An Efficient Synthesis of Carborane Amines via One-Step Reaction of Carborane Triflates with N-Nucleophiles (original) (raw)
Related papers
Synthesis of new ω-amino- and ω-azidoalkyl carboranes
New Journal of Chemistry, 2013
Materials, instruments and general procedures The triethylammonium salt of 1-mercapto-ortho-carborane was prepared according to our previous work procedure 1. All reactions were carried out in air. Thinlayer chromatograms (Merck F254 silica gel on aluminium plates) were visualized using 0.1% PdCl 2 in 3 M HCl(aq). Acros organics silica gel (0.060-0.200 mm) was used for column chromatography. The 1 H, 11 B, and 11 B{ 1 H}, 13 C NMR spectra were collected using Bruker Avance-400 spectrometer. The residual signal of the NMR solvent relative to tetramethylsilane was taken as the internal reference for 1 H NMR and 13 C NMR spectra. 11 B NMR spectra were referenced using a BF 3. Et 2 O external standard. Infrared spectra were recorded on Specord IR 75 and Infralum FT-801 spectrophotometers. Mass spectra were obtained using Kratos MS 890 mass spectrometer. Elemental analyses were performed at the Laboratory of Microanalysis of the Institute of Organoelement Compounds. Synthesis of 1-C 6 H 4 (CO) 2 NCH 2 S-1,2-C 2 B 10 H 11 (1). To solution of triethylammonium salt of 1-mercapto-ortho-carborane (0.40 g, 1.5 mmol) in ethanol (50 ml), N-(bromomethyl)phthalimide (0.35 g, 1.5 mmol) was added, stirred at room temperature for 15 min and heated under reflux for 20 h. The reaction mixture was cooled and evaporated to dryness in vacuo. The residue was treated with diethyl ether (50 ml) and water (50 ml). The organic layer was separated, washed with water (2 x 30 ml) and evaporated in vacuo. The crude product was purified using column chromatography on silica with CHCl 3 as eluent. The solvent was evaporated under vacuum to yield a white residue (0.31 g, 64% yield). 1 H NMR (CDCl 3): δ 7.91 (2H, m,
Structural effects in three-ring mesogenic derivatives ofp-carborane and their hydrocarbon analogues
Liquid Crystals, 2004
Several series of structurally related three-ring esters containing benzene, cyclohexane, bicyclo[2.2.2]octane and p-carborane rings were synthesized and their mesogenic properties investigated using thermal analysis and optical microscopy. Carborane derivatives show only nematic phases, while the richest smectic polymorphism (up to three phases) was observed in the biphenyl series D. The structure-property relationships were studied by comparison of T NI between series. The ring effectiveness in stabilization of nematic phases generally follows the order carboranevbenzeneycyclohexanevbicyclo[2.2.2]octane. The results indicate that fill fraction plays a significant role in the stabilization of the mesophase. A notable positional effect of the carborane ring on T NI was also observed. 11[n] were obtained according to Wade's general procedure for arylation of p-carborane [5]. Alternatively, C-arylation of 1-triphenylsilyl-p-carborane with 1-heptyloxy-4-iodobenzene followed by removal of the silyl group simplifies the isolation of the pure monoaryl derivative 11[7] [4]. 4-(12-Pentyl-p-carboran-1-yl)phenol (9A), the precursor to esters 1A-4A, was obtained by demethylation of the methoxy derivative 12 with BBr 3 according to a general method (scheme 3) [6]. The BBr 3 method was found to be significantly more efficient and convenient to use than the pyridine hydrochloride procedure previously reported for a similar reaction [7]. Derivative 12 was easily prepared by alkylation of 1-(4-methoxyphenyl)-pcarborane [6] (11[1]) but its purification was difficult due to similar polarities and volatilities of the starting material and the product. The pure methoxy derivative 12 was isolated in 75% yield using reverse phase column chromatography. Alternatively, the desired derivative 12 could be prepared by arylation of 1-pentyl-pcarborane [4] and conveniently separated from the starting material by distillation/sublimation, but this route was not investigated. The bicyclo[2.2.2]octyl analogue 9B was obtained according to a literature method (scheme 4) [8]. The phenol 9C was prepared by Baeyer-Villiger oxidation of 4-(E-4-pentylcyclohexyl) Scheme 1 Scheme 2 Scheme 3 672 K. Ohta et al.
