Refluxing solution

You see that vacuum adapter stuck to the top of the condenser in fig. 7a Well, a closer look at it in fig. 7b will show that it has some drying agent sandwiched between two cotton balls and the nipple (tee heel) sealed with plastic wrap or foil. The drying agent can be either a commercial product called Drierite or calcium chloride. This attachment is placed on top of a condenser when refluxing solutions that have no water in them and must remain that way during the time they are refluxed. All this is to prevent moisture in the outside air from coming into contact with the cold surface of the of the inside walls of the condenser. This will surely happen and the condensed outside-air water will drip down into the reaction flask and ruin the experiment. This is not so much a... 

To a refluxing solution 0. phenylmagnesium bromide in 650 ml of diethyl ether, prepared from 1.15 mol of broraobenzene (see Chapter 11, Exp. 5) was added 1.00 mol of ally] bromide at a rate such that refluxing was maintained (about 30 min). 

In the hot precipitation method, sodium carbonate solution is added slowly to a refluxing solution of mercuric chloride, followed by an additional reflux period of 1 to 2 h. The washed precipitate is then dried. A variation allows the substitution of mercuric nitrate for the chloride if substantial quantities of sodium chloride are used. Sodium hydroxide, ia the presence of sodium carbonate, is the precipitant. 

Bromo-A-homo-estra-4y5 0)-diene-3, l-dione (49). A solution of silver perchlorate (0.55 g, 5 mole-eq) in acetone (2 ml) is added to a refluxing solution of monoadduct (48 0.28 g) in acetone (30 ml) containing water (0.5 ml). After being heated at reflux for 25 min the reaction mixture is cooled and the precipitated silver bromide is removed by filtration, yield about 0.11 g. The filtrate is diluted with water (500 ml) and is thoroughly extracted with chloroform. The chloroform extracts are washed with water and saturated salt solution, dried over anhydrous magnesium sulfate, and evaporated at... 

Seyferth et al. (//O) have also synthesized N,N-diethyl-trichlorovinyl-amine (128, R CjHj) from the reaction of triethylamine and phenyl-(trichloromethyl)mercury (138). The best yield was 23 %, obtained when a benzene solution of the amine (45 mM) was added to a refluxing solution of phenyl(trichloromethyl)mercury (10 mM) in benzene. Although no mechanistic study was attempted because of the low yields and the intractable nature of the reaction mixture, the authors proposed the following mechanistic sequence ... 

To a stirred and refluxing solution of 40 parts of benzene and 35 parts of dimethylformamide (both solvents previously dried azeotropically) are added successively 1.6 parts of sodium hydride and 7.7 parts of Ct-(2,4-dichlorophenyl)imidazole-1-ethanol, (coolingon ice is necessary). After the addition is complete, stirring and refluxing is continued for 30 minutes. Then there are added 7.8 parts of 2,6-dichlorobenzyl chloride and the whole is stirred at reflux for another 3 hours. The reaction mixture is poured onto water and the product 1-[2,4-dichloro-/3 (2,6-dichlorobenzyloxy)phenethyl] imidazole, is extracted with benzene. The extract is washed twice with water, dried, filtered and evaporated in vacuo. The bese residue is dissolved in a mixture of acetone and diisopropyl ether and to this solution is added an excess of concentrated nitric acid solution. The precipitated nitrate salt is filtered off and recrystallized from a mixture of methanol and diisopropyl ether, yielding 1-[2,4-dichloro- (2,6-dichlorobenzyl-oxv)phenethyl] imidazole nitrate melting point 179°C. 

To a refluxing solution of 10 parts of 3-methoxy-17-ethynyl-17-hydroxy-13-methyl-1,4,6,7,-... 

A refluxing solution of 3-phenyl-2//-azirine (0.468 g, 4 mmol) in toluene (10 mL) was treated with 3,6-diphcnyl-l,2.4.5-tetrazine (0.702 g, 3 mmol) in toluene (10 mL) and the solution was boiled under reflux for 22 h. On cooling, the mixture deposited an orange precipitate, which was filtered off and washed with pentane. Further product was obtained from the mother liquor by chromatography (silica gel). The combined solids were recrystallized (benzene/pentane) to give the product yield 0.664 g (68%) orange plates mp 210 C. 

Cu(OAc), H20 (0.75 g, 3.7 mmol) was added to a refluxing solution of metal-free 1,4,8,11.15,18,22,25-octa(propyloxy)phthalocyanine (0.1 g, 0.1 mmol) in BuOH (5 mL). The solution was maintained at reflux for 0.5 h, cooled, and chromatographed (silica gel, CH2C12 and Et20). The green-blue fraction eluted first was crystallized from a slowly evaporating solution in CH2Cl2/py yield 0.086 g (81 %). 

