Synthesis of EDTA core dendrimers through a consecutive esterification-CuAAC process

A novel class of thermostable G0 and G1-dendrimers was synthesized from the coupling of both propargyl and azido esters derived from EDTA through copper catalyzed azide-alkyne cycloaddition. The branching and size in these compounds were controlled by a simple azide-alkyne group position change in the CuAAC reaction in conjunction with the use of 1,3-diazido-propan-2-ol as a polyfunctional compound.     

One-Pot Stereoselective Synthesis of Alkyl (Z)-2-[4-Oxo-3-phenyl-2-(phenylimino)-1,3-thiazolan-5-yliden]acetates from Acetylenic Esters and N,N′ -Diphenylthiourea

N, N′ -diphenylthiourea reacts with dialkyl acetylenedicarboxylates in acetone to form 1:1 adducts, which undergo a cyclization reaction to produce alkyl (Z)-2-[4-oxo-3-phenyl-2-(phenylimino)-1,3-thiazolan-5-yliden]acetates in fairly good yields. NMR spectra indicated that the reaction is completely stereoselective.     

One-Pot Stereoselective Synthesis of Alkyl Z-2-[2-Amino-4-oxo-1,3-selenazol-5(4H)-yliden] Acetates

Abstract

Selenourea reacts with dialkyl acetylenedicarboxylates in acetone to form 1:1 adducts, which undergo a cyclization reaction to produce alkyl Z-2-(2-amino-4-oxo-1,3-selenazol-5(4H)-yliden) acetates in fairly good yields. The reaction is completely stereoselective.     

Stereoselective Synthesis of Alkyl Z -2-(2-Amino-4-oxo-1,3-thiazol-5(4 H )-yliden)Acetates in Solventless Conditions

Tiourea reacts with dialkyl acetylenedicarboxylates in solventless conditions to form 1:1 adducts, which undergo a cyclization reaction to produce alkyl Z-2-(2-amino-4-oxo-1,3-thiazol-5(4H)-yliden)acetates in fairly good yields. The stereochemistry of the ethyl Z-2-(2-amino-4-oxo-1,3-thiazol-5(4H)-yliden)acetate was established by the use of X-ray single crystal structure analysis. The reaction is completely stereoselective.     

A Simple Synthesis of Stable Phosphorus Ylides Derived from 2-Benzoxazolinone and 2-Mercaptobenzoxazole

The reaction of triphenylphosphine with dialkyl acetylenedicarboxylates in the presence of a strong SH-acid or NH-acid, such as 2-mercaptobenzoxazole and 2-benzoxazolinone, has been studied. In some cases, stable phosphorus ylides are obtained in excellent yields. The ylide moiety of these compounds is strongly conjugated with the adjacent carbonyl group, and the rotation about the partial double bond in (E) and (Z) geometrical isomers is slow on the NMR time scale at an ambient temperature. Thus, these exist as a mixture of geometrical isomers.     

The Synthesis of Amino Acid Methyl Ester 5′-Phosphoamidates of Protected Uridine

In this article, we used the Atherton–Todd reaction to synthesize amino acid methyl ester 5′-phosphoamidates of uridine as prodrugs. Their structures were confirmed by ¹H NMR, ³¹P NMR, ¹³C NMR, IR, and mass spectrometry.

Supplemental materials are available for this article. Go to the publisher′s online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

SULFAMOYLATION OF ESTER ENOLATE ANIONS

Abstract

Stabilized carbanions such as the α-carbanions of carboxylic acid esters react with sulfamoyl chlorides by nucleophilic displacement at chlorine which results in chlorination of the carbanion. Thus direct sulfamoylation of these carbanions with sulfamoyl chlorides fails. Conversion of sulfamoyl chlorides to N-sulfonylamines followed by addition of carbanions at -78°C results in sulfamoylation of the carbanion. The method has not been successful with carbanions from diethyl acetamidomalonate and ethyl diphenylacetate.     

Anti‐static Agent Containing Zinc Oxide and its Modification for PA6 Fiber

A new anti‐static agent was synthesized from zinc oxide‐adipic acid‐polyethylene glycol and caprolactam by three‐step reactions. The antistatic agent (called poly(ether ester amide zinc oxide) or PEEAZ) was analyzed by IR and DSC. The results showed that zinc oxide existed in the main chain of PEEAZ. The glass temperature and melt temperature of poly(ether ester amide zinc oxide) (referred to as PEEAZ in the following) decreased with increasing poly(ether ester zinc oxide) increasing in PEEAZ. Antistatic PA6 fiber was obtained by adding PEEAZ 2–8% (wt/wt) to PA6 during blend spinning. The specific resistance and the static half‐value period of PA6 fiber was less than 10⁹Ω · cm and 60 sec, respectively. Excellent antistatic property remained after being washed 30 times.     

Amino Acid Based Epoxy-Poly(Ester Amide)s—A New Class of Functional Biodegradable Polymers: Synthesis and Chemical Transformations

A new class of biodegradable functional polymers – epoxy-poly(ester amide)s (EPEAs), was synthesized for the first time on the basis of naturally occurring α-amino acids, fatty diols and cis- and trans-epoxysuccinic acids. The syntheses were conducted via both solution Active Polycondensation and Interfacial Polycondensation using, accordingly, either activated di-p-nitrophenyl esters or dichlorides of cis- and trans-epoxysuccinic acids as bis-electrophilic monomers. Di-p-toluenesulfonic acid salts of bis-(L-phenylalanine)-1,6-hexylene and bis-(L-leucine)-1,6-hexylene diesters were used in both cases as bis-nucleophilic counter-partners. High-molecular-weight polymers (M_w up to 67.000) with desirable material properties were obtained via solution polycondensation using di-p-nitrophenyl-trans-epoxy succinate. The EPEAs were chemically modified further under mild conditions: oxirane groups along the backbone were reacted with both nucleophilic and electrophilic reagents, and also subjected to thermal and chemical curing. The macromolecular transformations of EPEAs substantially broaden material properties and, hence, the potential to apply amino acid-based biodegradable poly(ester amide)s as absorbable drug carriers and surgical devices.     

环己烷1,2-二甲酸二异壬酯增塑剂的气相色谱-质谱分析

建立了气相色谱-质谱联用法定性和定量分析塑料中环己烷1,2-二甲酸二异壬酯(DINCH)的方法。考察了DINCH分子离子的质谱断裂过程,并建立了快速鉴定塑料中DINCH的理论方法。通过对不同溶剂提取效率的对比,采用二氯甲烷作为最佳提取溶剂。在优化条件下,该方法的线性范围为0.24～1.60 mg/L,相关系数为0.998,定量下限(S/N=10)为1.2 mg/kg。在加标水平为80～400 mg/kg时,4种不同塑料(PE、PP、PU、PVC)的回收率和相对标准偏差分别为82%～113%和1.1%～9.0%。将该方法用于实际塑料样品的检测,结果满意。