Pressure cyclo

COT is prepared by the polymerization of ethyne at moderate temperature and pressure in the presence of nickel salts. The molecule is non-planar and behaves as a typical cyclic olefin, having no aromatic properties. It may be catalytically hydrogenated to cyclo-octene, but with Zn and dil. sulphuric acid gives 1,3,6-cyclooclairiene. It reacts with maleic anhydride to give an adduct, m.p. 166 C, derived from the isomeric structure bicyclo-4,2,0-octa-2,4,7-triene(I) ... 

Introduce a solution of 100 g. of sodium bisulphite in 200 ml. of water and continue the stirring, preferably for 10 hours with exclusion of air. A thick precipitate separates after a few minutes. Collect the bisulphite compound by suction filtration, wash it with ether until colourless, and then decompose it in a flask with a lukewarm solution of 125 g. of sodium carbonate in 150 ml. of water. Separate the ketone layer, extract the aqueous layer with four 30 ml. portions of ether, dry the combined organic layers over anhydrous magnesium sulphate, remove the ether at atmospheric pressure, and distil the residual oil under reduced pressure from a Qaisen flask with fractionating side arm (Fig. II, 24, 5). Collect the cyclo-heptanone at 64r-65°/12 mm. the yield is 23 g. 

Efficiency data for a representative structured packing at two column diameters are shown in Fig. 14-74. The Max-Pak packing has a surface area of 246 m /m (7.5 ft /fE). The same test mixture (cyclo-hexane//i-heptane) and operating pressure was used for both tests. It would appear that column diameter does not have an influence in this range of values (0.43 to 1.2 m). 

Preparation of 18,20-Cyclo-5a-pregnane-3, 20-diol 3-Acetate ° A solution of 5 g of 3j9-hydroxy-5oc-pregnan-20-one 3-acetate in 1000 ml of spectroscopically pure ethanol is irradiated with a 250 Watt Philips Biosol A mercury high pressure lamp No. 10/27 through a cental water cooled pyrex jacket under nitrogen for 4 hr. The solvent is then evaporated under reduced pressure and the residues from 2 such reactions are combined and chromatographed on 300 g of neutral alumina (activity II). 

Hydrolysis of 6p,l9-Oxido-3a,5a-cyclo steroids.A solution of 0.1 g of 3a,5a-cyclo-6)5,19-oxidocholestane in 20 ml of acetone is treated with 1.0 ml of water and 0.5 ml of 1 N sulfuric acid. After standing for 2 hr at room temperature, the solution is neutralized with saturated sodium bicarbonate solution and extracted with ether. The combined ether extracts are washed with water and concentrated to dryness under reduced pressure. Recrystallization of the crude product from methanol yields 85 mg choIest-5-ene-3, 19-diol mp 147-149° [aj —30°. 

Irradiations of Testosterone Acetate (114), —In t-Butanol. 1.25 g of (114) in 250 ml t-butanol is irradiated for 32 hr at 30° under nitrogen with a Hanau Q81 high-pressure mercury lamp placed in a central water-cooled Pyrex immersion well with acetone filter. The solvent is evaporated in vacuo and the residue chromatographed on 125 g silica gel with benzene-ethyl acetate (4 1) to yield 0.29 g 17 -hydroxy-la,5 -cyclo-10a-androstan-2-one acetate [(118) 23%] mp 164-165°, after crystallization from acetone-hexane [a]i3 37 (CHCI3) 0.14 g cyclopentanone (120) (11%) mp 106-107° [aJo 38° (CHCI3) and 0.58 g starting material [(114) 46%]. Ratio (118) (120) - 2 1. 

Dicyclohexylammonium nitrite s (DCHN) has a solubility of 3-9g in 100 g of aqueous solution at 25°C, giving a solution pH of about 6-8. Its vapour pressure at 25°C appears to be about 1-3 x 10 N/m but the value for commercial materials depends markedly on purity. It may attack lead, magnesium, copper and their alloys and may discolour some dyes and plastics. Cyclohexylammonium cyclohexyl carbamate (the reaction product of cyclohexylamine and carbon dioxide, usually described as cyclo-hexylamine carbonate or CHC)" is much more volatile than DCHN (vapour pressure 53 N/m at 25°C), and much more soluble in water (55 g in 100cm of solution at 25°C, giving a pH of 10-2). It may attack magnesium, copper, and their alloys, discolour plastics, and attack nitrocellulose and cork. It is said to protect cast iron better than DCHN, and to protect rather better in the presence of moderate concentrations of aggressive salts. 

Irradiation of cyclo-S% dissolved in CS2 by a high-pressure mercury lamp at 20 °C produces the homocycles S7, S, S12, S9, Sio, and probably S5 in concentrations decreasing in this order. Irradiation of Se in CS2 gives mainly Ss and S7 while irradiation of S7 generates Ss and S. Similarly, photolysis of S12 in CS2 yields Ss, S7, and Se [51]. For these reasons UV-Vis spectra of compounds containing S-S bonds must be recorded with caution not to trigger decomposition reactions. 

The crystal of 2 OPr recrystallized from EtOH/H20 solution, and the mixed crystal of the same ethyl and propyl cinnamate derivatives (2 OEt and 2 OPr), on photoirradiation for 2h at room temperature with a 500 W super-high-pressure Hg lamp, afforded the highly strained tricyclic [2.2] paracyclophane (2 OEt-2 OPr-cyclo) crystal quantitatively (Maekawa et ai, 1991b). A crystal structure analysis was carried out of a single crystal of the complex of 2 OEt-2 OPr-cyclo with HFIP (recrystallization solvent) in a 1 2 molar ratio. Fig. 13 shows the molecular structure of 2 OEt-2 OPr-cyclo viewed along the phenylene planes. The short non-bonded distances and deformation of the benzene rings, as seen in Fig. 13, are common to those of [2.2] paracyclophanes, as previously reported (Hope et ai, 1972a,b). 

