An Unusual Reaction of Dimethyl Azodicarboxylate with H-Dimethylphosphonate

When the commonly used phosphorus components of the cocktail of the classical Mitsunobo reaction are changed from triphenylphosphine and trialkylphosphite to H-dimethylphosphonate, the course of the reaction changes and leads to products arising from the involvement of the free radical reaction. This article presents the mass spectral characterization of the novel compounds along with the probable mechanism of their formation.     

Reaction of Crossed Diperoxidation Between Cyclic Ketones and Alkyl Ketones

IntroductionThe thermal and photochemical decompositionof the diperoxides of cyclic ketones has been foundto provide a general method for the facile synthesisof macrocyclic compounds[1,2 ] .In addition,the useof diperoxides as initiators in polymerization hasbeen studied[3] .Forthose reasons,a better methodfor the synthesis of the requisite diperoxides isrequired.There are two different methods for thepreparation of the diperoxides. Griesbaum[4 ]obtained cyclopentanone diperoxide(yield 1 3 % …     

Unusual Reaction of Trifluorophenylsilane with Dimethyl Sulfoxide

Russian Journal of General Chemistry -     

Chlorination of Sulfonium Derivatives of closo-Decaborate Anion with Carboxyl-Containing Substituents

Doklady Chemistry - The reaction of sulfonium closo-decaborate derivatives containing carboxyl groups with sulfuryl chloride SO2Cl2 as a halogenating agent was studied. The reaction gave fully...     

Some Unusual Products from the Thermal Reaction of Azulenes with Dimethyl Acetylenedicarboxylate

The thermal reaction of azulene-1-carbaldehydes 5 and 6 with excess dimethyl acetylenedicarboxylate (ADM) in decalin leads mainly to the formation of (1 + 1) and (1 + 2) adducts arising from the addition of ADM at the seven-membered ring of the azulenes (cf. Schemes 2 and 4). The (1 + 2) adducts are formed in a homo-Diels-Alder reaction of ADM and isomeric tricyclic carbaldehydes which are derived from the primary tricyclic carbaldehydes by reversible [1s5s]-C shifts (cf. Schemes 3 and 5). The thus formed pentacyclic carbaldehydes seem to undergo deep-seated skeletal rearrangements (cf. Scheme 7) which result finally in the formation of the formyl-tetrahydrocyclopenta[bc]acenaphthylene-tetraesters 12 and 19 , respectively. In other cases, e.g., azulene-1-carbaldehydes 7 and 8 (cf. Scheme 8), the thermal reaction with excess ADM furnishes only the already known tetracycfic (1 + 2) adducts of type anti- 26 to ‘anti’- 29 . The thermal reaction of 1,3,4,8-tetramethylazulene ( 9 ) with excess ADM in decalin resulted in the formation of two (1 + 2) and one (1 + 3) adduct in low yields (cf. Scheme 9). The latter turned out to be the 2,6-bridged barrelene derivative 32 . There are structural evidences that 32 is formed by similar pathways as the formyl-tetrahydrocyclopenta[bc]acenaphthylene-tetraesters (cf. Schemes 7 and 11). [²H₃]Me-Labelling experiments are in agreement with the proposed mechanisms (cf. Scheme 13).     

Formation of Unusual Products from the Acid-Catalyzed Reaction of Azulenes with Dimethyl Acetylenedicarboxylate

The reaction of guaiazulene ( 4 ) and dimethyl acetylenedicarboxylate (ADM) in tetralin or toluene, catalyzed by 5 mol-% of trifluoroacetic acid (TFA) at ambient temperature, leads to the formation of the corresponding heptalene-4,5-dicarboxylate 6 and a guaiazulenyl-substituted 2,2a,4a,8b-tetrahydrocyclopent[cd]azulene derivative 7 beside the expected guaiazulenyl-substituted ethenedicarboxylates (E)- 5 and (Z)- 5 as main products (Scheme 2). The structure of 7 was unequivocally established by an X-ray crystal-structure analysis (Fig. 1). Precursor of 7 must be the 2a,4a-dihydrocyclopent[cd]azulene-3,4-dicarboxylate 9 which reacts, under TFA catalysis, with a second molecule of 4 (Scheme 3). No formation of products of type 7 has been observed in the TFA-catalyzed reaction of 4,6,8-trimethyl- and 1,4,6,8-tetramethylazulene ( 13 and 16 , respectively) and ADM (Scheme 4). On the other hand, the TFA-catalyzed reaction of azulene ( 18 ) itself and ADM at ambient temperature gives rise to a whole variety of new products (Scheme 5), the major part of which is derived from dimethyl 2a,4a-dihydrocyclopent[cd]azulene-3,4-dicarboxylate ( 25 ) as the main intermediate (Scheme 6). Nevertheless, for the formation of the 2a,4a,6,8b-tetrahydrocyclobut[a]azulene derivatives (E)- 24a and (E)- 24b , a corresponding 2a,8b-dihydro precursor 29 has to be postulated as crucial intermediate (Scheme 8).     

Features of Reaction of Dialkyl Perfluoroadipic and Perfluoropimelic Acids with Alkyl(Aryl) Methyl Ketones

Reaction of dialkyl esters of perfluoroadipic and perfluoropimelic acids with ketones form diketo esters. The possibility of cyclization of the products is discussed.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 2, 2005, pp. 318–321.Original Russian Text Copyright © 2005 by Chapurkin, Litinskii, Baklanov, Leont’eva.     

Reaction of Mercaptothiazoles with O,O-Dimethyl-chlorothiophosphate: An Unusual Reaction

The condensation of different 2-mercaptothiazoles with O, O-dimethylchlorothiophosphate, gave the corresponding S-methyl derivatives instead of the expected dithiophosphates.     

