4- pyridine DMAP

Caprolactone (CL) (Acros, 99%) was dried over calcium hydride at r.t. for 48h and then distilled under reduced pressure. 2-(N,N-dimethylamino)ethyl methaciylate (DMAEMA) (Aldrich, 98%) was deprived of its inhibitor by filtration through a basic alumina column, and depending on samples (see text) dried over calcium hydride at r.t. for 24h and then distilled under reduced pressme. Butane-1,4-diol (Acros, > 99%) was dried over calcium hydride for 48h at r.t. and distilled at 70°C under reduced pressure. Triethylamine (NEts, Fluka, 99%) was dried over barium oxide for 48h at r.t. and distilled under reduced pressure. Copper bromide (CuBr, Fluka, 98%) was purified in acetic acid and recrystallized in ethanol under inert atmosphere until a white powder is obtained. Tin(ll) bis-2-ethyl hexanoate (Sn(Oct)2, Aldrich, 95%), methacrylic anhydride (Aldrich, 94%), N,N-dimethylamino-4-pyridine (DMAP, Acros 99%), 1,1,4,7,10,10-hexamethyltriethylene tetramine (HMTETA, Aldrich, 97%), ethyl-2-bromoisobutyrate (E BBr, Aldrich, 98%), N,N-dicyclohexylcarbodiimide (DCC, Acros, 99%), were used as received. Tetrahydrofuran (THF, Labscan, 99%) was dried over molecular sieves (4A) and distilled over polystyryl lithium (PS LC) complex under reduced pressure just before use. Toluene (Labscan, 99%) was dried by refluxing over CaH2. 

The product of bis-coordination, 20 at phosphorus, could be also achieved utilizing the more nucleophilic p-dimethylamino pyridine (DMAP) [57, 58]. As shown in Scheme 12,bis-coordination of the two donors occurs in general by taking up the two orthogonal positions of the PN 7i-bonds [58]. 

Another example has been provided by Ito et al., who described the use of methanofullerene derivatives as powerful and stable precursors for glycofullerenes.217 Their study was based on the use of [60]fullerenoacetyl chloride (227), obtained from the ferf-butyl [60]fullerenoacetate derivative 226, which had been prepared in 56% yield by treatment of corresponding stabilized sulfonium ylides 225 with C6o-218 Subsequent transformation with p-TsOH in toluene gave [60]full-erenoacetic acid, which was directly converted into the corresponding acyl chloride 227 by using thionyl chloride. Standard ester formation with methyl 2,3,4-tetra-O-benzyI -/<-d-gl ucopyranoside (228) and 4-(dimethylamino)pyridine (DMAP) afforded the desired hybrid derivative 229 in 66% yield. 

Wang resin was purchased from Advanced ChemTech (1% DVB, 0.70mmol/g substitution, 100-200 mash, Cat. SA5009). Anhydrous tetrahydrofuran (THF), A/A-dimcthyl-formamide (DMF), methanol, dichloromethane, pyridine, 1,1 -carbonyldiimidazole (CDI), piperazine, homopiperazine, trans-1,4-diaminocyclohexane, 4-(dimethylamino)pyridine (DMAP), succinic anhydride, diglycolic anhydride, 3-methyl-glutaric anhydride, 2-aminophenol, 2-amino-p-cresol, 2-amino-4-tert-butyl phenol, /V-methylmorpholine (NMM), triphenylphosphine, diethyl azodicarboxylate (DEAD), and trifluoroacetic acid (TFA) were purchased from Aldrich Chemical Company, Inc. and used without further purification. PyBOP was purchased from Novabiochem. 

All attempts to achieve a direct transformation of the carbazomadurins A (253) and B (254), as well as the disilyl-protected carbazomadurins A (769a) and B (769b), into the epocarbazolins A (258) and B (259) were unsuccessful and resulted in complete decomposition. Therefore, prior to the epoxidation, the disilyl-protected carbazomadurins A (769a) and B (769b) were transformed to the corresponding trisilyl-protected carbazomadurins A (770) and B (771) by treatment with TPS chloride in the presence of stoichiometric amounts of 4-(dimethylamino)pyridine (DMAP). Epoxidation of the fully protected carbazomadurins A (770) and B (771) with dimethyldioxirane at — 20°C, followed by desilylation, provided racemic epocarbazolin A (258) and epocarbazolin B (259) (605) (Scheme 5.82). 

Bromo-2-naphthoic add (1, 98%, Sigma Chemical Co.), 3.5-dimethylphenol (2, >98%, Merck-Schuchard), 1,3-dicyclohexylcarbodiimide (DCC, 99%, Merck-Schuchard), and 4-(dimethylamino)pyridine (DMAP, 99%, Aldrich Chemical Co., Inc.) were used as received. Dichloromethane was distilled from phosphorus pentoxide and stored over activated molecular sieves (4A). 

