中长碳链α-氯代脂肪酸的合成

Hell-Volhard-Zelinsky反应仅对羧酸的α-溴化有高的选择性,而沿用到α-氯化则产生β,γ或α,α-二氯代羧酸等难以分离的副产物。早年曾用烷基丙二酸与硫酰氯反应然后脱羧制得C_4到C_12的α-氯代直链脂肪酸。该法若以丙二酸酯为原料,不仅全程总产率低,     

α-氯代丙烯酸甲酯和α-氟代丙烯酸甲酯的合成

合成了α-氯代丙烯酸甲酯和α-氟代丙烯酸甲酯两种单体,其结构经IR和^1H NMR表征。     

十二酸的α-氯代反应中的催化剂研究

α-氯代脂肪酸是一类可用于直接从脂肪酸合成α-氨基酸和甜菜碱类两性表面活性剂等精细化学品的重要中间体。本文从烯酮式反应机理出发,以α-氯代十二酸(α-CDA)的合成为模型,对酰氯化试剂(对甲苯磺酰氯、十二酰氯、氯磺酸等)和质子酸催化剂(如H型离子交换树脂、氯磺酸、对甲苯磺酸、醋酸等)进行组合和选择,并与文献报道的特殊添加剂乙酐比较,研究不同催化体系在酸催化合成α-氯代脂肪酸时的催化作用。氯磺酸既有磺酸基团提供强质子酸,又有磺酰氯基团作为酰氯化试剂,因而是催化十二酸的α-氯代反应的适宜催化剂。当w(氯磺酸)∶w(十二酸)=2%,搅拌转速1000r/min,氯气流量40L/h,反应温度为120℃时,反应3h后α-CDA产率达到96.4%。     

α-氯代脂肪酸对某些稀土的萃取研究

等曾报导用α-溴代己酸的氯仿溶液对钐、钕、钆和镥的萃取,其萃取曲线与无取代基的比较向酸性区移动了约1个pH单位。Preston报导了α-溴癸酸的二甲苯溶液对一系列金属离子的萃取,认为所试验的8个稀土金属与α-溴癸酸形成了不溶性的金属络合物。我们曾报导用α-氯代脂肪酸萃取金属离子。本文研究己酸、辛酸、癸酸和月桂酸等的α-单氯代物在盐酸体系中对镧、钕、钐和钇的萃取行为,讨论了这些酸的结构对萃取的影响。     

Z,E型—α—氯代桂皮酰胺类化合物的合成与抗惊活性的研究

由E,Z型-α-氯代桂皮酸经酰氯、胺解及层析分离制得10对Z,E型异构体。其中Z型-对溴-α-氯代桂皮酰另丁胺的抗惊作用(MES)较强。药理实验表明这些异构体的构型、酰胺氮上的取代基对其生物活性有重大影响。     

4－叔丁基－β－氯－α－甲基肉桂醛的合成

从苯和叔了醇出发，经过３步反应合成得标题化合物，总收率在６８％以上。     

氯代苄基葡萄糖在芳香碳苷立体选择性合成中的应用

Hosomi等人曾报道了1-α-氯代-2,3,4,6-四-O-苄基-D-吡喃葡萄糖(1)与烯丙基硅醚反应主要得到α异构体占优势的烯丙基碳苷。我们研究了化合物1在Lewis酸存在下和芳香醚反应,结果发现,产物都是β构型的芳香碳苷。这与Schmidt等人和Williams等     

铁(Ⅲ)催化氯代炔烃水化反应合成α-氯代甲基酮类化合物

研究了Fe(Ⅲ)催化氯代炔烃水化生成α-氯代甲基酮化合物的反应,考察了催化剂的种类、酸的种类、反应温度以及溶剂对反应的影响.结果表明,采用Fe Cl3·6H2O(摩尔分数5%)和甲基磺酸(摩尔分数20%),在1,2-二氯乙烷溶剂中,氯代炔烃于80℃进行水化反应3 h,可以高产率得到α-氯代甲基酮产物.所得化合物的结构采用IR,1H NMR,13C NMR及MS等方法进行了表征.该水化反应合成方法简单、条件温和且收率良好,为合成α-氯代甲基酮提供了一种简便途径.     

