Podstrony
- Strona startowa
- The NASA History Series Donald L. Mallick The Smell of Kerosene, A Test Pilot's Odyssey (#2) (2004)
- Robert Dallek Lyndon B. Johnson, Portrait of a President (2004)
- Science Fiction (40) lipiecc 2004
- Weronika R. Cichodajka 2004 2005
- Davis Lindsey Falkon 1 Srebrne Âœwinki
- Florystka Katarzyna Bonda
- Ludlum Robert Przesylka z salonik
- Cassandra Clare Kroniki Bane'a
- Clancy Tom Suma wszystkich strachow t.2
- Masterton Graham Wojownicy Nocy t.2 (2)
- zanotowane.pl
- doc.pisz.pl
- pdf.pisz.pl
- ugrzesia.htw.pl
[ Pobierz całość w formacie PDF ]
.The aqueous layer is then extracted with CH2Cl2 (threeportions).The combined organics are then washed with brine anddried over anhydrous magnesium sulfate; filtration followed by evapora-tion of the solvent to yield a dark brown oil, which crystallizes upon stand-ing.The brown solid is recrystallized from methanol (m.p.53 54.5, yield17.3 g, 83%).6.In a round-bottomed flask (1 L) equipped with a condenser N-benzenesulfonyl-3(6-bromohexanoyl) pyrrole (12.0 g, 31.3 mmol) is added together with amixture of 1,4-dioxane (300 mL) and NaOH solution (5 M, 300 mL).The reactionmixture is stirred at room temperature for 48 72 h until thin layer chromato-graphy (TLC) indicates the absence of starting material.d7.The dioxane is removed on the rotary evaporator and the pale yellow solidobtained is dissolved in dichloromethane and the aqueous layer is extractedwith two further portions of dichloromethane.The organics are then com-bined, washed with saturated NaCl solution, and dried with anhydrous mag-nesium sulfate.The solution is then filtered and the solvent removed to yielda pale yellow oil, which crystallizes on cooling.8.The solid is purified using column chromatography on neutral aluminae usingdiethyl ether and petroleum ether (1 : 1) to elute the product.The solid prod-uct (crude yield 8.0 g, 100%) is recrystallized from diethyl ether/petroleumether (60 80 fraction) to give white crystals (m.p.73.5 76 C).172 6: Conducting polymers from heterocyclesaThe N-tosylpyrrole derivative was also prepared in the same way.bConnected via the condenser to a double manifold (see Chapter 2).cA range of conditions have been investigated for a similar alkylation and it would seem that theregiospecificity is independent of the concentration of the sulfonylpyrrole, and the reaction temperature,but that the formation of the 3-product is favoured by performing the reaction in dilute homogeneoussolution; a more concentrated solution of the complex was found to favour 2-substitution.12dTLC indicated one major and one minor product.eWashed with water (10% w/v).Protocol 6.Preparation of 3-[6-(4 -cyanobiphenyl-4-yloxy)hexanoyl]pyrrole andreduction to 3-[6-(4 -cyanobiphenyl-4-yloxy)hexyl]pyrrole [Scheme2(iv) and (v)]Caution! Carry out all procedures in a well-ventilated fume-cupboard, wearappropriate disposable gloves, a lab-coat, and safety glasses.Never useflat-bottomed flasks with rotary evaporators.EquipmentÏ% Ï%Single-necked round-bottomed flask (500 mL) Apparatus for recrystallization, Erlenmeyerflask, Buchner flask, funnel, and water aspiratorÏ% Ï%Reflux condenser Vacuum ovenÏ% Ï%Hotplate magnetic stirrer Teflon-coated magnetic stirrer barÏ%Rotary evaporatorMaterialsÏ%3-(6-Bromohexanoyl)pyrrole, 8.00 g, 32.8 mmol treat as harmfulÏ%Anhydrous potassium carbonate, 13.83 g, 100 mmol harmful if swallowed, irritating toeyes, skin, and respiratory systemÏ%Potassium iodide (trace) irritantÏ%4-Cyano-4 -hydroxybiphenyl, 6.39 g, 32.7 mmolÏ%Dimethylformamide, 165 mL potentially teratogenic, harmful in contactwith skin, irritating to eyesÏ%Propan-2-ol highly flammableÏ%Phosphorous pentoxide causes severe burnsÏ%Sodium borohydride, 5.29 g, 139.8 mmol harmful if swallowed, irritating to eyesand respiratory systemÏ%Ethyl acetate highly flammableÏ%Petroleum ether (60 80 fraction) highly flammableÏ%Dichloromethane harmful by inhalation, potential carcinogenÏ%Silica harmful by inhalation, irritating torespiratory systemMethod1.A single-necked round-bottomed flask (500 mL) is equipped with areflux condenser and a Teflon®-coated magnetic stirrer bar.a To this isadded 3-(6-bromohexanoyl)pyrrole (8.00 g, 32.8 mmol), anhydrous pota-ssium carbonate (13.83 g, 100 mmol), 4-cyano-4 -hydroxybiphenyl (6.39 g,32.7 mmol), Potassium iodide (trace)b, and dimethylformamide (165 mL).The mixture is warmed to 90 100 C for 1 h.173 D.J.Walton et al.Protocol 6.Continued2.The product is precipitated from solution by addition of a large excess ofdemineralized water and filtered at the pump, washing with copiousamounts of water.3.The cream-coloured solid is dried at the pump, and then placed in a vacuumoven over P2O5 at 65 C overnight.The product is then recrystallized from amixture of propan-2-ol and water (10.1 g, 86%, m.p.131 C).4.To a single-necked round-bottomed flask (500 mL) fitted with a refluxcondenser, is added propan-2-ol (150 mL), then 3-[6-(4 -cyanobiphenyl-4-yloxy)hexanoyl]pyrrole (4.64 g, 13.0 mmol) and NaBH4 (5.29 g, 139.8 mmol)are added and the mixture refluxed for 48 h.5
[ Pobierz całość w formacie PDF ]