噁唑类化合物合成研究新进展

含N和O原子的噁唑环是十分重要的五元杂环,其特殊的结构使噁唑类化合物表现出许多独特的性能和生物活性,在医药、农药、材料等多方面具有广阔的潜在应用.因此,噁唑类化合物的合成备受关注,相关研究众多,发展迅速.根据我们唑类的研究工作,并参考国内外近5年文献,系统地综述了噁唑类化合物,包括噁唑、噁唑啉、噁唑烷酮、稠环噁唑类等的合成研究近况.     

手性5-异丙基-2-噁唑烷酮的酶催化立体选择性互补合成

以2-异丙基环氧乙烷为底物,氰酸钠为亲核试剂,筛选获得两种卤醇脱卤酶HheA10和HheG,可以分别催化合成(S)-5-异丙基-2-噁唑烷酮和(R)-5-异丙基-2-噁唑烷酮。通过对其反应条件进一步考察,建立了立体选择性互补合成手性5-异丙基-2-噁唑烷酮的生物催化技术路线。      

N-二氯乙酰基噁唑烷合成反应的薄层色谱法研究

 用薄层色谱法监测了用二氯乙酰氯、醇胺和酮合成的除草剂的安全剂N 二氯乙酰基 口恶唑烷的反应过程。方法操作简便、快速、准确。     

N-二氯乙酰基噁唑烷合成反应的薄层色谱法研究

用薄层色谱法监测了用二氯乙酰氯、醇胺和酮合成的除草剂的安全剂N 二氯乙酰基 口恶唑烷的反应过程。方法操作简便、快速、准确。     

5-芳氧甲基-2-噁唑烷酮的合成及表征

环氧氯丙烷;氯甲基噁唑烷酮;合成;芳氧甲基噁唑烷酮     

新型取代苯基噁唑类化合物的设计、合成及生物活性

通过活性亚结构拼接方法,将具有生物活性的噁唑基团与咪唑烷或噻唑烷拼接,设计合成了一系列新型取代苯基噁唑类化合物.以取代的苯甲酸为原料,经过3步反应制得目标化合物,其结构经核磁共振及元素分析确证.初步生物测定结果表明,部分化合物对小麦赤霉病、水稻纹枯病、黄瓜灰霉病和番茄早疫病表现出明显的抑制活性,尤其是化合物5q表现出较广的杀菌谱,且活性与多氧霉素相当.初步构效关系分析发现,苯环上取代基的类别和位置对活性有影响,其中卤素取代基对活性有利,邻位取代优于对位和间位取代.     

噁唑烷酮环氧树脂的研究进展

含噁唑烷酮结构的树脂具有优良的耐热性、电性能及物理机械性能等。将噁唑烷酮环引入环氧树脂,可提高固化物的玻璃化转变温度、粘结性、介电性和阻燃性等。本文综述了噁唑烷酮环氧树脂的一般合成方法,探讨了原料配比、反应温度、催化剂种类及用量对噁唑烷酮环氧树脂合成过程的影响,分析了固化剂与噁唑烷酮环氧树脂固化产物性能之间的联系,对噁唑烷酮环氧树脂在绝缘材料、涂料、粘合剂、印刷电路板以及高性能树脂基体等领域的应用情况进行了详细介绍,并对其发展前景予以展望。     

多官能度噁唑烷的合成及其改性聚氨酯材料

合成了2,2-二甲基-N-羟乙基-1,3-噁唑烷(OX),并以其为结构单元合成了2种多官能度的噁唑烷化合物——丙二酸二-2,2-二甲基-N-羟乙基-1,3-噁唑烷酯(OX1)和1,1,5,5-戊烷端四甲酸四-2,2-二甲基-N-羟乙基-1,3-噁唑烷酯(OX2).采用13C核磁共振谱、质谱、元素分析和傅里叶变换红外光谱对产物结构进行表征,并探索了产物用于单组份湿固化聚氨酯(SPU)体系的潜固化剂性能.研究了固化体系的表观性能、力学性能和热性能.结果表明:纯湿固化SPU发泡且膨胀,拉伸强度为3.2 MPa,断裂伸长率为364%;而SPU-OX2固化体系的拉伸强度达27.2 MPa,是纯SPU固化体系拉伸强度(3.2 MPa)的9倍;SPU-OX2固化体系断裂伸长率达457%,是纯SPU固化体系断裂伸长率(364%)的1.26倍.聚氨酯中加入噁唑烷OX1和OX2为潜固化剂,不仅较好改善了聚氨酯的表观性能,而且增加了聚氨酯预聚体的力学性能和热稳定性.     

