Unfairly forgotten member of the iodocarborane family: synthesis and structural characterization of 8-iodo-1,2-dicarba-closo-dodecaborane, its precursors, and derivatives

8-Iodo-1,2-dicarba-closo-dodecaborane (7) was prepared in three steps starting from decaborane-14 with 20% overall yield. In the presence of nucleophiles, compound 7 undergoes selective removal of the boron vertex in the position para to the iodine substituent to form the anionic nido-carborane 1-iodo-7,8-dicarba-nido-undecaborate. Capping of the corresponding dicarbollide dianion with BI(3) led to formation of the new carborane, 3,10-diiodo-1,2-dicarba-closo-dodecaborane (15). The same dicarbollide dianion reacts with cobalt and nickel acetylacetonates in anhydrous tetrahydrofuran to form the corresponding bis(dicarbollide) complexes with excellent yields. All compounds were characterized by multinuclear NMR and high-resolution mass spectroscopy. Structures of 2-iododecaborane (2), 8-iodo-1,2-dicarba-closo-dodecaborane (7), 1-ethoxycarbonyl-8-iodo-1,2-dicarba-closo-dodecaborane (10), cesium 1-iodo-7,8-dicarba-nido-undecaborate (13), 3,10-diiodo-1,2-dicarba-closo-dodecaborane (15), and cesium 3,3'-commo-(10-iodo-1,2-dicarba-3-cobalta-closo-dodecaborane)-(10'-iodo-1',2'-dicarba-3'-cobalta-closo-dodecaborane) (16) were established by X-ray analysis of single crystals.     

Efficient synthesis of substituted thieno[3,2-e]indoles

Efficient cyclization reactions of 5-aminobenzothiophene derivatives with internal and terminal acetylenes, giving 7- and 8-substituted thieno[3,2-e]indoles, are described. The reaction of 4-iodo-5-(methylsulfonamido)benzothiophene with terminal alkynes gave 7-substituted thienoindoles using general Sonogashira reaction conditions. Reaction of 5-amino-4-iodobenzothiophene with internal acetylenes, using Larock's heterocyclization reaction conditions, gave 7,8-disubstituted thieno[3,2-e]indoles.     

Facile Synthesis of Imidazole Fused Fluoroquinolones

Studies on synthetic design of 7,8‐imidazole fused fluoroquinolones from 8‐amino‐6‐fluoro‐4‐hydroxy‐N‐methyl‐7‐(methyl amino)quinoline‐3‐carboxamide and ketones/carboxylic acids and their antibacterial activity.     

Synthetic transformations of isoquinoline alkaloids. Synthesis of 1-halo derivatives of <Emphasis Type="Italic">endo</Emphasis>-ethenotetrahydrothebaine and their behavior in the heck reaction

Bromination of endo-ethenotetrahydrothebaine derivatives having a pyrrolidine ring fused at the C⁷-C⁸ bond, namely 1′-substituted 4,5α-epoxy-6α,14-etheno-3,6-dimethoxy-17-methyl-2′,5′,7β,8β-tetrahydro-1′H-14α-pyrrolo[3′,4′:7,8]morphinan-2′,5′-diones, 1′-aryl-4,5α-epoxy-6α,14-etheno-3,6-dimethoxy-17-methyl-2′,5′,7β,8β-tetrahydro-1′H-14α-pyrrolo[3′,4′:7,8]morphinans, and 4,5α-epoxy-6α,14-etheno-2′α-hydroxy-3,6-dimethoxy-17-methyl-1′-phenyl-2′,5′,7β,8β-tetrahydro-1′H-14α-pyrrolo[3′,4′:7,8]morpphinan-5′-one, with molecular bromine in formic acid smoothly afforded the corresponding 1-bromo derivatives. Iodination of 4,5α-epoxy-6α,14-etheno-3,6-dimethoxy-17-methyl-1′-phenyl-2′,5′,7β,8β-tetrahydro-1′H-14α-pyrrolo[3′,4′:7,8]-4,5α-epoxy-6α,14-etheno-3,6-dimethoxy-17-methyl-1′-phenyl-2′,5′,7β,8β-tetrahydro-1′H-14α-pyrrolo[3′,4′:7,8]-morphinan-2′,5′-dione with iodine(I) chloride gave 4,5α-epoxy-6α,14-etheno-1-iodo-3,6-dimethoxy-17-methyl-1′-phenyl-2′,5′,7β,8β-tetrahydro-1′H-14α-pyrrolo[3′,4′:7,8]morphinan-2′,5′-dione. The resulting 1-halo derivatives were brought into the Heck reaction with acrylic acid esters to obtain 1-[(E)-2-(alkoxycarbonyl)ethenyl]-substituted compounds. Demethylation of the 6-methoxy group in 1-bromo-endo-ethenotetrahydrothebaines was accomplished using boron(III) bromide in chloroform.     

