- Catalytic Imido-Transfer Reactions of Well-Defined Silica-Supported Titanium Imido Complexes Prepared via Surface Organometallic Chemistry
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We expand the series of well-defined silica-supported titanium imido complexes of general formula (SiO)Ti(═NtBu)X(py)n prepared via surface organometallic chemistry in order to analyze the effect of the X ligand on their catalytic properties. Two new surface complexes, (SiO)Ti(═NtBu)Cl(py)2 (2s) and (SiO)Ti(═NtBu)Cp(py) (3s), have been prepared and characterized with physicochemical techniques, and their performance in oxo/imido heterometathesis and other catalytic imido-transfer reactions has been studied and compared to that of the previously reported catalyst (SiO)Ti(═NtBu)(Me2Pyr)(py)2 (1s; Me2Pyr = 2,5-dimethylpyrrolyl).
- Zhizhko, Pavel A.,Pichugov, Andrey V.,Bushkov, Nikolai S.,Rumyantsev, Andrey V.,Utegenov, Kamil I.,Talanova, Valeria N.,Strelkova, Tatyana V.,Lebedev, Dmitry,Mance, Deni,Zarubin, Dmitry N.
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p. 1014 - 1023
(2020/02/26)
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- A facile method for the preparation of carbodiimides from thioureas and (Boc)2O
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A concise method for the preparation of carbodiimides from thioureas using di-tert-butyl dicarbonate [(Boc)2O] as the dehydrosulfurizative reagent has been developed. Using DMAP as the catalyst, a variety of symmetric and asymmetric 1,3-diaryl thioureas were converted into the corresponding carbodiimides efficiently in a short time.
- Wu, He,Sun, Yan-Fang,Zhang, Chen,Miao, Chun-Bao,Yang, Hai-Tao
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supporting information
p. 739 - 742
(2018/01/27)
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- RE[N(SiMe3)2]3-Catalyzed Guanylation/Cyclization of Amino Acid Esters and Carbodiimides
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The example of rare-earth metal-catalyzed guanylation/cyclization of amino acid esters and carbodiimides is well-established, forming 4(3H)-2-alkylaminoquinazolinones in 65-96% yields. The rare-earth metal amides RE[N(TMS)2]3 (RE = Y, Yb, Nd, Sm, La; TMS = SiMe3) showed high activities, and La[N(TMS)2]3 performed best for a wide scope of the substrates.
- Lu, Chengrong,Gong, Chao,Zhao, Bei,Hu, Lijuan,Yao, Yingming
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p. 1154 - 1159
(2018/02/10)
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- CERAMIDE GALACTOSYLTRANSFERASE INHIBITORS FOR THE TREATMENT OF DISEASE
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Described herein are compounds, methods of making such compounds, pharmaceutical compositions and medicaments containing such compounds, and methods of using such compounds to treat or prevent diseases or disorders associated with the enzyme ceramide galactosyltransferase (CGT), such as, for example, lysosomal storage diseases. Examples of lysosomal storage diseases include, for example, Krabbe disease and Metachromatic Leukodystrophy.
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Paragraph 000703; 000705; 000858; 000859
(2018/01/17)
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- A method of manufacturing a carbodiimide compound
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PROBLEM TO BE SOLVED: To provide a novel method that can efficiently produce a carbodiimide compound without using substances that are harmful, hazardous, expensive, or difficult to obtain.SOLUTION: The method of producing a carbodiimide compound includes converting a thiourea compound having a specific structure to a carbodiimide compound having a specific structure in the presence of at least one of an iron compound and a molybdenum compound.
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Paragraph 0058; 0059; 0062; 0063
(2018/03/02)
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- Ultrasonic-assisted synthesis of carbodiimides from N,N′-disubstituted thioureas and ureas
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A facile and efficient sonochemical method for the preparation of carbodiimides from their corresponding thioureas or ureas was described. Using Ph3P–I2 combination in the presence of triethylamine, various diaryl, aryl–alkyl, as well as dialkyl substituted substrates could be converted into carbodiimides in good-to-excellent yields within short reaction times under mild conditions with simple experimental setup. Graphical abstract: [Figure not available: see fulltext.]
- Duangkamol, Chuthamat,Pattarawarapan, Mookda,Phakhodee, Wong
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p. 1945 - 1949
(2016/10/21)
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- Dehydrogenative desulfurization of thiourea derivatives to give carbodiimides, using hydrosilane and an iron complex
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Dehydrogenative desulfurization of thiourea derivatives (RNHC(S)NHR′) has been achieved, to give carbodiimides (RNCNR′), in the reaction with hydrosilane and (η5-C5H5)Fe(CO) 2Me. The obtained carbodiimide reacted with (η5-C 5H5)Fe(CO)(SiR3) formed in the reaction to give an N-silylated η2-amidino iron complex, which was isolated and then characterized by X-ray analysis.
