cas 7188-38-7, TERT-BUTYL ISOCYANIDE | Articles data

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Facile Synthesis of Cyanide and Isocyanides from CO
The reaction of K[N(SiMe3)2] with 13CO proceeds in C6D6 or THF affording K13CN and O(SiMe3)2 under mild conditions as confirmed by crystallographic characterization of K(18-crown-6)CN. Similarly reaction of the alkali metal amides, M[N(SiR3)R′] (M=Li, K; R=Ph, Me; R′=alkyl, aryl) provides the corresponding 13C labeled isocyanide RN13C and MOSiR3, generally in high yields. In some instances, the use of the sterically bulky Ph3Si-substituent is required to preclude 1,2-silyl migration affording the silylcarbamoyl salt M[Me3SiC(O)NR′]. These reactions have been used to obtain 19 examples of 13C labelled isocyanides, and several examples of gram scale reactions are reported. The mechanism of the reactions is probed via reliable DFT calculations.
Grimme, Stefan,Kooij, Bastiaan,Lin, Jack H.,Qu, Zheng-Wang,Stephan, Douglas W.,Wang, Tongtong,Xu, Maotong
supporting information
p. 16965 - 16969
(2021/06/28)

Process method for preparing tert-butyl isocyanide
The invention discloses a process method for preparing tert-butyl isocyanide, which comprises the following step of: carrying out a reaction with tert-butylamine as a raw material and an ortho-formatecompound under the action of alkali and a catalyst to obtain the tert-butyl isocyanide. The method has the advantages of cheap and easily available raw materials, environment-friendly process, high safety, high yield and high product purity.
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Paragraph 0048-0057

(2020/06/09)

Magnesium Aldimines Prepared by Addition of Organomagnesium Halides to 2,4,6-Trichlorophenyl Isocyanide: Synthesis of 1,2-Dicarbonyl Derivatives
The selective addition of organomagnesium reagents to 2,4,6-trichlorophenyl isocyanide leading to magnesiated aldimines is reported. These aldimines react with Weinreb amides, ketones, or carbonates to provide the corresponding carbonyl derivatives after acidic cleavage. This allows for an efficient synthesis of 1,2-dicarbonyl compounds and α-hydroxy ketones.
Schw?rzer, Kuno,Bellan, Andreas,Z?schg, Maximilian,Karaghiosoff, Konstantin,Knochel, Paul
p. 9415 - 9418
(2019/05/10)

Facile, catalyst-free cascade synthesis of sulfonyl guanidines: Via carbodiimide coupling with amines
An expeditious catalyst-free cascade coupling of N,N-dibromoarylsulfonamides with isonitriles and amines via carbodiimide intermediates has been developed. The protocol represents an elegant pathway for sulfonyl guanidines at room temperature within a short time with high yields and wide substrate scope. The carbodiimide intermediate could also be isolated in an appreciable yield.
Hazarika, Debojit,Borah, Arun Jyoti,Phukan, Prodeep
supporting information
p. 1418 - 1421
(2019/02/05)

Tandem reaction strategy of the Passerini/Wittig reaction based on the in situ capture of isocyanides: One-pot synthesis of heterocycles
This paper reports the tandem reaction strategy of the Passerini/Wittig reaction based on the in situ capture of isocyanides. According to this strategy, plenty of isocyanides have been synthesized, which is immediately used for the tandem reaction of Passerini/Wittig reaction in one pot. Compared to the previous work, this strategy avoids the separation, purification, and storage of isocyanides, which prominently solves the problems of isocyanide-based multicomponent reaction such as: (a) The environmentally unfriendly (strong foul odor), (a) the labile of Isocyanides, (c) high toxicity of isocyanides. In the meantime, in order to expand the application scope of our strategy, 1H-isochromenes and 3H-2-benzoxepin-1-ones have also been synthesized, which undergoes four-step transformations in one-pot. In addition, a relatively credible reaction mechanism has also been proposed, based on a series of control experiments. Furthermore, preliminary testing was performed on biological activity of some obtained compounds; These results showed that the synthesized compounds exhibited certain activity over P. digitatum and P. italicum. 2019 Elsevier Science. All rights reserved.
Liu, Ming-Guo,Liu, Na,Xu, Wen-Heng,Wang, Long
p. 2748 - 2754
(2019/04/04)

Odorless Isocyanide Chemistry: One-Pot Synthesis of Heterocycles via the Passerini and Postmodification Tandem Reaction Based on the in Situ Capture of Isocyanides
This paper reports the tandem reaction strategy of the Passerini/Staudinger/aza-Wittig reaction based on the in situ capture of isocyanides. According to this strategy, isocyanides are synthesized in situ and immediately work as the substrate for the Passerini reaction and postmodification tandem reaction in one pot. In addition, two types of new compounds, 5-oxo-3,5-dihydrobenzo[e][1,4]oxazepines and 6-oxo-5,6-dihydro-2H-1,4-oxazines, were synthesized using the tandem reaction strategy that includes five-step transformations in one pot.
Liu, Na,Chao, Fei,Liu, Ming-Guo,Huang, Nian-Yu,Zou, Kun,Wang, Long
p. 2366 - 2371
(2019/05/16)

Scaffold hopping via ANCHOR.QUERY: β-lactams as potent p53-MDM2 antagonists
Using the pharmacophore-based virtual screening platform ANCHOR.QUERY, we morphed our recently described Ugi-4CR scaffold towards a β-lactam scaffold with potent p53-MDM2 antagonizing activities. 2D-HSQC and FP measurements confirm potent MDM2 binding. Molecular modeling studies were used to understand the observed SAR in the β-lactam series.
Shaabani,Neochoritis,Twarda-Clapa,Musielak,Holak,D?mling
p. 1046 - 1052
(2017/07/12)

