotometry in aprotic solvent solution. The products were isolated, characterized by IR, 1H NMR and 13C NMR methods and their structure was confirmed by single‐crystal x‐ray diffraction. Several substrate–nucleophile combinations (1a–d and 2a with some ureas and thioureas) reacted to give good yields of new compounds formed by the addition reaction of the two nitrogen atoms of the nucleophile to the two >CN— double bonds of the 1,2,5‐thiadiazole 1,1‐dioxide ring. Some systems (1a–dithioxamide and 2b–thiourea) did not react, whereas in others (e.g. 1a–sulfamide) a monoaddition equilibrium reaction was observed. Copyright © 2004 John Wiley & Sons, Ltd.

Reactions of the activated, rigid, α‐diazomethine group of 1,2,5‐thiadiazole 1,1‐dioxides with nitrogenated nucleophiles. Part III: aliphatic monoamines and phenylhydrazine

“…The peak at À2.56 V corresponds to 2a, as concluded by comparison with the CV of an authentic sample of the compound. Peaks at À1.83 and À2.40 V are similar to those found for 1,2,5-thiadiazoline 1,1-dioxides, [4][5][6] and were assigned to 1a.BuNH 2 (Eqn (1), Scheme 2).…”

“…The stability acquired by cycle formation and the intramolecular character of the second addition might justify the increased reactivity. 6 We report here the reactions of aliphatic monoamines: n-butylamine (BuNH 2 ), diethylamine (Et 2 NH), and 2aminoethanol (H 2 N(CH 2 ) 2 OH), and of phenylhydrazine (PhN 2 H 3 ) with 3,4-diphenyl-(1a) and phenanthro[9,10c]-1,2,5-thiadiazole 1,1-dioxide (1b) in aprotic solvent solution. The reacting systems were followed using cyclic voltammetry (CV) and 1 H-and 13 C-NMR.…”

On experimental versus theoretically calculated properties of thiadiazole derivatives

“…Adding to the evidence already available [4], we have recently reported that the initial reactions of o-phenylenediamine with 2, and ethylenediamine with 1 or 2 [7], diethylamine with 2 [8], or thiourea with 1 [10], are all additions to the heterocyclic C-atoms, thus supporting the theoretical results for 2, but only the new CHIH-DFT prediction for 1 (Table II).…”

Corrosion inhibition of mild steel in sulphuric acid using a bicyclic thiadiazolidine

“…(9) [21][22][23]. It is well known that the equilibrium position between cyclic thiamides and the tautomeric imidothiol form shifts towards the thioamide side [24,25]. …”