DMSO reaction

A direct method for preparing a carboxylic acid treats an alkyl halide with NaN02 in acetic acid and DMSO. Reaction of an alkyl halide with ClCOCOaMe and (Bu3Sn)2 under photochemical conditions leads to the corresponding methyl... 

The direct high yield synthesis of oxaspiropentanes from almost any type of aldehyde or ketone represents a particularly useful transformation because of the high reactivity of such compounds. This approach proves to be exceptionally simple. The DMSO reaction mixture can be directly extracted with pentane or hexane, the hydrocarbon solvent removed and the product isolated by distillation or crystallization. Since diphenyl sulfide is the only by-product extracted with the oxaspiropentane, the mixture can normally be used for most further synthetic transformations. Table 2 summarizes some of the oxaspiropentanes prepared by this method. 

Figure 6 Mechanism of intermolecular crosslink formation in lysine-containing polypeptides via condensation with bis(AA-hydroxysuccinimidyl)suberates (R = Hm DMSO reactions R = S03 Na in aqueous reactions). 

MSA concentrations were generally consistent with its formation from the OH-DMSO reaction if 80% of the reaction generated methanesulfinic acid and 50% of this compound was oxidized to MSA (Davis et al., 1998). 

With sulfoxides, OH reacts mainly by addition to the S-0 double bond [DMSO reaction (14) 92% k = 7 x 109 dm3 mol-1 s-1]. The resulting adduct has not been detected, because it decomposes very rapidly by 3-fragmentation [reaction (15) Dixon et al. 1964 Norman and Gilbert 1967 Veltwisch et al. 1980],... 

Figure I shows typical data for a N02/NO/isobutene/DMSO reaction mixture plotted in the form In Ct/Cp versus t. The rate constants for the reaction of OH with DMSO obtained from the analysis of such plots according to Equation 4 are listed in Table I. The values of k measured were independent of the OH source used and an average value of (6.5 2.5) x 10 11 cm3 s 1 has been obtained as rate constant for the reaction of OH with DMSO in 760 Torr air at 298 K, which is approximately a factor of 10 higher than the corresponding reaction of OH with DMS.

Hynes, A.J., Wine, P.H. (1996) The atmospheric chemistry of dimethylsulfoxide (DMSO) kinetics and mechanism of the OH + DMSO reaction. J. Atmos. Chem. 24, 23-37. 

The use of Dimethyl sulphoxide (DMSO) in dermatology has a long history.18,19 In concentrations up to 50% DMSO is used for topical treatment of amyloidosis,20 but in concentrations of 90% and higher it is known to induce whealing and a flare reaction. The procedure described here is a modification of that described by Frosch et al.21 for the identification of individuals with sensitive skin. The DMSO reaction can be assessed clinically or measured with the laser Doppler flowmeter.22 The recent development of laser Doppler imagers28 make it possible to measure the DMSO induced increase in blood flow with unparalleled accuracy. To elicit the reaction 15 /ul of 90%, 95%, and 100% DMSO were applied to three adjacent sites and immediately covered with a circular plastic disc,... 

DMF, in alkylation of aminothiazoles, 35 in ambident reactivity, 36 in cyclizations, 50 DMSO, reaction with CS2,61 Dopamine content in brain, 146 Dopamine hydroxylase inhibitor, 152 Double bond, addition to, 40 ozonolysis of, 71... 

DMSO, Reaction Medium and Reactant, Chemical Products Division, Crown Zellerbach Corporation, Camas, Washington (1962). 

Synthesis of the racemic cyclic telluride (2,7-dihydro-17/-dinaphthoR,i ]tellurepin 78), possessing a C2 axis, was based on the reaction of 2,2 -bis(chloromethyl)-l,10-binaphthalene 109 with potassium tellurocyanate in dry DMSO. Reaction of 109 with iodide gave the diiodo derivative (Scheme 7) <2004JOM(689)2377, 1996RTC427>. 