Multiple Roles of Isocyanides in Palladium-Catalyzed Imidoylative Couplings: A Mechanistic Study
Kinetic, spectroscopic and computational studies examining a palladium-catalyzed imidoylative coupling highlight the dual role of isocyanides as both substrates and ligands for this class of transformations. The synthesis of secondary amides from aryl halides and water is presented as a case study. The kinetics of the oxidative addition of ArI with RNC-ligated Pd0species have been studied and the resulting imidoyl complex [(ArC=NR)Pd(CNR)2I] (Ar=4-F-C6H4, R=tBu) has been isolated and characterized by X-ray diffraction. The unprecedented ability of this RNC-ligated imidoyl-Pd complex to undergo reductive elimination at room temperature to give the amide in the presence of water and an F?/HF buffer is demonstrated. Its behavior in solution has also been characterized, revealing an unexpected strong tendency to give cationic complexes, and notably [(ArC=NR)Pd(CNR)3]+with excess isocyanide and [(ArC=NR)Pd(PP)(CNR)]+with bidentate phosphines (PP). These species may be responsible for catalyst deactivation and side-reactions. Ab initio calculations performed at the DFT level allowed us to rationalize the multiple roles of RNC in the different steps of the catalytic cycle.
Perego, Luca A.,Fleurat-Lessard, Paul,El Ka?m, Laurent,Ciofini, Ilaria,Grimaud, Laurence
supporting information
p. 15491 - 15500
(2016/10/13)

Synthesis of Isoselenocyanates
Isoselenocyanates were synthesized by two methods under phase-transfer conditions (50% aq NaOH, CH2Cl2, Aliquat 336); the first started from isocyanides and selenium and gave isoselenocyanates in 61-89% yields, while the second started from amines and used chloroform and selenium, by applying sequentially the Hofmann isonitrile synthesis and the addition of selenium, in 4-70% yields.
Zakrzewski, Jerzy,Huras, Bogumi?a,Kie?czewska, Anna
p. 85 - 96
(2015/12/26)

One-pot synthesis of pyrroles using a titanium-catalyzed multicomponent coupling procedure
A simple one-pot procedure for the production of 2-carboxylpyrroles with 4-alkyl, 5-alkyl, 4-aryl, 4-aryl-5-alkyl, or 3,4-diaryl substitution patterns is presented. The procedure involves the titanium-catalyzed multicomponent coupling of alkynes, primary amines and isonitriles to give 1,3-diimines in situ; the multicomponent product is then treated with the ethyl ester of glycine hydrochloride to give the NH-pyrrole. The reaction can be carried out with the neutralized glycine ester or with the hydrochloride salt using DBU as a base. Yields of pyrrole based on starting alkyne varied from 25 to 65% over the one pot procedure, and in most cases only one regioisomer of the product is observed. Further, it is proposed that the regioselectivities of the reactions are a result of rate-determining ring closure after relatively fast transimination with glycine ethyl ester.
Pasko, Cody M.,Dissanayake, Amila A.,Billow, Brennan S.,Odom, Aaron L.
p. 1168 - 1176
(2016/02/16)

Synthesis and structure–activity relationship of α-keto amides as enterovirus 71 3C protease inhibitors
α-Keto amide derivatives as enterovirus 71 (EV71) 3C protease (3Cpro) inhibitors have been synthesized and assayed for their biochemical and antiviral activities. structure–activity relationship (SAR) study indicated that small moieties were primarily tolerated at P1' and the introduction of para-fluoro benzyl at P2 notably improved the potency of inhibitor. Inhibitors 8v, 8w and 8x exhibited satisfactory activity (IC50= 1.32 ± 0.26 μM, 1.88 ± 0.35 μM and 1.52 ± 0.31 μM, respectively) and favorable CC50values (CC50> 100 μM). α-Keto amide may represent a good choice as a warhead for EV71 3Cproinhibitor.
Zeng, Debin,Ma, Yuying,Zhang, Rui,Nie, Quandeng,Cui, Zhengjie,Wang, Yaxin,Shang, Luqing,Yin, Zheng
supporting information
p. 1762 - 1766
(2016/12/22)

Higher-order cyclopropenimine superbases: Direct neutral br?nsted base catalyzed michael reactions with α-aryl esters
The synthesis and characterization of six new classes of higher-order superbases, including five that incorporate cyclopropenimine functionality, has been achieved. We propose a nomenclature that designates these as the CG2, GC2, PC3, PC1, C3, and GP2 classes of superbases. The pKBH+ values were measured to be between 29.0 and 35.6 in acetonitrile. Linear correlations of ten superbase basicities vs that of their substituents demonstrated the insulating effect of the cyclopropenimine core. The molecular structures of several of these materials were obtained by single-crystal X-ray analysis, revealing interesting aspects of conformational bias and noncovalent organization. The types of superbasic cores and substituents were each reliably shown to affect selectivity for deprotonation over alkylation. Higher-order cyclopropenimine and guanidine superbase stability to hydrolysis was found to correlate to basicity. Finally, a GC2 base was found to catalyze conjugate additions of α-aryl ester pronucleophiles, representing the first report of a neutral Br?nsted base to catalyze such reactions.
Nacsa, Eric D.,Lambert, Tristan H.
supporting information
p. 10246 - 10253
(2015/09/01)

Palladium-catalyzed direct coupling of 2-vinylanilines and isocyanides: An efficient synthesis of 2-aminoquinolines
Palladium-catalyzed oxidative coupling of 2-vinylanilines and isocyanides constitutes a direct, facile, and efficient approach to 2-aminoquinolines. The procedure, employing palladium acetate and silver carbonate, is attractive in terms of assembly efficiency, functional group tolerance, and operational simplicity. A variety of 2-aminoquinolines were prepared in good to excellent yields.
Wang, Lijie,Ferguson, Jamie,Zeng, Fanlong
supporting information
p. 11486 - 11491
(2015/12/04)

