Oxidation with Chromium Trioxide-Pyridine Complex

D. Oxidation with Chromium Trioxide-Pyridine Complex General Procedure... [Pg.5]

A - -Steroid. Dauben and Fullerton chose the following route for conversion of A -androstenc-.3)S,17 -diol diacetate (1) into A - -androstadiene-3, 17 -diol diacetatc (4). The starting material was converted into the 7-ketonc (2) by oxidation with chromium trioxide-pyridine complex in methylene chloride (2, 74 75). The ketone OAc... [Pg.304]

OXIDATION WITH CHROMIUM TRIOXIDE-PYRIDINE COMPLEX... [Pg.283]

Oxidation, of primary alcohols to aldehydes, 52, 5 of terminal olefins with chromyl chloride, 51, 6 of 2,4,4-trimethyl-1-pentene with chromyl chloride, 51, 4 with chromium trioxide-pyridine complex, 52, 5... [Pg.62]

Conjugated acetylenic ketones can be prepared in about 40% yield by oxidation of alkynes with chromium trioxide-pyridine complex ... [Pg.96]

If homolytic reaction conditions (heat and nonpolar solvents) can be avoided and if the reaction is conducted in the presence of a weak base, lead tetraacetate is an efficient oxidant for the conversion of primary and secondary alcohols to aldehydes and ketones. The yield of product is in many cases better than that obtained by oxidation with chromium trioxide. The reaction in pyridine is moderately slow the intial red pyridine complex turns to a yellow solution as the reaction progresses, the color change thus serving as an indicator. The method is surprisingly mild and free of side reactions. Thus 17a-ethinyl-17jS-hydroxy steroids are not attacked and 5a-hydroxy-3-ket-ones are not dehydrated. [Pg.242]

OXIDATION WITH THE CHROMIUM TRIOXIDE-PYRIDINE COMPLEX PREPARED in situ ... [Pg.84]

CHROMIUM TRIOXIDE-PYRIDINE COMPLEX, preparation in situ, 55, 84 Chrysene, 58,15, 16 fzans-Cinnamaldehyde, 57, 85 Cinnamaldehyde dimethylacetal, 57, 84 Cinnamyl alcohol, 56,105 58, 9 2-Cinnamylthio-2-thiazoline, 56, 82 Citric acid, 58,43 Citronellal, 58, 107, 112 Cleavage of methyl ethers with iodotri-methylsilane, 59, 35 Cobalt(II) acetylacetonate, 57, 13 Conjugate addition of aryl aldehydes, 59, 53 Copper (I) bromide, 58, 52, 54, 56 59,123 COPPER CATALYZED ARYLATION OF /3-DlCARBONYL COMPOUNDS, 58, 52 Copper (I) chloride, 57, 34 Copper (II) chloride, 56, 10 Copper(I) iodide, 55, 105, 123, 124 Copper(I) oxide, 59, 206 Copper(ll) oxide, 56, 10 Copper salts of carboxylic acids, 59, 127 Copper(l) thiophenoxide, 55, 123 59, 210 Copper(l) trifluoromethanesulfonate, 59, 202... [Pg.114]

The above discussion has concentrated upon the reagents used, but it is equally of value to comment on the substrate, particularly in reactions for which other oxidation methods have been reported to fail. A good example is the oxidation of the iron-carbonyl complex (31) to the ketone (32 equation 14). The use of dimethyl sulfoxide activated with sulfur trioxide-pyridine complex gave a 70% yield of the product, in contrast to the use of the Pfitzner-Moffatt procedure (dimethyl sulfoxide-DCC) or the chromium... [Pg.299]

An attempted allylic oxidation of (68 equation 29) was found by Paquette to be difficult to achieve using a range of reagents due to problems with polymerization and rearrangement. The chromium trioxide-pyridine complex was the only reagent combination found to be successful, albeit in low yield. [Pg.102]

P. J. Garegg and B. Samuelsson, Oxidation of primary and secondary alcohols in partially protected sugars with the chromium trioxide-pyridine complex in the presence of acetic anhydride, Carbohydr. Res., 67 (1978) 267-270. [Pg.125]

Pyridine forms explosive mixtures with air, with LEL and UEL values of 1.8 and 12.4% by volume in air, respectively. Its reactions with strong oxidizers can be violent. There is a report of an explosion with chromium trioxide during the preparation of a chromium trioxide-pyridine complex (MCA 1967). Many metal perchlorates, such as silver perchlorate, form solvated salts with pyridine, which can explode when struck. It undergoes exothermic reactions with concentrated acids. [Pg.486]

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