Synthesis of N-Oxyureas by Substitution and Cope-Type Hydroamination Reactions Using O-Isocyanate Precursors

Abstract

Oxy-carbamate O-isocyanate precursors facilitate access to synthetically valuable N-oxyureas via substitution with amines. This work exploits the reactivity of suitable O-isocyanate precursors, identified by a thorough study highlighting the different reactivity of isocyanate masking groups. This led to bench-stable O-isocyanate precursors, offering improved versatility in the synthesis of N-oxyureas, and demonstrates the controlled reactivity of masked O-isocyanates. Suitable precursors also enabled the first example of Cope-type hydroamination of unsaturated hydroxyureas.

Synthesis and application of aminosiloxane‐modified cationic waterborne polyurethane as fixing agent for nylon fabric

“…It can be observed in Table 5 that the shades of the nylon fabrics dyed with red E‐BS, yellow E‐GS and blue B‐GN were changed slightly after being treated with KWPU10. This could be due to the Cope reaction of the tertiary amino group in MDEA during the high‐temperature drying process, which causes the film to darken and affect the color of the fabric 32,33 …”

Synthetic approaches towards avibactam and other diazabicyclooctane β-lactamase inhibitors

“…One synthetic bottleneck is the formation of the cyclic N-oxyurea as in all cases the formation of the highly constrained bicyclic scaffold is achieved from an aminopiperidine using a highly toxic triphosgene or diphosgene reagent (except in the industrial route to avibactam). Despite the importance of this key motif, alternative cyclization methods remain scarce, [60][61][62][63][64] which might curb the development of a broader range of DBO analogues. Indeed, despite the great superiority of this family of BLI compared to β-lactam-based BLIs such as clavulanic acid or tazobactam, some unmet challenges remain for the design of even better compounds.…”

Synthesis of N−H Bearing Imidazolidinones and Dihydroimidazolones Using Aza‐Heck Cyclizations

“…Inspired by the work of Beauchemin, [13] we designed a convenient two-pot, three component sequence that allows the assembly of the substrates from unsaturated carbonyls, amines, and 4-nitrophenyl 1-phenoxycarbamate in up to 85% yield over two steps ( 1 , Scheme 1). [14] …”

“…Themodel substrate 4 was isolated in 84 %yield, and closely related derivatives were prepared with similar efficiency (6)(7)(8)(9)(10)(11). More substituted alkenes,i ncluding tetrasubstituted alkene,also participate well in the reaction (12)(13)(14). Notably, the latter two cases result in imidazolidinones bearing fully substituted carbon centers.Inaddition, in these cases (as well as others noted in the table) alkene isomerization was not an issue and silver additives were not required.…”