Acetylenchemie, 33. Mitt.: Synthese von 2-substituierten Dihydrofuro[2,3-b]chinolinen

Summary The reaction of 3-iodo-4-methoxy-2(1H)-quinolinone (1) and 3-iodo-4,6,8-trimethoxy-2(1H)-quinolinone (2) with 2-methyl-3-butyn-2-ol under modified Heck-conditions gave the 2-substituted derivatives 2-(1-hydroxy-1-methylethyl)-4-methoxyfuro[2,3-b]-quinoline (3) and 2-(1-hydroxy-1-methylethyl-4,6,8-trimethoxyfuro[2,3-b]-quinoline (4). By a subsequent hydrogenation-reaction with a homogeneous catalyst (PtO₂/Rh₂O₃), the furoquinoline-derivatives yielded the dihydrofuro-[2,3-b]quinolines, identified as 2-(1-hydroxy-1-methylethyl-4-methoxy-2,3-dihydrofuro[2,3-b]quinoline (5) (racemic platydesmine) and 2-(1-hydroxy-1-methylethyl)-4,6,8-trimethoxy-2,3-dihydrofuro-[2,3-b]quinoline (6) (racemic precursor of O⁴-methylptelefolonium salt).

     

Phosphoramides—II: Synthesis of 2,4-bis(dimethylamino)quinolines by HMPT induced ring closure of anthranilates

6-Chloro-, 7-chloro-, 6-bromo-, 6-methyl-, 6,7-dimethyl-, 7,8-dimethyl- and unsubstituted 2,4-bis-(dimethylamino) quinoline 7 have been prepared by heating appropriately substituted ethyl anthranilates in HMPT at reflux temperature. By heating ethyl N-acetylanthranilate (3) at 205–209° in HMPT, N-acetylanthranilic acid (4), 2-acetamido-N,N-dimethylbenzamide (5) and an acetamidine (6) were produced and are belived to be intermediates in the formation of 2,4-bis(dimethylamino)quinoline (7) which was produced in trace amounts in the latter reaction.     

An unexpected [2+2]-cycloaddition reaction of 4-methyldithieno-[3,4-b:3′,2′-d]pyridinium iodide with dimethyl acetylenedicarboxylate

An unexpected [2+2]-cycloaddition occured in the reaction of 4-methyldithieno-[3,4-6:3′,2′-d]pyridinium iodide (3)with two equivalents of DMAD, giving 4-(trans-1,2-dicarbomethoxy-2- iodovinyl)-5-methyl-6,7-dicarbomethoxy-4,5-dihydrothieno [23-c]quinoline (4) in 54% yield. 4 is formed via 4-methyl-5-(trans-1,2-dicarbomethoxy-2-iodo-4,5-dihydrothieno [3,4-b:3′,2′-d]pyridine (16), followed by [2+2]-cycloaddition. The primary adduct rearranges via a thiepin to an episulfide which eliminates sulfur to give 4.     