手性2-噁唑烷酮的无溶剂合成法

手性2-噁唑烷酮的无溶剂合成法;手性氨基醇;脲;手性噁唑烷酮     

含氟1,3,4-噁唑啉和1,3,4-噁二唑类化合物的合成及其抗癌活性

对氟苯甲酰腙与乙酸酐或丙酸酐反应后再脱水环化制得2-苯基-3-乙酰基-5-对氟苯基-1,3,4-噁唑啉(3)或2-苯基-3-丙酰基-5-对氟苯基-1,3,4-噁唑啉(4).N-对氟苯甲酰基-N′-苯甲酰肼在POCl3存在下脱水环化制得2-苯基-5-对氟苯基-1,3,4-噁二唑(6).新化合物3,4和6的结构经1H NMR,IR,MS和元素分析表征.用MTT方法评价了其对HepG-2,A549-1和231-2癌细胞株的体外生长抑制活性.结果表明,3,4和6均具有潜在的体外抑制癌细胞生长活性,其中3的活性最强.     

Convergent stereoselective and efficient synthesis of furanic-steroid derivatives

The stereoselective synthesis of furanic-steroid derivatives involving ring-closing metathesis and catalytic hydrogenation as key steps is described. The synthetic strategy was first illustrated by the synthesis of the furanic-estrane derivative 1 in seven steps starting from estrone and 2-methylene-propane-1,3-diol. This compound initially targeted as a potential inhibitor of 17β-hydroxysteroid dehydrogenase type 1 by a docking experiment was found to inhibit the enzyme. The scope of this new strategy was also extended to furanic-androstane derivatives by synthesizing compound 20.     

新型四硫代富瓦烯衍生物的合成及其性质的研究

合成了3个新的含有卤素取代基的四硫代富瓦烯衍生物及6个新的相关化合物。利用溶液的电子吸收光谱对四硫代富瓦烯衍生物的性质进行了研究。研究结果表明, 四硫代富瓦烯衍生物的分子中π轨道之间的能级差较小, 因而分子具有较高的稳定性。     

Tricarbonylchromium(0) promoted stereoselective transformations of ephedrine and pseudoephedrine derivatives

(−)-(1S,2S)-(N,O-Dimethylephedrine)tricarbonyl chromium(0) (6) and (−)-(1S,2R)-(N,O-dimethylpseudoephedrine)tricarbonylchiromium(0) (22) undergo completely stereoselective ortho deprotonation upon treatment with alkyllithium base, followed by addition of an electrophile. In both cases, exclusive removal of the pro-(R)-ortho proton was confirmed by single crystal X-ray structure analyses of the methylated products. Addition of methyllithium onto the ortho-formylated derivative of complex (6) occurs stereoselectively, the stereochemistry of the major product being confirmed by a single crystal X-ray structure determination. The results presented demonstrate an efficient transfer of chirality from a side chain onto the (arene)tricarbonylchromium(0) complex and back to a different side chain.     

A new strategy for the stereoselective synthesis of 2,3-dideoxy-3-fluoro-D-ribofuranose derivatives

The important intermediate for syntheses of various anti-HIV nucleoside analogues, methyl 2,3-dideoxy-3-fluoro-6-O-(p-methylbenzoyl)-a-D-ribofuranoside, was synthesized starting from 2-deoxy-D-ribose in 5 steps with an overall yield of 24%. This strategy can be also used for synthesizing other analogues with various substitutions at 3-C position.     

Studies on stereoselective approaches to β-carboline derivatives

Transformation of β-carboline derivatives into optically active entities were studied and the de and ee values of the resulted compounds were detected. Dedicated to Professor Károly Lempert on his 80th birthday.     

