Nd:YAP激光辐照对雨生红球藻生理效应的荧光分析

目的：Nd：YAP激光辐照对雨生红球藻生理效应的荧光分析j方法：利用Nd：YAG激光（功率10W,辐照剂量为15s、35s、55s）辐照雨生红球藻,在对辐照细胞进行生长测定以及色素吸收光谱分析的基础上,进一步利用激光共聚焦扫描显微镜（LSCM）,在波长488nm的Ar^＋激发光条件下,对细胞的自体荧光以及吖啶橙染色的细胞核荧光物质进行定位定量分析,获得细胞自发荧光光谱和细胞核荧光物质的荧光光谱。结果：①低剂量的Nd：YAG激光辐照（15s左右）对藻细胞有促长作用,生长速率提高20．3％,色素吸收峰的峰值提高25．3％。较高剂量的Nd：YAG激光辐照（35s、55s）对藻细胞生长有抑制作用,并有明显的致死、致突效应。②对自体荧光的分析结果表明,与对照组相比,低剂量激光辐照组的细胞,在荧光光谱的峰型及峰值上变化不大,在682nm处均有较强的荧光发射,而高剂量激光辐照组的细胞多无明显的荧光发射。③对细胞核荧光物质的分析,雨生红球藻细胞在530nm（DNA）和640nm（RNA）处均有荧光发射峰。与对照组相比,低剂量激光辐照组的DNA荧光发射有所增强,但RNA的荧光发射则有所减弱;高剂量激光辐照组的核物质荧光发射谱,在峰型上与对照组存在差异,荧光强度也明显下降。结论：低剂量的Nd：YAP激光辐照对细胞核的DNA合成与复制有一定的刺激作用,可促进光合色素的合成并提高其对光能的吸收效率,从而增强光合活性,促进细胞的增殖与生长;高剂量激光辐照则对细胞的DNA有损伤作用,是致死率上升并发生突变的可能原因。     

不同激光不同能量对红色毛癣菌的体外抑制评估及部分机制的探讨

目的探讨多种激光在不同的能量下对红色毛癣菌的体外抑制作用以及可能的作用机制。方法将Q开关Nd:YAG 532nm激光、Q开关Nd:YAG 1064nm激光、长脉宽Nd:YAG1064nm激光和强脉冲光分为不同能量组及未照光组,体外照射红色毛癣菌的菌落,观察第0、1、3、7天时菌落直径的变化差异,用酶联免疫吸附测定激光照射后红色毛癣菌产生角蛋白酶的活性。结果与未照光组相比,上述激光在低能量时对红色毛癣菌的菌落直径与角蛋白酶活性无明显影响。2～4J/cm~2能量Q开关Nd:YAG 532nm激光、4～8J/cm~2能量Q开关Nd:YAG 1064nm激光、4J/cm~2长脉宽Nd:YAG 1064nm激光能显著抑制菌落的生长,红色毛癣菌角蛋白酶的活性出现明显下降。结论 2～4J/cm~2能量Q开关Nd:YAG 532nm激光、4～8J/cm~2能量Q开关Nd:YAG 1064nm激光、4J/cm~2长脉宽Nd:YAG 1064nm激光能抑制红色毛癣菌生长及角蛋白酶的活性。     

Ar+激光、Nd:YAG激光辐照亚心形扁藻生物学效应初探

采用Ar^＋激光（488 nm,照射时间分别为10 min、20 min、30 min）、Nd：YAG（1064 nm,照射时间为1 min、2 min、3 min）辐照扁藻,通过细胞计数以及扫描色素的吸收光谱研究激光辐照扁藻的生物效应.研究结果表明：非色素吸收峰的激光可以产生激光生物效应;不同波长,不同剂量的激光辐照扁藻可以表现出相类似的生物效应;Ar＋辐照20 min、Nd：YAG辐照2 min可以刺激扁藻生长,明显提高色素吸收光密度值,促进光合作用的进行.文中对不同激光辐照扁藻所产生的生物效应进行了比较和探讨.     