- Hayasaka, Kazumasa,Fukumoto, Kozo,Nakazawa, Hiroshi
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p. 10271 - 10276
(2013/07/26)
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- A New synthetic protocol for the preparation of carbodiimides using a hypervalent iodine(III) reagent
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A new, simple, and efficient preparation of symmetrical and unsymmetrical carbodiimides from the corresponding thioureas via dehydrosulfurization using a hypervalent iodine(III) reagent is described. The oxidation afforded carbodiimides in excellent yields and high selectivity. A possible mechanism for the transformation is proposed. Georg Thieme Verlag Stuttgart New York.
- Zhu, Chenjie,Xu, Dan,Wei, Yunyang
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supporting information; experimental part
p. 711 - 714
(2011/04/24)
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- Synthesis and X-ray crystal structures of imido and ureato derivatives of titanium(iv) phthalocyanine and their application in the catalytic formation of carbodiimides by metathesis from isocyanates
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The imido titanium phthalocyanine complex [PcTi(NDip)] (Dip = 2,6-diisopropylphenyl) 2a was synthesized from [PcTiO] 1 and one eq. of DipNCO. Due to the steric demand of the Dip group, addition of another isocyanate molecule to the TiN functionality of 2a does not occur even at high molar ratios of DipNCO. However, 1 reacts with 2 eq. of arylisocyanates containing sterically less demanding aryl groups producing N,N′- diarylureatotitanium(iv)phthalocyanines [PcTi{κ2-(NR)C(O) (N′R)}] (R = p-tolyl (Tol) 3a or mesityl (Mes) 3b). The N,N′ coordination (III) of the ureato ligand in 3a and 3b was proven by a single set of resonances for the aryl groups in their 1H-NMR spectra. An N,O coordination (IV) can therefore be excluded. This is also confirmed by the X-ray crystal structure of 3a. Upon heating [PcTiO] and an excess of aryl isocyanates for 6 days, a steady evolution of CO2 was observed and a white precipitate, identified as the corresponding diarylcarbodiimides (V), could be isolated. Therefore this reaction was applied in the metathetic conversion of two isocyanate molecules into diarylcarbodiimides (V) and CO2. Additionally, imido titanium Pc's 2b (R = tBu) and 2c (R = Mes) were prepared by a more general synthetic strategy, reacting the potassium salt of the ligand PcK2 with appropriate imido titanium precursors.
- Darwish, Wael,Seikel, Elisabeth,Kaesmarker, Ralf,Harms, Klaus,Sundermeyer, Joerg
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experimental part
p. 1787 - 1794
(2011/05/07)
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- Manganese-catalyzed cleavage of a carbon-carbon single bond between carbonyl carbon and α-carbon atoms of ketones
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Singled out: Treatment of ketones with carbodiimides in the presence of a catalytic amount of either [{HMn(CO)4}3] or [Mn 2(CO)10] gave amides in good to excellent yields. In this reaction, the carbon-carbon single bond of a ketone is cleaved efficiently. The reaction also proceeded by using isocyanates instead of carbodiimides. Copyright
- Kuninobu, Yoichiro,Uesugi, Tadamasa,Kawata, Atsushi,Takai, Kazuhiko
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supporting information; experimental part
p. 10406 - 10408
(2011/12/04)
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- A greener synthetic protocol for the preparation of carbodiimide
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A new and facile preparation of symmetrical and unsymmetrical 1,3-diaryl and aryl-alkyl carbodiimides via a dehydrosulfurisation of their corresponding thioureas is described. Herein, the classical method of oxidative desulfurisation of thiourea to carbodiimide involving toxic heavy metal oxides (HgO) has been replaced with an easily available, cost-effective and environmentally benign reagent, iodine. Simple reaction conditions, easy purification of the products and high yields are important attributes of the present methodology and perhaps the best alternative from a green chemistry perspective. The only limitation to this method however, is in the preparation of 1,3-dialkyl substituted carbodiimide.
- Ali, Abdur Rezzak,Ghosh, Harisadhan,Patel, Bhisma K.