Isocyanides as influenza A virus subtype H5N1 wild-type M2 channel inhibitors
Basic bulky amines such as amantadine are well-characterized M2 channel blockers, useful for treating influenza. Herein we report our surprising findings that charge-neutral, bulky isocyanides exhibit activities similar to - or even higher than - that of amantadine. We also demonstrate that these isocyanides have potent growth inhibitory activity against the H5N1 virus. The -NH2 to -N≡C group replacement within current anti-influenza drugs was found to give compounds with high activities at low-micromolar concentrations. For example, a tenfold improvement in potency was observed for 1-isocyanoadamantane (27), with an EC50 value of 0.487 μm against amantadine-sensitive H5N1 virus as determined by both MTT and plaque-reduction assays, without showing cytotoxicity. Furthermore, the isocyanide analogues synthesized in this study did not inhibit the V27A or S31N mutant M2 ion channels, according to electrophysiology experiments, and did not exhibit activity against amantadine-resistant virus strains. Charge-neutral bulky isocyanides were found to exhibit antiviral activities similar to - or even higher than - that of amantadine. Moreover, we demonstrated that these isocyanides have potent growth inhibitory activity against the wild-type H5N1 virus. The NH2 to N≡C group replacement within current anti-influenza drugs was found to result in compounds with low-micromolar activities.
Wu, Shuwen,Huang, Jing,Gazzarrini, Sabrina,He, Si,Chen, Lihua,Li, Jun,Xing, Li,Li, Chufang,Chen, Ling,Neochoritis, Constantinos G.,Liao, George P.,Zhou, Haibing,D?mling, Alexander,Moroni, Anna,Wang, Wei
p. 1837 - 1845
(2015/11/10)

Skeletal rearrangement of cyano-substituted iminoisobenzofurans into alkyl 2-cyanobenzoates catalyzed by B(C6F5)3
An efficient method for the direct conversion of cyano-substituted iminoisobenzofurans into their corresponding alkyl 2-cyanobenzoates has been developed. This transformation proceeds via cleavage of C-C, C-O, and C-N bonds in starting iminoisobenzofurans. DFT study revealed that intermediate α-iminonitriles are produced in situ via C-C bond formation between 2-iminium benzoates and a cyanide ion. Generation of isocyanide as the byproduct in a more thermodynamic manner in DFT calculations also supports the experimental results.
Li, Jing,Okuda, Yasuhiro,Zhao, Jiaji,Mori, Seiji,Nishihara, Yasushi
supporting information
p. 5220 - 5223
(2014/12/11)

Multicomponent cascade cycloaddition involving tropone, allenoate, and isocyanide: A rapid access to a 7,6,5-fused tricyclic skeleton
Multicomponent cascade cycloaddition of tropone, allenoate, and isocyanide has been disclosed. This method allows for the rapid construction of a highly unusual tricyclic skeleton in an efficient manner. The proposed transformation proceeds through [8 + 2 + 1] cycloaddition, [1,5]-H shift, and cyclization followed by an alkoxy group migration process.
Jia, Shuanglong,Su, Shikuan,Li, Chunju,Jia, Xueshun,Li, Jian
supporting information
p. 5604 - 5607
(2015/02/19)

A general simple methodology for synthesis of isonitriles using benzene-1,3-disulfonyl dichloride
Isonitrile derivatives have been synthesized in good to high yields by dehydration of aliphatic and aromatic formamides in the presence of benzene-1,3-disulfonyl dichloride as easy and efficient reagent.
Ghorbani-Vaghei, Ramin,Amiri, Mostafa,Veisi, Hojat
p. 37 - 41
(2013/07/26)

Odorless isocyanide chemistry: An integrated microfluidic system for a multistep reaction sequence
Can't smell this: An integrated continuous-flow microfluidic setup enables in situ generation, extraction, separation, and reaction of foul-smelling isocyanides with little exposure to the surroundings. Isocyanides were generated by dehydration of the corresponding N-substituted formamides, and several representative isocyanide-based organic reactions were successfully performed. DIPEA=N,N-diisopropylethylamine. Copyright
Sharma, Siddharth,Maurya, Ram Awatar,Min, Kyoung-Ik,Jeong, Guan-Young,Kim, Dong-Pyo
supporting information
p. 7564 - 7568
(2013/07/26)

Synthesis and evaluation of inhibitors of bacterial drug efflux pumps of the major facilitator superfamily
Inhibitors of drug efflux pumps have great potential as pharmacological agents that restore the drug susceptibility of multidrug resistant bacterial pathogens. Most attention has been focused on the discovery of small molecules that inhibit the resistance nodulation division (RND) family drug efflux pumps in Gram-negative bacteria. The prototypical inhibitor of RND-family efflux pumps in Gram-negative bacteria is MC-207,110 (Phe-Arg-β-naphthylamide), a C-capped dipeptide. Here, we report that C-capped dipeptides inhibit two chloramphenicol-specific efflux pumps in Streptomyces coelicolor, a Gram-positive bacterium that is a relative of the human pathogen Mycobacterium tuberculosis. Diversity-oriented synthesis of a library of structurally related C-capped dipeptides via an Ugi four component reaction and screening of the resulting compounds resulted in the discovery of a compound that is threefold more potent as a suppressor of chloramphenicol resistance in S. coelicolor than MC-207,110. Since chloramphenicol resistance in S. coelicolor is mediated by major facilitator superfamily drug efflux pumps, our findings provide the first evidence that C-capped dipeptides can inhibit drug efflux pumps outside of the RND superfamily.
Okandeji, Babajide O.,Greenwald, Daniel M.,Wroten, Jessica,Sello, Jason K.
experimental part
p. 7679 - 7689
(2012/02/05)

Syntheses of spirocyclic oxindole-butenolides by using three-component cycloadditions of isocyanides, allenoates, and isatins
Spiro workflow! Efficient syntheses of spirocyclic oxindole-butenolides from readily available isocyanides, allenoates, and isatins are disclosed (see scheme; R1=alkyl, aryl; R2=halide, nitro, methoxy; PG=protecting group). This protocol also allows the insertion of carbon monoxide into organic molecules without the aid of a transition-metal catalyst after the hydrolysis process. Copyright
Li, Jian,Liu, Yuejin,Li, Chunju,Jia, Xueshun
supporting information; experimental part
p. 7409 - 7413
(2011/08/05)