倍频Nd∶YAG激光对紫球藻生长与胞外多糖产量的影响

紫球藻经Nd:YAG激光(波长1060 nm)照射,以不同时间设置处理剂量,比较紫球藻细胞活力、生长速率、生物量、胞外多糖产量等方面的变化.高剂量处理组(Y-20、Y-30和Y-40)致死率为17～44%,继代培养后生长迅速,K值分别比对照组提高18%、23.4%和15.3%.各处理组培养10天后收获的生物量与对照组无显著差别,但胞外多糖产量均有较大幅度提高,增幅达50～150%.此外,YAG激光照射对藻细胞叶绿素含量也有影响.YAG激光有望成为紫球藻优良藻株选育的较佳诱变剂.     

倍频Nd：YAG激光对紫球藻生长与胞外多糖产量的影响

紫球藻经Nd:YAG激光（波长1060nm)照射,以不同时间设置处理剂量,比较紫球藻细胞活力,生长速率,生物量,胞外多糖产量等方面的变化。高剂量处理组（Y-20、Y-30和Y-40）致死率为17-44%,继代培养后生长迅速,K值分别比对照组提高18%、23.4%和15.3%,各处理组培养10天后收获的生物量与对照组无显著差异,但胞外多糖产量均有较大幅度提高,增幅达50-150%。此外,YAG激光照射对藻细胞叶绿素含量也有影响,YAG激光有望成为紫球藻优良藻株选育的较佳诱变剂。     

国产Nd:YAP激光组织热损伤效应的比较研究

目的:通过比较1 341 nm Nd:YAP与临床常用激光器脉冲Nd:YAG和连续Nd:YAG对皮肤、肌肉、静脉和肝脏组织的热损伤效应,了解Nd:YAP激光的作用特点,为其临床应用提供实验依据。方法:以大鼠作为实验对象,分为皮肤、肌肉组和静脉、肝脏组。皮肤、肌肉组:Nd:YAP激光、连续和脉冲Nd:YAG选择能量密度1000 J/cm2、2 000 J/cm2,静脉、肝脏组采用Nd:YAP激光和连续Nd:YAG两种激光器,能量密度选择500 J/cm2和1 000 J/cm2,对组织进行非接触式点状照射。照射过程中观察组织变化和损伤直径大小,并于照射后即刻、3天取材做病理切片,光镜下观察病理变化,比较相同能量密度下三种激光器对组织的热损伤和损伤修复情况。结果:皮肤、肌肉组:Nd:YAP激光在1 000 J/cm2条件下对组织的损伤以热凝固效应为主,2 000 J/cm2条件下组织发生明显气化、有一定的切割作用。相同能量密度下,脉冲Nd:YAP激光气化作用较两种Nd:YAG激光显著,而凝固损伤范围较连续Nd:YAG浅,较脉冲Nd:YAG深。肝脏、静脉组:Nd:YAP激光对肝脏的热凝固效应与Nd:YAG激光近似,气化作用明显;Nd:YAP激光对血管及其周围组织的凝固及气化作用均较连续Nd:YAG激光明显。结论:Nd:YAP激光具有良好的凝固与气化作用。     

氧化应激在长脉宽1064nm Nd: YAG激光治疗甲真菌病中的作用

目的探讨长脉宽1064nm Nd:YAG激光对引起甲真菌病的最常见致病菌-红色毛癣菌(Trichophyton rubrum)的体外抑制/杀灭作用及活性氧簇(ROS)介导的氧化应激反应在其中发挥的作用。方法改变长脉宽1064nm Nd:YAG激光脉冲数(7次脉冲、9次脉冲、11次、13次脉冲),固定其他参数照射红色毛癣菌菌落,绘制生长曲线,确定有抑制作用的最小脉冲数。在此脉冲数条件下干预红色毛癣菌菌落及孢子悬液,比较菌落形态学改变,检测孢子悬液相对活力的改变,同时检测ROS在不同处理后的表达水平变化。结果激光对红色毛癣菌的抑制/杀灭作用随能量的增加而增强,相对活力随时间的增加而下降,呈能量和时间依赖性;激光干预后,菌丝失去正常形态结构,孢子悬液的荧光强度及ROS含量较未照射的高,P=0.0157。结论长脉宽1064nm Nd:YAG激光体外对红色毛癣菌有抑制/杀灭作用,ROS介导的氧化应激反应可能在该激光治疗红色毛癣菌甲真菌病中发挥了一定的作用。     