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experimental part
p. 1019 - 1021
(2010/04/02)
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- Copper(II) acetate/oxygen-mediated nucleophilic addition and intramolecular C-H activation/C-N or C-C bond formation: One-pot synthesis of benzimidazoles or quinazolines
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Diarylcarbodiimides or benzylphenylcarbodiimides are converted to 1,2-disubstituted benzimidazoles or 1,2-disustituted quinazolines via addition/intramolecular C-H bond activation/C-N or C-C bond forming reaction using copper(II) acetate/oxygen [Cu(OAc)2/O2] as the oxidant at 100°C in one-pot cascade procedure. Copyright
- He, Hua-Feng,Wang, Zhi-Jing,Bao, Weiliang
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supporting information; experimental part
p. 2905 - 2912
(2010/12/29)
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- Catalytic metathesis of carbon dioxide with heterocumulenes mediated by titanium isopropoxide
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The insertion of an isopropoxide ligand of titanium isopropoxide into heterocumulenes gives a product that carries out metathesis at elevated temperatures by undergoing insertion of a second heterocumulene in a head to head fashion, followed by an extrusion reaction. The Royal Society of Chemistry 2005.
- Ghosh, Rajshekhar,Samuelson, Ashoka G.
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p. 2017 - 2019
(2007/10/03)
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- Preparation and evaluation of a polymer-supported Mukaiyama reagent
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The synthesis of a polymer-supported Mukaiyama reagent is described. This preparation was thoroughly optimized using a DoE approach to achieve optimum loading, and the procedure was successfully applied to prepare the supported reagent on a 10g scale. This reagent proved to be effective for the formation of carbodiimides through the dehydration of thioureas and for a one-pot guanylation of primary amines.
- Convers, Emmanuelle,Tye, Heather,Whittaker, Mark
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p. 3401 - 3404
(2007/10/03)
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- Heterocumulene metathesis by iridium guanidinate and ureylene complexes: Catalysis involving reversible insertion to form six-membered metallacycles
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The four-membered metallacycles Cp*Ir((NAr)2C=Z) have been prepared for Z = NAr and Z = O. These complexes undergo facile exchange with free heterocumulenes. This exchange process can be employed to effect the rapid, catalytic metathesis of aryl carbodiimides at room temperature and the metathesis of aryl carbodiimides with aryl isocyanates at slightly elevated temperature. The exchange process appears to proceed via a novel associative mechanism involving ring expansion to form a six-membered metallacycle rather than cycloreversion to give an imido complex. Observation of key intermediates and the results of crossover experiments support this hypothesis. Copyright
- Holland, Andrew W.,Bergman, Robert G.
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p. 9010 - 9011
(2007/10/03)
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- Preparation and intramolecular cyclization of bis(carbodiimides). Synthesis and X-ray structure of 1,3-diazetidine-2,4-diimine derivatives
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Aza-Wittig reactions of bis(iminophosphorane) 1 derived from 2,2'- diazidobiphenyl with aromatic isocyanates provided dibenzo[d,f]-1,3- diazetidino[1,2-a]diazepine derivatives 2 in moderate yields. Similar results can be achieved from the reaction of 2,2-bis(isothiocyanato)biphenyl 4 with aryliminophosphoranes. Treatment of bis(isothiocyanate) 4 with arylamines and further dehydrosulfurization of the resulting bis(thioureas) leads to the seven-membered ring guanidines 8. N-2(2'-Azido)biphenyl-N'-arylcarbodiimides 13 react with 1 equiv of triphenylphosphane to give zwitterionic compounds 15, which undergo either hydrolytic cleavage to afford the guanidines 8 or react with 1 equiv of aromatic isocyanates to provide 2. Cross-experiments suggest that the conversion 15 ← 2 takes place through a nonisolable bis(carbodiimide) that undergoes an intramolecular [2 + 2] cycloaddition at the final step. The reaction of bis(iminophosphorane) 1 with an excess of carbon dioxide leads to a mixture of the tricyclic 1,3-diazetidine derivative 6 and the 14-membered cyclic bis(carbodiimide) 23, which decomposes by thermal treatment. Compound 6 can also be obtained along with the seven- membered cyclic urea derivatives 24 from the reaction of bis(iminophosphorane) 1 with the carbon dioxide source Boc2O/DMAP system. A comprehensive mechanistic scheme for the aza-Wittig reactions studied is conveniently presented. The molecular and crystal structures of 1-(4- methoxyphenyl)-2-(4-methoxyphenyl)iminodibenzo[d,f]-1,3-diazetidino[1,2- a]diazepine (2c) and [a,c]bis[dibenzo[d,f][1,3]diazepino]-1,3-diazetidine (6) have been determined by X-ray analysis.
