Na2SO4 addition

Isoquinoline [119-65-3] M 129.2, m 24 , b 120 /18mm, d 1.0986, n 1.6148. Dried with Linde type 5A molecular sieves or Na2SO4 and fractionally distd at reduced pressure. Alternatively, it was refluxed with, and distd from, BaO. Also purified by fractional crystn from the melt and distd from zinc dust. Converted to its phosphate (m 135°) or picrate (m 223°), which were purified by crystn and the free base recovered and distd. [Packer, Vaughn and Wong JACS 80 905 795(S]. The procedure for purifying via the picrate comprises the addition of quinoline to picric acid dissolved in the minimum volume of 95% EtOH to yield yellow crystals which are washed with EtOH and air dried before recrystn from acetonitrile. The crystals are dissolved in dimethyl sulphoxide (previously dried over 4A molecular sieves) and passed through a basic alumina column, on which picric acid is adsorbed. The free base in the effluent is extracted with n-pentane and distd under vacuum. Traces of solvent are removed by vapour phase chromatography. [Mooman and Anton JPC 80 2243 1976. ... 

A 1,3,5-triphosphinine was liberated from the coordination compound 25 by oxidation with hexachloroethane in toluene. If, however, the chlorination of complex 25 was conducted in pentane complex 26 was obtained in 44% yield. The hafnium complex 26 was hydrolyzed by an excess of water to the bicyclic diphosphirane 27 in 53% yield together with 10% of the 1,3,5-triphosphinine. Under milder and more controlled conditions, for example, the treatment of 26 with silica gel containing 2% H2O or with Na2SO4 10H2O, the addition of the second equivalent of water was suppressed and the two heterocycles 28 and 29 were formed in equal amounts (Scheme 10) <1999EJI763>. 

Dimethylsulfoxide (1.25 mL, 17.6 mmol) was added to a solution of 2,4,6-trichloro-[l,3,5]-triazine (TCT, 0.66 g, 3.6 mmol) in THF (20 mL), stirred, and maintained at -30 °C. After 30 min, A-benzyloxycarbonyl-2-amino-3-phenylpropan-l-ol, (0.86 g, 3 mmol) in THF (10 mL) was added slowly at -30 °C with stirring, and after an additional 30 min, NEts (2 mL, 14.3 mmol) was added. After 15 min, the mixture was warmed to room temperature, the solvent evaporated in vacuo, and I T O (50 mL) added to the resulting solid. The mixture was quenched with 1 N HCl, and the organic phase washed with 15 mL of a saturated solution of NaHCOs, followed by brine. The organic layer was dried (Na2SO4) and the solvent evaporated to yield pure A-benzyloxycarbonyl-2-amino-3-phenylpropionaldehyde (0.77 g, 90%). 

To a solution of the P-hydroxy-/V-methyl-O-methylamide (0.272 g, 1.55 mol) in tetrahydrofuran (THF) (30 mL) were added carbon disulfide (6.75 mL, 112 mmol) and iodomethane (6.70 mL, 108 mmol) at 0 °C. The mixture was stirred at this temperature for 0.25 h, and then sodium hydride (60% suspension in mineral, 136.3 mg, 3.4 mmol) was added. After 20 min at 0 °C, the reaction was quenched by slow addition to 60 g of crushed ice. (Caution hydrogen gas evolution ). The mixture was raised to room temperature and separated, and the aqueous layer was extracted with CH2CI2 (4x15 mL). The combined organic extracts were dried (Na2SO4), concentrated in vacuo, and purified (SiO2, 5% EtOAc in hexanes) to afford 0.354 g (86%) of the xanthate. To a solution of the xanthatc (2.95 g, 11.1 mmol) in toluene (100 mL) was added tributyltin hydride (15.2 mL, 56.6 mmol) and 2,2 -azobisisobutyronitrilc (AIBN, 0.109 g, 0.664 mmol). The reaction mixture was then heated to reflux for 1 h. The mixture was cooled, concentrated in vacuo, and purified (SiO2, 100% hexanes to remove tin byproducts, followed by 10% EtOAc in hexanes to elute product) to afford 1.69 g (96%) of the/V-methyl-O-methylamide. 

Triethylamine (0.32 mL, 2.22 mmol) and H-Phe-Leu-OMe (0.72 g, 2.16 imnol) were added to a solution of the aldehyde (0.67 g, 1.66 mol) in 1,2-dichloroethane (25 inL). The solution was stirred for 5 min, after which time sodium triacetoxyborohydride (0.57 g, 2.67 mmol) was added in 1 portion. Stirring was continued for 45 min followed by addition of saturated aqueous NaHCOs and separation of the two phases. The aqueous phase was extracted with CH2CI2. The combined organic phases were washed with brine, dried over Na2SO4, and concentrated under reduced pressure. The residue was purified by flash chromatography (heptane/EtOAc (3 1 to 1 1) to give 0.93 g (82%) of the secondary amine as a slightly yellow oil. 

Dipotassium azodicarboxylate (DAPA) (20 mg, 0.123 mmol) was added to a solution of the isomeric olefin (149 mg, 0.197 mmol) in methanol (10 mL). Glacial acetic acid (10 pL) was added, and the reaction mixture was heated to 40 °C open to the atmosphere. As the yellow color of the solution started to fade, more DAPA (20 mg) and acetic acid (10 pL) were added. The addition procedure was repeated several times over the course of 10 h, and the reaction progress was monitored by NMR. On completion of the reaction, the reaction mixture was cooled and then a saturated aqueous solution of NaHCOs (15 mL) was added. The product was then extracted into CI bCb (3 X 25 mL), and the combined organic layers were dried over Na2SO4. After evaporation of the solvent, the clear residue was purified by chromatography (2 1, hexaneiEtOAc) to give 130 mg (87%) of the reduced product as a clear oil. 

To a mixture of L-phenylalanine methyl ester hydrochloride (20.0 g, 93 nunol) suspended in toluene (93 mL) was added benzyl chloroformate (15.8 g, 93 nunol) with cooling in an ice bath. An aqueous solution of Na2CO3 (1 M, 130 mL) was added dropwise with vigorous stirring at 7 °C or lower. After this addition was complete, the mixture was stirred for 3 h. The organic layer was separated, washed with 0.1M HCl (60 mL) and saturated NaHCOs solution (60 mL), and then dried over anhydrous Na2SO4. Concentration of the solution in vacuo provided Cbz-L-Phe-OMe (28.8 g, 96%) as a colorless oil. 

Zinc nitrate [Zn(N03)2-6H20] and zinc sulphate [ZnS04-7H20], both with 99% purity, were adopted as the source materials for the zinc species. NaOH with 97% purity was employed as a base for all experiments. SS (Na2SO4-10H2O) and SDS [H3(CH2)n0S03Na] with 99 and 98% purity, respectively, were chosen as the additives to be evaluated. All reagents were purchased from Prolabo. 

Figure 7-37. Sequence showing sintered SiC with boron and carbon additives before corrosion after corrosion with Na2SO4/(0.0l SO3 + O2) at 1273 K for 48 h, showing glassy product layer and with glassy product layer removed, revealing highly pitted SiC. (Jacobson, 1993. Reprinted with permission of the American Ceramic Society.)...

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