Reaction of oxaziridine with sulfur-containing heterocumulenes

Abstract

The reactions of oxaziridines 1 with carbon disulfide (2) and phenyl isothiocyanate (8) have been studied. With carbon disulfide, 2-n-alkyl-or see-alkyloxaziridines give alkyl isothiocyanates (quantitatively), carbonyl compounds, and sulfur. Similar reactions between 1 and 8 form carbodiimides 9, but under mild experimental conditions 1 and 8 react to yield considerable amounts of either and/or the thiadiazolidinethione isomers 10 and 11. 2-tert-Butyloxaziridine If does not react with 2, but reacts with 8 to afford oxadiazolidinethione 12 and oxadiazolidinone 13.In the preceding paper,l we reported the reactions of oxaziridines with a ketene, isocyanates, and a carbodiimide, showing that the results are quite different from those of oxiranes and of aziridines. In the reactions, oxaziridines gave 1: 1 cycloadducts or unstable three-membered intermediates, which further reacted with the cumillenes to give stable heterocycles, with the release of carbonyl compounds.In the present study, the reactions with sulfur-containing heterocumulenes such as carbon disulfide and an isothiocyanate are described. From one heterocumulene, in these reactions, another heterocumulene was obtained along with a carbonyl compound and sulfur uia unstable intermediates. The further reactions of the intermediates giving heterocycles were also observed.Such a characteristic difference caused by a sulfur atom, which is generally a good leaving group or easily exchangeable with an oxygen atom, can be expected from the following reactions of the cumulenes. In the reactions with ethylene oxide, for example, carbon disulfide gives ethylene carbonate and ethylene trithiocarbonate2S3 and phenyl isothiocyanate gives 1,3-oxazolidin-%one4 9 5 or isocyanate t~i m e r ,~,~ though 1:l cycloadditions are observed in the reactions of propylene oxide,3 ethylene ~u l f i d e ,~ or aziridines7v8 with carbon disulfide, aziridines with phenyl isothiocyanate,8 and ethylene oxide with N-acyl isothiocyanate .5 Results and DiscussionReaction with Carbon Disulfide. In the reaction of 2-n-alkyl-or 2-cycloalkyloxaziridine la,c,e,g,j with carbon disulfide (Z), an isothiocyanate 3 was quantitatively obtained. The results are shown in Table I.The products were characterized by the strong infrared absorption band at 2120 cm-1 (N=C=S). They were identified and determined by glpc or by converting them into thiourea derivatives. No reaction was observed for 2-tert-butyloxaziridine If in refluxing carbon disulfide; and the rearrangement of the oxaziridine If to a-phenyl-Ntert-butylnitrone ( 5 ) occurred under severe conditions, but a small quantity of tert-butyl isothiocyanate was detected by ir and glpc. The reaction is assumed to proceed via a thiaziridinethione intermediate 6 (Scheme I), which readily decomposes into an isothiocyanate 3 and sulfur. A similar assumption has been proposed for the reactions of the oxaziridines with diphenylketene and with diphenylcarbodiimide. The decomposition of the intermediate 6 occurs much faster than its further reaction with carbon d...

Novel Thiotetraazapentalene Complexes from the Reaction of a Ruthenium Azide Complex with Alkyl Isothiocyanates

“…[17,18] In the 1 H NMR spectrum of 3a at room , and an AB pattern at δ ϭ 5.13 and 5.07 ppm (J H,H ϭ 17.02 Hz). The 31 P NMR spectrum at room temperature displays a broad singlet resonance at δ ϭ 37.54 ppm, which splits into two doublets at δ ϭ 40.51 and 34.81 ppm with J P,P ϭ 51.7 Hz at 233 K. This is possibly because of the hindered rotation of the RuϪS bond at low temperature.…”

Carbon disulfide as a 2-.pi. component in its cycloaddition with 1-azirines

“…tions of carbon disulfide proceed from an initial nucleophilic attack on carbon. [8][9][10][11] The few cycloadditions known are 1,3 dipolar in nature with carbon disulfide as the dipolarophile. 12,13 We wish to report on the reaction of carbon disulfide with 1-azirines and discuss its mechanistic implications.…”

Reaction of oxaziridine with heterocumulene. A ketene, isocyanates, and carbodiimide

“…Mole ratio of 1:2 was 0.8-1.0; benzene was employed as a solvent. 6 Allowed to react until ir absorption of C=C=0 disappeared. ® f-BuNHCOPh (8) was obtained in 97% yield.…”

“…2300 cm'1) disappeared. 6 In a sealed tube. c Unreacted Id was recovered (88%) and most of the unreacted isocyanate was recovered in trimeric form.…”