Syntheses and15N NMR Spectra of Iminodiaziridines - Ring-Expansions of 1-Aryl-3-iminodiaziridines to 1H- and 3aH-Benzimidazoles, 2H-Indazoles, and 5H-Dibenzo[d,f] [1,3]diazepines
Iminodiaziridines are synthesized, by (i) 1,3-dehydrochlorination with potassium, teri-butoxide of N-chloroguanidines, generated in situ from. N,N′,N″-substituted guanidines with tert-butyl hypochlorite, and (ii) base-mediated 1,3-elimination of sulfuric acid from N,N',N″- substituted hydroxyguanidine O-sulfonic acids. At elevated temperatures, (alkylimino)diaziridines undergo valence isomerization by 1,3shift, [2+1] cycloelimination to afford isocyanides and diazenes, and ring-opening elimination to yield alkylideneguanidines. N′-Aryl-N-hydroxyguanidine O-sulfonic acids furnish (N-arylimino)diaziridines, but no 1-aryl-3- iminodiaziridines, instead giving rearranged isomere. Precursors containing perdeuterated feri-butyl groups give rearranged products that show complete scrambling. This indicates that l-aryl-3iminodiaziridines are intermediates that undergo very rapid I degenerate valence isomerization. Provided that the ortho aryl positions are substituted, high yields of (arylimino)diaziridines are obtained, along with 2-imino-2,3-dihydro-3aHbenzimidazoles, Otherwise, 2-amino-lH-benzimidazoles and strongly fluorescent 3-amino-2H-indazoles, originating from rearrangements of the elusive l-aryl-3-iminodiaziridines, predominate. N',N″-Diaryl-N-hydroxyguanidine O-sulfonic acids give only rearranged products: a 2-amino-1H-benzimidazole and a 6-amino-5H-dibenzo[d,f][1. 3]diazepine if aryl = phenyl, or a 2-imino-2,3-dihydro-3aH-benzimidazole if aryl = mesityl. 3aH-Benzimidazoles slowly dimerize through Diels-Alder reactions. 15N NMR signals were assigned, to the syn and anti ring nitrogen atoms of iminodiaziridines with the help of a combination of homonuclear NOE and HNHMBC or HN-gHMBC experiments.
Quast, Helmut,Ross, Karl-Heinz,Philipp, Gottfried,Hagedorn, Manfred,Hahn, Harald,Banert, Klaus
supporting information; experimental part
p. 3940 - 3952
(2010/03/01)

Synthesis, configuration, and 15N NMR spectra of iminoaziridines. Synthons equivalent to three components of the ugi reaction
Monocyclic iminoaziridines and exo-endo diastereomers of spirocyclic iminoaziridines that are derived from norbornane are prepared in batches of up to 10 g to foster applications as building blocks in syntheses. N,N′-Disubstituted α-haloamidines, which are readily available in two steps from N-substituted α-halocarboxamides, are 1,3- dehydrohalogenated by strong bases such as alkali-metal hydrides or tert-butoxides to afford distillable oils or low-melting solids, which consist of slowly interconverting E-Z diastereomers of the title compounds. The scope and limitations are outlined for this reaction. The configurations E and Z that were assigned on the basis of homoallylic 1H-1H coupling and asymmetric solvent-induced shifts required that, in 13C NMR spectra, the observed γ-effects of substitutents at the imino nitrogens were deshielding, contrary to the well-known shielding γ-effects in all other types of C=N compounds. However, an NOE NMR study demonstrated unequivocally that the previous assignments are correct and hence the observed γ-effects actually deshielding. The ranges of 15N NMR chemical shifts span more than 60 ppm. Neither the β- nor the γ-effects of substituents on both types of nitrogen follow a uniform increment pattern.
Quast, Helmut,Aldenkortt, Sven,Freudenreich, Bernd,Schaefer, Peter,Hagedorn, Manfred,Lehmann, Jens,Banert, Klaus
p. 1659 - 1666
(2007/10/03)

Microwave-assisted synthesis of isonitriles: A general simple methodology
(Chemical Equation Presented) A facile conversion of formamides to isonitriles under very mild conditions and microwave irradiation is described. This simple and efficient method has been applied for the synthesis of both aliphatic and aromatic isonitriles in high yields.
Porcheddu, Andrea,Giacomelli, Giampaolo,Salaris, Margherita
p. 2361 - 2363
(2007/10/03)

Isonitrile insertion into the Ru-O bond and migratory C-C bond formation. Novel organoruthenium imidic ester and acyl species
A report on isonitrile insertion into the Ru-O bond and migratory C-C bond formation was presented in the article. It was found that the equatorial coordination planes are RuC4, RuC2OCl, and RuC3O, respectively, the axis being uniformly defined by the trans RuP2 fragment. Logarithmic rate constants were found to vary linearly with the Hammett constant of the R substituent, consistent with nucleophilic aryl migration.
Panda, Bikash Kumar,Chattopadhyay, Swarup,Ghosh, Kaushik,Chakravorty, Animesh
p. 2773 - 2780
(2008/10/08)