脱卤亚磺化研究——连二亚硫酸钠作为新的脱卤亚磺化试剂

全氟碘代烷与亚硫酸盐发生单电子转移反应生成全氟亚磺酸盐;连二亚硫酸钠水溶液热分解时,ESR表明生成SO_2~-主阴离子自由基,这两者促使我们尝试用连二亚硫酸钠代替亚硫酸盐与全氟卤代烷反应.实验表明对于全氟碘代烷及溴代烷它是一种有效的     

One-pot palladium-catalyzed C-I and C-H bond activation and subsequent Suzuki-Miyaura cross-coupling of 2-aryl-3-iodo-4-(phenylamino)quinolines with arylboronic acids

The 2-aryl-3-iodo-4-(phenylamino)quinolines undergo one-pot palladium-mediated C-I and C-H bond activation and subsequent Suzuki-Miyaura cross-coupling with arylboronic acids under anhydrous conditions to afford mixture of 2,3-diaryl-4-(phenylamino)quinolines (minor) and 2-aryl-4-([(1,1′-biaryl)-2-yl]amino)quinoline derivatives (major). The 2,3-diaryl-4-(phenylamino)quinolines were isolated as major products when 2 M K₂CO₃ was used as a base. A plausible mechanism, which implicates a six-membered palladacycle intermediate is proposed for the formation of the observed mixture of products. The prepared compounds were characterized using a combination of spectroscopic and X-ray crystallographic techniques.     

瓜环与喹啉衍生物包结配合行为研究

利用¹H NMR以及荧光技术研究了六、七、八元瓜环与2-苯基喹啉、N-正丙基溴化异喹啉、3-氨基喹啉及7,8-苯并喹啉的相互作用.两种方法的考察结果均表明,2-苯基喹啉能与这3种瓜环发生相互作用,其中六、七元瓜环与2-苯基喹啉形成1∶1的稳定包结配合物,包结常数分别为1.6×10⁴和3.2×10³L/mol.八元瓜环能与2-苯基喹啉形成1∶2包结物.¹H NMR结果还表明,3种瓜环均能与N-正丙基溴化异喹啉相互作用,其化学计量比均为1∶2;七元瓜环与7,8-苯并喹啉相互作用,化学计量比约为1∶1.荧光法也表明八元瓜环能与N-正丙基溴化异喹啉、3-氨基喹啉及7,8-苯并喹啉发生相互作用,并且荧光强度随瓜环浓度增加而下降,其化学计量比为1∶2.同时,讨论了上述主客体包结配合物的作用模式.     

Reactions of dispiro[2.0.2.2]oct-7-ene. Electrophilic and free radical additions

Dispiro[2.0.2.2]oct-7-ene 1 was synthesized by debrominatioa of cis- and trans-7,8-dibromodispiro[2.0.2.2]octane 3a with LAH and by dechlorination of cis- and trans-7,8-dichlorodispiro[2.0.2.2]octane 3b with magnesium. Stepwise electrophilic additions to 1 of HBr, HI, Br₂ and Cl₂ were studied. The major products (and yields) from these reactions were: 7-bromodispiro[2.0.2.2]octane 2a (43%), 4-iodo-4,5-ethanospiro[2,3]hexane 4b (ca. 50%); trans-3a (40%); and cis-3b (20%). Free-radical addition of hydrogen bromide to 1 gave an 80% yield of 7-bromodispiro[2.0.2.2]octane 2a. At ?10°, hydroboration-oxidation of 1 was found to give mainly 7-hydroxydispiro[2.0.2.2]octane 2a in ca. 90% yield; at 25°, near equal amounts of 2c and 4-(2-hydroxyethyl) spiro[2.3]hex-4-ene 14 were obtained.     

Nitrenes-XV: 1-Hydroxymethyl-4,5-dimethoxy-7H-azirino[1,2-a]-indole-7a-carboxylic acid γ-lactone,a nitrene addition compound

Triethyl phosphite deoxygenation of α-(6-nitroveratrylidene)-γ-butyrolactone 1 under moderate conditions affords a mixture of 3-(6-nitroveratryl)-2(5H)-furanone 5, α-(6-ethylaminoveratrylidene)-γ-butyrolactone 6 and 1-hydroxymethyl-4,5-dimethoxy-7H-azirino[1,2-a]indole-7a-carboxylic acid γ-lactone 7, in addition to 3,4-dihydro-7,8-dimethoxy[1,3-a]oxazino[3,4-a]indol-1-one 2, ethyl 5,6-dimethoxyindole-2-carboxylate 3, and 2,3-dihydro-6,7-dimethoxyfuro[2,3-b]quinoline 4, obtained under more drastic reaction conditions.The isolation of lactones 5 and 7 provides strong evidence for the intermediacy of nitrenes in this reaction which appears to provide the first example of intramolecular aziridine formation from a nitro-aromatic compound and triethyl phosphite.     