A. 3,5-Dimethylphenyl 1-bromo-2-naphthoate (3). Under a nitrogen atmosphere, a 250-mL, oven-dried, round-bottomed flask containing anhydrous dichloromethane (100 mL) is charged with 1-bromo-2-naphthoic acid (1, 2.51 g, 10.0 mmol), 3,5-dimethylphenol (2, 1.23 g, 10.1 mmol), dicyclohexylcarbodiimide (DCC, 2.26 g. 11.0 mmol), and 4-(dimethylamino)pyridine (DMAP, 244 mg, 2.00 mmol) (Note 1). After the mixture is stirred for 12 hr at room temperature, the white precipitate that forms (Note 2) is discarded by filtration through a Buchner funnel. From the clear filtrate, the solvent is removed by rotary evaporation (35°C, 720 mbar, 540 mm) to give a colorless solid. RItration through a short silica gel column (5 x 40-cm column, silica gel 0.063 - 0.2 mm, 150 g eluent hexane / diethyl ether 5 1) delivers 3.35 g (94%) of the ester 3, which Is recrystallized from diethyl ether / hexane to give 3.28 g (92%) of a colorless solid (Note 3). 

With the carboxylic acid 123, dicyclohexylcarbodiimide (DCC) mediated esterification and amidation reactions can be carried out (Scheme 4. 27) [113]. For example, the reaction of 123 with EtOH in the presence of DCC and IH-benzotriazol (BtOH) in bromobenzene with a catalytic amount of 4-(dimefhylamino)pyridine (DMAP)... 

C-aryl glycals in 75-92% yields. It consisted in the addition of aryllithium reagents to variously protected 2-deoxy-aldono-l,5-lactones, followed by treatment with a mixture of pyridine (Py), 4-(Dimethylamino)pyridine (DMAP), and trifluoroacetic anhydride (TFAA). 

The Glaxo synthesis of zanamivir (2) started with the esterification of commercially available A-acetyl-neuraminic acid (88) with methanolic HCl to give the methyl ester as shown in Scheme 7.14 (Chandler and Weir, 1993 Chandler et ah, 1995 Patel, 1994 Weir et al., 1994). Global acetylation of all the hydroxyl groups with acetic anhydride in pyridine with catalysis by 4-(dimethylamino)pyridine (DMAP) led to the penta-acetoxy compound 89. Treatment of 89 with trimethylsilyl triflate in ethyl acetate at 52°C introduced the oxazoline as well as the 2,3-double bond to provide 86. Addition of trimethysilyl azide to the activated allylic oxazoline group led to the stereoselective introduction of azide at the C-4 position to afford 83 as in Scheme 7.13. 

On the other hand, Wyeth-Ayerst chemists ° encountered limitations with this methodology during their syntheses of spirocyclic 2,4-oxazolidinediones derived from isoindole (Scheme 6.55). For example, reaction of 246 with chlorosulfonyl isocyanate followed by cyclization with potassium terf-butoxide afforded poor to modest yields of 247 when R was a substituted benzyl group. Cyclization of 246 using ethyl chloroformate (ECF), triethylamine and 4-(dimethylamino)pyridine (DMAP) in refluxing tetrahydrofuran (THF) gave 247 in only 29% yield when R was methyl and failed completely if R was an isopropyl group. However,... 

Dynamic kinetic resolution is an excellent methodology to prepare enantiomeri-cally pure compounds and, in this context, chiral 4-(dimethylammo)pyridine (DMAP) iron and ruthenium " complexes have been reported to catalyze the... 

Methode 2,65 g (11 mmol) 4-Chlorcarbonyl-3,5-dioxo-4-aza-tricyclo[5 2.1.02-6]dec-8-cn lost man in 20 ml THF und kiihlt auf 0° ab. Zu dieser Losung wird bei 0° miter Riihren ein Gcmisch aus 10 mmol Carbonsaure-hydrazid, 30-50 ml THF, 869 mg (11 mmol) Pyridin und 3,66 mg (0,03 mmol) 4-Dimethyl-amino-pyridin (DMAP) zugetropft. Danach riihrt man 1 h bei 0 und 3 b bei 20". Nach Eincngen der Reaktionsmischung versetzt man mit 30 ml Wasser, riihrt 10 min, saugt ab und kristallisiert aus Ethanol um. 

Two isomeric complexes, 60 and 61, have been analyzed by Cl MS (reagent gas CH4), producing [M -b I] and [M -b 29]+ ions. Electron ionization mass spectrometry was applied in the analysis of the product of the reaction between Zn(CF3)Br-2CH3CN (62) and 4-(Af,Af-dimethylamino)pyridine (DMAP). The El (20 eV) mass spectrum of the product, Zn(CF3)Br DMAP (63), was recorded at 280 °C and consisted mainly of [C6H3BrF2NZn]+, [ZnBr2]+ and [ZnBr]+ ions. At lower temperatures, this compound did not yield any Zn-containing ions, and the spectra were dominated by the peaks of the [DMAPJ+ and [C2HgN]+ ions . 

Examples of nonasymmetric organocatalysts that were introduced in the 1950s include analogs of thiamine reported by Breslow in 1957 as an alternative to cyanide as a catalyst for the benzoin condensation [8]. Asymmetric versions of these thiazolium catalysts were used in organocatalytic benzoin condensations by Sheehan and Hunneman in 1966 [9]. In another important development, in 1969 the nucleophilic catalyst 4-(dimethylamino)pyridine (DMAP), which is now widely used for difficult esterifications, was reported by Steglich [10]. 

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