Kinetic and mechanistic studies of sulfur transfer from imidomethylrhenium sulfides
The bis(2,6-diisopropylphenylimido)methylrhenium(VII) sulfide dimer, {CH3Re(NAr)2}2(μ-S)2 (1), reacts with a 1:1 amount of a phosphine or an alkyl isocyanide to yield a dimeric rhenium(VI) species, {CH3Re(NAr)2}2(μ-S) (2), which has been structurally characterized. The two rhenium atoms in 2 are within bonding distance, 280 pm, more than 90 pm shorter than in 1. With excess L, 1 reacts to give a monomeric rhenium(V) complex, CH3Re(NAr)2L2 (3A, L = PZ3, Z = alkyl, aryl; 3B, L = isocyanide). The rate of formation of 3A is first-order with respect to [1] and second-order with respect to monodentate phosphine concentrations. With bidentate phosphines, however, the order with respect to the phosphine drops to unity. The addition of another (nonoxidizable) coordinating ligand, such as pyridine or one of its derivatives, accelerates the formation of 3A. In the presence of a pyridine ligand the reaction is first-order with respect to phosphine concentration, both monodentate and bidentate. The reactions between phosphines and 2 are slower than those with 1, which excludes [CH3Re(NAr)2]2(μ-S) from being the intermediate in the reactions of 1. To account for that, we have proposed an intervening species that partitions between transformation to 3 with excess L and to 2 otherwise.
Wang, Wei-Dong,Guzei, Ilia A.,Espenson, James H.
p. 4780 - 4787
(2008/10/08)

About four new trityl-substituted α-lactams
This investigation comprises the synthesis, a description of the physical and spectroscopic properties, determination of the limits of thermal stability, and reactions with protic and aprotic nucleophiles of four new trityl-substituted α-lactams. With the exception of 3,3-dimethyl-1-tritylaziridin-2-one (4a), which is unstable at room temperature, all new compounds have been fully characterized.
Lengyel, Istvan,Cesare, Victor,Adam, Ian,Taldone, Tony
p. 73 - 95
(2007/10/03)

α-Thioxothioamides: A formal [4+1] cycloaddition reaction with isocyanides and diisocyanides and its application to a new straightforward formation of extended tetrathiafulvalenes
A number of 2-(alkylimino) and 2-(arylimino)-l,3-dithioles (aza DTFs) bearing push-pull substituents have been prepared under mild conditions according to the title procedure. This novel strategy relies upon the fact that the use of conjugated diisocyanides allows an effective synthesis of new extended tetrathiafulvalenes (TTFs). The two dithiole moieties are linked by a conjugated framework that incorporates a phenyl, biphenyl or azobiphenyl group. High and low temperature measurements are required in order to understand the complex 1H and 13C NMR spectra of the prepared mono-bis- and tris-(1,3-dithiole) derivatives. Their electrochemical oxidations are also described.
Morel, Georges,Marchand, Evelyne,Sinbandhit, Sourisak,Carlier, Roger
p. 655 - 662
(2007/10/03)

Novel zwitterionic diallylzirconium complexes: Synthesis, structure, polymerization activity, and deactivation pathways
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Pindado, Gerardo Jimenez,Thornton-Pett, Mark,Bouwkamp, Marco,Meetsma, Auke,Hessen, Bart,Bochmann, Manfred
p. 2358 - 2361
(2007/10/03)

Synthesis and Thermal Reorganisations of Iminoaziridines. Ab Initioo Calculations of Their Transition States, of Diazatrimethylenemethanes, and Some Cyclic Members of the C2H4N2 Potential-Energy Hypersurface
2-Iminoaziridine 19 and the pairs of isomers 22/23 and 32/33 can be obtained in high yields by base-induced 1,3-dehydrohalogenation of the corresponding α-halo amidines.Regioselectivity of the ring closure reaction of 21 is achieved by treatment with potassium hydride as base in the presence of 18-crown-6 to afford almost exclusively 23.At low temperatures, the cyclisation of 21a under the influence of potassium tert-butoxide occurs diastereoselectively yielding (Z)-22 and (Z)-23 (87:13).Resolution of racemic 21a can be attained by single recrystallisation of the nicely crystallised mandelates of the like configuration, thus providing an efficient route to (R)- and (S)-23 of high enantiomeric purity.Chiroptical data are reported for 21a and 23. - (E)- and (Z)-22 equilibrate faster by more than one order of magnitude than (E)- and (Z)-23 but almost the same preference for the E diastereomer is found in both cases. - Only first-order decomposition into isocyanides 6 and imines is observed on thermolysis of 19, 22, 23, and 32 with activation parameters depending on the substitution pattern.In contrast, the thermal valence isomerisation 35 -> 36 is fast enough to complete with the cycloreversion of 35.Thermal racemisation of (R)-23 does not occur.Quantum-chemical calculations were performed on the parent iminoaziridines (E)- and (Z)-38, 3-amino-2H-azirine (39), the methylenediaziridines cis- and trans-40, and diastereomeric closed-shell and open-shell planar (41) and (open-shell) "mono-orthogonal" diazatrimethylenemethanes 42, 43.Complete geometry optimisations were appropriately performed with the RHF/6-31+G** and the UHF/6-31+G** basis sets.Energies of the closed-shell states were calculated on the RHF, MP2, MP4SDTQ, and CCSD(T) levels, those of open-shell states on the UHF, UMP2, UMP4SDTQ, and CCSD(T)/UHF levels. - (E)-38, being lowest in energy of the parent iminoaziridines (Erel = 0.0), equilibrates with (Z)-38 via an almost linear transition state (Erel = 113.4 kJ mol-1) and decomposes into hydrogen isocyanide and formaldimine in a one-step cheletropic process rel = 179.8 kJ mol-1, CCSD(T)/RHF> with a highly unsymmetrical transition state in which the N1-C2 bond is almost completely broken whereas the C2-C3 bond is still strong.The same is true for the cheletropic decomposition of (Z)-38 the transition state of which (Erel = 168.2 kJ mol-1) is even lower by 11.6 kJ mol-1. - Energy-rich zwitterionic transition states are found with the RHF method among which 1A'-(E,Z)-41 is lowest in energy rel = 203.0 ... - Keywords: Aziridines, 2-imino-, chiral, non-racemic; Amidines, N,N'-dialkyl-2-halo-; 1,3-Dehydrohalogenation, regioselectivity and diastereoselectivity of; E/Z Diastereomerisation; Cycloreversion of isocyanides and imines; Valence isomerisation; Calculations, high-level ab initio, RHF, UHF, MPn, CCSD(T); 2H-Azirine, 3-amino; Diaziridine, 3-methylene; Diazatrimethylenemethanes, diastereomeric, closed-shell and open-shell; Reorganisations, transition states of thermal
Quast, Helmut,Aldenkortt, Sven,Schaefer, Peter,Schmitt, Edeltraud,Wuerthwein, Ernst-Ulrich
p. 2171 - 2188
(2007/10/03)

