Construction of sulfur-containing N-vinylimides: N-addition of imides to propargyl sulfonium salts

An N-addition reaction between imides and propargyl sulfonium salts was developed to afford sulfur-containing N-vinylimides with moderate to excellent yields. Under the activation of NaOAc·3H₂O, imides could undergo deprotonation and propargyl sulfonium salts could isomerize to allenic sulfonium salts. The N-nucleophilic attack initiates the reaction and gives the desired products. Various imides, including arylimides, aliphatic imides and N-(arylsulfonyl) alkyl acylamides, and even bioactive saccharin, thalidomide and pomalidomide could provide organosulfur N-vinylimides compounds. The simple, mild and metal-free reaction conditions, the broad scope of substrates, gram-scale synthesis and convenient transformation embody the synthetic superiority of this process.

An N-addition reaction between imides and propargyl sulfonium salts was developed to afford sulfur-containing N-vinylimides with moderate to excellent yields.

N-vinylimides represent crucial structural motifs due to the importance of these frameworks (Fig. 1), which are the core structure found in biologically active structures,¹ functional materials² and natural products such as the parazoanthines A–E.³ They can also serve as versatile synthetic intermediates in the synthesis of β-2-amino acid derivatives⁴ and other complex structures.⁵Open in a separate windowFig. 1Representative functional N-vinylimides scaffolds.Due to the importance of these N-vinylimides frameworks, the growing interest in this featured moiety has catalyzed a recent spurt of attention for methodology appropriate for its construction. Conventionally, protocols for the synthesis of this important substrate class included transition-metal-catalyzed en-imidic C(sp²)–N bond formation reactions of imides with vinyl halides, pseudohalides or alkynes. The main strategies involved Cu-catalyzed Chan–Lam–Evans reactions,⁶ Ru-catalyzed hydroimidation reaction of imide with alkyne⁷ and Pd-catalyzed oxidative amination of alkenes.⁸ In 2021, Sandtorv''s group reported Cu-catalyzed Chan–Lam–Evans reaction for coupling cyclic imides and alkenylboronic acids by forming C(sp²)–N-bonds, enables the practical and mild preparation of (E)-enimides (Scheme 1a).^6a In 2020, Schaub''s group reported Ru-phosphine catalyzed hydroimidation reaction of cyclic amides with acetylene under low pressure, affording new method for synthesis of N-vinylimides (Scheme 1b).^7a Hull''s group reported Pd-catalyzed anti-Markovnikov oxidative amination reaction, alkenes are shown to react with imides in the presence of a palladate catalyst to generate the terminal imide, providing mild and robust complementary routes (Scheme 1c).^8a Besides, rarely examples of organo-catalytic conjugate additions of imides to acetylene can also provide methods for the synthesis of N-vinylimides.⁹Open in a separate windowScheme 1Approaches for vinylation of imides.The previously reported synthesis strategies mainly involved the use of expensive Ru and Pd-catalysts, otherwise toxic copper catalyst, and the structural limitations imposed to phthalimide and therefore specialized. Considering the limitation in generality, the harsh reaction condition, and the use of metal-catalysis decreased the attractiveness for synthetic applications, the development of new kind of vinylation reagents and their application of building N-vinylimides in a simple, mild, metal-free and efficient manner are highly desirable.Our earlier work inspired our interest in synthesis of N-vinylimides by employing propargyl sulfonium salts as vinylation reagent. We have been exploring new reaction patterns of sulfonium salts and developed propargyl sulfonium salts involved [3 + 2] annulation/substitution reaction and N-addition/[2,3]-sigmatropic rearrangement reaction in an acyclic model.¹⁰ Based on our processive interests on constructing N-functionalized vinylation reaction and exploring the diverse reactive pathway of propargyl sulfonium salts, we herein report the realization of inorganic base promoted N-addition reaction of imides and propargyl sulfonium salts, delivering potential bioactive sulfur-containing N-vinylimides in moderate to excellent yields (Scheme 1).We began our investigation by selecting phthalimide 1a and propargyl sulfonium salt 2a as model substrates (†).Optimization of the reaction conditions^a

