Pyridine diimide

From 1995 to 2000, catalyst profiles of several ruthenium catalysts bearing pyridine-diimide 1 [13], diiminocarbene 2 [14], diamine-arene 3 [15],phos-phino-arene 4 [16], and substituted cyclopentadienyl 5 and 6 [17, 18] were shown to have good activity for the cydopropanation (Fig. 1). At the relatively high reaction temperature of 60-100 °C,they also gave moderate-to-high yields over 90%. It is interesting in that the dipyridine-diimide complex 1 and the p-cymene-carbene complex 2 show high trans selectivity, 86 14 and 82 18, respectively. 

Pyridine (1) is a weak and good base and good solvent for effecting aminolysis of acyl fluorides (see Section 7.12) and for preparing Boc-amino-acid iV-carboxyanhydrides (see Section 7.14) and activated esters by the carbo-diimide method (see Section 7.7), especially the esters of Boc-amino acids, as it prevents decomposition of the activated residue (see Section 7.15). It is the preferred base for aminolysis of acyl fluorides in dichloromethane. 

The favored formation of a nucleoside 3 -(alkyl phosphate) was observed on treating the diphenyl phosphate anhydride of uridine 2, 3 -cyclic phosphate with benzyl alcohol.273 In a somewhat related reaction, on treatment with dicyclohexylcarbodiimide in aqueous pyridine, adenosine 2 (3 )-phosphate gave, initially, the 2, 3 -cyclic phosphate, which, on further reaction with the diimide, gave a mixture of the N-phosphonourea nucleoside 44 and its 2 -isomer, in unequal amounts.269 This type of reaction does not seem to occur with... 

Symmetrical 1,2,4,5-dioxadiazines are formed by [3 + 3] dimerization of arene nitrile oxides in the presence of pyridine (74JCS(Pl)l95l). The sulfonylsulfur diimide (579) cyclizes to the 1,3,2,4,6-dithia-triazine (580) on heating in DMF (71AG(E)264). 

To prepare DCC from dicyclohexylurea recrystallise the recovered urea from ethanol m.p. 234 °C. Add dropwise with stirring 17.1 g (47 ml, 0.11 mol) of phosphorus oxychloride to 22.5 g (0.1 mol) of dicyclohexylurea in 50 ml of pyridine at 50 °C, and heat at 60-90 °C for 1.5 hours. Pour the reaction product on to crushed ice, extract with light petroleum (b.p. 60-80 °C) and dry the extract over anhydrous sodium sulphate. Remove the solvent using a rotary evaporator and distil the residual oil under reduced pressure. The yield of diimide, b.p. 157-159°C/15mmHg (131 °C/3-4mmHg), is about 14g (68%). 

Besonders stabil sind 2-Dichlormethylen- und 2-Chlormethylen-A3-oxazolinone-(5), die durch Behandeln von N-Trichloracetyl- und N-Dichloracetyl-aminosauren mit POCls/Pyridin oder Dicyclohexylcarbo-diimid/Pyridin leicht zuganglich sind 177,179). 

Ac, acetyl AIBN, azobis(isobutanonitrile) All, allyl AR, aryl Bn, benzyl f-BOC, ferf-butoxycarbonyl Bu, Butyl Bz, benzoyl CAN, ceric ammonium nitrate Cbz, benzyloxycarbonyl m-CPBA, m-chloroperoxybenzoic acid DAST, diethylaminosulfur trifluoride DBU, l,8-diazabicyclo[5.4.0]undec-7-ene DCC, /V. /V - d i eye I oh e x y I c ar bo -diimide DCM, dichloromethyl DCMME, dichloromethyl methyl ether DDQ, 2,3-dichloro-5,6-dicyano-l,4-benzoquinone DEAD, diethyl azodicarboxylate l-(+)-DET, L-(+)-diethyl tartrate l-DIPT, L-diisopropyl tartrate d-DIPT, D-diisopropyl tartrate DMAP, 4-dimethylaminopyridine DME, 1,2-dimethoxyethane DMF, /V./V-dimethylformamide DMP, 2,2-dimethoxypropane Et, ethyl Im, imidazole KHMDS, potassium hexamethyldisilazane Me, methyl Me2SO, dimethyl sulfoxide MOM, methoxymethyl MOMC1, methoxymethyl chloride Ms, methylsulfonyl MS, molecular sieves NBS, N-bromosuccinimide NIS, /V-iodosuccinimide NMO, /V-methylmorpho-line N-oxide PCC, pyridinium chlorochromate Ph, phenyl PMB, / -methoxvbenzyl PPTs, pyridiniump-toluenesulfonate i-Pr, isopropyl Py, pyridine rt, room temperature TBAF, tetrabutylammonium fluoride TBS, ferf-butyl dimethylsilyl TBDMSC1, f-butylchlorodimethylsilane Tf, trifhioromethylsulfonyl Tf20, trifluoromethylsulfonic anhydride TFA, trifluoroacetic acid THF, tetrahydrofuran TMS, trimethylsilyl TPAP, tetra-n-propylammonium perruthenate / -TsOH. / -toluenesulfonic acid... 

Reaction of HNF2 diluted with nitrogen with a nitroso compound in pyridine-dichloromethane solution gives N-substituted N -fluoro-diimide IV-oxides (278) ... 

A different type of trimerization is exemplified by 1,4-dithiintetra-carboxylic acid diimide which, on heating at 120° in pyridine, gave a mellitic acid triimide (181 R = H, Me, CH2Ph) probably through the highly strained intermediate260 [Eq. (11)]. 

