甲基酮的二氟同系化-卤化反应:一锅法合成β-卤代-α,α-二氟代酮

以（溴二氟甲基）三甲基硅烷（TMSCF₂Br）为二氟卡宾源,利用其兼具TMS转移特性及自活化特性,仅在催化量的n-Bu₄NBr的催化启动下,直接完成甲基酮的烯醇化-二氟环丙烷化反应以及与卤正离子的开环卤化反应,并使用卤负离子作为卤源,采用其原位氧化形成卤正离子的方法实现了偕二氟环丙烷硅醚的开环-卤化,合成了β-卤代-α,α-二氟代酮类物质.     

阳离子光固化活性单体氧杂环丁烷的合成及表征

以3-乙基-3-羟甲基氧杂环丁烷为原料，与甲基磺酰氯磺酰化，得到3-乙基-3-甲磺酰基甲基氧杂环丁烷；在碱性条件下，以PEG600作相转移催化剂，用3-乙基-3-甲磺酰基甲基氧杂环丁烷与乙二醇醚化得到2-[（3-乙基-3-氧杂环丁基）甲氧基]乙醇；然后与甲基丙烯酸甲酯进行酯交换得到目的产物2-[（3-乙基-3-氧杂环丁烷）甲氧基]甲基丙烯酸乙酯。3-乙基-3-羟甲基氧杂环丁烷与3-溴丙烯反应，生成3-乙基-3-[（2-丙烯-1-基氧基）甲基]氧杂环丁烷，然后在氯铂酸的催化下，与三乙氧基硅烷反应得到3-乙基-3-[[3-（三乙氧基硅）丙氧基]甲基]氧杂环丁烷。产物经红外光谱和核磁共振谱表征得到确证。     

基于2-卤甲基-3-喹啉甲酸乙酯的反应研究进展

喹啉及其衍生物是一类重要的杂环化合物,许多具有生物活性的稠杂环化合物中都含有喹啉骨架。由2-卤甲基-3-喹啉甲酸乙酯合成多环或稠杂环化合物的研究进展还未见文献报道。为更好地了解这方面的研究动态,本文综述了近几年有2-卤甲基-3-喹啉甲酸乙酯参与反应的研究进展,主要涉及了2-氯(溴)甲基-3-喹啉甲酸乙酯与酚、胺、水杨醛和芳香醛等的一系列反应。     

新型2-苯并呋喃取代奠类衍生物的合成

以溴乙酰溴为酰化剂，对2-甲基奠进行酰基化反应，其酰化产物通过与水杨醛缩合，溴代反应及硫代乙酰胺的环化反应，以较好的收率，高选择性合成了新型的1-（2-苯并[b]呋喃酰基）奠和3-（2-苯并呋喃基）奠类[1，2-c]噻吩类衍生物，其结构经1HNMR，IR及元素分析表征。     

过渡金属配合物催化氯代芳烃亲核取代反应的新进展

苯、萘以及各种芳香杂环的多官能化衍生物是聚合物、药物、香料、染料、炸药、杀虫剂等的重要中间体 ,从相应的卤代芳烃出发合成这些化合物是经济和合理的 .但由于卤代芳烃对亲核取代的不活泼性 ,使这一设想受到很大的限制 .近年来 ,金属有机化学的发展 ,给卤代芳烃的化学带来了勃勃生机 .以过渡金属催化碘代或溴代芳烃与各种亲核试剂反应 ,作为形成碳 -碳键、碳 -杂原子键的有效手段 ,已进行了广泛而深入的研究 .而对相应的氯代芳烃的研究起步较晚 ,这主要是受 C- Cl键强度的影响 (如氯苯的键能为 40 2 k J/mol;而溴苯、碘苯分别为 339.4…     

“一锅法”合成2-氨基-N,3-二甲基-5-卤代苯甲酰胺

报道了从3-甲基-2-氨基苯甲酸出发一锅三步合成2-氨基-N,3-二甲基-5-卤代苯甲酰胺的方法.3-甲基-2-氨基苯甲酸(1)与固体光气反应生成中间体8-甲基-2H-3,1-苯并噁嗪-2,4(1H)-二酮(2),化合物2与甲胺水溶液发生胺解反应生成2-氨基-N,3-二甲基苯甲酰胺(3),3再与氯代丁二酰亚胺(NCS)、溴代丁二酰亚胺(NBS)或碘代丁二酰亚胺(NIS)发生芳香亲电取代反应生成目标产物2-氨基-N,3-二甲基-5-卤代苯甲酰胺(4～6).整个反应过程不需分离中间产品,最终产物经减压浓缩除去有机溶剂后,直接从水中析出针状晶体,总收率达到87%～94%,较文献报道的分步法收率提高30%以上.该方法工艺操作简单、反应条件温和、反应时间短、收率高,是一条环境友好的绿色合成路线.     

