甲基丙烯酸酐改性胶原蛋白的研究

用甲基丙烯酸酐改性胶原蛋白,采用单因素和正交试验研究所得的胶原蛋白乙烯基化改性条件为：温度50℃,反应时间2h,甲基丙烯酸酐的用量为1．5mL。通过核磁（^1H-NMR）和红外光谱（FT-IR）对乙烯基化改性前后的胶原蛋白进行表征,证明胶原蛋白被成功改性并在其分子链上引入C—C双键。并对3种不同相对分子质量的胶原蛋白G1、G2和G3进行乙烯基化改性,发现小分子质量的胶原蛋白改性得到的乙烯基胶原蛋白的取代度较大。     

羟基磷灰石负载氯化锌催化剂用于苯甲醚酰化反应

 以羟基磷灰石(HAP)为载体,采用水热法制备了羟基磷灰石负载 ZnCl₂催化剂(ZnCl₂/HAP)。采用 FT-IR、XRD、BET 等手段对载体和催化剂进行了表征,并将制备的 ZnCl₂/HAP 应用于苯甲醚与烷基酰氯的酰基化反应,考察了反应条件对酰基化反应的影响和 ZnCl₂/HAP 的稳定性。结果表明,当催化剂活化温度为150℃、ZnCl₂负载量为1 mmol/g、反应时间5 h、ZnCl₂/HAP 与酰氯的摩尔比为1∶25时,ZnCl₂/HAP 对该酰基化反应的催化活性最高,对烷酰基苯甲醚的产率可达78%~88%。ZnCl₂/HAP重复使用5次仍具有较高的催化活性。     

Rhodium‐Catalyzed Direct Oxidative C?H Acylation of 2‐Arylpyridines with Terminal Alkynes: A Synthesis of Pyrido[2,1‐a]isoindoles

A synthesis of pyrido[2,1‐a]isoindoles is reported by the rhodium‐catalyzed direct oxidative C H acylation of 2‐aryl pyridines with terminal alkynes. The desired products were obtained in moderate to excellent yields. This is an efficient and clean method to construct C C/C N bonds in one step. In addition, the effective rhodium(III) catalyst was isolated and characterized by X‐ray crystallography.

     

Efficient Photochemical Synthesis of Peptide‐α‐Phenylthioesters

Low yields and substantial epimerization of peptide‐α‐thioesters often compromise the overall efficiency of native chemical ligation (NCL). Peptide arylthioesters are more reactive than peptide alkylthioesters in NCL, but are also more difficult to handle due to their propensity to hydrolyze, and are therefore often generated in situ. However, pre‐prepared peptide arylthioesters are required for some NCL applications. Here we present a 7‐nitroindoline‐based photochemical method that generates protected peptide phenylthioesters under neutral reaction conditions via their activated esters from photoreactive peptide precursors in high isolated yields, and with low levels of epimerization. This method is fully compatible with Fmoc‐strategy solid‐phase peptide synthesis. Global deprotection with trifluoroacetic acid furnishes peptide phenylthioesters for NCL. Photoreactive peptide precursors can also be converted into their hydrazides in two steps by this method.     

Characterization of Red Radish Anthocyanins

Red radish (Raphanus sativus L.) anthocyanins were extracted from liquid nitrogen powdered epidermal tissue using acetone, partitioned with chloroform and isolated using C-18 resin. The monomeric anthocyanin content, determined by pH-differential, was 154 ± 13 mg/100g epidermal tissue (pelargonidin-glucoside basis). Thermal processing of radishes showed that the pigments were stable to heat. Four major pigments were identified by Mass Spectroscopy, HPLC, and spectral analyses as pelargonidin-3-sophoroside-5-glucoside derivatives. The two major pigments were acylated with malonic acid and either ferulic or p-coumaric acid. The two other pigments were acylated with only ferulic or p-coumaric acid. Acylation increased pigment resistance to acid hydrolysis.     