自然和热凝固的人肝组织对KTP/YAG激光的光学特性的比较研究

本文采用双积分球测量系统和Inverse Add ing-Doub ling方法,研究了自然和热凝固的人肝组织对532nm的KTP激光和1 064 nm的Nd:YAG激光的光学特性。结果表明:热凝固的人肝组织对532 nm的KTP激光的吸收系数较自然的肝组织的吸收系数增大了23.5%(P<0.05),热凝固的肝组织对1 064 nm的Nd:YAG激光的吸收系数较自然的肝组织的吸收系数减小了34.3%(P<0.05)。热凝固的人肝组织对532 nm的KTP激光的散射系数较自然的肝组织的散射系数增大了4.50倍(P<0.05),热凝固的肝组织对1 064 nm的Nd:YAG激光的散射系数较自然的肝组织的散射系数增大了6.41倍(P<0.05)。热凝固的人肝组织对532 nm的KTP激光的各向异性因子较自然的肝组织的各向异性因子减小了5.47%,热凝固的肝组织对1 064 nm的Nd:YAG激光的各向异性因子较自然的肝组织的各向异性因子减小了1.95%。     

LD和YAG激光对极大螺旋藻生理特性的影响

采用Nd:YAG和LD激光辐射极大螺旋藻。Nd:YAG激光波长λ=532nm,功率P＝500mW,功率密度S＝160mW/cm^2,辐射10min,λ=1060nm,功率P＝7W,功率密度S＝35.84mW/cm^2,辐照20s:Nd:YAG激光（λ=532nm）辐照10min,再用LD激光（波长λ=650nm,功率P＝40mW功率密度S＝13mW/cm^2)辐照20min。实验结果表明,所设计的三种实验方 均能促进极大螺旋藻生长、β－胡萝卜素积累和胞外多糖含量的增加,且波长532nm的Nd:YAG激光的促进作用最明显,它可使β－胡萝卜素提高14＝．31％,胞多糖含量增加19．12％,红外光谱分析表明,经激光辐照后的藻细胞官能基团没有发生变化。     

脉冲Nd:YAG激光对单层KB细胞损伤效应的研究

目的：观察脉冲Nd：YAG激光照射体外单层培养KB细胞后的形态改变及损伤后HSP70,c-Fos的表达情况,初步探讨较强脉冲激光对细胞的损伤效应及损伤修复机制。方法：建立单层培养细胞的脉冲Nd：YAG激光损伤模型,每个脉冲能量密度为160J／cm^2～186J／cm^2或220J／cm^2～257J／cm^2,分别于照后即刻、2h和6h,用台盼蓝染色、TUNEL检测分析该激光对KB细胞的损伤特点,免疫组化法检测HSP70,c-Fos的表达水平。结果：当照射剂量为220J／ecm^2～257J／cm^2时,照后即刻,光斑中央细胞形态严重破坏,直接坏死;周围细胞形态未发生明显改变。2h后周围细胞TUNEL。着色也增强,呈强阳性。照后6h光斑中央及周围细胞着色均减弱。TUNEL着色区直径随时间先扩大后缩小。当照射剂量为160J／cm^2～186J／cm^2时,细胞内HSP70、c-Fos表达随时问先显著增强,而后减弱至正常。结论：脉冲Nd：YAG激光在所选剂量下,可以引起单层KB细胞的损伤,包括即刻坏死、延迟性死亡及可逆性损伤。HSP70、c-Fos的高表达说明它们在保护受损细胞、修复激光所致损伤中发挥重要作用。     