A synthesis of 22,23-epoxyergocalciferol from the 4-phenyl-1,2,4-triazoline-3,5-dione adducts (272) employed the K2CO3-DMSO reaction for deprotection of the A -diene cf. ref. 53). The Reporter observes that the assignment of the 22/3,23/3-configuration is dubious in view of earlier work in this area. " Syntheses have been reported for la,25-dihydroxy-24-nor-cholecalciferol, 25-hydroxy-24 -nor- 5,6- frans-cholecalcif erol, and 2 5 -hydroxy- 24a-homo- 5,6-... 

Base-catalysed cyclization of proximate diacetyl aromatics [e.g. o-diacetylbenzene (36)] gives the corresponding enone (37). Relative rates, activation parameters, and isotope effects are reported for (36), and also for 1,8-diacetylnaphthalene, 4,5-diacetylphenanthrene, and 2,2 -diacetylbiphenyl, in aqueous DMSO. Reaction proceeds via enolate formation (rate determining for the latter three substrates), followed by intramolecular nucleophdic attack [rate determining for (36)], and finally dehydration. 

Table II. Inhibition of chltln synthetase extracted from fourth-Instar Trlchoplusla nl Integuments. 100 yl of enzyme suspension were preincubated for 15 min at 21°C with 200 yl trls-HCl buffer (pH 7.25), lOmM MgCl2, ImM DTT, 18 mM GlcNAc, and either plumbagln dissolved In 10 yl DMSO or simply 10 yl pure DMSO. Reaction Initiated at room temperature with 0.3 yCl UDP-3H-GlcNAc.

The synthesis of allenes of the type RpCH C CHa is an easier task, now made even easier by a new method based on the reaction of perfluoroalkyl coppers with propargyl halides or alcohols. The alkyl copper is generated in situ from copper bronze and a perfluoroalkyl iodide in DMSO reaction with propargyl bromide is extremely rapid and a minor explosion occurred during work-up. 

A comprehensive discussion of the factors that influence the kinetics for ring closure and opening has been made by Tobe, Romeo, and co-workers. They studied the formation and cleavage of six- and seven-membered rings under the large rra/w-effect of DMSO, reaction (5),... 

Complex Formation Inert Cations. Several reports deal with the formation of chromium(m) complexes in dipolar aprotic solvents, especially DMF and DMSO. Reactions of [Cr(DMSO)e] + with Ns or NCS are /a, the reaction with Cl perhaps more complicated. lon-triples as well as ion-pairs may be kinetically significant in DMSO. Kinetics of reactions of complexes of the type fm 5 -[Cr(DMSO)2-(en)al + and rraKj-[Cr(DMF)a(en)2] with halide ions have also been described. ... 

This unusual enhancement is attributed to relative rotamer populations in the two solvents. Extensive intramolecular hydrogen-bonding is observed in chloroform but intermolecular bonding to the solvent in DMSO. Consequently only in chloroform does the hydroxy-group hydrogen-bond to the cyclobutene and in DMSO reaction is facilitated by orbital interaction through space between the and orbitals. In view of the relation between rate and the difference in energy between HOMO and LUMO orbitals these results are not unexpected. 

Reaction of CO with 7 in DMSO/H2O gave reversibly [Ir(CO)3(TPPTS)2]Cl 216 in H2O and DMSO and Ir(CO)2Cl(TPPTS)2 217 in DMSO only. In H2O, further reactions occur slowly, including WGS reaction and formation of [Ir(CO)2(TPPTS)3] 218. In DMSO, reaction with CO readily forms [Ir(CO)3(TPPTS)2] 219 no reaction with CO is observed in H2O. Reaction of 218 with H2 occurs through TPPTS dissociation giving [Ir(CO)2(H)2(TPPTS)2] 220 initially before reaction with free TPPTS gives [Ir(CO)(H)2(TPPTS)3] 221 as the final product. ... 

---