A solution of 1.93 g (6.91 mmol) of methyl 4-nitrobenzyl diazomalonate in 100 mL of dry benzene is added dropwise over 1 h to a refluxing solution of 1.79 (4.48 mmol) of (4S,5R/S )-4-acetoxy-l-(2-benzoyl-oxyethyl)-5-phenylthio-2-pyrrolidinone in 100 mL of dry benzene in the presence of a catalytic amount of rhodium acetate. The mixture is stirred under reflux for an additional hour after which the solvent is removed. The residue is chromatographed (silica gel, benzene/ethyl acetate 8 2) to furnish an oil yield 2.32 g (85%). 

Figure 3.12 Complexes produced by refluxing solutions of Pt(PPh3)4.

The submitters report this reaction to be a radical chain process that requires less than 0.2 mole of dibenzoyl peroxide per mole of starting material. The checkers can offer additional evidence of the radical chain nature of the reaction from their finding that the cycli-zation reaction is almost completely inhibited if the refluxing solution is not protected from atmospheric oxygen. 

Our group has also reported that the alkylation products of 4-cyano-l,3-diox-anes can serve as substrates for radical atom transfer reactions [41]. One such example is shown below (Eq. 17). Slow addition of tributyltin hydride/AIBN to a refluxing solution of cyanohydrin 115 generated the radical nitrile transfer product 116. This method, though somewhat limited in scope, can provide access to syn-l,3-diols which maybe unstable to the vigorous Li/NHg reduction conditions. 

The temperature of the refluxing solution should be above 165°. Efficient stirring is essential otherwise the precipitating potassium carbonate entrains much material, causing reduction of yield. 

SOCl2 (208 g, 1.75 mol) is added in one portion to a refluxing solution of TEBA-Cl (0.27 g, l. 2 mmol) and the acid (0.826 mol) in Cl(CH2)2Cl (l. 5 l). The solution is refluxed for a further period of time, and then filtered hot and evaporated to yield the acid chloride, which is purified, if necessary, by chromatography from silica [e.g. trans-cyclohexane-1,4-dicarbonyl chloride (30 min), 96% naphthalene-2,6-dicarbonyl chloride (12 h), 94% biphenyl-4-carbonyl chloride (25 min), 60% biphenyl-4,4 -dicarbonylchlo-ride (16 h), 90%]. 

A solution of 3-methyl-2-butenyl diazoacetate (14.9 g, 96.7 nunol) in dichlo-rometh e (450 mL) is added over 30 h to a refluxing solution of Rh2(5/ -... 

A bicyclic -y-pyranone was isolated in —1% yield from an acidified, refluxed solution of D-erythrose (6). It was proposed that the compound, 4a,5,6,7a-tetrahydrocyclopenta[ >]pyran-4,7-dione (10), is formed (by way of 9) from two molecules of D-erythrose, namely, an enediol (8) and a dehydrated form (7). Feather and Harris pointed out that D-erythrose would lose two molecules of water to form an intermediate (7) prior to coupling with the enediol 8 (see Scheme 2) to give 9. 

Di-p-tolyl ditelluride (typicalprocedure) A solution of hydrazine hydrate (3.2 g, 0.1 mol) in EtOH (20 mL) is added slowly dropwise to a refluxing solution of p-tolylteUurium trichloride (3.25 g, 10 mmol) in EtOH until evolution of N2 ceases. The hot mixture is filtered, and the ditelluride crystallizes by cooling (0.96 g (44% m.p. 52°C). 

Bis-[tellura-9-xanthenyl] ° Zinc powder (1.0 g, 15 mmol) is added to a refluxing solution of 1.5 g (4.9 mmol) of telluraxanthone in 30 mL of glacial acetic acid. Then, 1.5 mL of concentrated hydrochloric acid are added to the stirred, refluxing mixture over 1 h. The resultant mixture is poured into 200 mL of 6 M hydrochloric acid, and stirred until the zinc has dissolved. The mixture is filtered, and the precipitate is washed with water and dried. Yield 1.0 g (74%) m.p. >300°C (from chlorobenzene). 

Rearrangement of l-Mehtyl-4-chloro-4-benzoylpiperidine. Add 50 ml of xylene (containing 3.5 g of the above product) to a stirred refluxing solution containing 200 ml dry xylene and 18 g of finely powdered, dried sodium NaOH. Stir while refluxing for 30 min, then cool, extract with 25 ml portion of water until the ph of the extracts reaches neutrality (approximately). 

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