肾组织脱水对组织光学吸收和散射特性的影响

研究肾组织脱水对组织的吸收和散射特性的影响,实验利用带积分球附件的分光光度计和采用反向倍增法获取组织对532 nm和1064 nm波长的吸收和散射特性。结果表明:在37℃下脱水的肾组织对532 nm和1064 nm的吸收系数和约化散射系数都是随着脱水率的增大而明显地增大的,在37℃下脱水的肾组织对532 nm和1064 nm的吸收系数均明显地较自然的肾组织对相应波长的吸收系数要大,而在37℃下脱水的肾组织对532 nm和1064 nm的约化散射系数也明显地较自然的肾组织对相应波长的约化散射系数要大,在相同脱水率下的肾组织对于532 nm的吸收系数和约化散射系数都明显地较其对1064 nm的吸收系数和约化散射系数要大。研究结果提示,组织脱水、脱水的温度和脱水时间是影响肾组织的吸收和散射特性的重要因素。     

两种微创方法治疗颈椎间盘突出症的疗效比较

目的:比较经皮激光椎间盘减压术(PLDD)和经皮颈椎间盘等离子消融术治疗单节段突出的神经根型颈椎间盘突出症的临床疗效及安全性。方法:回顾2007年6月至2011年5月的颈椎间盘突出症住院患者36例。其中PLDD治疗17例(A组),等离子消融治疗19例(B组)。根据VAS评分和JOA评分,评价术前和术后一月内的疗效,同时记录两组患者的不良反应和并发症。结果:所有病例均成功穿刺并完成随访。两组手术后一月内各观察点的VAS评分和JOA评分均明显优于术前(P<0.05),其中B组患者术后3d和7d的VAS评分低于A组(P<0.05),而两组间术后JOA评分无明显差异。两组均未发生严重并发症。结论:与经皮激光椎间盘减压术相比,经皮椎间盘等离子消融术治疗颈椎间盘突出症患者症状消失更快。     

Synthesis of an octasaccharide fragment of high-mannose-type glycans of glycoproteins.

O-(alpha-D-Mannopyranosyl)-(1----2)-O-(alpha-D-mannopyranosyl)-(1----3)- O- [(alpha-D-mannopyranosyl)-(1----2)-O-(alpha-D-mannopyranosyl)-(1----6)]- O- (alpha-D-mannopyranosyl)-(1----6)-O-(beta-D-mannopyranosyl)-(1----4)-O-( 2- acetamido-2-deoxy-beta-D-glucopyranosyl)-(1----4)-2-acetamido-2-deoxy- glucopyranose, an octasaccharide fragment of high-mannose type glycan of glycoproteins, was synthesized. Crucial glycosylation of trisaccharide intermediate, benzyl O-(2,4-di-O-benzyl-beta-D-mannopyranosyl)-(1----4)-O-(2-acetamido-3,6-di -O- benzyl-2-deoxy-beta-D-glucopyranosyl)-(1----4)-2-acetamido-3,6-di-O-benz yl-2- deoxy-beta-D-glucopyranoside, was successful only with a di-O-acetyltetradeca-O-benzyl-D-mannopentaosyl chloride. The use of the corresponding hexadeca-O-acetyl-D-mannopentaosyl bromide did not give the desired product.     

