Sulfur dioxide mediated one-pot, three- and four-component syntheses of polyfunctional sulfonamides and sulfonic esters: study of the stereoselectivity of the ene reaction of sulfur dioxide

The ene reaction of sulfur dioxide with enoxysilanes or with allylsilanes generates silyl sulfinates that can be brominated (Br(2) or NBS) or chlorinated (NCS or Cl(2)) to produce the corresponding sulfonyl halides. They react with primary and secondary amines or alcohols to give the corresponding sulfonamides and sulfonic esters, respectively. The hetero-Diels-Alder addition of sulfur dioxide to 1-oxy- or 1,3-dioxy-1,3-dienes generates zwitterions that add to enoxysilanes or allylsilanes giving silyl sulfinates that can be converted in situ into polyfunctional sulfonamides or sulfonic esters. This realizes quick access to libraries of complicated sulfonamides and sulfonic esters applying one-pot, three- and four-component methods.     

Effect of surfactants on the stability of thin liquid film flow on a rotating disk

The effect of surfactants on surface instabilities of thin liquid film flow on a rotating disk was studied at different flow rates Q (0.5相似文献   

Hydrolytic reactions of 3'-N-phosphoramidate and 3'-N-thiophosphoramidate analogs of thymidylyl-3',5'-thymidine

The diastereomeric thiophosphoramidate analogs [(R(P))- and (S(P))-3[prime or minute],5[prime or minute]-Tnp(s)T] and the phosphoramidate analog [3[prime or minute],5[prime or minute]-TnpT] of thymidylyl-3[prime or minute],5[prime or minute]-thymidine were prepared and their hydrolytic reactions over the pH-range 1-8 at 363.2 K were followed by RP HPLC. At pH < 6, an acid-catalyzed P-N3[prime or minute] bond cleavage (first-order in [H(+)]) takes place with both 3[prime or minute],5[prime or minute]-Tnp(s)T and 3[prime or minute],5[prime or minute]-TnpT, the former being about 12 fold more stable than the latter. At pH > 4, Tnp(s)T undergoes two competing pH-independent reactions, desulfurization (yielding TnpT) and depyrimidination (cleavage of the N-glycosidic bond) the rates of which are of the same order of magnitude. Also with 3[prime or minute],5[prime or minute]-TnpT the pH-independent depyrimidination competes with P-N3[prime or minute] cleavage at pH > 5.     

The synthesis of naphthothiopyranopyranones and naphthothiopyranopyranthiones

The synthesis of fused tetracyclic naphthothiopyranopyranones from dihydronaphthothiopyranones I or II has been studied. Compounds I or II have been cyclised in good yield to the corresponding dioxaborin difluoride complexes III, IV, XIII and XIV by treatment with acetic or propionic anhydride and boron trifluoride etherate. These complexes and the Vilsmeier reagent reacted to produce fused tetracyclic 3-substituted naphthothiopyranopyranones V, VI, XV or XVI . The reaction of dioxaborin difluoride complexes III or IV with dimethylthioformamide (DMTF) afforded dimethylaminovinyldioxaborin difluoride complexes IX or X . Treatment of IX or X with hydrochloric acid solution gave naphthothiopyranopyranones VII or VIII . The reaction of VII, VIII, XV or XVI with DMTF/acetic anhydride yielded new products, which was identified as naphthothiopyranopyranthions XI, XII, XVII or XVIII .     

Synthesis of azacrown ethers and benzocryptands by macrocyclization of podands at high concentrations of reactants

The reactions of 1,2-bis(2-Y-ethoxy)benzenes, N,N-bis(2-Y-ethyl)-N-phenylamines, or 2,6-bis(Y-methyl)pyridines (Y = I, Br, or OTs) with α,ω-polyoxaalkanediamines or diazacrown ethers in the presence or absence of alkali carbonates in a concentrated acetonitrile solution of the reactants afforded the corresponding azacrown ethers or cryptands in high yields.     