小鼠同种异体移植卵巢组织的功能及形态学差异

目的:研究同种异体移植卵巢组织在昆明种小鼠(KM小鼠)和重症免疫缺陷鼠(SCID鼠)体内存活、卵泡发育及内分泌功能。方法:分别将同种异体卵巢组织移植到两种去势小鼠肾被膜下,通过阴道脱落细胞涂片观察小鼠动情周期变化;移植后1、2个月取移植物和子宫进行形态学观察,并测定血清中雌、孕激素水平。结果:两种小鼠在卵巢移植后均恢复了动情周期,血清中雌、孕激素水平明显高于去势组。术后2个月内,SCID鼠体内移植物存活良好,可见各级卵泡和黄体,但Oct-4阳性细胞逐渐减少;KM小鼠体内移植物则渐进性炎症细胞浸润,最终发生坏死或纤维化。结论:免疫排斥影响移植卵巢的卵泡发育和内分泌功能的发挥;同种异体卵巢在SCID鼠体内存活良好,具有内分泌功能、卵泡发育并可能排卵。     

中国人手腕骨发育标准——中华05.IV.中国儿童手腕骨发育特征

目的:观察中国儿童手腕骨发育特征,为应用国外研究成果提供参考。方法:受试者为2005年骨发育调查样本2~18岁的16035名儿童。使用TW3方法评价手腕骨成熟度,与文献中的日本、欧美儿童的数据相比较。结果:中国和日本儿童的手腕骨发育特征相似。在儿童期,中国男儿童TW3-RUS和TW-腕骨成熟度延迟于欧美儿童0.3~0.6岁,女儿童在5~10岁TW3-RUS骨发育与欧美儿童非常接近;但在男12岁、女10岁以后,中国男女儿童TW-RUS骨成熟度加速而分别提前1.1~1.6岁和1.2岁。与欧美儿童相比,中国男儿童在3~10岁、女儿童在2~5岁,TW-腕骨成熟度分别延迟0.3~0.6岁和0.2~0.4岁;在男10岁和女5岁后,中国儿童TW-腕骨成熟度加速而提前,腕骨发育成熟的年龄均提前1.4岁。结论:与1970s~1990s的欧美儿童相比,中国儿童骨发育的延迟已不明显,但是青春期TW3-RUS骨发育加速提前的程度以及腕骨发育成熟年龄的提前则更加显著。     

多普勒组织成像对冠心病患者PCI术后左室舒张功能的评价

目的应用多普勒组织成像（DTI）对冠心病患者PCI术后左室舒张功能进行评价,为临床治疗提供帮助。方法测定冠心病患者PCI术后的左室舒张功能,指标包括：二尖瓣口舒张期血流速度E和A峰、E/A值;二尖瓣环舒张早期运动速度（Ea）以及舒张晚期运动速度（Aa）,Ea/Aa值。结果与对照组比较,冠心病组二尖瓣环DTI的Ea值、Ea/Aa比值有非常显著性差异（P〈0.01或P〈0.05）,E、E/A比值有显著性差异（P〈0.05）。结论利用DTI可对左室整体舒张功能进行评价。     

彩色多普勒超声对医源性股动脉假性动脉瘤的临床应用

目的：探讨彩色多普勒超声对医源性股动脉假性动脉瘤的诊断及治疗价值。方法对22例经皮股动脉穿刺介入术后触及搏动性肿块的患者采用二维超声、彩色多普勒超声、频谱多普勒超声检查,对声像图进行总结分析,在超声引导下压迫及注射治疗。结果本组22例假性动脉瘤彩色多普勒超声诊断与临床符合率100%（22/22）,18例经超声引导下压迫治疗后瘤腔闭合,3例经瘤腔内注射凝血酶治疗取得满意疗效,总治愈率95%（21/22）,1例行外科手术治疗。结论彩色多普勒超声是医源性假性动脉瘤首选的诊断及治疗方法。     