Chemical characterization of milk oligosaccharides of the common brushtail possum (Trichosurus vulpecula)

Structural characterizations of marsupial milk oligosaccharides have been performed in only three species: the tammar wallaby, the red kangaroo and the koala. To clarify the homology and heterogeneity of milk oligosaccharides among marsupials, 21 oligosaccharides of the milk carbohydrate fraction of the common brushtail possum were characterized in this study. Neutral and acidic oligosaccharides were separated from the carbohydrate fraction of mid-lactation milk and characterized by ¹H-nuclear magnetic resonance spectroscopy and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The structures of the 7 neutral oligosaccharides were Gal(β1-3)Gal(β1-4)Glc (3’-galactosyllactose), Gal(β1-3)Gal(β1-3)Gal(β1-4)Glc (3”, 3’-digalactosyllactose), Gal(β1-3)Gal(β1-3)Gal(β1-3)Gal(β1-4)Glc, Gal(β1-3)Gal(β1-3)Gal(β1-3)Gal(β1-3)Gal(β1-4)Glc, Gal(β1-3)[Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc (lacto-N-novopentaose I), Gal(β1-3)Gal(β1-3)[Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc (galactosyl lacto-N-novopentaose I), Gal(β1-3)[Gal(β1-4)GlcNAc(β1-6)]Gal(β1-3)Gal(β1-4)Glc (galactosyl lacto-N-novopentaose II). The structures of the 14 acidic oligosaccharides detected were Neu5Ac(α2-3)Gal(β1-3)Gal(β1-4)Glc (sialyl 3’-galactosyllactose), Gal(β1-3)(O-3-sulfate)[Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc (lacto-N-novopentaose I sulfate a) Gal(β1-3)[Gal(β1-4)(O-3-sulfate)GlcNAc(β1-6)]Gal(β1-4)Glc (lacto-N-novopentaose I sulfate b), Neu5Ac(α2-3)Gal(β1-3)Gal(β1-3)Gal(β1-4)Glc, Neu5Ac(α2-3)Gal(β1-3)[Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc (sialyl lacto-N-novopentaose a), Gal(β1-3)(?3-O-sulfate)Gal(β1-3)[Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc, Gal(β1-3)Gal(β1-3)[Gal(β1-4)(?3-O-sulfate)GlcNAc(β1-6)]Gal(β1-4)Glc, Gal(β1-3)[Neu5Ac(α2-6)Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc (sialyl lacto-N-novopentaose b), Neu5Ac(α2-3)Gal(β1-3)Gal(β1-3)Gal(β1-3)Gal(β1-4)Glc, Gal(β1-3)(?3-O-sulphate)Gal(β1-3)Gal(β1-3)Gal(β1-3)Gal(β1-4)Glc, Neu5Ac(α2-3)Gal(β1-3)Gal(β1-3)[Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc, Gal(β1-3)(?3-O-sulphate)Gal(β1-3)Gal(β1-3)[Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc, Gal(β1-3)Gal(β1-3)Gal(β1-3)[Gal(β1-4)(?3-O-sulphate)GlcNAc(β1-6)]Gal(β1-4)Glc and Gal(β1-3)Gal(β1-3)[Neu5Ac(α2-6)Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc (galactosyl sialyl lacto-N-novopentaose b). No fucosyl oligosaccharides were detected. Galactosyl lacto-N-novopentaose II, lacto-N-novopentaose I sulfate a, lacto-N-novopentaose I sulfate b and galactosyl sialyl lacto-N-novopentaose b are novel oligosaccharides. The results are compared with those of previous studies on marsupial milk oligosaccharides.     

Biotransformation of raspberry ketone and zingerone by cultured cells of Phytolacca americana

