Triol samples

A total of 50 ml (0.15 moles) of a 3 ethereal solution of methylmagnesium bromide is added slowly to a vigorously stirred solution of 5.8 g (12.5 mmoles) or 3,3 20,20-bisethylenedioxy-5a,6a-epoxy-5a-pregnane-ll/l,17a,21-triol in 400 ml of tetrahydrofuran. The solution is heated under reflux for 24 hr, cooled and treated with 32 ml of saturated ammonium chloride solution. The supernatant is decanted and the residue is washed with several portions of tetrahydrofuran. The combined supernatants are evaporated and extracted with ethyl acetate, washed with saturated salt solution, dried and concentrated to give 4,55 g (75%) of 3,3 20,20-bisethylenedioxy-6 -methyl-5a-pregnane-5a,ll, 17a,21-tetrol mp 170-172° after crystallisation from acetone-petroleum ether. The analytical sample is crystallized from acetone-petroleum ether mp 175-177° [aJo —11° (CHCI3). 

The above crude bromohydrin was mixed with 2.5 grams of potassium acetate and 60 cc of acetone and refluxed for 6 hours, at the end of which the acetone was distilled, water was added to the residue and the product was extracted with methylene chloride. The extract was washed with water, dried over anhydrous sodium sulfate and the solvent was evaporated. Recrystallization of the residue from methanol furnished 800 mg of the 16,21-diacetate of 6o-fluoro-9(3,11(3-oxido-A -pregnene-16o,l7a,2l-triol-3,20-dione with MP 120° to 124°C by chromatography of the mother liquors on silica gel there was obtained 180 milligrams more of the same compound with MP 117° to 119°C. The analytical sample was obtained by recrystallization from methanol it showed MP 125° to 127°C. 

One system studied by the authors(3) used LG56 triol which had been characterised by molar-mass as well as end-group determinations. The data for the samples used are given in Table III, indicating a true number-average functionality (fn) of between 2.95 and 2.99. The triol was reacted with HDI in bulk (see Figure 1) and at various dilutions in benzene, and values of Nr and ac determined. To estimate functionality from ac, equations... 

Polyurethane networks were prepared from polyoxypropylene (POP) triols(Union Carbide Niax Polyols) after removal of water by azeotropic distillation with benzene. For Niax LHT 240, the number-average molecular weight determined by VPO was 710 and the number-average functionality fn, calculated from Mjj and the content of OH groupSj determined by using excess phenyl isocyanate and titration of unreacted phenyl isocyanate with dibutylamine, was 2.78 the content of residual water was 0.02 wt.-%. For the Niax LG-56, 1 =2630, fn=2.78, and the content of H2O was 0.02wt.-%. The triols were reacted with recrystallized 4,4"-diphenylmethane diisocyanate in the presence of 0.002 wt.-% dibutyltin dilaurate under exclusion of moisture at 80 C for 7 days. The molar ratio r0H = [OH]/ [NCO] varied between 1.0 and 1.8. For dry samples, the stress-strain dependences were measured at 60 C in nitrogen atmosphere. The relaxation was sufficiently fast and no extrapolation to infinite time was necessary. 

C-5 epimers of 6,7-didehydro-5,6,5, 6 -tetrahydro-)3,/3-carotene-3,5,3 5, 6 -pentol (15), isolated as minor constituents of a sample of neoxanthin [5, 6 -epoxy-6,7-didehydro-5,6,5, 6 -tetrahydro-j8,j8-carotene-3,5,3 -triol (16)] from Trollius europaeus, may be artefacts. In Sarcina lutea, sarcinaxanthin [2,2 -bis-(4-... 

The residue was chromatographed on 90 grams of silica gel eluting the product with methylene chloride-acetone (9 1) and then recrystallizing from methylene chloride-methanol. There was thus obtained 1.6 grams of the 16,21-diacetate of 6a-fluoro-84/9(11)-pregnadiene-16a,-17a,21-triol-3,20-dione with MP 110° to 114°C the analytical sample melted at 115° to 117°C, [a]D+23.5° (chloroform), X max. 234 to 236 nm, log e 4.18. 

Recently, a sexual pheromone of the hair crab Erimacrus isenbeckii has been identified from the feeding seawater of pre- and postmolt females.113 The purified sample elicited guard behavior in male hair crabs at a dose of 2.0 mg per sponge and was composed of 13 ceramides. On the basis of detailed NMR and fast atom bombardment tandem mass spectrometry (FAB-MS/MS) analysis, the structure of one of the major ceramides, ceramide A (49), was determined to be (26, 35,4i )-2-[(R)-2-hydroxy-21-methyldocosanoylamino]-l,3,4-pentadecane-triol.114 Similarly,... 

However, these workers have noted the ability of monoterpene dlols and triols, which are also present In musts and wines, to act as precursors of volatiles (6) Accordingly, variations In monoterpene abundance between samples could be reflective of the method used in preparing the sample or of the analysis Itself. A similar questioning of the emphasis given to the analytical characterization of grapes and wines based on quantification of free monoterpenes had been expressed previously when the lability of various precursor forms of these compounds was first recognized (18,19). Nevertheless these caveats questioned only the detailed interpretation of the statistical data and the need for appropriate techniques to avoid artefact formation. The fundamental soundness of the correlations remains intact. 

Two forms of GAP, the diol and triol, have been under evaluation. The experiments described in this section were performed on the diol having a molecular weight in the neighborhood of 2,350. The sample of GAP used in these experiments was designated L-11391 (3M Company) and contained approximately 2.5% of nonfunctional cyclic and oligomeric material. The structure of GAP diol is given in figure 9.31. 

In fast atom bombardment (FAB), the sample is introduced as a viscous liquid - often dissolved in a solvent such as glycerol (propane-1,2,3-triol) -which is then bombarded with a stream of energetic atoms or ions (typically argon or xenon at energies up to 30 keV) rather than electrons. This results in sputtering of molecules from the sample, and a proportion of them are also ionized. Fragmentation may also occur during collision and ionization. This cloud of ions is then directed into the mass spectrometer for analysis. This method is typically useful for peptides or small proteins of RMM up to about 10,0(X). 

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