Unexpectedly Stable (Chlorocarbonyl)(N-ethoxycarbonylcarbamoyl)disulfane, and Related Compounds That Model the Zumach–Weiss–Kühle (ZWK) Reaction for Synthesis of 1,2,4-Dithiazolidine-3,5-diones

Abstract

The Zumach-Weiss-Kühle (ZWK) reaction provides 1,2,4-dithiazolidine-3,5-diones [dithiasuccinoyl (Dts)-amines] by the rapid reaction of O-ethyl thiocarbamates plus (chlorocarbonyl)sulfenyl chloride, with ethyl chloride and hydrogen chloride being formed as coproducts, and carbamoyl chlorides or isocyanates generated as yield-diminishing byproducts. However, when the ZWK reaction is applied with (N-ethoxythiocarbonyl)urethane as the starting material, heterocyclization to the putative "Dts-urethane" does not occur. Instead, the reaction directly provides (chlorocarbonyl)(N-ethoxycarbonylcarbamoyl)disulfane, a reasonably stable crystalline compound; modified conditions stop at the (chlorocarbonyl)[1-ethoxy-(N-ethoxycarbonyl)formimidoyl]disulfane intermediate. The title (chlorocarbonyl)(carbamoyl)disulfane cannot be converted to the elusive Dts derivative, but rather gives (N-ethoxycarbonyl)carbamoyl chloride upon thermolysis, or (N-ethoxycarbonyl)isocyanate upon treatment with tertiary amines. Additional transformations of these compounds have been discovered, providing entries to both known and novel species. X-ray crystallographic structures are reported for the title (chlorocarbonyl)(carbamoyl)disulfane; for (methoxycarbonyl)(N-ethoxycarbonylcarbamoyl)disulfane, which is the corresponding adduct after quenching in methanol; for [1-ethoxy-(N-ethoxycarbonyl)formimidoyl](N'-methyl-N'-phenylcarbamoyl)disulfane, which is obtained by trapping the title intermediate with N-methylaniline; and for (N-ethoxycarbonylcarbamoyl)(N'-methyl-N'-phenylcarbamoyl)disulfane, which is a short-lived intermediate in the reaction of the title (chlorocarbonyl)(carbamoyl)disulfane with excess N-methylaniline. The new chemistry and structural information reported herein is expected to contribute to accurate modeling of the ZWK reaction trajectory.

Non-isocyanate Polythiourethane Network from Biowaste: Achieving Circularity via Multidimensional Chemical Recycling with Valuable Small-Molecule Recovery and Reprocessability by Understanding the Dynamic Chemistry

“…The recovered di­(thiocarbamate) holds great potential in various applications. Blencowe et al , used a di­(thiocarbamate) that is almost identical to our recovered di­(thiocarbamate) to obtain masked isocyanate for PU synthesis, which is a safer synthesis route that is free of the use of toxic phosgene as a precursor. Moreover, our recovered di­(thiocarbamate) is O -organyl thiocarbamate, which can be easily converted into S -organyl thiocarbamate by a simple one-step reaction (see Figure S14).…”

Reflections on a Copenhagen–Minneapolis Axis in Bioorganic Chemistry

“…Over a period of four decades, we have developed a thorough mechanistic understanding of the canonical ZWK reaction (Scheme 4A), including several variations to its original formulation 11,12,13 [9,95,[100][101][102]. A wide range of R groups (parent amine = H 2 N-R (3); note that the chemistry is different for R = H) have been studied, and conclusions were in some cases corroborated by sophisticated isotope labeling/mass spectrometric analytical experiments.…”

“…The CLEAR family of supports (108) were prepared by radical copolymerization, either in the bulk or suspension mode, of the branched cross-linker trimethylolpropane ethoxylate (14/3 EO/OH) triacrylate (102) with either allylamine (103) or 2-aminoethyl methacrylate•HCl (104), along with (optionally) one or more of poly(ethylene glycol-400) dimethacrylate (105), poly(ethylene glycol) ethyl ether methacrylate (106), or trimethylolpropane trimethacrylate (107) (Figure 4). The resultant highly cross-linked copolymers, when made by bulk procedures, were ground and sieved to give particles.…”