三氟甲基烷基酮的生物活性及合成方法

三氟甲基烷基酮类化合物（TFMKs）具有独特的生理活性,三氟甲基能够增强化合物的亲脂性、代谢稳定性以及生物利用度。由于三氟乙酰基强烈的吸电子特性,TFMKs能够与目标水解酶形成稳定的半缩酮加合物,对生命体内多种活性酶起到抑制作用。最新的两个重要发现是TFMKs可以抑制SARS病毒和应用于眼科疾病,含氟原子数目、部位、有机碳链长度、不饱和度、其他官能团种类都是影响TFMKs作用的因素。TFMKs类化合物的合成方法,包括烃基金属试剂与三氟乙酸衍生物反应、使用三氟甲基化试剂TMS-CF₃与羰基衍生物反应、三氟甲基仲醇氧化、羧酸与三氟乙酸酐/吡啶反应等方法。本文按照其作用的途径进行分类,归纳了三氟甲基烷基酮类化合物的药理活性,对现有的三氟甲基烷基酮类化合物合成方法进行了总结。     

Synthesis of Stable Sulfonium Ylides from Sulfoxides and Dimethyl Acetylenedicarboxylate

Stable sulfonium ylides are readily prepared from thermolysis of dimethyl-, dibenzyl-, dibutyl-, and diphenyl- sulfoxides with dimethyl acetylenedicarboxylate in reasonable yields.     

傅克反应的异常产物

苯和草酰氯单乙酯在三氯化铝作用下发生傅克反应,在低温(0 ℃)条件下生成苯乙酮酸乙酯,而在高温(70 ℃)条件下首次得到了9,10-二甲基蒽,其结构经1H NMR,13C NMR和单晶X-衍射仪表征.     

Asymmetric Aziridination by Reaction of Chiral Sulfinimine Derived From (+)-Camphor with Dimethyloxosulfonium Methylide

Addition of dimethyloxosulfonium methylide to chiral nonracemic pure (+)-camphor-derived sulfinimine I affords N-sulfinyl aziridine. which are easily separated The N-(+)-camphor-based-sulfinyl auxiliary was removed without ring opening by treatment with MeLi.     

Copper-Catalyzed Coupling Reaction of Secondary Alkyl 2-Pyridinesulfonates with Alkyl Lithium-Based Reagents

The Cu(OTf)₂-catalyzed alkyl–alkyl coupling reaction of a secondary substrate MeCH(OSO₂Py)CH₂CH₂C₆H₄(4-OMe) with a nBuLi-based reagent prepared by transmetalation with MgBr₂ ⋅ THF₃ in THF produced a coupling product in 74 % yield. The use of soluble MgBr₂ ⋅ THF₃ in THF was required for this reaction. This method was applied to sBuLi and Ph(CH₂)₄Li. In contrast, transmetalation of MeLi with soluble MgCl₂ ⋅ THF₂ in THF produced the Me reagent, which was reactive for the coupling reaction. The reaction proceeded with inversion of the stereogenic carbon. Furthermore, (S)-14-methyloctadecan-2-one, a sex pheromone produced by lichen moths, was synthesized.     

Reaction of Dimethyl Sulfoxide with 4-Acyloxycoumarins

Dimethyl sulfoxide converts 4-acetoxycoumarin (1) exclusively to 2-(2-hydroxybenzoyl)-2-[(methylthio)methyl]-2,3-dihydro-4 H-furo[3,2-c]chromen-4-one (3) at 180°C under a nitrogen atmosphere, but in the absence of nitrogen, the products obtained are dicoumarol and its dehydrative cyclization products 7 H-bis[1]benzopyrano[4,3-b: 3′,4′-c]pyran-6,8-dione (9) and (3). Under similar conditions, 4-benzoyloxycoumarin (1a) affords benzoic acid, 4-hydroxy-3-({2-[(methylthio)methyl]-3-oxo-2,3-dihydro-1-benzofuran-2-yl}methyl)-2H-chromen-2-one (7), and 3-(2-hydroxybenzoyl)-3,4-dihydro-2H,5H-pyrano[2,3-b] chromen-5-one (8).     

Sulfonium Salt Reagents for the Introduction of Deuterated Alkyl Groups in Drug Discovery

The pharmacokinetics of pharmaceutical drugs can be improved by replacing C−H bonds with the more stable C−D bonds at the α-position to heteroatoms, which is a typical metabolic site for cytochrome P450 enzymes. However, the application of deuterated synthons is limited. Herein, we established a novel concept for preparing deuterated reagents for the successful synthesis of complex drug skeletons with deuterium atoms at the α-position to heteroatoms. (d_n-Alkyl)diphenylsulfonium salts prepared from the corresponding nondeuterated forms using inexpensive and abundant D₂O as the deuterium source with a base, were used as electrophilic alkylating reagents. Additionally, these deuterated sulfonium salts were efficiently transformed into d_n-alkyl halides and a d_n-alkyl azide as coupling reagents and a d_n-alkyl amine as a nucleophile. Furthermore, liver microsomal metabolism studies revealed deuterium kinetic isotope effects (KIE) in 7-(d₂-ethoxy)flavone. The present concept for the synthesis of deuterated reagents and the first demonstration of a KIE in a d₂-ethoxy group will contribute to drug discovery research based on deuterium chemistry.     

含不同取代基的Cardo聚芳醚酮的气体透过性能

研究了带有不同烷基取代基的Ｃａｒｄｏ聚芳醚酮均质膜对Ｈ２，Ｏ２，ＣＯ２和ＣＨ２气体的透气性能，讨论气体透过对温度的依赖性。