4-Oxa(thia)-9-oxa-2-azabicyclo[4.2.1]nonane-3-on(thion) derivatives

The synthesis of 7,8-dihydroxy-2-(2-methoxycarbonylethyl)-4,9-dioxa-2-azabicyclo[4.2.1]nonane- 3-thione ( 16 ) and of its parents 9-oxa-4-thia-3-thione 17 , and 9-oxa-4-thia-3-one 18 is described. The conversion of 5′-deoxy-5′-iodo-2′,3′-O, O-isopropylidene-5,6-dihydrouridin ( 1 ) into the 2-O-methyl-5,6-dihydrouridine 5 , the 5′-O-acetyl-5,6-dihydrouridine 4 , and into the N-(5-O-acetyl-2,3-O, O-isopropylidene-β-D -ribofuranosyl)-N-(2-methoxycarbonyl thyl)-urea ( 6 ) invoked 2′,3′-O, O-isopropylidene-2,5′-anhydro-5,6-dihydrouridine ( 2 ) as the common intermediate.     

Reactions of 3-iodo-7-dialkylaminocoumarins with secondary amines

The reaction of 3-iodo-7-diethylaminocoumarin and 2,3,6,7-tetrahydro-10-iodo-1H,5H-quinolizino[9,9a,1-gh]coumarin with secondary amines (diethylamine, piperidine, morpholine, imidazole, and benzimidazole) leads to 4,7-diaminocoumarins. The corresponding 3-iodo-4-chloro-7-dialkylaminocoumarins under similar conditions give 3-iodo-4,7-diaminocoumarins. 4-Aminomethyl derivatives of coumarins are formed in the reactions of 3-iodo-4-methyl-7-diethylaminocoumarin and 2,3,6,7-tetrahydro-9-methyl-10-iodo-1H,5H-quinolizino[9,9a,1-gh]coumarin with these secondary amines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 609–618, May, 1991.     

Condensation of hydroxycoumarins with chloral

Derivatives of a new class of 1,3-dioxanocoumarins -4-methyl-(2′,4′-bistrichloromethyl)-7,8-coumarinodioxane and 3-chloro-4-methyl-(2′,4′-bistrichloromethyl)-7,8-coumarinodioxane, respectively — were synthesized by condensation of 4-methyl- and 3-chloro-4-methyl-7-hydroxycoumarin with chloral in concentrated sulfuric acid. 8-(1,2,2,-2-Tetrachioroethyl)-7-hydroxycoumarin was obtained under similar conditions from 4-methyl-7-hydroxycoumarin methyl ether and chloral.     

Synthesis of coumarin based fluorescent compounds

The reaction of different 7,8-disubstituted coumarin 4-acetic acids with 7-diethylaminocoumarin-3-carbaldehyde in the presence of piperidine in methanol gives highly fluorescent (E)-1-(7-diethylaminocoumarin-3-yl)-2-(7,8-disubstituted coumarin-4-yl)ethenes in good yield. Only the (E) diastereomers of these are obtained. The compounds are new, orange to red in colour and show emission in yellow to red region. These compounds were further studied for their emission properties.     

2-Acyl(aroyl)-1,1,3,3-tetracyanopropenides: VI. Reaction with hydrogen halides

Reactions of 2-aroyl-1,1,3,3-tetracyanopropenides with hydrogen halides in solvents of low dielectric permittivity result in the formation of 6-amino-2-aroyl-2-halopyridine-3,5-dicarbonitriles. 2-Acyl-1,1,3,3-tetracyanopropenides under similar conditions afford 2-(2-alkylidene-5-amino-4-cyano-2,3-dihydrofuran-3-ylidene)propanedinitriles. In solvents of high dielectric permittivity the result of the reaction depends on the nature of the hydrogen halide and the acyl(aroyl) substituent: With HCl and HBr 2-aroyl-1,1,3,3-tetracyanopropenides form 2-(5-amino-2-aryl-2-halo-4-cyano-2,3-dihydrofuran-3-ylidene)-propanedinitriles, and 2-acyl-1,1,3,3-tetracyanopropenides give 2-(2-alkylidene-5-amino-4-cyano-2,3-dihydrofuran-3-ylidene)propanedinitriles; with HI depending on the reaction conditions and the structure of the acyl substituent 2-(5-amino-2-aryl-4-cyano-2,3-dihydrofuran-3-ylidene)propanedinitriles, 2-(5-amino-4-cyano-2,3-dihydrofuran-3-ylidene) propane-dinitrile, 2-amino-4-(dimethoxybenzyl)-6-iodo-5-cyanonicotinamide, 4-amino-6-iodo-3-oxo-2,3-dihydro-1H-pyrrolo[3,4-c]pyridine-7-carbonitrile, or 4-amino-6-iodo-3-oxo-1-ethylidene-1,3-dihydrofuro[3,4-c]pyridine-7-carbonitrile are obtained.     

