3,4-二氢-1H-2-苯并吡喃衍生物化合成

3,4-二氢-1 H-2-苯并吡喃也俗称异色满(isochroman)。近年来,将该类化合物引入到药物合成中的研兖引起了人们的兴趣。虽然,已经合成出许多具有镇痛、降血压、抗组胺。和抗肿瘤等药理活性的3,4-二氢-1 H-2-苯并吡喃类化物,合但大都为异色满环上的1,3,4位取代衍生物或者螺环化合物,关于并杂环合成方面的研究至今不多见,作者前     

N-(3,4-二氢-2H-1-苯并吡喃-4)异硫脲类化合物的合成及其血管舒张活性

根据苯并吡喃类钾通道开放剂的作用机理和构效关系, 设计合成了13个苯并吡喃-4-异硫脲衍生物, 其结构经IR, ¹H NMR, MS和元素分析确证. 大鼠体外血管扩张实验研究表明, 多数化合物在1×10^－5 mol•L^－1 浓度下对30 mmol•L^－1 KCl诱导的大鼠主动脉条收缩具有一定程度的抑制作用, 其中化合物6l的血管收缩抑制活性较强.     

Synthesis of 3,4-Dihydro-5H-1-Thia-3,5,6,8-tetraazaacenaphthylenes

Reaction of ethyl 5-amino-4-(substituted amino) -2-methylthiothieno[2, 3-dlpyrimidne-6-carboarytates with formaldehyde in the presence of hydrochloric acid resulted in the synthesis of the corresponding ethyl 3, 4-dihydro-7-methylthio-5H-1-thia-3, 5, 6, 8-tetraazaacenaphthylene-2-carboxylates, which are examples of anew heterocyclic system.     

4-Halogeno-3-oxides and sulfides of the 3,4-dihydro-2h-1,2,3-diazaphosphole system

4-Bromodiazaphosphole-3-oxides or sulfides can be obtained by reaction of the corresponding unsubstituted derivative with appropriate reagents. PTAB was demonstrated to be very regio- and stereoselective, allowing bromination exclusively at the 4-position of the ring with prevalent or exclusive formation of one of the two possible isomers. However, when regioselectivity is not required, cheaper and more available bromine or NBS can be used conveniently. 4-Chlorodiazaphosphole-3-oxides can be obtained by reaction of the corresponding unsubstituted derivative with NCS. 4-Bromodiazaphosphole-3-oxides undergo stereoselective methanolysis as well as parent unsubstituted oxides.     

Synthesis of 2-Acyl-2H-1,2,3-diazaphospholes and Their Diels-Alder Reaction with Cyclopentadiene

2H-1,2,3-Diazaphospholes 3a-3h were prepared from various ketone acylhydrazones and phosphorus trichloride in the presence of triethylamine. Compounds 3 underwent feasible hetero-Diels-Alder reactions with cyclopentadiene to afford the respective anellated [1,2,3]diazaphospholes 4a--4d as well as 4a‘--4d‘ in moderate yields. The endo rule in the reaction was observed under kinetic control conditions.     

Microwave-Assisted Three-Component Reaction for Rapid Synthesis of Some 5,6-Dihydro-4H-1,3-thiazine Derivatives Under Solvent-Free Conditions

Microwave irradiation was found to efficiently promote the three-component reaction of aromatic aldehyde, thiourea, and vinylbenzene at the presence of TMSCl. The products of 5,6-dihydro-4H-1,3-thiazines were formed in a very short time with good to excellent yields as well as excellent diastereoselectivity. This newly developed protocol provided a much more facile route of preparing functionalized thiazine compounds.

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A novel dilithiation approach to 3,4-dihydro-2H-1,3-benzothiazines, 3,4-Dihydro-2H-1,3-benzoxazines,and 2,3,4,5-tetrahydro-1,3-benzothiazepines

3,4-Dihydro-2H-1,3-benzothiazines 4, 3,4-dihydro-2H-1,3-benzoxazines 9, and 2,3,4,5-tetrahydro-1,3-benzothiazepines 6 were synthesized by directed ortho-lithiation of thiophenols and phenols and by side-chain lithiation of substituted thiophenols, respectively, in one-pot by reacting with N,N-bis[(benzotriazol-1-yl)methyl]amines 3 as 1,3-biselectrophile synthons.     

