DMSO and acetic anhydride

The initiating step in these reactions is the attachment of a group to the sulfoxide oxygen to produce an activated intermediate (5). Suitable groups are proton, acyl, alkyl, or almost any of the groups that also initiate the oxidations of alcohols with DMSO (40,48). In a reaction, eg, the one between DMSO and acetic anhydride, the second step is removal of a proton from an a-carbon to give an yUde (6). Release of an acetate ion generates the sulfur-stabilized carbonium ion (7), and the addition of acetate ion to the carbonium ion (7) results in the product (eq. 15) ... 

For DMSO and acetic anhydride, step d is intermolecular, as shown by 0 isotopic... 

In 1965, Albright and Goldman3 demonstrated that alcohols are oxidized to aldehydes and ketones by the action of a mixture of DMSO and acetic anhydride at room temperature. Two years later,56 they presented a full paper, in which optimized conditions for this oxidation were established using yohimbine (16) as a model substrate. Thus, it was found that treatment of yohimbine with a mixture of DMSO and AC2O produces the desired oxidation to yohim-binone (17), accompanied by formation of the methylthiomethyl ether 18. 

Protocol 4 describes the oxidation of alcohol 8 by dimethylsulfoxide (DMSO) and acetic anhydride at room temperature.20 This Albright-Goldman method is more economical and simpler to perform on a large scale than other... 

The methylthiomethyl ether (MTMOR) Tertiary hydroxyl groups, which are susceptible to acid-catalyzed dehydration, can be easily protected as MTM ethers and recovered in good yield. The MTM ether of a hydroxyl group can be formed either by a typical Williamson ether synthesis or on reaction with dimethylsulfoxide (DMSO) and acetic anhydride (AC2O). In the latter case, the reaction proceeds with the Pummerer rearrangement " (Scheme 1.25). 

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... 

C.iii. Other DMSO Oxidations. Albright and Goldman developed a reagent using DMSO and acetic anhydride that formed an active sulfoxonium complex. 12 jj (jje initial work, yohimbine was oxidized to the ketone (yohimbinone) in 85% yield, at ambient temperatures in 24 h. 2 As with DCC, DMSO initially reacts with acetic anhydride to form sulfoxonium salt 66, which then reacts with the alcohol. Acetate is the leaving... 

A direct preparation of 1-nitroisoquinolines from the corresponding isoquinolines was accomplished with potassium nitrite and acetic anhydride in DMSO <96JCS(P1)1777>. This method has preparative merit since 1-nitroisoquinolines are not readily accessible by other methods. 

The one-step reaction of H2prCl6] with MeC02Li under 02 in a mixed solvent of acetic acid and acetic anhydride yields the Ir11 binuclear complex [Ir2(/u-02CMe)2Cl2(C0)2].483 Crystal-structure determinations of [Ir2(/x-02CMe)2Cl2(C0)2L2], (295), where L = MeCN, DMSO, and py, are reported. The one-electron oxidation product for (295), L = py, is EPR active at 77 K the odd electron occupies the 6Ir Ir orbital. 

Solutions of acetyl nitrate, prepared from fuming nitric acid and acetic anhydride, can react with alkenes to yield a mixture of nitro and nitrate ester products, but the /3-nitroacetate is usually the major product. ° Treatment of cyclohexene with this reagent is reported to yield a mixture of 2-nitrocyclohexanol nitrate, 2-nitrocyclohexanol acetate, 2-nitrocyclohexene and 3-nitrocyclohexene. °/3-Nitroacetates readily undergo elimination to the a-nitroalkenes on heating with potassium bicarbonate. /3-Nitroacetates are also reduced to the nitroalkane on treatment with sodium borohydride in DMSO. ... 

This reaction was first reported by Albright and Goldman from the American Cyanamid Company in 1965. It is a mild conversion of primary and secondary alcohols into corresponding aldehydes and ketones using the mixture of dimethyl sulfoxide and acetic anhydride as the oxidant. This reaction is particularly useful for the oxidation of the steri-cally hindered hydroxyl groups. In general, the oxidation is carried out by allowing a mixture of 1 mmol primary or secondary alcohol, 3 mL DMSO, and 2 mL (20 mmol excess) acetic anhydride to stand at room temperature for 18-24 h. ... 

Potassium amide in liquid ammonia will react with isoquinoUne to form 1-aminoisoquinoline. The corresponding 1-nitroisoquinoline can be synthesized when isoquinoUne is treated with potassium nitrite and acetic anhydride in DMSO (eq 3). ... 

