Synthesis of N-substituted-4-methylene-oxazolidinones via base-catalyzed cyclization of propargylic alcohols with p-toluenesulfonyl isocyanate

Abstract

A practical method is developed for the synthesis of oxazolidinone derivatives, an important class of heterocyclic compounds. The effect of bases and solvents on this cyclization reaction is discussed and a simple new base–solvent system (triethylamine in toluene) is found to be the most effective. The reaction conditions developed here are mild and no by-products are observed. Moreover, using optimized conditions, a number of differently substituted propargylic alcohols are cyclized to the corresponding N-substituted-4-methylene-oxazolidinones in yields of up to 99%.

Rare-Earth-Metal-Complex-Catalyzed Hydroalkoxylation and Tandem Hydroalkoxylation/Cyclohydroamination of Isocyanates: Synthesis of Carbamates and Oxazolidinones

“…11 Very recently, it was found that 50 mol % NEt 3 in toluene can promote the reaction of propargylic alcohols with 1.5 equiv of p-toluenesulfonyl isocyanate to give N-substituted 4-methyleneoxazolidinones in 42−99% yields. 12 The utilization of metal-mediated catalytic systems that play an important role in the construction of oxazolidinone derivatives, such as CuI with NEt 3 , silver acetate (AgOAc) with 4-dimethylaminopyridine (DMAP), Pd(OAc) 2 with tetrabutylammonium a c e t a t e ( n -B u 4 N O A c ) , A u C l w i t h N E t 3 , and triphenylphosphinegold(I) chloride (AuPPh 3 Cl) with AgSbF 3 , has been well explored. 13 However, in most of the reported methods, a high loading of catalysts and cocatalysts is usually required.…”

“…The first catalyst employed in the cyclohydroamination of propargylic carbamates was potassium hydroxide; later, other bases, such as NaOMe, LiOH, and DBU, were developed . Very recently, it was found that 50 mol % NEt 3 in toluene can promote the reaction of propargylic alcohols with 1.5 equiv of p -toluenesulfonyl isocyanate to give N-substituted 4-methyleneoxazolidinones in 42–99% yields . The utilization of metal-mediated catalytic systems that play an important role in the construction of oxazolidinone derivatives, such as CuI with NEt 3 , silver acetate (AgOAc) with 4-dimethylaminopyridine (DMAP), Pd­(OAc) 2 with tetrabutylammonium acetate ( n -Bu 4 NOAc), AuCl with NEt 3 , and triphenylphosphinegold­(I) chloride (AuPPh 3 Cl) with AgSbF 3 , has been well explored .…”

An Ecofriendly Synthesis of 2-oxazolidinone From 2-aminoethanol and Urea Under Solvent-free Condition Using CeO2 Nanoparticles

“…Conventionally, these nitrogen-containing heterocyclic compounds are synthesized using highly toxic reagents such as phosgene [14,15]. 2-oxazolidinones are important cyclic carbamates which are widely used in drugs [16], antibiotics [17], herbicides [18], organic synthesis [19], solvents for lithium-ion batteries and ink-jet printing [16]. Moreover, polymers containing 2-oxazolidinone are used for applications as foams, adhesives, and fibers [20].…”