One‐Pot Synthesis and Hydroxylaminolysis of Asymmetrical Acyclic Nitrones
摘要:
Aromatic aldehydes 1 were reductively aminated to the corresponding secondary amines 2 using NaBH4 in methanol in good yields. Amines 2 were oxidized with H2O2-WO42- regioselectively to nitrones 3, the structures of which were easily determined by reacting them with hydroxylamine hydrochloride as well as by spectral means. The products of hydroxylaminolysis in ether proved to be the corresponding benzaldehyde oximes 4 and benzyl or methyl hydroxylamine hydrochlorides 5.
One‐Pot Synthesis and Hydroxylaminolysis of Asymmetrical Acyclic Nitrones
摘要:
Aromatic aldehydes 1 were reductively aminated to the corresponding secondary amines 2 using NaBH4 in methanol in good yields. Amines 2 were oxidized with H2O2-WO42- regioselectively to nitrones 3, the structures of which were easily determined by reacting them with hydroxylamine hydrochloride as well as by spectral means. The products of hydroxylaminolysis in ether proved to be the corresponding benzaldehyde oximes 4 and benzyl or methyl hydroxylamine hydrochlorides 5.
Cycloaddition of Acyclic Nitrones with Phenyl Isocyanate: Synthesis and Ring‐Opening Reactions of 1,2,4‐Oxadiazolidin‐5‐ones
作者:Necdet Coşkun、Aydın Parlar
DOI:10.1080/00397910500501466
日期:2006.5
unsubstituted or electron‐donating substituents on the C‐phenyl 1a,c,f with phenyl isocyanate proceeds smoothly for a short time with high yields to give the corresponding 1,2,4‐oxadiazolidinone 2, and 1b,d,e with electron‐withdrawing substituents gave the corresponding oxadiazolidinone in moderate yields after prolonged heating. Oxadiazolidinones 2a,c,f undergo diethylamine‐inducedfragmentation for a short
Molecular and crystal structure of 2-methyl-3-(2-nitro-phenyl)-4-phenyl-[1,2,4]oxadiazolidin-5-one, C15H13N3O4, have been determined by single crystal X-ray diffraction study. The title compound is monoclinic, with a = 10.0313(8) Å, b = 9.0372(5) Å, c = 15.5964(14) Å, β = 96.926(7)∘, Z = 4, D x = 1.42 g/cm3, μ (Mo-Kα) = 0.105 mm−1, and space group is P 21/c. The structure was solved by direct methods and refined to a final R = 0.036 for 1894 reflections with I > 4σ (I). The crystal structure is stabilized by C–H⋅sO type inter-molecular, C–H⋅sN and C–H⋅sO type intra-molecular, π–π stacking and edge to face (C–H⋅s π-ring) interactions. To enlighten conformational flexibility of the title molecule, selected two torsion angles are varied from −180∘ to +180∘ in every 10∘ separetely and then molecular energy profile is calculated and construed.
通过单晶 X 射线衍射研究确定了 2-甲基-3-(2-硝基苯基)-4-苯基-[1,2,4]恶二唑烷-5-酮 C15H13N3O4 的分子和晶体结构。标题化合物为单斜晶系,a = 10.0313(8) Å, b = 9.0372(5) Å, c = 15.5964(14) Å, β = 96.926(7)∘, Z = 4, D x = 1.42 g/cm3, μ (Mo-Kα) = 0.105 mm-1, 空间群为 P 21/c。该结构通过直接方法求解,并在 1894 次反射中精炼出最终 R = 0.036,I > 4σ (I)。该晶体结构通过 C-H⋅sO 型分子间相互作用、C-H⋅sN 和 C-H⋅sO 型分子内相互作用、π-π 堆积和边到面(C-H⋅s π-环)相互作用而得到稳定。为了揭示标题分子的构象灵活性,所选的两个扭转角从 -180∘ 到 +180∘ 每隔 10∘ 变化一次,然后计算和解释分子能谱。