PYROLYTIC FRAGMENTATION AND REARRANGEMENT OF 1-METHOXYCYCLOPROPYLAMINES
N-Alkyl 2,2-dialkyl-1-methoxycyclopropylamines undergo a pyrolytic fragmentation into alkylisocyanides, methanol, 1,1-dialkylethylenes and novel α,β-unsaturated ketimines.Synthetic methods were developed for the generation of the latter 1-aza-1,3-dienes.
Kimpe, Norbert de,Buck, Kurt de,Booten, Karl
p. 393 - 396
(2007/10/02)

Thermal Reorganization and Cycloaddition Reactions of a Chiral, Non-Racemic Aziridinone (α-Lactam) and Ab Initio Calculations of the C2H3NO Energy Hypersurface
The thermal reorganization of the racemic (1a) and the non-racemic aziridinone (R)-1a (92percent e.e.) is studied in solution in the temperature range of 100-140 deg C.Besides traces of the imine 8, which is the product of a direct cycloreversion of 1a, the aldehyde 2a and the isocyanide 4a are formed in almost quantitative yield.A small fraction of the latter rearranges to the nitrile 3 or adds to unchanged 1a to afford the iminoazetidinone (E)-5a (5-10percent), which is obtained when neat 1a is heated in the presence of 4a.The configuration of (E)-5a is based on nuclear Overhauser experiments.The disappearance of 1a follows a first-order rate law with k = 44 * 10-6 s-1 at 130 deg C, while racemization of (R)-1a is observed with k (S)-1a> = 8.1 * 10-6 s-1.The formal cycloaddition of tert-butyl isocyanide (4a) to (R)-1a produces (E,R*)-5a of unknown absolute configuration and a low enantiomeric excess (ca.10percent).The product (E,R*)-5a is not racemized under the reaction conditions.The results are interpreted in terms of a nucleophilic attack of the isocyanide 4a to C-3 of (R)-1a resulting in an acyclic nitrilium type zwitterion (R)-21 which, to a large extent racemizes via the ketene imine 22 before ring-closure to the final product (E,R)-5a. - Dimethylformamide reacts with (R)-1a at temperatures as low as 80-100 deg C to give the diastereomeric oxazolidin-5-ones cis- and trans-15.The former is formed first and subsequently isomerizes to trans-15.The configuration of cis- and trans-15 is based on nuclear Overhauser experiments.The proton signals of the dimethylamino group of both cis- and trans-15 are temperature-dependent and split into two singlets of equal intensity at Tc = 271 and 250 K as a result of the retardation of two processes, viz. the N inversion and the rotation around the (C-NMe2) bond.In the reaction of (R)-1a with dimethylformamide, the oxazolidinones (2R,5S)- and (2S,5S)-15 (85-90percent e.e.) are formed which are hydrolyzed to the known α-hydroxyamide (S)-16.Hence, the configuration at C-5 of both cis- and trans-15 is (S), and the cycloaddition of (R)-1a to dimethylformamide involves inversion at C-3 of (R)-1a.This result strongly suggests a nucleophilic attack of dimethylformamide to (R)-1a rather than trapping of an acyclic aziridinone isomer. - In order to rationalize the observed reactions and reactivities, we performed high-level calculations on the parent aziridinone 29 and its cyclic (30, 31) and acyclic (32-35) isomers as well.Among the three-membered rings, 29 (MP2/6-31G*//6-31G*, Erel = 0.00 kJ mol-1) is lowest in energy, followed by the iminooxiranes (E)- and (Z)-31 (Erel = 30.8 and 26.0 kJ mol-1) and the methyleneoxaziridine 30 (Erel = 195.6 kJ mol1-).Energy-rich zwitter-ionic transition states (E)- and (Z)-32 (Erel = 281.9 and 234.6 kJ mol-1) are found the RHF method.The UHF method is used for open-shell species.Thus, UHF/6-31G*//6-31G* optimizations result in the planar triplet states 33 having very low relative energies, but high spin conta...
Quast, Helmut,Leybach, Holger,Wuerthwein, Ernst-Ulrich
p. 1249 - 1262
(2007/10/02)

Synthesis, fragmentations and rearrangements of 3-(1-haloalkyl) oxaziridines
A variety of new 3-(1-haloalkyl)oxaziridines was synthesized by oxidation of α-chloro-, α-bromo-, α,α-dichloro-, α,α-dibromo- and α,α,α-trichloroaldimines with meta-chloroperbenzoic acid. Attempts to induce dehydrohalogenation into the elusive methyleneoxaziridines were unsuccessful. However, presumptive evidence is presented that 2-t-butyl-3-(trichloromethyl)oxaziridine is dehydrochlorinated into a transient methyleneoxaziridine, which underwent valence isomerization into an intermediate iminooxirane, the latter being fragmented into t-butyl isocyanide. Various types of reactions of the title compounds are reported. Among others, 2-alkyl-3-(1-chloro-1-methyl) ethyloxaziridines rearranged with methyllithium into 2-(N-alkyl)aminoisobutyraldehydes.
De Kimpe, Norbert,De Corte, Bart
p. 7345 - 7362
(2007/10/02)

SYNTHESIS AND REACTIVITY OF THE IMINOMETHYLENEPHOSPHANE F3C-P=C=N-tBu
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Grobe, Joseph,Van, Duc Le,Grosspietsch, Thomas
p. 320
(2007/10/02)

