Natural acylsucrose, often found in the glandular trichomes of Solanaceae plants, has potential applications in many industries, including food, cosmetics, and pharmaceuticals. In this study, we engineered an Escherichia coli strain to complete the biosynthesis of acylsucroses through whole-cell transformation. Using acylsucrose acyltransferases and CoA ligases, acylsucroses, including monoacylsucrose S1:5 ("S" represents an acylsucrose backbone, the number before the colon indicates the number of acyl chains, and the number after the colon indicates the sum of carbons in all acyl chains), diacylsucrose S2:10, triacylsucrose S3:14, and triacylsucrose S3:15 were synthesized from the substrate sucrose and short branched-chain fatty acids by the engineered E. coli EcoSE07, of which S3:15 was the primary product. Several strategies were applied to improve acylsucrose production, including codon optimization, constitutive promoter replacement, and serial resting cell assays. The use of fed-batch fermentation with an engineered E. coli strain of EcoSE22 containing a constitutive promoter further improved the production of acylsucroses. Serial resting cell assays with an optical density of 50 at 600 nm significantly increased the production of acylsucroses S3:15 and S2:10. These findings will facilitate the synthesis of natural acylsucroses through whole-cell transformations and provide the potential for future industrial applications.

建立定量核磁共振波谱法测定枣果实中葡萄糖、果糖、蔗糖3种可溶性糖含量的方法.样品用氘代水超声提取,以邻苯二甲酸氢钾为内标,Zgpr作为测定序列进行氢谱测定.结果表明,葡萄糖、果糖、蔗糖线性方程斜率的测定值与理论值误差小于2％,线性相关系数均大于0.9999,精密度RSD小于0.5％,3种糖的检出限分别为23.9、20.0、18.0 μg/mL,定量限分别为79.7、66.7、60.0 μg/mL,回收率分别为93.0％～98.5％、92.3％～94.7％、94.9％～99.2％.对市售样品进行测定,结果与国标高效液相色谱法一致,表明该法测定枣果实中葡萄糖、果糖、蔗糖含量准确可靠,且简便、快速,可为枣原料及其加工食品的质量控制提供参考.

为了解加拿大烟叶与云南KRK26 烟叶的品质区别,通过主成分分析、正交偏最小二乘判别分析等方法,对二者香气成分的差异进行比较分析.结果表明:两种烟叶中共检测出 9 类 117 种香气成分,加拿大烟叶有114 种,云南KRK26 烟叶有113 种,其中110 种为两者共有;筛选得到两种烟叶差异成分65 种,占共有香气成分的 50.6%,其中加拿大烟叶中 22 种成分含量较高,占比为 33.8%,主要为半挥发性有机酸类和倍半萜类,43 种成分含量较低,占比为 66.2%,主要为类胡萝卜素降解产物;相较于云南KRK26 烟叶,加拿大烟叶中长链脂肪酸和倍半萜类含量较高,而类胡萝卜素降解产物(如巨豆三烯酮、大马酮、二氢大马酮等)含量相对较低.类胡萝卜素降解产物和半挥发性有机酸的差别,可能是造成两种烟叶香气风格差异的主要因素之一.

Significant progress has been demonstrated in the development of bifunctional oxide-zeolite catalyst concept to tackle the selectivity challenge in syngas chemistry. Despite general recognition on the importance of defect sites of metal oxides for CO/H2 activation, the actual structure and catalytic roles are far from being well understood. We demonstrate here that syngas conversion can be steered along a highly active and selective pathway towards light olefins via ketene-acetate (acetyl) intermediates by the surface with coordination unsaturated metal species, oxygen vacancies and zinc vacancies over ZnGaOx spinel-SAPO-34 composites. It gives 75.6% light-olefins selectivity and 49.5% CO conversion. By contrast, spinel-SAPO-34 containing only a small amount of oxygen vacancies and zinc vacancies gives only 14.9% light olefins selectivity at 6.6% CO conversion under the same condition. These findings reveal the importance to tailor the structure of metal oxides with coordination unsaturated metal sites/oxygen vacancies in selectivity control within the oxide-zeolite framework for syngas conversion and being anticipated also for CO2 hydrogenation.

