Dichloromethane, unreactivity

Yields higher than about 70% for any of these isonitrile preparations generally indicate incomplete fractionation. The purity of the product may be conveniently checked by proton magnetic resonance spectroscopy. The characteristic 1 1 1 triplet for tert-butyl isocyanide appears at <5 1.45 (chloroform-d). A small upheld peak usually indicates the presence of unreacted amine. Other common contaminants are dichloromethane and chloroform The purity may be determined more accurately by gas chromatographic analysis on a 230 cm. by 0.6 cm. column packed with 10%SE30 on Chromosorb G, 60-80 mesh, at 80°. 

Solid palladium scavengers, PVPy, QTU were pmchased from commercial somces. The mesoporous silica material, S102-SH, was prepared via reaction of SBA-15 (110 A pore diameter) with 3-mercaptopropyltrimethoxysilane (16). Specifically, a toluene suspension of SBA-15 and 3-mercaptopropyltrimethoxysilane was heated at reflux for two days under Ar. Water was then added to promote the cross-linking and the mixture was heated at reflux for an additional day. The sohds were filtered and washed with copious amounts of toluene, hexanes, and methanol to remove unreacted silanes. The solids were finally Soxhlet extracted with dichloromethane at reflux temperature for 3 days, dried, and stored in a nitrogen dry box. The final solid contained 7.5 wt% sulfur (2.3 mmole S/g solid). 

The solids were collected, washed with water (2 x 250 mL) and methanol (500 mL), and dried in a vacuum oven. The dried polymer was dissolved in dichloromethane and reprecipitated from methanol. The precipitate was washed with methanol and dried in a vacuum oven, yielding 1.25 g of product. Both H NMR and IR indicate essentially unreacted S-b-MM. 

The soluble polymer support was dissolved in dichloromethane and treated with 3 equivalents of chloroacetyl chloride for 10 min under microwave irradiation. The subsequent nucleophilic substitution utilizing 4 equivalents of various primary amines was carried out in N,N-dimethylformamide as solvent. The resulting PEG-bound amines were reacted with 3 equivalents of aryl or alkyl isothiocyanates in dichloromethane to furnish the polymer-bound urea derivatives after 5 min of micro-wave irradiation (Scheme 7.75). After each step, the intermediates were purified by simple precipitation with diethyl ether and filtration, so as to remove by-products and unreacted substrates. Finally, traceless release of the desired compounds by cyclative cleavage was achieved under mild basic conditions within 5 min of micro-wave irradiation. The 1,3-disubstituted hydantoins were obtained in varying yields but high purity. 

Dichloromethane solutions of some sterically congested benzyl chlorides and triethylsilane need only the addition of excess trifluoroacetic acid to promote rapid conversion of the chlorides to the related hydrocarbons.128 Thus 2,4,6-trimethylbenzyl chloride produces a 79% yield of isodurene at room temperature after 2.5 hours, 2-methyl-4,6-di-/m-bu(ylbenzyl chloride gives 50% 1, 2-di-methyl-4,6-di-tm-butylbenzene after 40 minutes at reflux, and 2,4,6-tm-butyl-benzyl chloride gives a 100% yield of 2,4,6-tri-rm-butyltoluene within 17 minutes at reflux (Eq. 54). The unsubstituted parent benzyl chloride remains unreacted under these conditions even after 30 days.128... 

The glycosylations were carried out in dry dichloromethane in the presence of 0.1 equiv of triphenylmethylium perchlorate. It was assumed that the triphenylmethy-lium cation attacks the nitrogen of the thiocyanate group whereas the oxygen of the trityl ether attacks the anomeric carbon in a push-pull fashion. The trityl isothiocyanate formed was found to be unreactive under the reaction conditions. The disaccharide derivatives with (1-6), (1-4), (1-3) and (1-2) linkages have been obtained in good yields. 

Bis(dimethyl hydrogen phosphite-/ )bis(dimethyl phosphito-P)platinum(lI) (0.420 g, 0.66 mmole) and c/s-[dichlorobis(triphenylphosphine)platinum(ll)] (0.524 g, 0.66 mmole) are refluxed in toluene (25 mL) for 30 hours. The colorless reaction mixture is filtered while hot using vacuum to remove any unreacted c/s-[dichlorobis(triphenylphosphine)platinum(Il)]. The filtrate is transferred to a 100-mL, round-bottomed flask and evaporated to dryness on a rotary evaporator, using gentle heating if necessary. The cream-colored residue is dissolved in a mixture of dichloromethane (15 mL) and methanol (15 mL) and the solution is allowed to concentrate slowly under water aspirator vacuum on a rotary... 

The compound [Ph4As][Pt(CO)Cl3] is characterized by IR absorption at 2077 cm 1 (Nujol) and 2095 cm 1 in dichloromethane. Yellow crystals of the compound decompose in air at 179°C. The compound is unreactive in air, but decomposes slowly in water. It is soluble in dichloromethane and dimethyl-formamide, slightly soluble in ethanol, and insoluble in water, diethyl ether, and hexane. The chlorine ligand trans to the CO is readily displaced by other halogens and other ligands.6 The compound reacts with chlorine to form [Pt(CO)Cl5]-.7... 

Powdered crystals of 1 (670 mg, 3.9 mmol) that were recrystallized from /r-hexane were evacuated in a 1 L flask and heated to 45 °C. Hydrogen gas was fed in from a steel cylinder (1 bar, 45 mmol) and the system kept at 45 °C for 2 days. The crystals changed their appearance and contained 67 mg (10%) unreacted 1, 502 mg (74%) 2 and 110 mg (16%) 3. The products were separated by preparative TLC on 200 g Si02 with dichloromethane. 

A sample of 10.2 mg (24.4 mmol) of powdered lb was irradiated with UV light for 6 h. The resulting violet solid was then extracted with dichloromethane for 4 h to remove unreacted monomer. Drying in vacuo to constant mass gave 1.8 mg (18%) of 2b as a light-violet solid, mp >320°C. 

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