Reactive E=C(p-p)?-Systems, XXVIII. Synthesis and Reactivity of the Iminomethylenephosphane F3C-P=C=N-tBu
Iminomethylenephosphanes, Fluorophosphaalkenes, Bis(trifluormethyl)phosphane, Chiral Aminophosphanes The reaction of perfluoro-2-phosphapropene F3CP=CF2 (1) with tert-butylamine or isopropylamine in a 1:3 molar ratio leads to the novel iminomethylene phosphanes F3CP=C=N(tBu) and F3CP=C=N(iPr) , respectively. 2 slowly decomposes at room temperature giving tert-butylisonitrile and the cyclophosphanes (F3CP)n (n = 3,4,5). 3 is found to be less stable than 2 and for example is attacked by primary amines.The reaction of 2 with 2,3-dimethyl-1,3-butadiene or trimethylphosphane yields, on the one hand, the cycloaddition product of bis(trifluormethyl)diphosphene (4), and on the other hand, the phosphorus ylid Me3P=PCF3 (5) together with (tBu)NC. 2 and 3, respectively, are not obtained from (F3C)2PH and the corresponding primary amines in a series of HF elimination and H2NR addition reactions.The main products formed from a 1:4 molar mixture of (F3C)2PH and H2N(iPr) in a one-pot procedure were shown to be the chiral phosphanes F3CPCH (6), F3CPCHF2 (7) and F3CPCH2F (8) (60:35:5).The corresponding reaction of (F3C)2PH with H2N(tBu) mainly yields the compound F3CPCH2F (10).
Grobe, Joseph,Van, Duc Le,Grosspietsch, Thomas
p. 978 - 984
(2007/10/02)

iron(II) Compounds with Isocyanides as Axial Ligands
Aliphatic and aromatic monodentate isocyanides RNC (R = t-Bu, c-Hx, substituted Ph) react with iron(II) (TPyPFe) to form the corresponding diaxially substituted iron(II) compounds TPyPFe(RNC)2 1a-8a.The spectroscopic data and thermal properties of the complexes are described and compared with the analogous PcFe(CNR)2 compounds 1b-8b.
Hanack, Michael,Thies, Ruediger
p. 1225 - 1230
(2007/10/02)

Uebergangsmetall - Carbin-Komplexe XCIII. Thermodynamisches Gleichgewicht zwischen einem neutralen und einem kationischen Isonitril-substituirten Diethylaminocarbin-Komplex des Wolframs
The reaction of I(CO)2(t-C4H9NC)2WCNEt2 (I) with t-C4H9NC in n-heptane at 70 deg C leads to an approximately equimolar mixture of neutral, yellow carbyne complex mer-I(t-C4H9NC)3(CO)WCNEt2 (II) and cationic, orange carbyne complex CNEt2>+I- (III).In the presence of t-C4H9NC, there is a thermodynamic equilibrium between II and III, which permits the quantitative conversion of II to III in CH2Cl2 at room temperature, and of III to II in toluene at + 70 deg C.The composition and structure of the new complexes II and III were determined by elemental analyses, and from their IR, (1)H NMR, (13)C NMR, and by mass spectra.
Filippou, Alexander Constantin,Fischer, Ernst Otto
p. 141 - 148
(2007/10/02)

Cationic complex of technetium-99m.
The invention relates to a cationic complex of technetium-99m with (a) at least one bidendate ligand X having the formula where each Z is phosphorus or arsenic, Q is a (CH2)n linking group where n is 2 to 8 or a 1,2-phenylene linking group, each of R1, R2, R3 and R4 is hydrogen, C1 to C5 alkyl or phenyl; and (b) at least one monodentate isonitrile ligand Y. The invention also relates to a radiopharmaceutical composition comprising said complex, to a kit for preparing said composition, and to the use of said composition for a radiodiagnostic examination.
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(2008/06/13)

Screw Sense Selective Polymerization of Achiral Isocyanides Catalysed by Optically Active Nickel(II) Complexes
Poly(isocyanides), (RN=Cn, can be prepared from isocyanides, , by the catalytic action of nickel(II) compounds.The main chain of these polymers is a rigid helix.This helical conformation results from a restricted rotation around the single bonds that connect the main-chain carbon atoms.Polymerization of achiral isocyanides generally gives a racemic mixture of left- and right-handed helices, whereas polymerization of optically active isocyanides results in helices with an excess of one screw sense.We describe a procedure for obtaining poly(isocyanides) with predominantly one screw sense, starting from an achiral monomer.A catalyst is prepared by adding an optically active amine to a tetrakis(isocyanide)nickel(II) perchlorate complex.Polymerization of various achiral isocyanides with this catalist yields optically active polymers with an enantiomeric excess up to 83percent.
Kamer, Paul C. J.,Nolte, Roeland J. M.,Drenth, Wiendelt
p. 6818 - 6825
(2007/10/02)

Thermolysis and Some Reactions of 3-Alkyl-3,5-dihydro-5,5-dimethyl-4H-1,2,3-triazol-4-ones and 1-tert-Butyl-3,3-dimethyl-2-aziridinone. Is the Acyclic Aziridinone a Zwitterion?
Solvent polarity influences only little the thermolysis of both aziridinone 2a (40 deg C) and dihydro-1,2,3-triazolone 1a (70 deg C) which quantitatively decompose into acetone and tert-butyl isocyanide (5a) (besides molecular nitrogen in the case of 1a).In contrast to earlier reports, 2a does not produce the α, β-unsaturated amide 7 on heating. Dimethylformamide converts 1a and 2a into the oxazolidinone -6.While solvolysis of both 1a and 2a in pure methanol predominantly yields the α-methoxyamide -10a, 1a and 2a react differently with sodium methoxide in methanol.This reagent converts 1a into 10a, as does methanol itself, but 2a into the α-aminoester 12.Small amounts of acetone and tert-butyl isocyanide (5a) are formed as by-products in almost all reactions.The results are consistent with the occurence as intermediate of the acyclic "non-Kekule"-molecule 3a, a diradical, which exhibits the same polarity as its precursors 1a and 2a.The intermediate 3a is trapped by the solvent (-> -6, 10a) or decomposes via the iminooxirane 4a into acetone and the isocyanide 5a.
Quast, Helmut,Meichsner, Georg,Seiferling, Bernhard
p. 217 - 224
(2007/10/02)