为了提高大环二萜类化合物β-2,7,11-西柏三烯-4,6-二醇(β-CBT)的活性,对其C-6位羟基进行酯化、醚化修饰,合成了11个未见活性报道的化合物,利用1 H NMR,13 CNMR,IR,HR-MS对目标化合物结构进了表征.对合成的化合物进行了体外抗肿瘤活性评价,结果显示,部分化合物对白血病HL-60和肺癌A-549肿瘤细胞的具有一定的抑制作用,其中β-2,7,11-西柏三烯-4-醇-6-O-苯甲酸酯(1g)对HL-60以及β-2,7,11-西柏三烯-4-醇-6-O-乙基(2b)对肺癌细胞株SMMC-7721 IC50值分别为12.59和26.56μmol·L-1,显著高于母体化合物.

以乙酰溴-α-D-葡萄糖(Ⅰ)和愈创木酚(Ⅱ)为原料,分别采用银盐法、相转移催化法和离子液体法,合成了愈创木酚-2,3,4,6-四-O-乙酰基-β-D-葡萄糖苷(Ⅲ);中间体Ⅲ脱去乙酰基得到了目标产物愈创木酚-β-D-葡萄糖苷(Ⅳ).中间体及产物结构经1HNMR、13CNMR、FTIR和HRMS确认.通过TG-DSC和感官评吸分别考察了糖苷Ⅳ的热稳定性和加香效果.结果表明,3种方法均可得到中间体Ⅲ,离子液体法优于相转移催化法及银盐法.离子液体法的反应条件为:1-丁基-3-甲基咪唑四氟硼酸盐([bmim]BF4)为催化剂,无水K2CO3为缚酸剂,二氯甲烷为溶剂,n(Ⅱ):n(Ⅰ):n(催化剂)=1.0:1.0:0.3,室温反应4 h,在该条件下糖苷Ⅲ的收率为52.6％.糖苷Ⅲ在甲醇钠/甲醇体系中脱去乙酰基,得到目标糖苷Ⅳ,收率77.4％.TG-DSC结果表明,糖苷Ⅳ在228.0℃以下具有较好的热稳定性.将糖苷Ⅳ添加于卷烟中能改善香气品质.

分别以麦芽酚和乙基麦芽酚为起始原料,经乙酰化、钯碳氢化、羰基α位乙酰氧化和脱乙酰基4步反应,合成了双羟基吡喃酮化合物2,3-二氢-3,5-二羟基-6-甲基-4H-吡喃-4-酮(Ⅴa)和2,3-二氢-3,5-二羟基-6-乙基-4H-吡喃-4-酮(Ⅴb).利用1HNMR、13CNMR和HRMS对每步反应的产物进行了结构表征,优化了合成反应工艺,通过清除自由基实验对化合物的抗氧化活性进行了测试.结果表明,双羟基吡喃酮化合物表现出优异的抗氧化活性,其中Ⅴb对2,2′-偶氮-双-(3-乙基苯并噻唑啉-6-磺酸)二铵盐自由基(ABTS+?)、2,2-二(4-叔辛基苯基)-1-苦肼基自由基(DPPH?)和Galvinoxyl自由基(Galvinoxyl?)的清除率分别为88.9％、83.8％和68.4％,明显高于维生素E(VE)和2,6-二叔丁基对甲酚(BHT).构效关系表明,在吡喃酮结构中引入羟基或增强侧链取代基的给电子能力均能提高化合物清除自由基的能力.

It is well known that 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP) is usually formed in the Maillard reaction and it contributes to the antioxidant properties of Maillard reaction intermediates. A series of hydroxyl group protected DDMP derivatives were synthesized to further understand the source of antioxidant activity. Antioxidant abilities of the DDMP derivatives were evaluated by scavenging the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS˙+), 2,2'-diphenyl-1-picrylhydrazyl radical (DPPH), and galvinoxyl radical, respectively. It was found that the introduction of protecting groups to the free hydroxyl groups of DDMP decreases their reducing abilities. In particular, the hydroxyl group at the olefin position exhibited a remarkable impact on the antioxidant activity of DDMP, indicating that the unstable enol structure in the DDMP moiety is the key factor for its antioxidant activity.

以葡萄糖酸 δ-内酯为原料,合成了2,3,4,6-四-O-三甲基硅烷基-葡萄糖酸内酯(Ⅰ),然后利用CH3Li加成,得到2,3,4,6-四-O-三甲基硅烷基-1-甲基-葡萄糖(Ⅱ),将其溶于乙腈与水(体积比4:1)的溶液中,加入H+阳离子交换树脂脱去三甲基硅烷(TMS)保护,得到1-甲基葡萄糖(Ⅲ).目标产物结构经1HNMR、13CNMR、HRMS确证,同时对其热裂解产物进行了分析.结果表明,以该方法合成的化合物为1-甲基-α-D-葡萄糖,在优化的条件下,3步反应总产率达到86％;1-甲基葡萄糖在甲醇中经酸催化易转化为相应的糖苷;1-甲基葡萄糖热裂解后可释放出具有焦甜香气的物质2-乙酰基呋喃、5-甲基-2-乙酰基呋喃、5-羟甲基-2-乙酰基呋喃等,可用于食品、烟草等行业.