The biotransformation of raspberry ketone and zingerone were individually investigated using cultured cells of Phytolacca americana. In addition to (2S)-4-(4-hydroxyphenyl)-2-butanol (2%), (2S)-4-(3,4-dihydroxyphenyl)-2-butanol (5%), 4-[4-(beta-d-glucopyranosyloxy)phenyl]-2-butanone (19%), 4-[(3S)-3-hydroxybutyl]phenyl-beta-d-glucopyranoside (23%), and (2S)-4-(4-hydroxyphenyl)but-2-yl-beta-d-glucopyranoside (20%), two biotransformation products, i.e., 2-hydroxy-4-[(3S)-3-hydroxybutyl]phenyl-beta-d-glucopyranoside (12%) and 2-hydroxy-5-[(3S)-3-hydroxybutyl]phenyl-beta-d-glucopyranoside (11%), were isolated from suspension cells after incubation with raspberry ketone for three days. On the other hand, two compounds, i.e., (2S)-4-(4-hydroxy-3-methoxyphenyl)but-2-yl-beta-d-glucopyranoside (17%) and (2S)-2-(beta-d-glucopyranosyloxy)-4-[4-(beta-d-glucopyranosyloxy)-3-methoxyphenyl]butane (16%), together with (2S)-4-(4-hydroxy-3-methoxyphenyl)-2-butanol (15%), 4-[4-(beta-d-glucopyranosyloxy)-3-methoxyphenyl]-2-butanone (21%), and 4-[(3S)-3-hydroxybutyl]-2-methoxyphenyl-beta-d-glucopyranoside (24%) were obtained upon addition of zingerone. Cultured cells of P. americana can reduce, and regioselectively hydroxylate and glucosylate, these food ingredients to their beta-glycosides.     

Chemical characterization of milk oligosaccharides of the polar bear, Ursus maritimus

Two trisaccharides, three tetrasaccharides, two pentasaccharides, one hexasaccharide, one heptasaccharide, one octasaccharide and one decasaccharide were isolated from polar bear milk samples by chloroform/methanol extraction, gel filtration, ion exchange chromatography and preparative thin-layer chromatography. The oligosaccharides were characterized by ¹H-NMR as follows: the saccharides from one animal: Gal(α1-3)Gal(β1-4)Glc (α3′-galactosyllactose), Fuc(α1-2)Gal(β1-4)Glc (2′-fucosyllactose), Gal(α1-3)[Fuc(α1-2)]Gal(β1-4)Glc (B-tetrasaccharide), GalNAc(α1-3)[Fuc(α1-2)]Gal(β1-4)Glc (A-tetrasaccharide), Gal(α1-3)Gal(β1-4)GlcNAc(β1-3)Gal(β1-4)Glc, Gal(α1-3)[Fuc(α1-2)]Gal(β1-4)GlcNAc(β1-3)Gal(β1-4)Glc, Gal(α1-3)Gal(β1-4)GlcNAc(β1-3)[Gal(α1-3)Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc; the saccharides from another animal: α3′-galactosyllactose, Gal(α1-3)Gal(β1-4)[Fuc(α1-3)]Glc, A-tetrasaccharide, GalNAc(α1-3)[Fuc(α1-2)]Gal(β1-4)[Fuc(α1-3)]Glc (A-pentasaccharide), Gal(α1-3)Gal(β1-4)[Fuc(α1-3)]GlcNAc(β1-3)Gal(β1-4)Glc, Gal(α1-3)Gal(β1-4)[Fuc(α1-3)]GlcNAc(β1-3)Gal(β1-4)[Fuc(α1-3)]Glc (difucosylheptasaccharide) and Gal(α1-3)Gal(β1-4)[Fuc(α1-3)]GlcNAc(β1-3){Gal(α1-3)Gal(β1-4)[Fuc(α1-3)]GlcNAc(β1-6)}Gal(β1-4)Glc (difucosyldecasaccharide). Lactose was present only in small amounts. Some of the milk oligosaccharides of the polar bear had α-Gal epitopes similar to some oligosaccharides in milk from the Ezo brown bear and the Japanese black bear. Some milk oligosaccharides had human blood group A antigens as well as B antigens; these were different from the oligosaccharides in Ezo brown and Japanese black bears.     

Successive Isolation of Proteinase Hyperproductive Mutants of Aspergillus sojae

Hydrochloric acid treatment of methyl 3-(4-isobutylphenyl)-3-methylglycidate and methyl 2-hydroxy-3-(4-isobutylphenyl)-3-butenoate, a rearrangement product of the former, in acetic acid gave 3-(4-isobutylphenyl)-3-methylpyruvic acid and 2-(4-isobutylphenyl)-pro-panal. The same treatment of 2-hydroxy-3-(4-isobutylphenyl)-3-butenoic acid gave 2-(4-isobutylphenyl)-propanal. Both 3-(4-isobutylphenyl)-3-methylpyruvic acid and 2-(4-iso-butylphenyl)-propanal were oxidized to 2-(4-isobutylphenyl)-propionic acid.     