4-甲基-5-卤代-2-噻吩甲醛和2,4-二甲基-5-卤代噻吩的合成

以3-甲基噻吩为原料,经过卤代反应、Vilsmeier甲酰化反应和Wollf L-Kishner-Huang minion反应合成了4-甲基-5-卤代-2-噻吩甲醛和2,4-二甲基-5-卤代噻吩,其结构经NMR,IR,MS和元素分析确证.     

离子液体中卤代炔烃高效水解制取α-卤代甲基酮的研究

在离子液体中,硫酸促进卤代炔烃水解生成α-卤代甲基酮,反应收率高达85%~94%.离子液体-硫酸反应体系可多次(5次以上)循环使用而不影响反应收率.同时,此反应体系底物适用性强,高效制得一系列芳环上不同取代基的(如甲基、甲氧基、羟基、硝基等)α-氯/溴/碘代苯乙酮及脂肪类卤代甲基酮.     

吡啶高三蝶烯的合成

2-溴-4-甲基吡啶（1）经氯代和碘代反应合成了2-溴-4-碘甲基吡啶（3）,3和蒽酮（4）反应生成10,10-二（2-溴-4-吡啶甲基）-9（10H）蒽酮（5）,5在3 MPa下与NaOCH3反应得到10,10-二（2-甲氧基-4-吡啶甲基）-9（10H）蒽酮（6）,6经硼氢化钠还原得到蒽醇（7）,7在对甲苯磺酸催化...     

2-氟-6-三氟甲基苄胺的合成新方法

以2-甲基-3-三氟甲基苯胺（1）为原料,经Balz-Schiemann反应制得3-氟-2-甲基三氟甲苯（3）;3经溴代制得2-氟-6-三氟甲基苄溴(4）,最后经Gabriel反应合成2-氟-6-三氟甲基苄胺,总收率53.4%,其结构经¹H NMR和MS(ESI)确证。     

Stereoselective synthesis of 3-heteroaromatic-substituted alanines

An asymmetric synthesis of (R)-3-heterocyclic-substituted alanines starting from (2S)-(+)-2,5-dihydro-3,6-dimethoxy-2-isopropylpyrazine (Schöllkopf reagent) and heteroaromatic halogenomethyl derivatives via hydrolysis of intermediate adducts is reported. The diastereocontrolled addition gives mainly compounds with the (2S,5R) configuration whose formation is explained on the basis of the accepted model for the alkylation reaction of the Schöllkopf reagent, and structure confirmed by spectroscopic data.     

Heterogeneous asymmetric hydrogenation of heteroaromatic methyl ketones catalyzed by cinchona-modified iridium catalysts

A heterogeneous iridium catalyst was synthesized with silica particles as support for the hydrogenation of heteroaromatic methyl ketones. The catalyst and support were characterized by solid-state NMR, HTEM, SEM, XPS, and BET. A series of heteroaromatic methyl ketones were investigated at room temperature. The catalytic system was effective and more than 99% conversion and up to 83.6% enantioselectivity were obtained in the hydrogenation of heteroaromatic methyl ketones.     

α,β-Unsaturated ketones based on allobetulone

Crotonization of allobetulone with aromatic and heteroaromatic aldehydes gave a number of new α,β-unsaturated ketones of the lupane series, and their steric structure was determined by X-ray analysis of (E)-4-[(3-oxoallobetulan-2-ylidene)methyl]benzonitrile as an example.     

Benzotriazolyl-mediated 1,2-shifts of electron-rich heterocycles

The anion formed from the lithiation of 1-[(methylthio)methyl]-1H-benzotriazole 1 with n-BuLi adds to heteroaryl ketones to give 2-benzotriazolyl alcohols 3a-m. Thermolysis of 3a-g in the presence of zinc bromide induces a 1,2-shift of heteroaromatic groups to form ketones 4a-g. By contrast, in the rearrangement of 2-benzotriazolyl alcohols 3h,i,k-m migration of the phenyl group rather than the corresponding heteroaromatic groups occurred to give ketones 4h,i,k-m.     

