1,2,4-Dithiazolidine-3,5-dione

Abstract

(1; R = H) [35371-97-2] C2HNO2S2 (MW 135.16) InChI = 1S/C2HNO2S2/c4-1-3-2(5)7-6-1/h(H,3,4,5) InChIKey = BPVALDZRWMHTCJ-UHFFFAOYSA-N InChI = 1S/C2HNO2S2.K/c4-1-3-2(5)7-6-1;/h(H,3,4,5);/q;+1/p-1 InChIKey = FFHZHAQLNGYGBX-UHFFFAOYSA-M (2; R = K) C2NO2S2K (MW 173.26) (heterocyclic system used as a protecting group for primary amines. Reagents 1 and 2 both used as a nucleophilic, protected primary amine, or isocyanate equivalent. Reagent 1 can be used for oxidative sulfurization of phosphorus(III) species) Physical Data: 1 mp 141–143 °C; d 1.880 g cm−3 (calculated from crystallographic data); pKa 2.85 (H2O, I = 0.5, 25 °C). 2 mp 170–180 °C (some decomposition observed at 140–142 °C); d 2.100 g cm−3 (calculated from crystallographic data). Solubility: 1 is soluble in most common organic solvents, except those of very low polarity. 2 is soluble in N,N-dimethylformamide, acetonitrile, and ethanol. Form Supplied in: At the time of writing, neither 1 nor 2 is commercially available. Purification details for both compounds are given below. Preparative Method: The parent heterocycle 1 can be readily prepared on a multigram scale by acidic hydrolysis of 3-ethoxy-1,2,4-dithiazolin-5-one 3 (eq 1).1-3 (1) The latter reagent is obtained from the reaction between ethyl thiocarbamate 4 and commercially available chlorocarbonylsulfenyl chloride 5 in the presence of triethylamine (eq 2).1-3 The outcome of this key reaction is highly solvent dependent, with anhydrous diethyl ether giving the optimum yield, while also minimizing the formation of unwanted by-products.2, 3 (Note: Reference 3 details the fully optimized preparations of 3 and 1). (2) Two methods facilitate the preparation of the potassium salt 2 of 1.4 Firstly in a procedure analogous to that used in the preparation of potassium phthalimide,5 2 can be obtained by treatment of 1 with an equimolar quantity of ethanolic potassium hydroxide (eq 3). (3) Alternatively, potassium hydride can be used as the base in anhydrous acetonitrile solvent (eq 4). (4) In both cases, analytically pure material can be obtained by recrystallization of the crude product from ethanol–diethyl ether. Purification: 1 recrystallization from toluene. 2 recrystallization from ethanol–diethyl ether. Handling, Storage, and Precautions: 1 in its crystalline state can be stored at room temperature in air for at least 2 years without detectable decomposition. Stability studies have not been reported on 2 although it can certainly be stored for several days under vacuum at room temperature, after recrystallization. No particular hazards, handling problems, or precautions have been reported for the use of either 1 or 2. This is, however, most likely to be a result of no detailed safety testing having been carried out and hence appropriate care should be taken in their use.