Monoterpene ketones in the synthesis of optically active insect pheromones

This review considers the synthetic possibilities of monoterpene ketones, such as (R)-(+)- and (S)-(-)-pulegones, (-)-menthone, (R)-(-)- and (S)-(+)-carvones, (2R,5S)-dihydrocarvone, (S)-(+)- and (R)-(-)-camphors, (R)-(-)-nopinone, (R)-(+)- and (S)-(-)-verbenones by the examples of synthesis of optically pure and enantiomerically enriched insect pheromones.     

Syntheses of a series of lacto-N-neotetraose clusters using a carbosilane dendrimer scaffold

4-Pentenyl (2,3,4,6-tetra-O-acetyl-beta-d-galactopyranosyl)-(1-->4)-(3,6-di-O-acetyl-2-deoxy-2-phthalimido-beta-d-glucopyranosyl)-(1-->3)-(2,6-di-O-benzoyl-beta-d-galactopyranosyl)-(1-->4)-2,3,6-tri-O-benzoyl-beta-d-glucopyranoside (4) was synthesized by regioselective glycosylation of 4-pentenyl (2,6,-di-O-benzoyl-beta-d-galactopyranosyl)-(1-->4)-2,3,6-tri-O-benzoyl-beta-d-glucopyranoside and (2,3,4,6-tetra-O-acetyl-beta-d-galactopyranosyl)-(1-->4)-3,6-di-O-acetyl-2-deoxy-2-phthalimido-beta-d-glucopyranosyl chloride. By conversion of the protecting groups followed by thioacetylation, 4 was transformed into the corresponding lacto-N-neotetraose derivative, 5-(acetylthio)pentenyl (2,3,4,6-tetra-O-acetyl-beta-d-galactopyranosyl)-(1-->4)-O-(3,6-di-O-acetyl-2-acetamido-2-deoxy-beta-d-glucopyranosyl)-(1-->3)-(2,4,6-di-O-acetyl-beta-d-galactopyranosyl)-(1-->4)-2,3,6-tri-O-acetyl-beta-d-glucopyranoside (6). The lacto-N-neotetraose derivative 6 was introduced into carbosilane dendrimer cores of three shapes, and three kinds of new carbosilane dendrimers peripherally functionalized by lacto-N-neotetraose were obtained.     

Synthesis of enantiopure 2-aryl-2-methoxypropionic acids and determination of their absolute configurations by X-ray crystallography

Racemic 2-aryl-2-methoxypropionic acids were enantioresolved by the use of (S)-(-)-phenylalaninol 4. For instance, racemic 2-methoxy-2-phenylpropionic acid (+/-)-7 was condensed with phenylalaninol (S)-(-)-4 yielding a diastereomeric mixture of amides, which was easily separated by HPLC on silica gel affording the first-eluted amide (-)-13a and the second-eluted amide (+)-13b: alpha = 3.19, Rs = 3.49. The absolute configuration of amide (-)-13a was determined to be (R;S) by X-ray crystallography by reference to the S configuration of the phenylalaninol moiety. Amide (R;S)-(-)-13a was converted to oxazoline (R;S)-(-)-14a, from which enantiopure 2-methoxy-2-phenylpropionic acid (R)-(-)-7 was recovered. Other 2-aryl-2-methoxypropionic acids, (R)-(-)-8, (R)-(-)-9, (R)-(+)-10, (R)-(-)-11, and (R)-(-)-12, were similarly prepared in enantiopure forms with the use of phenylalaninol (S)-(-)-4, and their absolute configurations were clearly determined by X-ray crystallography or by chemical correlation.