2,3-Dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP) exists in many foods, and its effect on taste is controversial. The aim of this study was to clarify whether DDMP has bitter taste or not. For this purpose, DDMP was synthesized from maltol instead of from glucose for the first time. In contrast, DDMP derived from glucose was also prepared and further purified. Their structures were identified by NMR and MS, and considered to be the same substance. The sensory analysis showed that DDMP derived from maltol was tasteless. Further studies indicated that some impurities in Maillard reaction made DDMP derived from glucose taste bitter.

3-(2-Aminoethyl)pyrroles are important intermediates for the formation of the 6-azaindole skeleton. It was difficult to synthesize 3-(2-aminoethyl)pyrroles from pyrrole by Friedel-Crafts alkylation directly because of the inactive site. The electron withdrawing groups were introduced at the alpha-position of pyrrole to form a positioning effect at the diagonal beta-position. With anhydrous AlCl3 as the catalyst, nitroalkenes could be added to the 3-position of pyrrole via Friedel-Crafts alkylation to obtain substituted 3-(2-aminoethyl)pyrroles.

以方酸二甲酯及N-酰基-L-脯氨醛为原料,合成了4种新型方酰胺-N-酰基吡咯烷双功能手性催化剂,利用1 H NMR,13 CNMR,HR-MS,IR对催化剂结构进了表征.将该类催化剂应用于2,4-戊二酮对硝基烯烃的不对称Michael加成反应中,考察了溶剂、温度和催化剂用量对反应的影响,得到的最优反应条件为:甲苯为溶剂,催化剂用量为0.5 mol％,室温下反应.在最优反应条件下,以3a为催化剂,合成了12个具有光学活性的3位取代的2,4-戊二酮,最高产率达到97％,最高ee值达到95％.该催化体系能够适合含有吸电子和供电子基团的各种硝基烯烃的不对称加成.

以烟草中含量丰富的大环二萜类化合物2,7,11-西柏三烯-4,6-二醇（CBT）为母体,其C6位羟基经酯化/醚化,合成了28个西柏三烯-4-醇-6-羧酸酯及西柏三烯-4-醇-6-烷氧类化合物.采用核磁共振波谱（NMR）和高分辨质谱（HRMS）对目标化合物进行了结构表征,并初步评价了其生物活性.细胞毒活性测试结果表明,部分化合物对肿瘤细胞的抑制作用与阳性对照顺铂相当,其中α-2,7,11-西柏三烯-4-醇-6-O-苯乙酸酯（1i）对乳腺癌细胞株MCF-7的IC50值为15. 45μmol/L,α-2,7,11-西柏三烯-4-醇-6-O-（2-氟）苯乙酸酯（1t）对肺癌细胞株SMMC-7721的IC50值为11. 44μmol/L.

以提取率为指标,无水乙醇为溶剂,对超声波萃取木槿皮的影响因素进行了研究,在单因素试验基础上进行正交试验,通过GC×GC-Q-TOFMS对提取物挥发性成分进行分析,并研究了其抑菌性能.试验结果表明,木槿皮提取的最佳工艺条件为液料比15:1,粉碎度100目,提取时间20 min,提取温度40℃;提取物中共鉴定出41种挥发性成分,占总萃取物的63.78％;主要成分为己二酸-(2-乙基己基)酯(21.35％)、亚油酸(6.25％)、油酸(5.70％);提取物对大肠埃希菌、枯草芽孢杆菌、金黄色葡萄球菌、地衣芽孢杆菌、高地芽孢杆菌、粪肠球菌、肺炎克雷伯氏菌均有一定的抑制作用.