SnCl4-Catalyzed Aza-Acetalization of Aromatic Aldehydes: Synthesis of Aryl Substituted 3,4-Dihydro-2H-1,3-benzoxazines

Stannic tetrachloride was an efficient Lewis acid catalyst for the aza-acetalization of aromatic aldehydes with o-arylaminomethyl phenols, and a series of novel aryl substituted 3,4-dihydro-2H-1,3-benzoxazines were prepared in good yields under mild conditions. SnCl₄ was a more efficient catalyst for the reaction than p-toluenesulfonic acid, sulfuric acid, and aluminium chloride.     

Synthesis of 2-Hydrazinylpyridine-3,4-dicarbonitriles and Their Reaction with Salicylaldehyde Derivatives

2-Chloropyridine-3,4-dicarbonitriles reacted with hydrazine hydrate in ethanol to give 2-hydrazinylpyridine- 3,4-dicarbonitriles. Condensation of the latter with salicylaldehyde and its substituted derivatives afforded the corresponding 2-{2-[2-hydroxyphenylmethylidene]hydrazinyl}pyridine-3,4-dicarbonitriles. The fluorescence spectra of the hydrazones obtained from 3-methoxysalicylaldehyde showed sensitivity toward zinc ions.     

A New and Facile Synthesis of Chroman-3-ols, 3,4-Dihydro-2H-[1]-Benzopyran-3-ols

o-Allyl phenols react with m-chloroperoxybenzoic acid (m-CPBA) in dry chloroform to give chroman-3-ols in a single step in good yields (93–96%).     

Design and Synthesis of Novel 3,4-Dihydro-2H-1,2,4-benzothiadiazine 1,1-Dioxides-based Strobilurins as Potent Fungicide Candidates

To discover novel strobilurins analogues with good and broad spectrum activity, a series of novel 3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxides-based strobilurins was designed, synthesized, and tested against various phytopathogenic fungi. Compounds 7b, 7c, and 7k exhibited substantial and broad spectrum antifungal activities against the tested phytopathogenic fungi, especially compound 7b, which showed 100%, 80%, 90%, and 90% antifungal activity(in virto) against Erysiphe graminis(E. graminis), Puccinia sorghi Schw.(P. sorghi Schw.), Colletotrichum lagenarium(C. lagenarium), and Pseudoperonospora cubensis(P. cubensis) at 300 μg/mL, respectively, better or comparable to the positive control azoxystrobin. Moreover, compound 7b exhibited 85% greenhouse inhibition activity(in vivo) against E. graminis even at 0.2 μg/mL, equal to azoxystrobin(90%) and trifloxystrobin(90%). Meanwhile, compound 7b against P. cubensis displayed 70% and 55% greenhouse inhibition activity(in vivo) at 1.56 and 0.2 μg/mL, respectively, much better than those of azoxystrobin and trifloxystrobin(both 0% at 1.56 and 0.2 μg/mL). Therefore, compound 7b could be considered as the most promising fungicidal candidate for further study. Furthermore, based on the effective concentration(EC₅₀) against C. arachidicola, the built CoMSIA model provided the useful reference for the further structural optimization design.     

KF－Al2O3催化下3，4－二氢－2H－吡喃[3,2-h]喹啉衍生物的合成

芳醛、8－羟基喹啉与丙二腈或氰乙酸乙酯KF－Al2O3催化下反应生成一系列新 的3，4－二氢－2H－吡喃[3,2-h]喹淋衍生物，产物的结构通过单晶X射线确证。     

Synthesis of 3,4-Dihydro-2H-1,3-benzoxazines by Condensation of 2-Hydroxyaldehydes and Primary Amines: Application to the Synthesis of Hydroxy-Substituted and Deuterium-Labeled Compounds

We report the synthesis of several substituted 3,4-dihydro-2H-1,3-benzoxazines by simple ring closure of 2-hydroxybenzylamines with paraformaldehyde. The facile synthesis of the benzylamine precursors from commercially available salicylaldehyde derivatives affords a powerful general synthetic way to prepare a variety of substituted benzoxazines, avoiding the formation of undesirable oligomeric species, thus leading to a simple workup and improving the yield and purity of the final product. This straightforward method allows synthesis of hydroxy-substituted and deuterium-labeled 1,3-benzoxazines that are not attainable using other synthetic ways.