6-羟基-1,4-苯并二恶烷的合成及其在油脂中的抗氧化性研究

本文研究了芝麻酚类似物6-羟基-1,4-苯并二恶烷的合成及其在油脂中的抗氧化性。以邻苯二酚、二氯乙烷为起始原料,在碱性回流条件下经环化反应得到1,4-苯并二恶烷,然后通过Friedel-Crafts酰基化反应得到6-乙酰基-1,4-苯并二恶烷,之后经Bayer-Villiger氧化、水解酸化及柱层析分离得到目标化合物。对环化反应中Na OH溶液浓度、酰基化反应中溶剂种类以及氧化反应中氧化剂选择分别进行优化,得到实验较优条件:Na OH溶液浓度为50%,酰基化反应溶剂为硝基苯,Bayer-Villiger氧化反应氧化剂选择间氯过氧苯甲酸。采用红外光谱(IR)、质谱(MS)以及核磁共振(13C-NMR)对终产物进行结构鉴定和表征,确定目标产物为6-羟基-1,4-苯并二恶烷。测定了其在油脂中的抗氧化能力,结果表明该芝麻酚类似物在动植物油脂中都具有一定的抗氧化性。     

Stability and bioaccessibility of curcumin emulsions stabilized by casein hydrolysates after maleic anhydride acylation and pullulan glycation

The effects of maleic anhydride (MA) acylation and pullulan glycation on casein hydrolysates (CH) and the physicochemical stability of modified or unmodified CH-stabilized emulsions were explored. Compared with casein, the solubility of CH was improved, and CH₁ (hydrolysis degree 4%) exhibited the optimal emulsifying properties. After the acylation of MA, degrees of acylation (DA) increased with increasing addition of MA. Fourier-transform infrared spectroscopy revealed that a covalent bond was formed between MA and CH₁. The results of pullulan glycation indicated that the degree of glycation decreased with increasing DA. Acylation combined with glycation effectively reduced the surface hydrophobicity of CH. Results of analysis of physicochemical stability and gastrointestinal fate of curcumin in emulsions revealed that CH modified by MA acylation and pullulan glycation played a positive role in enhancing the stability and bioaccessibility of curcumin loaded in emulsions.     

吡啶-对甲苯磺酸功能化离子液体催化2-萘甲醚的酰化

吡啶与1,4-丁基磺内酯反应首先制备具有磺酸基团的两性盐,然后再与对甲苯磺酸反应合成吡啶-磺酸功能化离子液体,通过核磁共振(NMR)和红外光谱(IR)表征其结构。该离子液体作为催化剂及溶剂,催化2-萘甲醚的乙酰基化反应,设计正交试验L₉(3⁴)优化其反应件。结果表明,2-萘甲醚的物质的量为5mmol、2-萘甲醚/乙酸酐的物质的量比为1∶5,离子液体质量0.3g,120℃下反应6.0h,2-萘甲醚的转化率达90.7%。主产物2-甲氧基-1-萘乙酮的选择性为99.4%;其中,影响反应物转化率和产物选择性的主要因素为反应时间和温度。     

丁酰化壳聚糖的制备及结构性能表征

考察了催化剂和反应时间对丁酰化反应的影响。利用红外(IR)和氢核磁共振(1H-NMR)对丁酰化壳聚糖进行了结构表征,结果表明酰化反应主要发生了O-酰化反应。同时,利用热失重(TG)考察了丁酰化壳聚糖的热稳定性,发现酰化度对丁酰化壳聚糖的初始热分解温度影响不大。     

肉豆蔻酰矢车菊素-3-O-葡萄糖苷在混合溶剂体系中的酶法合成

为了提高矢车菊素-3-O-葡萄糖苷(C3G,Cyanidin-3-O-glucoside)的稳定性及亲脂性,本研究用固定化脂肪酶Lipozyme 435催化肉豆蔻酸甲酯对C3G进行酰基化修饰.首先分别在单一有机溶剂和混合有机溶剂中进行酰基化反应,然后通过半制备液相色谱对C3G酰基化衍生物进行分离纯化,并通过液质联用和核...