Easily synthesized antimalarial ferrocene triazacyclononane quinoline conjugates

Starting from triazacyclononane, easily accessible ferrocenic quinoline derivatives were synthesized. Their antiplasmodial properties were investigated against chloroquine sensitive (HB3) and chloroquine-resistant (Dd2) Plasmodium falciparum. One of them, 7-chloro-4-[4-(7-chloro-4-quinolyl)-7-ferrocenylmethyl-1,4,7- triazacyclononan-1-yl]quinoline (4) showed potent antimalarial activity in vitro against the chloroquine-resistant strain Dd2 and therefore revealed to be the most promising lead from the present work for new organometallic antimalarial agents.     

Size matters: room temperature P-C bond formation through C-H activation in m-terphenyldiiodophosphines

m-Terphenyl- and biphenyl-2-diiodophosphines, TerphPI 2 and BiphPI 2, have been obtained by halide exchange from the chloro derivatives TerphPCl 2 and BiphPCl 2 and excess LiI in a benzene solution at room temperature. Whereas BiphPI 2 compounds are stable, the TerphPI 2 species undergo intramolecular C-H activation at room temperature and cyclize to form unsymmetrical 9-iodo-9-phosphafluorenes 1-(3,5-dimethylphenyl)-6,8-dimethyl-9-iodo-9-phosphafluorene, 4; 1-(4-t-butylphenyl)-7-t-butyl-9-iodo-9-phosphafluorene, 5; and 1-(2-methylphenyl)-5-methyl-9-iodo-9-phosphafluorene, 6, albeit the latter reaction is rather slow due to unfavorable steric interactions. Cyclization of the alkyl-substituted 4,4'-di- tert-butyl-biphenyl-2-diiodophosphine, 11, is slow in refluxing benzene solution, but faster than that for the parent biphenyl-2-diiodophosphine. Ab initio and density functional theory calculations are in agreement with an electrophilic aromatic substitution mechanism that is facilitated by steric strains in the terphenyl compounds 2,6-(3,5-Me2C6H3)2C6H3PI2, 1; 2,6-(4-t-BuC6H4)2C6H3PI 2, 2; and 2,6-(2-MeC6H4)2C6H3PI 2, 3. All new compounds have been characterized by multinuclear NMR spectroscopy and direct analysis in real time mass spectrometry. 9-Iodo-9-phosphafluorene, 12, was also analyzed by X-ray diffraction.     

A new neolignan glycoside from the leaves of Acer truncatum

A new neolignan glycoside, (7R,8R)-7,8-dihydro-9'-hydroxyl-3'-methoxyl- 8-hydroxymethyl-7-(4-hydroxy-3-methoxyphenyl)-1'-benzofuranpropanol 9'-O-beta-D- glucopyranoside (1) was isolated from the leaves of Acer truncatum along with (7R,8R)-7,8-dihydro-9'-hydroxyl-3'-methoxyl-8-hydroxymethyl-7-(4-O-alpha-L-rhamno- pyranosyloxy-3-methoxyphenyl)-1'-benzofuranpropanol (2), schizandriside (3), lyoniresinol (4), berchemol (5), (-)-pinoresinol-4-O-beta-D-glucopyranoside (6), hecogenin (7), chlorogenic acid (8) and neochlorogenic acid (9). Their structures were elucidated on the basis of extensive spectroscopic data. The absolute configuration of compounds 1 was established by its CD spectrum. The antibacterial activities of compounds 1-7 were evaluated.