Dimethyl sulfoxide-acetic anhydride

The use of dimethyl sulfoxide-acetic anhydride as a reagent for the oxidation of unhindered steroidal alcohols does not appear to be as promising due to extensive formation of by-products. However, the reagent is sufficiently reactive to oxidize the hindered 11 j -hydroxyl group to the 11-ketone in moderate yield. The use of sulfur trioxide-pyridine complex in dimethyl sulfoxide has also been reported. The results parallel those using DCC-DMSO but reaction times are much shorter and the work-up is more facile since the separation of dicyclohexylurea is not necessary. Allylic alcohols can be oxidized by this procedure without significant side reactions. 

Vicinal glycols may be oxidized to the corresponding 17a-hydroxy-20-ketones in reasonable yields by means of chromium trioxide in dimethylfor-mamide in the presence of manganese dichloride, or by treatment with dimethyl sulfoxide-acetic anhydride. ... 

On treatment with dimethyl sulfoxide-acetic anhydride followed by sequential oximation, reduction, detritylation, and acid hydrolysis, a tetra-(6-0-trityl)-cyclohexaamylose was reported to afford 2-amino-2-deoxy-D-glucose, in addition to D-glucose, indicating459 that... 

Useful syntheses of D- and L-lyxose from 1,3-O-benzylidene-D- and L-arabinitol have been achieved through the highly selective oxidation of the primary hydroxyl groups by dimethyl sulfoxide-dicyclohexylcarbodiimide.463 Oxidation of but one of the two (equivalent) hydroxyl groups in 1,3,4,6-tetra-O-benzyl-D-mannitol464 and l,6-di-0-benzyl-2,5-0-methylene-D-mannitol465 was possible with dimethyl sulfoxide-acetic anhydride. 

Transformations of Methyl 5-0-Benzyl-2-0-methyl-/3-I)-glueofuranosidurono-6,3-lae-tone (86) to Dimethyl (Z,E)-2-Methoxy-5-(phenylmethoxy)-2,4-hexadienedioatevl (87). ( Elimination employing DBU b oxidation with silver oxide-sodium hydroxide followed by diazomethane esterification c acidic glycoside cleavage, oxidation by dimethyl sulfoxide-acetic anhydride with formation of 5-0-benzyl-2-0-methyI-D-glucaro-1,4 6,3-dilactone, elimination by using DBU, followed by short treatment with diazomethane d elimination by DBU with subsequent diazomethane esterification e sodium borohydride in hexamethylphosphoric triamide 1 catalytic oxidation followed by short treatment with diazomethane " dimethyl sulfoxide-sulfur trioxide-pyridine-triethylamine.150)... 

Oxidation of l,2 5,6-di-0-isopropylidene-o-mannitol (269) with dimethyl sulfoxide-acetic anhydride gave the 3,4-diulose derivative 270, which on hydrolysis led to crystalline 271. Some derivatives, such as 272 and 273 have been prepared.496... 

In comparison to some of the other activation methods however, the dimethyl sulfoxide-acetic anhydride procedure has certain disadvantages. The method often requires the use of long reaction times (1 24 h), which can result in many side reactions, especially with sensitive substrates. Notable in this respect is that it is not uncommon for this procedure to result in the formation of substantial yields of the thiomethyl ethers obtained from the Pummerer rearrangement product as described above. In fact upon attempted oxidation of cholesterol with this system, the major product obtained was the corresponding (methylthio)methyl ether. Acetates may also be formed if the alcohol is unhindered. For example the sugar derivative (9) reacts under these conditions to form an enol acetate (derived from the requir carbonyl compound) in 40% yield contaminated with 30% of the acetate (10 equation S). ... 

In an example of the use of this activation method testosterone, with a IT -hydroxy group, was oxidized to A -androstene-3,17-dione very rapidly in high yield, in contrast to the use DMSO-acetic anhydride. During a reaction, when other oxidizing agents were found to be ineffective, sulfur trioxide/dimethyl sulfoxide led to smooth oxidation of the df-diol (16 equation 8) to an o-quinone in 49% yield and the ci.r-diol (17) to (18 equation 9) in 98% yield. - The use of dimethyl sulfoxide-acetic anhydride for this oxidation gave large amounts of the diacetate as the by-product. 

Dimethylsulfonium mcthylide, 81, 188 Dimethyl sulfoxide, 130, 189 Dimethyl sulfoxide-Acetic anhydride, 190 Dimethyl sulfoxide-r-Butyl bromide, 190 Dimethyl sulfoxide-Chloro trimethylsilane, 190... 

Aldehyde bisulfite adducts are oxidized by dimethyl sulfoxide/acetic anhydride and converted to simple amides in good yield. ... 

Dimethyl sulfoxide-Acetic anhydride, 199 Dimethylsulfoxide-N-Bromosuccinimide, 199-200... 

Dimethyl sulfoxide-Acetic anhydride [1, 305, after citation of ref. 43J. Albright and Goldman433 have reported further on the oxidation of secondary alcohols to ketones with DMSO-Ac20 at room temperature. In the case of yohimbine and the steroid secondary alcohols studied, oxidation apparently was faster than acetylation. The method is particularly useful for sterically hindered alcohols. The following mechanism is proposed ... 

Dimethyl sulfoxide-Acetic anhydride (1, 305 2, 163-165). Clement et al.16 report that DMSO and acetic anhydride can be used for normal oxidation of... 

A few years later the Swem laboratory then developed an activator which they claimed to be the most successful in activating dimethyl sulfoxide toward oxidation, namely, oxalyl chloride. Since oxalyl chloride reacted violently and exothermically with dimethyl sulfoxide, successful activation required the use of low temperatures to form the initial intermediate.6 Swem et al. reported the oxidation of long chain primary alcohols to aldehydes which was previously unsuccessful by first converting to the sulfonate ester (either mesylate or tosylate) and then employing the dimethyl sulfoxide-acetic anhydride procedure. They found that long-chain saturated, unsaturated, acetylenic and steroidal alcohols could all be oxidised with dimethyl sulfoxide-oxalyl chloride in high yields under mild conditions. 

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