胸腰椎骨折后路单节段椎弓根钉固定与结合骨水泥强化固定的生物力学比较

目的 比较胸腰椎骨折后路单节段椎弓根钉固定与结合骨水泥强化固定的生物力学效果.方法 在8具新鲜小牛胸腰椎标本(T11～L3)的L1椎体上制作不完全爆裂骨折模型.标本依次行单节段椎弓根钉固定及单节段椎弓根钉固定+骨水泥强化固定.对标本施加扭矩为4 Nm的疲劳载荷共2 000次,加载频率为0.5 Hz.经脊柱三维运动测量系统测量完整、骨折、固定和周期性加载后固定节段前屈、后伸、左侧屈、右侧屈、左旋转和右旋转运动时固定节段的角位移运动范围(ROM).结果 两种固定状态及疲劳后各方向ROM均明显小于正常及骨折状态(P<0.05);单节段椎弓根钉固定结合骨水泥强化固定状态前屈、后伸、侧屈、旋转ROM分别为0.40°、0.53°、0.86°、0.55°,疲劳后前屈、后伸、侧屈、旋转ROM变化值分别为0.10°、0.07°、0.19°、0.08°,均小于单纯单节段椎弓根钉固定组,尤其在旋转和前屈方向,差异有统计学意义(P<0.05).结论 两种固定方式均可重建脊柱骨折的即刻稳定性并具有良好的抗疲劳载荷效果.但在前屈和旋转方向,单节段椎弓根钉固定并骨水泥强化优于单纯单节段椎弓根钉固定.     

姜黄素下调miR-155抑制缺血性脑卒中炎性应答的实验研究

目的 分析姜黄素对缺血性脑卒中的抗炎作用,并探讨miR-155、Toll样受体4(TLR4)信号通路是否参与该抗炎机制. 方法 线栓法建立Sprague Dawley大鼠大脑中动脉闭塞模型(MCAO),将大鼠分为假手术组(8例)、MCAO模型组(8例)、姜黄素治疗组(8例),检测大鼠梗死体积、miR-155 mRNA相...     

腕管综合征的MRI诊断

研究腕管综合征（CTS）的MRI特征及应用价值。材料和方法：经临床及手术证实的CTS12例，行MRI检查，以横断面为主。结果：12例CTS的MRI表现为：正中神经进入腕管时肿胀增粗12例，正中神经肿胀率（MNSR）为2．25：1。正中神经腕管内受压变扁12冽，正中神经扁平率（MNFR）为3．4。腕横韧带向掌侧膨隆10例，腕横韧带膨隆率（BR）为15．8％。T2WI像正中神经信号增高12例。结论：MRI对CTS的诊断、治疗方式的选择及疗效观察有重要的价值。     

放射科医务人员职业性照射的血液效应

木文收集了1957年以来放射科工作者的血液改变,从中找出与射线接触有关的白细胞减少、白细胞增多,再生障碍性贫血、嗜酸粒细胞增多症、真性红细胞增多症和白血病等六种变化,其中明确为辐射引起的白细胞增多13例,辐射诱发再障3例,与辐射有关的嗜酸粒细胞增多症6例,辐射诱发白血病2例.除辐射诱发多发性骨髓瘤和继发性血小板减少性紫癍外,几乎包括了射线对血液系纺损伤的各种类型.     

Hyperdynamic hemangioma with proximal arterioportal shunting: a rare manifestation

Arterioportal shunting, when associated with hemangioma, is usually small, peripherally located, and without hemodynamic significance. Proximal arterioportal shunting occurring in hemangioma has rarely been reported. Herein we report a patient with renal cell carcinoma who simultaneously was found to have a hyperdynamic hemangioma in the liver. The imaging features were confusing and evoked diagnostic difficulty before operation.