Preparation of polyfluorodihydrobenzothiophenes and investigation of some of their chemical properties

Co-pyrolysis of thiophenol or diphenyl disulfide with tetrafluoroethylene or chlorotrifluoroethylene in the presence of oxidants gave 2,2,3,3-tetrafluoro-2,3-dihydrobenzo[b]thiophene (I) or the corresponding chlorotrifluorodihydrobenzothiophenes. Reactions of compounds synthesized by use of electrophilic and nucleophilic reagents and with oxidants have been studied.     

Application of tin and nanometer tin in allylation of carbonyl compounds in tap water

[reaction: see text] Nanometer tin-mediated allylation of aldehydes or ketones in distilled or tap water gave rise to corresponding homoallyl alcohol in high yield without any other assistance such as heat or supersonic or acidic media.     

三苯基锗不饱和烃基膦酸衍生物的合成和性质

随着倍半锗氧类化合物的合成及应用研究的日益广泛,含Ge_O键的烃基锗衍生物的合成及应用也逐渐引起了人们的关注.1984年,Lukevics等[1]合成了具有抗癌活性的介吗川类化合物,1990年Kakimoto等[2]报道了具有杀菌活性的环状烃基羧酸的合成与应用.     

Synthesis of alpha-trifluoromethyl-beta-lactams and esters of beta-amino acids via 1,3-dipolar cycloaddition of nitrones to fluoroalkenes

Nitrones derived from aromatic or aliphatic aldehydes or ketones react with hexafluoropropene (HFP) or 2H-pentafluoropropene (PFP) to give the respective fluorinated isoxazolidine derivatives in good yields with complete regioselectivity and moderate diastereoselectivity. Catalytic hydrogenolysis of the N-O bond under ambient pressure and temperature leads to fluorides of beta-amino acids that undergo cyclization to alpha-trifluoromethylated beta-lactams or, under acidic conditions, form esters of alpha-trifluoromethylated beta-amino acids.     

Halogenation of Xanthenyl and Thioxanthenylallenes

Reactions of acids with vinylidenexanthenes (or thioxanthenes) 1 and 9-methoxy-9-vinylxanthenes (or thioxanthenes) 8 give xanthene- (or thioxanthene-) 9-spiro-1′-indenes 7 . With bromine or sulfuryl chloride they give the corresponding 2′-halogenoxanthene- (or thioxanthene-)9-spiro-1′-indenes 5 . Formation of such derivatives depends on preferential attack of the reagents on allenes 1 to give initially xanthylium (or thioxanthylium) ions 3 which cyclize. One π bond of the allenes 1 can be selectively reduced in acid media. Chemical and spectral evidence for these routes are presented.     

Studies on the regio- and stereoselectivity of halohydroxylation of 1,2-allenyl sulfides or selenides

It was observed that the halohydroxylation of 1,2-allenyl sulfides or selenides with Br2 (CuBr2 or NBS) or I2 and water demonstrated a fairly good regioselectivity (i.e., the C=C bond that is remote from the S or Se atom was halohydroxylated with the halogen atom connecting to the middle carbon atom and the hydroxyl group connecting to the non-S terminal carbon or Se-substituted terminal carbon atom of the allene moiety), leading to the synthesis of synthetically important 3-organosulfur or seleno-2-haloallylic alcohols. The stereoselectivity depends on the nature of X+ and S or Se, showing a Z-selectivity with the matched Lewis acid-base pair.     