Chiral recognition model for the resolution of ephedrine and related alpha,beta-aminoalcohols as enantiomeric oxazolidine derivatives

The mechanism of chiral recognition has been investigated for a series of enantiomeric cis-oxazolidines on a commercially available high-performance liquid chromatographic chiral stationary phase (HPLC-CSP). The oxazolidine molecules were synthesized through the condensation of ephedrine and ephedrine-related molecules with aromatic aldehydes. The resulting molecules are rigid five-membered rings whose configuration has been determined by proton magnetic resonance and single-crystal X-ray diffraction. The oxazolidines derived from the condensation of ephedrine and aldehydes containing a pi-basic moiety such as naphthaldehyde were resolved on the HPLC-CSP as were those oxazolidines synthesized by using a pi-acidic aldehyde such as p-nitrobenzaldehyde. However, there was a reversal in the elution order for the two types of oxazolidines. Oxazolidines resulting from the condensation of ephedrine and a pi-neutral aldehyde such as benzaldehyde were not resolved. The results of this study suggest a chiral recognition model based on the formation of diastereomeric solute-CSP complexes through a single attractive interaction and chiral discrimination resulting from the difference in steric fit.     

Studies on the stereoselective synthesis of C-allyl glycosides

An investigation was carried out to explore the use of sulfoxide donors as common precursors to stereoisomeric C-glycoconjugates of glycoprotein and glycolipid tumor antigens. A study focusing on the effects of reaction conditions and substrate structure on the stereoselectivity of allylation was carried out. Although conditions were realized to selectively afford alpha-allylation products in good to excellent yields, the search for conditions favoring beta-selectivity proved less successful.     

Efficient and versatile stereoselective synthesis of cryptophycins

The cryptophycins are a family of cyclic depsipeptides with four retrosynthetic units A to D which correspond to the respective amino acids and hydroxy acids. A new synthetic route to unit A allows the selective generation of all four stereogenic centres by introducing two of them in a catalytic asymmetric dihydroxylation, followed by substrate-controlled diastereoselective reactions. The diol also serves as the epoxide precursor. This approach provides selective access to stereoisomers of unit A (enantiomers, epimers) for structure-activity relationship studies. The unit A derivatives were incorporated into cryptophycin-1, cryptophycin-52 and a novel epimer of cryptophycin-52.     

A stereoselective and short total synthesis of the polyhydroxylated gamma-amino acid (-)-detoxinine,based on stereoselective preparation of dihydropyrrole derivatives from lithiated alkoxyallenes

Based on our earlier results employing lithiated methoxyallene 2 as C(3) building block and imines 3 for the synthesis of dihydropyrrole derivatives 5, we have investigated chiral imines 6, 10, and 15 as electrophilic components. Combined with lithiated alkoxyallenes, these imines provide the corresponding primary adducts and finally the dihydropyrrole derivatives 8, 12, 17, 20, and 22 in good yields and with high to excellent syn selectivities. This stereochemical outcome is interpreted as a result of alpha-chelate control. Treatment with hydrochloric acid converted syn-8 and syn-12 into bicyclic compounds 9 and 13, whereas under more mildly acidic conditions adduct syn-17 was transformed into diol syn-18. The total synthesis of the uncommon gamma-amino acid (-)-detoxinine could be achieved by starting from (S)-malic acid, which was converted into imine 15 in four steps. Lithiated benzyloxyallene added to imine 15 and efficiently furnished the crucial dihydropyrrole derivative syn-22. The hydrogenolysis of this compound did not directly provide the protected triol 29 as anticipated, but a stepwise protocol made the triol available in a fairly satisfactory manner. A second crucial step of the synthesis was the selective oxidation of 29, which could be achieved by employing platinum dioxide and oxygen. The resulting bicyclic lactone 30 was smoothly transformed into enantiopure (-)-detoxinine. Thus, a fairly short synthesis of this natural product based on a lithiated alkoxyallene could be performed, demonstrating the potential of these intermediates for syntheses of interesting functionalized heterocyclic compounds.