Electrochemistry of 2-Bromo-2-methylpropanamides. Reduction Mechanism and Cyclocoupling Reaction with Amide Solvents
The electrochemical reduction of series of secondary and tertiary α-bromoisobutyramides has been studied in dipolar aprotic solvents.A carbanion is formed at the mercury electrode as a consequence of two-electron C-Br bond cleavage.Voltammetry and macroelectrolysis point to a self-protonation mechanism, the carbanion undergoing protonation by a parent molecule to yield the isobutyramide.Concurrently, tertiary 2-bromoamides undergo 1,2-elimination to yield an αβ-unsaturated amide, while secondary 2-bromoamides are deprotonated at the nitrogen atom, affording a bromo-containing anion.The decay of the latter is strongly dependent on the solvent and the substituent at nitrogen.In acetonitrile, elimination and fragmentation products are identified in the electrolysed solution.On the other hand, in N,N-dimethylformamide or N,N-dimethylacetamide, the bromo-containing anion is eventually cyclocondensed onto the carbonyl group of the amide solvent, to yield an oxazolidin-4-one derivative.Preliminary data suggest that an analogous cyclocoupling reaction takes place when the reduction is carried out in 1-methyl-2-pyrrolidone.
Maran, Flavio,Vianello, Elio,D'Angeli, Ferruccio,Cavicchioni, Giorgio,Vecchiati, Giorgio
p. 33 - 39
(2007/10/02)

Photochemical Elimination of Molecular Nitrogen from 3,5,5-Trialkyl-3,5-dihydro-4H-1,2,3-triazol-4-ones. Aziridinones, Iminooxiranes and Products
The dihydro-1,2,3-triazolones 6 lose molecular nitrogen on irradiation (λ >/= 300 nm).Aziridinones 7, 1:1 mixtures of ketones 10 and isocyanides 11, and small amounts of isocyanates 12 are formed in inert solvents and at temperatures between -90 and +20 deg C.In dimethylformamide as solvent, however, the oxazolidinone -14 arises almost quantitatively from 6c besides traces of acetone and tert-butyl isocyanide (11c).On irradiation in pure methanol, 6b-d produce the α-methoxyamides -17b-d as major product and less acetone and 11c than in inert solvents.In contrast, the presence of sodium methoxide gives rise to the formation from 6c of significant amounts of the α-aminoester -15 besides -17c as well as acetone and 11c.The photolysis of 6c in dimethylformamide and methanol, respectively, is compared to the reaction of 6c in the dark but under otherwise identical conditions.The results are interpreted in terms of the nitrogen-extrusion leading to the acyclic aziridinone isomers 16 which either cyclize to yield the aziridinones 7 and the unstable iminooxiranes 9 or react with dimethylformamide or methanol.
Quast, Helmut,Meichsner, Georg,Seiferling, Bernhard
p. 225 - 230
(2007/10/02)

Photochemical Reactivity of Aldimines from 2,2-Dimethyl-3-oxo-3-phenylpropanal
The syntheses of some thermally labile aldimines of 2,2-dimethyl-3-oxo-3-phenylpropanal are described.The aldimines (7a-c) are photochemically reactive and undergo fission mainly into isopropyl phenyl ketone.Several other minor products are also formed.On
Armesto, Diego,Ramos, Ana,Perez-Ossorio, Rafael,Horspool, William M.
p. 91 - 94
(2007/10/02)

TRIMETHYLSILYL CYANIDE PROMOTED CYANATION OF TERTIARY ALKYL CHLORIDES AND OTHER SN1 ACTIVE COMPOUNDS
Tertiary chlorides are readily cyanated in a one-pot procedure using trimethylsilyl cyanide in the presence of SnCl4.The mechanism of this novel and synthetically useful reaction involves initial isonitrile formation followed by rearrangement to the tertiary nitrile.Other SN1 active compounds also undergo smooth cyanation.
Reetz, Manfred T.,Chatziiosifidis, Ioannis,Kuenzer, Hermann,Mueller-Starke, Hans
p. 961 - 966
(2007/10/02)

Formimidoyl Group Transfer from Activated Amidines. Part 1. Hydrolysis of 1-(N-t-Butylformimidoyl)imidazole and Related Imidazole-containing Formamides
The hydrolysis of 1-(N-t-butylformimidoyl)imidazole (7a) to t-butylformamide and imidazole has been examined in the absence of buffer species at 25 deg C in water.The rate of hydrolysis was pH-independent at pH 7-14 and reaction in this region is shown to occur via HO- attack on the protonated substrate (whose pKa is 5.0; protonation site, imidazole nitrogen).Alternative mechanisms such as H2O attack on the neutral substrate and reaction via the zwitterion (15) were eliminated using solvent isotope effect, deuterium labelling, and substituent effects.Below pH 6 acid catalysis of hydrolysis is observed due to H2O reaction with the protonated substrate (pH 4-6) and with the diprotonated substrate (pH 0-4); at pH 0, t1/2 for hydrolysis is -2s.The N-arylformamidines (7b) and (7c) react via similar acid catalysed pathways but a new reaction (identified as HO- attack on the amidine) occurs in base, in preference to the pH independent pathways. p-Nitrophenylformamide is itself hydrolysed in basic solution so that complex kinetics result.The C-substitued amidines (7e) and (7f) react 104-102-fold more slowly than the corresponding formamidines.Buffer catalysis of the hydrolysis of (7a) by phosphate and amines is complex, the slope of kobs. versus plots being greater at low than at high buffer concentrations.This is consistent with the formation of a tetrahedral intermediate in the reaction pathway whose formation and beakdown is subject to general acid-base catalysis.
Chandler, Anne,Hegarty, Anthony F.,McCormack, Margaret T.
p. 1318 - 1325
(2007/10/02)