While (Z)-l,2-bis(phenylsulfonyl)ethylene (140) does not add to dienes such as furan, cyclopentadiene, cyclo-octatetraene, indene and )S-naphthol, ( )-l,2-bis(phenylsulfonyl)ethylene (141) is more reactive and the reaction with furan proceeds at room temperature for 2 h to give the adduct in 95% yield. The reactivity of dienophiles having sulfonyl group in the [4 -t- 2]cycloaddition is shown in equation 103 °X Due to the low reactivity of ethylene and acetylene as dienophiles, forcing conditions, such as high temperature and high pressure, are necessary for [4 -1- 2]cycloaddition. The hazards associated with handling acetylene under these conditions are well known and... 

For PR3/P(OR)3-stabilized nickel complexes, there are two borderline cases known from the experimental investigation of Heimbach et al. 1 which, unlike the usual behavior, redirect the cyclo-oligomerization reaction into the Ci2-cyclo-oligomer production channel. Catalysts bearing either strong a-donor ligands that must also introduce severe steric pressure (e.g., PBu Pr2) or sterically compact n-acceptors (like P(OMe)3) are known to yield CDT as the predominant product. From a statistical analysis it was concluded,8a,8c that the C8 Ci2-cyclo-oligomer product ratio is mainly determined by steric factors (75%) with electronic factors are less important. 

Cyclobutylcyclopropanol [133] To a well-stirred solution of ethyl cyclobutanecarboxylate [134] (56.47 g, 0.441 mol) and titanium tetraisopropoxide (26.3 mL, 88.2 mmol, 20 mol%) in anhydrous diethyl ether (200 mL), ethylmagnesium bromide (0.980 mol, 276 mL of a 3.55 m solution in Et20) was added over a period of 3 h. The temperature was maintained at between 20 and 25 °C with a water bath. After the addition was complete, the mixture was stirred for an additional 0.5 h at the same temperature, then cooled to —5 °C, whereupon the reaction was quenched by the careful addition of ice-cold 10 % aqueous sulfuric acid (500 mL) while the temperature was maintained between —5 and 0°C with an acetone/dry ice bath. The mixture was stirred at 0°C for an additional 1 h and then the aqueous phase was extracted with Et20 (100 mL). The combined ethereal phases were washed with saturated aq. NaHC03 solution (2 X 200 mL) and brine (200 mL), dried, and concentrated at water-pump pressure at 20 °C to give 48.92 g (99%) of 1-cyclo-butylcyclopropanol. The spectroscopic data of the product were identical to those reported in the literature [135]. 

B. 2,2-(Trimethylenedithio)cyclohexanone. A solution of 3.02 g. (0.02 mole) of freshly distilled 1-pyrrolidinocyclohexene, 8.32 g. (0.02 mole) of trimethylene dithiotosylate4 (Note 2), and 5 ml. of triethylamine (Note 3) in 40 ml. of anhydrous acetonitrile (Note 4), is refluxed for 12 hours in a 100-ml., round-bottom flask under a nitrogen atmosphere. The solvent is removed under reduced pressure on a rotary evaporator, and the residue is treated with 100 ml. of aqueous 0.1 N hydrochloric acid for 30 minutes at 50° (Note 5). The mixture is cooled to ambient temperature and extracted with three 50-ml. portions of ether. The combined ether extracts are washed with aqueous 10% potassium bicarbonate solution (Note 6) until the aqueous layer remains basic to litmus, and then with saturated sodium chloride solution. The ethereal solution is dried over anhydrous sodium sulfate, filtered, and concentrated on a rotary evaporator. The resulting oily residue is diluted with 1 ml. of benzene and then with 3 ml. of cyclohexane. The solution is poured into a chromatographic column (13 x 2.5 cm.), prepared with 50 g. of alumina (Note 7) and a 3 1 mixture of cyclohexane and benzene. With this solvent system, the desired product moves with the solvent front, and the first 250 ml. of eluent contains 95% of the total product. Elution with a further 175 ml. of solvent removes the remainder. The combined fractions are evaporated, and the pale yellow, oily residue crystallizes readily on standing. Recrystallization of this material from pentane gives 1.82 g. of white crystalline 2,2-(trimethylenedithio)cyclo-hexanone, m.p. 52-55° (45% yield) (Note 8). 

Cyclo(His-D-Leu) acts as a hydrolytic catalyst. Cyclo(Leu-Gly) blocks the development of (1) physical dependence on morphine, (2) tolerance to the pharmacological effects of /3-endorphin, (3) tolerance to haloperidol-induced catalepsy and hypothermia, and (4) dopaminergic supersensitivity after chronic morphine administration. Cyclo(Tyr-Arg), a synthetic analogue of kyortorphin (an endogenous analgesic peptide), and its A-methyl tyrosine derivatives are more potent than kyotorphin in the mouse tail pressure test. ... 

During ventricular pressure experiments the heart rate was kept constant by pacing. Even with the heart rate constant, both DKPs displayed a decrease in coronary flow. Cyclo(Cys-Ile) was found to decrease coronary... 

Hence, two methods are available that can be applied to follow nanoparticles formation and growth (i) an indirect method that utilizes the consumption of molecular hydrogen pressure versus time and (ii) a direct method that follows the loss of precursor by the 1 1 conversion of its cyclo-octadiene ligand to cyclo-octane by GLC measurements. The mechanism developed by Watzky and Finke suggests that the nanoparticles act as Hving-metal polymers -a concept that could be used to obtain particles with defined sizes simply by adding the appropriate amounts of catalyst precursors [32]. 

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