为了改进糖苷化反应的合成工艺,以D-葡萄糖为原料,合成了溴代四乙酰葡萄糖(Ⅱ),化合物Ⅱ与麦芽酚(Ⅰ)分别经相转移催化和Koenigs-Knorr糖苷化反应合成了麦芽酚-2,3,4,6-四-O-乙酰基-β-D-葡萄糖苷(Ⅲ),化合物Ⅲ脱乙酰基得到目标产物麦芽酚-β-D-葡萄糖苷(Ⅳ).产物结构经1HNMR、13CNMR、IR、HRMS确证.考察了糖苷Ⅳ的热裂解和加香评吸效果.结果表明,对于糖苷化反应,相转移催化法优于Koenigs-Knorr法.相转移催化法的反应条件为:丙酮为溶剂,无水K2CO3为缚酸剂,四丁基溴化铵(TBAB)为相转移催化剂,n(麦芽酚):n(溴代四乙酰葡萄糖)=1.0:1.2,室温反应4 h,化合物Ⅲ的产率为75.6％.化合物Ⅲ在甲醇钠/甲醇体系进行水解得到化合物Ⅳ.糖苷Ⅳ受热裂解能释放出麦芽酚等特征香味成分,将其添加于卷烟中能够改善香气品质.

以柠檬醛为原料,以D6-丙酮为稳定同位素标记前体物,经碱催化羟醛缩合及酸催化关环反应合成了[2H4]-β-紫罗兰酮,考察了碱和酸的种类、用量及温度对反应的影响,确定了最优路线:先在20％ NaOH重水溶液中于55 ℃反应2h合成假性紫罗兰酮,再经浓硫酸于-10℃反应10 min合成目标产物,两步总收率为60％.目标化合物结构通过质谱、核磁共振氢谱、核磁共振碳谱、红外光谱进行表征,经高效液相色谱确认化学纯度＞99％,经计算同位素丰度为98.1％.该方法所得目标产物可作为稳定同位素稀释分析法中的对照物质.

以3,5-双(三氟甲基)苯基异硫氰酸酯、1,2-二胺和取代脯氨醛为原料,经过加成、还原氨化等反应,合成了一系列新型硫脲-酰胺有机小分子催化剂,利用1HNMR、13CNMR、IR、MS等手段对化合物结构进行了表征,并对其催化2,4-戊二酮对各种取代硝基烯烃的不对称Michael加成反应进行了研究.结果 表明,以甲苯为溶剂,在催化剂用量为1 mol％的情况下,Michael加成产物具有较高的产率(最高95％)和对映选择性(最高e.e.91％).

以提取率为指标,对超声波萃取香根油的影响因素进行了研究.在单因素试验基础上进行正交试验,通过GC-MS对香根油进行了成分分析,并进行了抑菌试验.试验结果表明,香根油提取的最佳工艺条件为:以无水乙醇为溶剂,料液比为1∶30,粉碎度为100目,提取时间为20 min,香根油提取率为5.98％;共鉴定出24种化合物,占总萃取物的35.77％;香根油对大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌、绿脓杆菌、地衣芽孢杆菌、高地芽孢杆菌均有一定的抑制作用.

New bifunctional chiral thiourea-amide organocatalysts were developed.Their applications in asymmetric conjugate addition of 2,4-pentandione to various nitroalkenes were investigated.The corresponding adducts were obtained in excellent yields with high enantioselectivities up to 94% ee in present of 1 mol% catalyst.The catalytic system could also suit for various nitroalkenes bearing electron-donating or electron-withdrawing groups.The preliminary structure-activity relationship study reveals that the acyl group in pyrrolidine N position plays an important role in catalyzing the reaction.

为了开发新型糖苷类香料,首先以D-葡萄糖为原料,合成了溴代四乙酰葡萄糖（Ⅲ）,再以5-甲基糠醛（Ⅰ）为原料,经还原制备了5-甲基糠醇（Ⅱ）,化合物Ⅱ与Ⅲ进行糖苷化反应,分别采用Koenigs-Knorr法和相转移催化法,合成了5-甲基糠醇-2, 3, 4, 6-四-O-乙酰基-β-D-葡萄糖苷（Ⅳ）;最后,将化合物Ⅳ水解,得到目标产物5-甲基糠醇-β-D-葡萄糖苷（Ⅴ）。中间体和产物结构经1HNMR、13CNMR、IR、HRMS确证,并对糖苷Ⅴ的热裂解性能进行了测定。结果表明:两种糖苷化方法所得到的产物均为糖苷Ⅳ,Koenigs-Knorr法更优。Koenigs-Knorr法的最佳反应条件为:n（5-甲基糠醇）:n（溴代四乙酰葡萄糖）=1:1.6,n（5-甲基糠醇）:n（Ag2CO3）=1:1.5,回流反应4 h,化合物Ⅳ的产率为42.9%。目标糖苷Ⅴ热裂解后能够释放出5-甲基糠醛、5-甲基糠醇等香味成分,可用于食品、烟草等行业。