Scheme 6. Reaction conditions a, 3-chloroperoxybenzoic acid (MCPBA)/dichloromethane/aq. bicarbonate, then lithium diisopropylamide (LDA) b, diimide c, POCl3/pyridine d, LiAlH4, BuLi/PhCOCI e, MCPBA f, (PhSe)2/NaBH4/EtOH, then MCPBA/Pr2NH g, 0s04/pyridine h, acetonide formation, then Barton deoxygenation i, Ba(OH)2, then H +. ...

Reviews. Hamersma and Snyder studied the effect of variation in reaction conditions in reductions with diimide generated from dipotassium azodicarboxylate. Air does not have a deleterious effect. Rate of reduction decreases with solvents in the following order pyridine > dioxane > dimethyl sulfoxide > methanol > ethanol > n-butanol, Water is a powerful inhibitor of the reaction in nonhydroxylic solvents but has practically no effect in hydroxylic solvents. 

Reducing agents Aluminum hydride. Bis-3-methyl-2-butylborane. n-Butyllithium-Pyridine. Calcium borohydride. Chloroiridic acid. Chromous acetate. Chromous chloride. Chromous sulfate. Copper chromite. Diborane. Diborane-Boron trifluoride. Diborane-Sodium borohydride. Diethyl phosphonate. Diimide. Diisobutylaluminum hydride. Dimethyl sulfide. Hexamethylphosphorous triamide. Iridium tetrachloride. Lead. Lithium alkyla-mines. Lithium aluminum hydride. Lithium aluminum hydride-Aluminum chloride. Lithium-Ammonia. Lithium diisobutylmethylaluminum hydride. Lithium-Diphenyl. Lithium ethylenediamine. Lithium-Hexamethylphosphoric triamide. Lithium hydride. Lithium triethoxyaluminum hydride. Lithium tri-/-butoxyaluminum hydride. Nickel-aluminum alloy. Pyridine-n-Butyllithium. Sodium amalgam. Sodium-Ammonia. Sodium borohydride. Sodium borohydride-BFs, see DDQ. Sodium dihydrobis-(2-methoxyethoxy) aluminate. Sodium hydrosulflte. Sodium telluride. Stannous chloride. Tin-HBr. Tri-n-butyltin hydride. Trimethyl phosphite, see Dinitrogen tetroxide. 

A multitude of iV-sulfinyl compounds and sulfur diimides bearing a variety of substituents on the nitrogen atom(s) have been prepared. The iV-sulfinyl compounds are commonly generated by treatment of the parent aniline, amine, sulfonamide, etc., with thionyl chloride and pyridine [Eq. 

The resulting iV-sulfinyl derivatives can often be distilled and/or crystallized but are water sensitive and thus are frequently prepared in situ for subsequent cycloaddition reactions. Symmetrically substituted sulfur diimides can usually be prepared by the reaction of SCI2 or S2CI2 with the parent NH2 compound in the presence of a base such as pyridine or triethylamine [Eq. (4)]. ... 

Phthaloylleucylvaline ethyl ester 710 DL-Valine ethyl ester hydrochloride (1.82 g, 10 mmoles) in dry tetrahydrofuran (20 ml) is treated at 0° with triethylamine (1.38 ml). The triethylamine hydrochloride is filtered off after an hour and washed well with tetrahydrofuran. Phthaloyl-leucine (2.57 g, 10 mmoles) is dissolved in the filtrate, and then at —8° dicyclohexylcarbo-diimide (2.26 g, 11 mmoles). The mixture is left for 2 h at — 5° and then at room temperature overnight. The separated 1,3-dicyclohexylurea is filtered off and the filtrate is evaporated in a vacuum, leaving a syrup which is dissolved in ethyl acetate (25 ml) and washed with 2n-hydrochloric acid (25 ml) and water (two 25-ml portions). The solution is dried over sodium sulfate, filtered, and evaporated in a vacuum, the residue (3.5 g, 90%) solidifying to a glass on storage this product is very soluble in alcohols, chloroform, ethyl acetate, pyridine, or dimethylformamide, moderately soluble in benzene or toluene, but insoluble in ether, light petroleum, or water. 

RCOOH, diimide ArOH, preformed handle RCOOH, DIPCDI, DMAP RCOOH, PPhs, DEAD RCOOH, pyridine, 2,6-dichlorobenzoyl chloride... 

Succinic anhydride, pyridine vinylamide, HCl-THF Meldrum s acid, TFH, heat RCOOH, diimide... 

Related Reagents. iV-Chlorosuccinimide-Dimethyl Sulfide Chromic Acid Dimethyl Sulfide-Chlorine Dimethyl Sulfoxide-Acetic Anhydride Dimethyl Sulfoxide-Dicyclohexylcarbo-diimide Dimethyl Sulfoxide-Methanesulfonic Anhydride Dimethyl Sulfoxide-Oxalyl Chloride Dimethyl Sulfoxide-Sulfur Trioxide/Pyridine Dimethyl Sulfoxide-Trifluoroacetic Anhydride Dimethyl Sulfoxide-Triphosgene Manganese Dioxide Pyridinium Chlorochromate Pyridinium Dichromate Ruthenium(IV) Oxide Silver(I) Carbonate on Celite 1,1,1-Triacetoxy-1,1-dihydro-1,2-benziodoxol-3( l/ -one. 

By aza-Wittig reactions of iminophosphoranes with isocyanates, carbodiimide-mediated syntheses of pyrrole and indole derivatives [1270], pentasubstituted pyridines [1271], pyrimidine derivatives [1272-1274], bis( -ferrocenylvinyl)carbo-diimide [1274], amino-tetrazolyl-deoxythymidines [1275], the marine alkaloid leu-cettamine B [1276], and aza-analogues of aplysinopsins [1277] have also been accomplished. 

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