Syntheses and structural characterization of o-carboranylamides with direct cage–amide bond
Reactions of lithio-o-carborane with isocyanates under various conditions were studied, and the structural features of the resulting carboranylamides are described. The reactions of o-carborane (o-C 2 B 10 H 12 ), n-BuLi (two equiv.) and two equiv. of (substituted) phenylisocyanate, pentylisocyanate and p-ethylphenylthioisocyanate in diethyl ether, respectively, led, after workup, to the corresponding mono-substituted carboranylamide 2a-g and carboranylthioamide 5 in low to moderate yields, and only with RNCO (R = Ph, m-MeOC 6 H 4 , pentyl) could disubstituted products 3a-c be isolated. The reaction with phenylisocyanate afforded the mono-amide and di-amide products in a ratio of approximately 1 : 2, whereas in the other two reactions the ratios are approximately 4 : 1 and 3 : 2, respectively. In tetrahydrofuran all the reactions attempted with RNCO (R = Ph, p-IC 6 H 4 , m-NCC 6 H 4 and pentyl) gave more monoamide products than those in diethyl ether. With phenylisocyanate no diamide product was isolated and with pentylisocyanate the ratio between monoamide and diamide is approximately 3.5 : 1. The new carboranylamides were characterized by means of elemental analyses, IR and NMR spectroscopy and mass spectrometry, as well as single-crystal X-ray diffraction analyses of 2a-f, 3a and 5. † Electronic supplementary information (ESI) available. CCDC 937467, 952824, 950184, 937468, 958414, 958415, 937469 and 963492. For ESI and crystallographic data in CIF or other electronic format see
Synthesis of novel carboranyl amidines
Journal of Organometallic Chemistry, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Synthesis of quadruped-shaped polyfunctionalized o-carborane synthons
Chemical Communications, 2011
General Procedures. Elemental analyses were performed using a Carlo Erba EA1108 microanalyser. IR spectra were recorded from KBr pellets on a Shimadzu FTIR-8300 spectrophotometer. 1 H and 1 H{ 11 B} NMR (300.13 MHz), 13 C{ 1 H} NMR (75.47 MHz) and 11 B and 11 B{ 1 H} NMR (96.29 MHz) spectra were recorded with a Bruker ARX 300 instrument equipped with the appropriate decoupling accessories. Chemical shift values for 11 B NMR spectra were referenced to external BF 3 ←OEt 2 and those for 1 H, 1 H{ 11 B}, 31 P{ 1 H} and 13 C{ 1 H} NMR spectra were referenced to SiMe 4. Chemical shifts are reported in units of parts per million downfield from reference, and all coupling constants in Hz. MS spectra were recorded using a FIA-ES/MS (Shimadzu AD VP/ API 150) instrument for neutral species. Materials: Unless otherwise noted, all manipulations were carried out under a nitrogen atmosphere using standard vacuum line techniques. Diethyl ether and THF were distilled from sodium benzophenone prior to use. Hexane was dried over molecular
Synthesis of new nido-carborane based carboxylic acids and amines
Polyhedron, 2018
A series of new nido-carborane based carboxylic acids 10-HOOC(CH 2) n (Me)S-7,8-C 2 B 9 H 11 (n = 1-4) was prepared by alkylation of tetrabutylammonium salt of 10-methylthio-7,8-dicarba-nido-caborane with x-halogenoalkyl esters or nitriles followed by acid hydrolysis. Likewise nido-carborane based amines 10-H 2 N(CH 2) n (Me)S-7,8-C 2 B 9 H 11 (n = 2, 3) were obtained using x-bromoalkylphthalimides as alkylating agents followed by removal of the protecting group with hydrazine. Structure of 10-C 6 H 4 (CO) 2 NCH 2 CH 2 (Me)S-7,8-C 2 B 9 H 11 was determined by single crystal X-ray diffraction.
Synthesis of new arylcarboranes as precursors for oligomers
Journal of Organometallic Chemistry, 1999
Some new aryl o-carboranes have been synthesized. From methyl 3-iodo-5-(trimethylsilyl-ethynyl)-benzoate (1) or butyl 3-(3,3-diethyltriazeno)-5-ethynyl-benzoate (2), 5-ethynyl-3-iodo-benzoates (3a, 3b) were obtained, which after the reaction with the decaborane-acetonitrile complex led to the corresponding 5-(1%-(1%,2%-dicarba-closo-dodecaboranyl))-3-iodo-benzoates (4a, 4b). Furthermore, the methyl 3-iodo-5-(trimethylsilyl-ethynyl)-benzoate (1) is the starting material for the synthesis of a bis-carborane. Compound 1 is modified to the methyl 3,5-bis(trimethylsilyl-ethynyl)-benzoate (5), which is deprotected to give the methyl 3,5-bis(ethynyl)-benzoate (6). Compound 6 reacted with the decaborane-acetonitrile complex to the methyl 3,5-bis(1%-(1%,2%-dicarba-closo-dodecaboranyl))-benzoate (7), which was partially degraded to the bis(tetramethylammonium)-3,5-bis(7%-(7%,8%-dicarba-nido-undecaboranyl))methoxycarbonylphenyl (8).
Chemistry – A European Journal, 2003
Reactions of both closo‐9,12‐I2‐1,2‐C2B10H10 and closo‐9,10‐I2‐1,7‐C2B10H10 with an excess of aryl magnesium bromide in the presence of [PdCl2(PPh3)2] afford the corresponding closo‐9,12‐(4‐R‐C6H4)2‐1,2‐C2B10H10 [R=H (1), Me (2), OMe (3), SMe (4), N(CH3)2 (5), Cl (6)] and closo‐9,10‐(4‐R′‐C6H4)2‐1,7‐C2B10H10 [R′=Me (7), OMe (8), N(CH3)2 (9), Cl (10), and ‐C[(OCH2)2]CH3 (11)] compounds in high yields. The anisole derivatives 3 and 8 were deprotected to yield the corresponding bis‐phenols 12 and 13, respectively. Structural analyses of compounds 1, 3, 6, and 12 are reported. Re‐etherification of compound 12 by using γ‐bromotriethyleneglycol methyl ether provided 14 (R=(CH2CH2O)3CH3). Oxidation of 4 with ceric(IV) ammonium nitrate (CAN) generated the bis‐sulfoxide 15 (R=S(O)Me). Deprotection of compound 11 led to the corresponding acetyl derivative 18 (R′=C(O)Me). Bis‐anisole 3 was tethered with 1,3‐dibromopropane, 1,6‐dibromohexane, 1,8‐dibromooctane, 4,4′‐bis(iodomethyl)‐1,1′‐bipheny...