α-氯代脂肪酸对某些稀土的萃取研究

Гавриловаа等^[1]曾报导用α-溴代己酸的氯仿溶液对钐、钕、钆和镥的萃取,其萃取曲线与无取代基的比较向酸性区移动了约1个pH单位。Preston报导了α-溴癸酸的二甲苯溶液对一系列金属离子的萃取,认为所试验的8个稀土金属与α-溴癸酸形成了不溶性的金属络合物^[2]。     

PHOTOFRAGMENTATION OF α-OXOCARBOXYLIC ACIDS IN AQUEOUS SOLUTION. AN EPR STUDY. FORMATION OF SEMIDIONE RADICALS BY DECARBOXYLATIVE SUBSTITUTION OF α-OXOCARBOXYLIC ACIDS BY ACYL RADICALS-I: GLYOXYLIC, PYRUVIC, α-OXOBUTYRIC, α-OXOGLUTARIC AND α-OXOISOCAPROlC ACIDS

Abstract— By means of in situ photolysis EPR of aqueous solutions of α-oxocarboxylic acids (RCO-CO₂H) at pH values above 5, semidione radical anions [RC(O^-)=C(O')R] and α-hydroxy-α-carboxy alkyl radicals [RC(OH)CO₂-] were detected. C0₂ was identified as a reaction product. On photolysis of mixtures of α-oxocarboxylic acids (RCOCO₂H and R'COCC₂H), "mixed" semidione radical anions [RC(O^->=C(O)R'] were observed in addition to RC(O^-)=C(O')R, R'C(O^-)=C(O')R', RC(OH)CO₂^- and R'C(OH)CO₂^-. The experimental results are explained in terms of photodecarboxylation (α-clea-vage) of electronically excited RCOCOJ to yield RCO and CO₂. The radicals RC(OH)CO₂^- are formed by reduction of RCOCO₂^- by CO₂^-. The semidione radicals are produced by addition of RCO to RCOCO₂^- followed by decarboxylation of the intermediate adduct. This mechanism was confirmed by generating acyl radicals independently and reacting them with α-oxocarboxylic acids. Selected product studies support the mechanism suggested.     

主链含有苯并噁唑环的PPV型齐聚物的合成

以-甲基-2-氯甲基苯并(口恶)唑和对二苯甲醛为主要原料,通过两次Wittig-Horner反应,合成了未见文献报道的主链含有苯并-NFDA1-唑环的PPV型齐聚物.目的在于在PPV聚合物主链中嵌入电子传输型结构单元,提高聚对苯撑乙烯共轭链的电子传输能力,改变PPV的发光特性.分析数据表明,该齐聚物的M_w为2500,并且分子结构中的乙烯基 C＝C 双键均为反式结构特征.UV-Vis吸收光谱特征峰λ_max等于497 nm.     

β-二酮缩β-丙氨酸希夫碱的锰(Ⅲ)配合物

合成了锰(Ⅲ)的双核配合物Mn_2(Hacala-β)_2(O_2CMe)_4和三核配合物Mn_3O(bzala-β)_2(O_2CMe)_3·4H_2O,其中Hacala-β~-和bzala-β~(2-)分别是乙酰丙酮缩β-丙氨酸和苯甲酰丙酮缩β-丙氨酸希夫碱负离子。用电导率、磁化率、热分析、红外及紫外可见光谱等对它们的结构和性质进行了研究。     

肝素化聚甲基丙烯酸的合成及抗凝血性能的研究

本工作采用四价铈盐作引发剂,进行了甲基丙烯酸在肝素上的接枝聚合,合成了肝素化的交联型聚甲基丙烯酸,并对接枝聚合的反应条件及接枝聚合物的抗凝血性能进行了研究.实验结果表明,肝素化的聚甲基丙烯酸具有优良的抗凝血性能,是一种很有应用前景的新型聚合物.     

UPTAKE AND BIOCONVERSION OF α-TOCOPHERYL ACETATE TO α-TOCOPHEROL IN SKIN OF HAIRLESS MICE

Abstract— The photoprotective effect of topically applied α-tocopheryl acetate (vitamin E acetate), a stable derivative of α-tocopherol (vitamin E), and its possible bioconversion to the active antioxidant species (α-tocopherol) was examined in skin tissue of female hairless mice (HRS/J) exposed to UV-B irradiation. Our results indicate that topically applied α-tocopheryl acetate is absorbed into and retained by skin tissue. Furthermore, skin tissue from UV-B-irradiated animals that received daily topical α-tocopheryl acetate treatments contained significantly higher levels (P < 0.001) of α-tocopheryl acetate than non-UV-B-irradiated mice that received identical daily topical α-tocopheryl acetate treatments. Finally, free α-tocopherol levels in skin also were significantly increased (P < 0.00 1) by topical applications of α-tocopheryl acetate and skin levels of free α-tocopherol were significantly greater (P < 0.001) in UV-B-irradiated animals that received daily topical α-tocopheryl acetate treatments than in non-UV-Birradiated animals. These results suggest that UV-B irradiation enhances both the absorption of α-tocopheryl acetate and its bioconversion to free α-tocopherol.     

FORMATION OF REARRANGEMENT PRODUCT IN PHOTOLYSIS OF α,α-DIMETHYLDEOXYBENZOIN UPON CYCLODEXTRIN COMPLEXATION

Abstract Solid-state irradiation of cyclodextrin complexes of α,α-dimethyldeoxybenzoin results in the formation of a significant amount of rearrangement product, 4-isopropylbenzophenone, in addition to cage products. This behavior is not observed in the photolysis in solution or in micellar media.