三苯基锗不饱和烃基酸衍生物的合成和性质

随着倍半锗氧类化合物的合成及应用研究的日益广泛 ,含 Ge_ O键的烃基锗衍生物的合成及应用也逐渐引起了人们的关注 .1 984年 ,L ukevics等 [1]合成了具有抗癌活性的介吗川类化合物 ,1 990年Kakimoto等 [2 ] 报道了具有杀菌活性的环状烃基羧酸的合成与应用 .但是三烃基锗的膦酸类衍生物的合成及生物活性研究均未见文献报道 .为了研究该类化合物的生理活性 [3～ 5] ,本文以三苯基氯化锗和炔基 (烯基 )膦酸钠为原料 ,在苯中反应 ,合成了一系列双 - O- (三苯基锗 )炔基 (烯基 )膦酸酯和单 - O-三苯基锗炔基 (烯基 )膦酸 ,部分化合物初步生理…     

Amidomethylation of the benzene ring of indoles

The benzene ring of indoles was amidomethylated by various agents in the presence of sulfuric acid. The amidomethylation of 2-methyl- and 2,3-dimethylindoles takes place in the 5 position. When there is a methyl or methoxy group in the 5 or 7 position, the substituent enters the 6 position. Hydrazinolysis or hydrolysis of the amidomethylation products gives 5- or 6-aminomethylindoles.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1066–1069, August, 1978.     

Preparation of fluorine-containing exo- and endocyclic enamine derivatives of 2-acylcyclopentane-1,3-diones

The interaction of aromatic amines (4-fluorinebenzylamine, 3-trifluoromethylbenzylamine, 4-fluoroaniline, or 3,4-difluoroaniline) with either 2-acylcyclopentane-1,3-diones (fluorine-substituted or fluorine-free) or their enol derivatives (chlorovinyldiketones) has led to fluorine-containing exo- or endocyclic enamine derivatives of 2-acylcyclopentane-1,3-diones.     

A Convenient Method of Synthesis of Dialkyltellurides and Dialkylditellurides

Elemental tellurium is reduced by thioureadioxide in alkaline medium, leading to disodium telluride or ditelluride, depending on the amount of thioureadioxide used. The intermediate disodium telluride or ditelluride reacts “in situ” with alkyl halides to give dialkyltellurides or dialkylditellurides in high yield.     

Addition-cyclisations of ethoxycarbonyl isothiocyanate with hydrazine derivatives as a source of thiadiazoles and triazoles

Ethoxycarbonyl isothiocyanate reacts additively with hydrazine, ethoxycarbonylhydrazine, as well as amino- and 1,2-diaminoguanidine. Simultaneous or subsequent cyclisation of the resulting 1:1- or 2:1-adducts in acidic or alkaline media yields substituted 1,3,4-thiadiazoles or 1,2,4-triazoles, respectively.     

Infrared determination of calcium or lithium nitrate in acetone solution determination of calcium or lithium in the presence of strontium or barium

A method is proposed for the infrared determination of calcium or lithium in the presence of strontium or barium. A mixture of the nitrates is treated with acetone which dissolves only the calcium or lithium nitrate. The strontium or barium nitrate is filtered off. The nitrate is evaporated to about 2 ml with a stream of dry air and then diluted to 5 ml with acetone. The infrared spectrum is scanned from 860 to 800 cm(-1) and the nitrate peak at 824 cm(-1) for calcium and 827 cm(-1) for lithium is measured. The recommended range is 1-80 mg of calcium or lithium nitrate in the presence of up to about 200 mg of strontium or barium nitrate.     

Synthesis and Characterization of New Polyetheramides

Polyetheramides (PEAs) are prepared by polycondensation of N,N′-diacetyl-o-tolidide with Bisphenol A, C, or F, phenolphthalein, resorcinol, catechol, hydroquinone, or 1,5- or 2,7-dihydroxynaphthalene or ethylene, butylene, propylene, diethylene, or triethylene glycol. The fusible and soluble oligomers are characterized. An attempt is made to bring out the relationship between various properties of PEAs and their structures.     

Rich chemistry of nitroso compounds

Nitrosobenzene or nitrosopyridine are found to be attractive electrophiles in catalytic enantioselective carbon-nitrogen and/or carbon-oxygen bond forming reactions. In the presence of designer Lewis or Br?nsted acid catalysts, catalytic enantioselective O- and N-nitroso aldol reaction or nitroso Diels-Alder reaction proceed smoothly. The scope and limitation of new catalytic processes are described.