Synthesis of methyl 7-aryl(hetaryl,cyclohexenyl)-10,10-dimethyl-8-oxo-7,8,9,10,11,12-hexahydrobenzo[<Emphasis Type="Italic">b</Emphasis>][1,7]phenanthroline-9-carboxylates

Three-component condensation of quinolin-5-amine with methyl 2,2-dimethyl-4,6-dioxocyclohexane-1-carboxylate and aromatic (heteroaromatic) aldehydes or cyclohex-3-ene-1-carbaldehyde gave previously unknown 1,7-phenanthroline derivatives. The reactions in butan-1ol were characterized by 100% regioselectivity but low stereoselectivity, and mixtures of cis- and trans-isomeric methyl 7-aryl(hetaryl, cyclohexenyl)-10,10-dimethyl-8-oxo-7,8,9,10,11,12-hexahydrobenzo[b][1,7]phenanthroline-9-carboxylates were obtained at a ratio of ∼45: 55.     

Lewis base activation of Lewis acids. Catalytic enantioselective addition of silyl enol ethers of achiral methyl ketones to aldehydes

A highly enantioselective addition of silyl enol ethers derived from simple methyl ketones is described. The catalyst system of silicon tetrachloride activated by a chiral bisphosphoramide (R,R)-7 effectively promotes the addition of a variety of unsubstituted silyl enol ethers to aromatic, olefinic, and heteroaromatic aldehydes in excellent yield. [reaction: see text]     

Parallel synthesis of novel heteroaromatic acromelic acid analogues from kainic acid

A range of new C-4 heteroaromatic acromelic acid analogues has been synthesized in a parallel fashion from (-)-alpha-kainic acid 1. Protection of the amine and carboxylate groups of 1 followed by ozonolysis gave methyl ketone 8. A silyl enol ether 9, generated regiospecifically from the methyl ketone 8 using "kinetic" conditions, was brominated in situ with phenyltrimethylammonium perbromide to give the key alpha-bromo ketone 10. Parallel cyclization reactions of bromo ketone 10 with thioamides and thioureas were then performed. The aromatic heterocyclic derivatives 11a-d and 19 produced were deprotected to give the new kainoid amino acids 6a-d and 25 in excellent yield. Compounds 6a and 6c show strong binding to the kainate receptor. Reaction of 10 with alternative condensing agents was also briefly investigated.     

NMR studies of bond orders in heteroaromatic systems

Fifty-seven values for the ortho-benzylic coupling constant ⁴J_{Me? C?C? H} (henceforth denoted as ⁴J_OB) were obtained for a variety of heteroaromatic systems. It was shown that a good correlation exists between ⁴J_OB when the methyl group is not α to the heteroatom and the SCF-MO bond order. This method can therefore be used as an experimental means of determining bond orders in heteroaromatic systems. An examination of bond alternation in thirteen heteroaromatic systems has given a measure of relative “degree of aromaticity” for a larger number of systems than previously reported by any single method.     

A Convenient Synthesis of Methyl 4-Substituted Benzoates via Diels-Alder Reaction in the Presence of Palladium on Activated Carbon

The thermal reaction of methyl 2-oxo-2H-pyran-5-carboxylates with substituted styrenes in the presence of 10% palladium on activated carbon afforded directly the corresponding methyl 4-biphenylcarboxylates in good yields. By the similar procedure, methyl 4-heteroaryl- and 4-alkyl-substituted benzoates were obtained from heteroaromatic olefins and alkenes, respectively.     

Design and the synthesis of 1-heteroaryl-1,2,3-triazoles connected to coumarins via ether linker

In this paper, we report an efficient and versatile methodology for the synthesis of a series of novel heteroaryl-1,2,3-triazoles connected to 4-methylcoumarin (4-methyl-2H-chromen-2-one) via oxymethylene linker. The desired molecules were accessed by both two-step synthesis and the one-pot copper catalyzed cycloaddition reaction of heteroaromatic azides with coumarin containing acetylenes. The developed protocol was found to be facile and effective for preparing a series of novel heteroaryl-1,2,3-triazole-coumarin conjugates in excellent yields. Practical utility of one-pot protocol has been confirmed by the successful gram-scale synthesis of 1,3-Dimethyl-6-(4-[([4-methyl-2-oxo-2H-chromen-7-yl]oxy)methyl]-1H-1,2,3-triazol-1-yl)pyrimidine-2,4(1H,3H)-dione.