无限维s空间内无条件发散级数的Dvoretzky—Hanani定理

本文推广了Ｄｖｏｒｅｔｚｋｙ－Ｈａｎａｎｉ定理于无限维Ｓ空间。     

注入控制铜蒸气激光方向性时间过程测量

实验研究了注入控制对铜蒸气激光非稳腔输出光束质量的影响，从输出光发散角时间分辨过程的测量结果说明注入加速被注入腔内激光发散角的减小过程。由于被注入腔内放大自发辐射的存在，为得到较好的注入控制效果，注入光的脉宽和进入被注入腔的延时必须恰当。     

Synthesis of dendritic polyamide with protected amino functional groups in the periphery

A homologous series of first-to third-generation dendritic polyamides 2a, 3, and 5 with tris(aminoethyl) amine (TREA) as the core and the protected amino functional groups at the periphery were synthesized via active ester route from “Schlüter” type dendron 1a. Their structures were characterized by ¹H-NMR and mass spectra. Based on the efficient synthesis of the first generation dendrimer 2a (yield 75%), the synthesis of second-generation dendrimer 3 was found to be more efficient via the convergent method (yield 69%), while the mixed strategy was applied efficiently for the synthesis of the higher generation dendrimer 5 (yield 37%). The overall yield for the third generation dendrimer 5 from Schlüter dendron is 12%. __________ Translated from Huaxue Tongbao (Chemistry), 2005, 68(12) (in Chinese)     

Divergent Synthesis of All Possible Optically Active Regioisomers of Myo‐Inositol Mono‐ and Bisphosphates

All possible optically active regioisomers of myo‐inositol mono‐ and bisphosphates were synthesized using inositol derivatives suitably protected with various protecting groups (IR_ns) as key intermediates. A series of procedures including Novozym 435 catalyzed enzymatic resolution of (3aR,4S,7S,7aR)‐rel‐3a,4,7,7a‐tetrahydro‐2,2‐dimethyl‐1,3‐benzodioxole‐4,7‐diol diacetate, several protection and deprotection reactions, and acyl migration afforded two enantiomeric pairs of IR₅ and six enantiomeric pairs of IR₄. Phosphorylation of these key intermediates by the phosphitylation and oxidation procedure gave the target products after removal of the protecting groups.      

Transition-metal-free mono- or dinitration of protected anilines

Abstract

An amide-assisted arene nitration is presented, and both mono- and dinitration of protected anilines could be effected by using NaNO₂ and NaNO₃ as the mono- and bisnitrating agents, respectively. This divergent synthesis is transition-metal- and acid-free, and features a broad substrate scope, low cost, and ortho–para selectivity.     

Divergent Synthesis of Monosubstituted and Unsymmetrical 3,6‐Disubstituted Tetrazines from Carboxylic Ester Precursors

Since tetrazines are important tools to the field of bioorthogonal chemistry, there is a need for new approaches to synthesize unsymmetrical and 3‐monosubstituted tetrazines. Described here is a general, one‐pot method for converting (3‐methyloxetan‐3‐yl)methyl carboxylic esters into 3‐thiomethyltetrazines. These versatile intermediates were applied to the synthesis of unsymmetrical tetrazines through Pd‐catalyzed cross‐coupling and in the first catalytic thioether reduction to access monosubstituted tetrazines. This method enables the development of new tetrazine compounds possessing a favorable combination of kinetics, small size, and hydrophilicity. It was applied to a broad range of aliphatic and aromatic ester precursors and to the synthesis of heterocycles including BODIPY fluorophores and biotin. In addition, a series of tetrazine probes for monoacylglycerol lipase (MAGL) were synthesized and the most reactive one was applied to the labeling of endogenous MAGL in live cells.     

聚酰胺-胺树枝状高分子的柱色谱提纯研究

采用发散法合成了0.5～4.0代(G)聚酰胺-胺(PAMAM)树枝状高分子,通过薄层色谱分析产物组成,并进一步选用柱色谱法对半代产物进行了提纯与精制.用红外,核磁,高效液相色谱(HPLC)和热重分析等方法对提纯后产物进行了表征.结果表明,提纯得到的各PAMAM产物具有较完整的分子结构,小分子含量很少;且0.5GPAMAM产物HPLC测试纯度达到97.81%.     

Direct Asymmetric α-Selective Mannich Reaction of β,γ-Unsaturated Ketones with Cyclic α-Imino Ester: Divergent Synthesis of Cyclocanaline and Tetrahydro Pyridazinone Derivatives

The first regio-, diastereo-, and enantioselective direct Mannich reaction of β,γ,-unsaturated ketones with benzoxazinone cyclic imines was enabled by Lewis acid/Brønsted base cooperative catalysis. The dinuclear zinc complex catalyzed the reaction of a broad range of β,γ-unsaturated ketones to proceed at the α-site exclusively, leading to corresponding adducts with two consecutive tertiary carbon stereocenters in diastereomeric ratios of up to >20:1 and enantioselectivities generally in the 90–99 % ee range. These products were used as general intermediates in the synthesis of multisubstituted cyclocanalines, tetrahydro pyridazinones, and 4H-furo[2,3-b][1,4]benzoxazine derivatives.     

A method of summation of divergent series to any accuracy

We propose a new method of summation to any accuracy for a wide class of divergent series, using only a finite number of terms of the series. Translated fromMatematicheskie Zametki, Vol. 68, No. 1, pp. 24–35, July, 2000.