Phenol, trimellitic acid anhydride [TMA], 4-aminobenzoic acid [PABA], thionyl chloride, DMF, DMAc, DMSO and NMP were purchased from Aldrich Chemical. Phenol, thionyl chloride and acetic anhydride were distilled prior to use. [TMA] and [PABA] were crystallized from appropriate solvents. All the solvents were purified according to the method described in the literature.21 Pseudomonas putudia and horseradish peroxidase and were obtained from Sigma Chemical. Water was doubly distilled. Oxygen was technical grade. 

Full details have now appeared of the general method for formation of methylthiomethyl (MTM) ethers from alcohols by treatment with DMSO in acetic anhydride containing acetic acid. These authors also report their mild cleavage method of methyl iodide in moist acetone the use of volatile reagents is advantageous as it allows easier product isolation than the previous Ag and Hg procedures. 

Fused Heteroaromatic Compounds.— The halogen in 4-chloroquinoline is readily replaced by the enolate anions from isopropylidine alkylmalonates and acetic anhydride in the presence of the heterocycle acylation of the nitrogen provides the necessary activation of the system. Attempted overall methylation of 2-methylquinoline by MeSOCH2 and DMSO gives only a minute amount of the... 

Cellulose dissolved in suitable solvents, however, can be acetylated in a totally homogeneous manner, and several such methods have been suggested. Treatment in dimethyl sulfoxide (DMSO) with paraformaldehyde gives a soluble methylol derivative that reacts with glacial acetic acid, acetic anhydride, or acetyl chloride to form the acetate (63). The maximum degree of substitution obtained by this method is 2.0 some oxidation also occurs. Similarly, cellulose can be acetylated in solution with dimethylacetamide—paraformaldehyde and dimethylformamide-paraformaldehyde with a potassium acetate catalyst (64) to provide an almost quantitative yield of hydroxymethylceUulose acetate. 

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. 

Perfluoroalkylation can be accomplished via direct reaction of peifluoroalkyl halides and copper with aromatic substrates [232, 233, 234, 235, 236] Thus, perfluoroalkyl iodides or bromides react with functionalized benzenes m DMSO m the presence of copper bronze to give the corresponding perfluoroalkylated products directly in moderate to good yields [233] (equation 157) Mixtures of ortho, meta, and para isomers are obtained [232, 233], The use of acetic anhydride as solvent gives similar results [234, 235], Similarly, the direct reaction of perfluoroalkyl iodides and pyrroles with copper metal regiospecifically gives the 2-perfluoroalkylpyrroles [236] (equation 158). 

As previously discussed, solvents that dissolve cellulose by derivatization may be employed for further functionahzation, e.g., esterification. Thus, cellulose has been dissolved in paraformaldehyde/DMSO and esterified, e.g., by acetic, butyric, and phthalic anhydride, as well as by unsaturated methacrylic and maleic anhydride, in the presence of pyridine, or an acetate catalyst. DS values from 0.2 to 2.0 were obtained, being higher, 2.5 for cellulose acetate. H and NMR spectroscopy have indicated that the hydroxyl group of the methy-lol chains are preferably esterified with the anhydrides. Treatment of celliflose with this solvent system, at 90 °C, with methylene diacetate or ethylene diacetate, in the presence of potassium acetate, led to cellulose acetate with a DS of 1.5. Interestingly, the reaction with acetyl chloride or activated acid is less convenient DMAc or DMF can be substituted for DMSO [215-219]. In another set of experiments, polymer with high o -celliflose content was esterified with trimethylacetic anhydride, 1,2,4-benzenetricarboylic anhydride, trimellitic anhydride, phthalic anhydride, and a pyridine catalyst. The esters were isolated after 8h of reaction at 80-100°C, or Ih at room temperature (trimellitic anhydride). These are versatile compounds with interesting elastomeric and thermoplastic properties, and can be cast as films and membranes [220]. 

Similar oxidation of alcohols has been carried out with DMSO and other reagents in place of DCC acetic anhydride, SO3-pyridine-triethyla-... 

The following four-step mechanism has been proposed for the reaction between acetic anhydride and DMSO ... 

The aziridine aldehyde 56 undergoes a facile Baylis-Hillman reaction with methyl or ethyl acrylate, acrylonitrile, methyl vinyl ketone, and vinyl sulfone [60]. The adducts 57 were obtained as mixtures of syn- and anfz-diastereomers. The synthetic utility of the Baylis-Hillman adducts was also investigated. With acetic anhydride in pyridine an SN2 -type substitution of the initially formed allylic acetate by an acetoxy group takes place to give product 58. Nucleophilic reactions of this product with, e. g., morpholine, thiol/Et3N, or sodium azide in DMSO resulted in an apparent displacement of the acetoxy group. Tentatively, this result may be explained by invoking the initial formation of an ionic intermediate 59, which is then followed by the reaction with the nucleophile as shown in Scheme 43. 

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