- Alajarin,Molina,Sanchez-Andrada,Foces-Foces
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p. 1121 - 1130
(2007/10/03)
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- Preparation of -, -, and -Bicyclic Guanidines from C,C'-Bis(iminophosphoranes)
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A one-pot synthesis of -, -, and -rigid bicyclic guanidines (6, 8, 19, 21, 23) based on a bis(iminophosphorane)-mediated annulation strategy is reported.The crystal and molecular structure of the parent -bicyclic guanidine 8 has been established by X-ray diffraction.The crystallographically independent molecule forms dimers through a centre of symmetry by N-H***N hydrogen bonds.The molecule, and therefore the dimer, is statistically disordered in a 65/35 ratio.A statistical study of N-H***N hydrogen bonds of this kind of dimers has been carried out by using the Cambridge Structural Database. - Key Words: Bis(iminophosphoranes) / Guanidines, bicyclic / Aza Wittig reaction
- Molina, Pedro,Obon, Rosario,Conesa, Carlota,Arques, Antonio,Desamparados Velasco, M. de los,et al.
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p. 1641 - 1652
(2007/10/02)
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- A convenient synthesis of triaryl and trialkyl phosphine dichlorides by oxidation of tertiary phosphines with bis(trichloromethyl) carbonate(triphosgene)
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Tertiary phosphines are quantitatively oxidised by 1/3 of an equivalent of triphosgene to the corresponding P(V)dihalides. This reaction provides an excellent preparation of Ph3PCl2.
- Wells
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p. 1715 - 1719
(2007/10/02)
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- SYNTHESIS AND REACTIONS OF TRIPHENYLARSINIMINES
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Triphenylarsinimines formed in situ from isocyanates and triphenylarsine oxide have been found to react smoothly with carbonyl compounds like aldehydes, quinones and aromatic ketones giving the corresponding Schiff's bases in high yields.In the case of aldehydes, quinones or activated ketones, e.g., α-diketones, only a catalytic amount of triphenylarsine oxide is necessary for the reaction to proceed to completion.Quinones react with particular ease.Thus the previously unknown 9,10-phenanthrenequinone N-phenylimine 12 (R = Ph, Scheme IV) can be prepared in high yield from 9,10-phenanthrenequinone and phenyl isocyanate under catalytic influence of triphenylarsine oxide.Orthoquinones like 9,10-phenanthrenequinone react with vinylic isocyanates, forming monoimines 13 which rearrange to 1,4-oxazines 14 (Scheme V).Diisocyanates react under the catalytic action of triphenylarsine oxide with dialdehydes under mild conditions, forming some interesting new polymers 25, 26 in high yields.Reactions with aliphatic isocyanates give N-alkyl-N'-arylcarbodiimides, whereas reactions with isothiocyanates proceed through intermediates 20 and 21 to mixed carbodiimides 16, 24 and 25. Key words: Triphenylarsinimines; synthesis; reactions; Schiff's bases; unsymmetrical carbodiimides; polymers.
- Froeyen, Paul
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- SYNTHESIS, STRUCTURE AND REACTIVITY OF BIS(N-ARYL-IMINOPHOSPHORANYL)METHANES. X-RAY CRYSTAL STRUCTURES OF (4-CH3-C6H4-N=PPh2)2CH2 AND (4-NO2-C6H4-N=PMe2)2CH2
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The synthesis of novel bis(N-aryl-imino-phosphoranyl)methanes of the type CH2(PR2=N-Ar)2 has been accomplished by reaction of methylene-bisphosphines with arylazides.These compounds have been fully characterized by 1H, 31P and 13C NMR, IR spectroscopy, Field Desorption Mass Spectroscopy (=FDMS) and elemental analysis.Variable temperature NMR experiments and single crystal X-ray structure determination of CH2(PPh2=N-C6H4-CH3-4)2 (1a) and CH2(PMe2=N-C6H4-NO2-4)2 (1f) reveal that bis(N-aryl-imino-phosphoranyl)methane occurs as tautomer 1.Crystals of 1a are orthorhombic, space group Pcab, with a=26.602(2), b=20.521(1), c=11.8859(7) A and V=6488.5(7) A3 (Z=8, R=0.045 and RW=0.066).The crystals of 1f are monoclinic, space group C/2c, with a=20.153(4), b=5.952(1), c=16.930(5) A, β=106.24(3) deg and V=1949.6(6) A3 (Z=4, molecular symmetry C2, R=0.051 and RW=0.079).Both molecules consist of 2 iminophosphoranyl units bridged by a methylene group.The P=N bond distances of 1.568(2) and 1.566(2) A for 1a and 1.580(4) A for 1f represent normal values for iminophosphoranyl compounds.The N-C bond lengths of 1.386(2) and 1.390(2) A (1a) or 1.372(5) A for 1f indicate that some electron delocalization over the N-aryl moiety takes place.In 1a the electron delocalization takes place separately in each iminophosphoranyl entity, while in 1f electron delocalization occurs only in the N-aryl-NO2 moiety.Compound 1a is easily deprotonated using lithium-diisopropylamide or NaH and shows typical iminophosphoranyl chemistry, since with CO2 an aza-Wittig reaction has been found and with HX (X=Cl, Br) protonation of both imide nitrogen atoms has been observed.
