Hexan ethers from

Nitro-n-hexane. Use 41 g. of dry silver nitrite, 51 g. of n-hexyl iodide (35-5 ml.) and 100 ml. of sodium dried ether. Reflux on a water bath for 8 hours decant the ethereal solution and wash the sohd well with sodium dried ether. Distil the residue, after the removal of the ether from the combined extracts, from 5 g. of dry silver nitrite, and collect the fraction of b.p. 190-192° (13 g.) as 1-nitro -hexane. The pure compound is obtained by distilling under diminished pressure b.p. 81 6°/15 mm. 

The progress of the reaction may be followed by analytical thin-layer chromatography on alumina. The submitters used polygram pre-coated plastic sheets (Alox N/UV254) purchased from Macherey-Nagel, Inc. The plates were developed with 1 1 hexane-ether and stained with basic permanganate. The Rf of the product is 0.56. 

Amino-4,6-dimethylpyridine [5407-87-4] M 122.2, m 69-70.5 , pK 7.84. Crystd from hexane, ether/pet ether or benzene. Residual benzene was removed over paraffin-wax chips in an evacuated desiccator. 

Cholesterol [57-88-5] M 386.7, m 148.9-149.4 , [a]D -35 (hexane). Crystd from ethyl acetate, EtOH or isopropyl ether/MeOH. [Hiromitsu and Kevan J Am Chem Soc 109 4501 I987. For extensive details of purification through the dibromide, see Fieser [J Am Chem SoclS 5421 1953] and Schwenk and Werthessen [Arch Biochem Biophys 40 334 7952], and by repeated crystn from acetic acid, see Fieser [J Am Chem Soc 75 4395 1953]. 

Tetraethylammonium chloride hydrate [56-34-8] M 165.7, m dec>200 . Crystd from EtOH by adding diethyl ether, from warm water by adding EtOH and diethyl ether, from dimethylacetamide or from CH2CI2 by addition of diethyl ether. Dried over P2O5 in vacuum for several days. Also crystd from acetone/CH2Cl2/hexane (2 2 1) [Blau and Espenson J Am Chem Soc 108 1962 1986 White and Murray J Am Chem Soc 109 2576 1987]. 

P, lp-Dihydroxy-5fi,6P-difluorom thyleneandrostane Diacetate 17)- A solution of 2.25 g (0.006 mole) of 3, 17/ -dihydroxyandrost-5-ene diacetate, mp 164-166° in diglyme (100 ml), is treated with 7.2 g (0.048 mole) of sodium chlorodifluoroacetate as previously described. The crude product, mp 123-130°, is crystallized from hexane affording unchanged olefin (16 1.64 g) mp 163-165°. The mother liquor is adsorbed from hexane on Florisil (100 g). Elution with hexane-ether (4 1) furnishes an additional 0.3 g of the... 

The crude ketone is chromatographed on acid-washed alumina (600 g, activity II). Elution with hexane-ether (4 1) gives a white solid (8.5 g) as the major fraction mp 77-82°. Recrystallization from methanol gives A-homo-5a-cholestan-4-one (3b 5.77 g 41% yield) mp 86-88° ... 

A mixture of 6.65 g of 3-chloro-6-nitroacetanilide, 3.2 ml of propylmercaptan, 5.6 g of 50% sodium hydroxide and 100 mi of water Is heated at reflux overnight. The cooled mixture is filtered to give the desired 2-nitro-5-propyithioaniline, MP 69.5°-71.5°C after recrystailiza-tion from ethanoi then hexane-ether. NMR (CDCi3) 40%. 

The excess thionyl chloride was removed under vacuum and by distilling from the residue two portions of dry benzene. The crystalline residue was crystallized twice from hexane-ether to yield 3,4,5-trimethoxycinnamoyl chloride which was obtained in the form of bright yellow prisms, MP 95° to 96°C. 

To 5.4 mmol of LDA, prepared in 25 mL of diethyl ether from diisopropylamine and 2 M butyllithium in hexane, are added 847 mg (5.00 mmol) of 2-(trimethylsilyloxy)-3-pentenenitrile in 10 mL of diethyl ether at — 78 "C. After stirring for 45 min, 671 mg (5.00 mmol) of 2-phenylpropanal, dissolved in 10 mL of diethyl ether are added. After stirring for 2 h at — 78 X, 1.20 g (10.5 mmol) of trifluoroacetie acid are added carefully to the mixture at below —70CC. 15 mL of sat. aq NH4C1 and then diethyl ether are added and the reaction mixture is allowed to reach r.t. The phases are separated and extracted with aq NH,CI and... 

MacMillan and Wright [133] identified and measured saturated and unsaturated 1,3- and saturated 1,4-sultones in anionic surfactants by a series of separation maneuvers. Ion exchange treatment separates sultones from the bulk of the ionic surfactant. TLC concentrates the sultones systems for HPLC analysis. They found that pentane-ether is preferable to the usual hexane-ether system and that the addition of a little methanol sharpens the separations. Finally, HPLC using a micro-Porasil column with 90 1 isooctane/ethanol provides quali-... 

The isolation of product is usually possible after evaporation of the solvent and extraction with hexane, ether, or toluene. Supported versions, for example on polystyrene grafted with PPh2 groups, have proved unsatisfactory because the rate of deactivation is greatly enhanced under these conditions [37]. Asymmetric versions exist, but the ee-values tend to be lower than in the Rh series [38]. With acid to neutralize the basic N lone pair, imine reduction is fast. Should it be necessary to remove the catalyst from solutions in order to isolate a strictly metal-free product, a resin containing a thiol group should prove satisfactory. A thiol group in the substrate deactivates the catalyst, however. 

The submitters used silica gel (mesh 100-200, BW-820 MH) from Fuji Davison Chemical, Ltd. (Japan). The checkers used radial chromatography (silica gel 60 PF 254 with gypsum, EM Science) with hexane/ethyl acetate (4/1) as eluent for small scale reactions. The checkers used flash chromatography (240 g of silica gel, grade 633, 47 x 61 microns, Davison Chemical) with hexane (1.5 L), hexane/ether (10/1,1.5 L), and ether (1.5 L) as eluent for large scale reactions (100 mmol). 

The purity of the ligand depends largely on the purity of the dibenzyl ester. Flash chromatography was carried out with silica gel purchased from Merck (Kieseigel 60, Art. 9385). For TLC analysis, Merck silica gel F-254 TLC plates were used, with, 3 1 5 hexane-ether-dichloromethane as eluent. Mono(2,6-dimethoxybenzoyl)tartrate has an Rf of ca. 0.35 in this solvent system. 

Arnett and Moe studied the protodelithiation of organolithiums with isopropyl alcohol in hexane/ether mixtures. These authors found protodelithiation enthalpies for n- and iec-butyl lithium of —209.2 4.2 and —220.9 2.9, respectively. The difference between their enthalpies of reaction, and so of the enthalpies of formation of the two organolithiums, is 11.7 5.1 kJmor, about half the difference between these species as found in Table 1. The protodelithiation enthalpy of terf-butyl lithium is —237.7 7.5 kJmoP. From equation 10 with n-butyl lithium as the benchmark species, and the butane hydrocarbons in their liquid reference states, the derived enthalpy of formation of ferf-butyl lithium is —87.5 kJmoP, in good agreement with that found before by Hohn . 

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