Treatment of (2-hydroxyethyl) urea derivatives (Ia-e) with sodium nitrite in the presence of acids or with nitrosyl chloride in chloroform gave 3-nitroso-2-oxazolidinones (IIa-e) in 10-77% yields. These 3-nitroso-2-oxazolidinones were denitrosated with hydrogen chloride in methanol to give the corresponding 2-oxazolidinones (IIIa-e) in 35-60% yields. An N, N-disubstituted urea, 1-(2-hydroxyethyl)-1-methylurea (If) also cyclized to give 3-methyl-2-oxazolidinone (IIf) under the same conditions. The mechanism of this type of cyclization is discussed.
(2-羟乙基)
脲衍
生物(Ia-e)在酸的存在下与
亚硝酸钠反应,或在
氯仿中与亚硝基
氯反应,得到了3-亚硝基-
2-噁唑烷酮(IIa-e),产率为10-77%。这些3-亚硝基-
2-噁唑烷酮在
甲醇中与
氯化氢脱亚硝,得到相应的
2-噁唑烷酮(IIIa-e),产率为35-60%。一种N,N-二取代
脲,即1-(2-羟乙基)-1-甲基
脲(If)在相同条件下也环化,生成
3-甲基-2-噁唑烷酮(IIf)。文中讨论了这种环化反应的机制。