- Imhoff, P.,van Asselt, R.,Elsevier, C. J.,Vrieze, K.,Goubitz, K.,et al.
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p. 401 - 415
(2007/10/02)
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- THERMAL REACTIONS OF 1-ARYL-5-METHYLTETRAZOLES
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The mechanism of the thermal reactions of 1-aryl-5-methyltetrazoles, which involve isomerization to the azide, elimination of a nitrogen molecule, and formation of singlet nitrenes followed by isomerization to benzimidazoles and carbodiimides, has been studied by combinig the methods of derivatography and the current arsenal of mass-spectrometric techniques.The influence of the electronic properties of the substituent (in the para position of the benzene ring) on the course of the thermolysis has been established.
- Shurukhin, Yu. V.,Klyuev, N. A.,Grandberg, I. I.,Konchits, V. A.
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p. 1177 - 1182
(2007/10/02)
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- Polystyrene-Supported Carbodiimide Catalysts
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Polystyrene-anchored triphenylarsine oxide 8 has been prepared from brominated polystyrene beads by a lithium-mediated arsenation-hydrogen peroxide oxidation sequence.Compound 8 with only 0.6 mequiv of As/g has been found to be a highly effective, insoluble catalyst for the conversion of aryl isocyanates to diarylcarbodiimides in high yield.Up to 5.6 x 104 turnovers of the catalyst 8 in the carbodiimide-forming reaction have been measured when appropriate measures are taken to prevent its deactivation.Several arylcarbodiimides have been prepared in high yield by using 8.
- Smith, Curtis P.,Temme, George H.
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p. 4681 - 4685
(2007/10/02)
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- Activation of CO2-like molecules: Synthetic and structural studies on a η2-C,N metal-bonded carbodiimide and its conversion into a η2-C,N metal-bonded amidinyl ligand
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Vanadocene reacts with p-tolylcarbodiimide (p-TCD) producing a metallaazacyctopropane-like complex Cp2V(RN-C=NR) (I) (R = p-CH3C6H4; Cp = η5-C5H5; vCN(Nujol) 1645 cm-1; μeff = 1.76 μB at 293.5 K). The X-ray analysis performed on complex I shows that vanadium is η5 bonded to the two Cp rings, which are in a bent arrangement, making a cavity in the equatorial plane for the CN2 unit. The C-N bond distances agree with the presence of a single C-N bond interacting with the metal and a free C=N double bond. Complex I reacts with both O2 and I2, releasing p-TCD. Coordinated p-TCD is converted in a η2-C,N metal-bonded trialkylamidinyl ligand by the action of CH3I on complex I. The reaction with CH3I, followed by the addition of I2, allowed isolation of [Cp2V(R(CH3)NC=NR)]I3 (II) (R = p-CH3C6H4; vCN(Nujol) 1680 cm-1; μeff = 1.78 μB at 293 K). The X-ray analysis showed an overall structure of the cation similar to that of I, with the amidinyl ligand acting as a three-electron-donor ligand and displaying a bonding mode similar to that observed for η2-C,O acyls and η2-C,N iminoacyls. The two C-N bond distances within the CN2 unit have a high double-bond character (1.26 (2) and 1.33 (2) A?), indicating a significant electronic delocalization all over the VCN2 unit with a carbenoid character for the carbon bonded to the vanadium atom. In both complexes, V-C bond distances (about 2.0 A?) fall in the expected range for a V-C (sp2) bond. Crystallographic details for complex I: space group Pna21 (orthorhombic); a = 14.446 (3) A?, b = 14.186 (2) A?, c = 20.903 (4) A?, V= 4283.7 A?3; Z = 8; Dcalcd = 1.251 g cm-3. The final R factor was 8.4% for 1439 observed reflections. Crystallographic details for complex II: space group P21/c (monoclinic); a = 14.260 (6) A?, b = 19.176 (5) A?, c = 10.628 (4) A?; β = 106.92 (5)°; V = 2780.4 A?3; Z = 4; Dcalcd = 1.910 g cm-3. The final R factor was 6.3% for 2283 observed reflections.
- Pasquali, Marco,Gambarotta, Sandro,Floriani, Carlo,Chiesi-Villa, Angiola,Guastini, Carlo
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p. 165 - 171
(2008/10/08)
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