Dimethyl iodine

The carbonylation of 2-methyl-3-butyn-2-oI (50) in benzene gives teraconic anhydride (51). Fulgide (53) (a dimethylenesuccinic anhydride derivative), which is a photochromic compound, can be prepared by the carbonylation of 2,5-dimethyl-3-hexyne-2,5-diol (52)[21], The reaction proceeds under milder conditions when PdlOAc) is used as a catalyst in the presence of iodine [23],... 

This test is a visual compahson of the color of dimethyl sulfate with that of a 0.0001 N iodine solution. Commercial dimethyl sulfate should be lighter in color. 

Imidazole, 4,5-dibromo-l-methyl-synthesis, S, 399 Imidazole, 4,5-di-t-butyl-synthesis, S, 483 X-ray diffraction, S, 350 Imidazole, 4,5-dichloro-chlorination, S, 398 synthesis, S, 398, 473 Imidazole, 4-(3,4-dichlorophenyl)-nitration, 5, 433 Imidazole, 4,5-dicyano-hydrolysis, S, 435-436 synthesis, S, 461, 472, 487 Imidazole, 4,5-dicyano-1-vinyl-synthesis, S, 387 Imidazole, 4,5-dihydro-mass spectra, 5, 360 Imidazole, 4-(dihydroxybutyl)-synthesis, S, 484 Imidazole, 4,5-diiodo-nitration, S, 396 synthesis, S, 400 Imidazole, 2,4-diiodo-5-methyl-iodination, S, 400 Imidazole, 1,2-dimethyl-anions... 

In a similar reaction, iodine fluonde also can be removed from perfluorobutyl-, perfluorohexyl-, and perfluorooctyl iodide by using zinc-copper couple in dimethyl sulfoxide or dimethylformamide [71]... 

CF,C02)2lPh, H2O, CH3CN, 85-99% yield. In the presence of ethylene glycol the dithiane can be converted to a dioxolane (91% yield) or in the presence of methanol to the dimethyl acetal. The reaction conditions are not compatible with primary amides. Thioesters are not affected. A phenylthio ester is stable to these conditions, but amides are not. The hypervalent iodine derivative l-(t-butylperoxy)-l,2-benziodoxol-3(l/f)-one similarly cleaves thioketals."... 

Preparation of (Me0)2P-0-R ROH, (MeO)3P, CBr4, Pyr, 70-98% yield. The alkyl dimethyl phosphite may then be oxidized to the corresponding phosphate by aq. iodine, t-butyl hydroperoxide, or peracid. 

The action of methyl iodide on chloro-substituted heterocychcs usually results, in addition to quatemization, in the replacement of the chlorine by iodine if the halogen is in a position alpha or gamma to the quaternary center, particularly so in the former case. This type of replacement is less likely if dimethyl sulfate is used but may still occur to give a sulfate betaine (see Section IV, C). An easy method to obtain a-halogeno-quatemary salts has recently been discovered by Balli and Kersting who reacted the readily accessible triethyloxonium borofluoride 12 with a variety of bases. The very... 

It is also interesting to note that quatemization of a chloropyrimi-dine at the nitrogen atom adjacent to the chloro group with methyl iodide results in the easy replacement of the chlorine by iodine, whereas similar salt formation on the remote nitrogen either leaves the chlorine unaffected or replacement occurs only at higher temperatures. A similar reaction occurs between 2-amino-6-chloro-4-methylpyrimidine and dimethyl sulfate in nitrobenzene to give the salt 45 and betaine 46. ... 

Silole reacts with Co2(CO)g to form the monosubstituted ri -silacyclopentadiene complex 286 [85JOM(293)295]. The 2,5-diphenyl analog of the latter with excess silole yields the corresponding disubstituted derivative 287 [87JOM(320)C7]. The similar complex was previously made for the 1,1-dimethyl derivative [76JCS(D)2484], Treatment of 287 with iodine gives 288. 

The crude iodinated acid was then dissolved in 500 ml of 95% alcohol, 10 g of dimethyl-aminoethanol was added, the solution was decolorized with activated charcoal and filtered at 70°C. After keeping the filtrate for several hours at 5°C, the heavy crystalline precipitate which formed was collected by filtration and washed with acetone. The mother liquors were concentrated to 150 ml and cooled to give a second crop which was further purified by recrystallization from 50 ml of 95% alcohol. In this way a total of 36.0 g of dimethyl-aminoethanol salt of dextro-/3-(3,5-diiodo-4-hydroxy)-o-phenylpropionic acid, MP 151° to 153°C, was obtained. The melting point of the dimethylaminoethanol salt of unresolved /3-(3,5-diiodo-4-hydroxy)-o-phenylpropionic acid was 142° to 144°C. 

Iodine azide, generated in situ from an excess of sodium azide and iodine monochloride in acetonitrile, adds to ethyl l//-azepine-l-carboxylate at the C4 — C5 and C2 —C3 positions to yield a 10 1 mixture of the rw-diazidodihydro-l//-azepines 1 and 2, respectively.278 The as stereochemistry of the products is thought to be the result of initial trans addition of the iodine azide followed by an SN2 azido-deiodination. The diazides were isolated and their stereochemistry determined by conversion to their bis-l,3-dipolar cycloadducts with dimethyl acetylene-dicarboxylate. 

Additional kinetic evidence supporting molecular iodine as an iodinating species is sparse. Li325 found that the iodination of tyrosine in acetate buffers at 25 °C showed the mixed inverse dependence on iodide ion concentration noted above, so that part of the reaction appeared to involve the molecular species. Subsequently, Doak and Corwin326 found that the kinetics of the iodination of (N-Me)-4-carboethoxy-2,5-dimethyl- and (N-Me)-5-carboethoxy-2,4-dimethyl-pyrroles in phosphate buffers in aqueous dioxane at 26.5 °C obeyed equation (162), viz. 

Aravamudan and Venkappayya75 oxidized dimethyl sulphoxide in acetate buffer of pH 4 to 4.5 and with a reaction time of only 1 min. They then added potassium iodide and acid and titrated with thiosulphate the iodine liberated by unused reagent. They reported that cerium(IV) and Cr(VI) were much less effective oxidizing reagents for the sulphoxide. A very similar procedure was used by Rangaswama and Mahadevappa76 to determine dimethyl sulphoxide and numerous other compounds with chloramine B. 

Bohme77 employed excess monoperphthalic acid in diethyl ether to oxidize dibenzyl and benzyl ethyl sulphoxides. Reaction time was 24 h at - 15 to + 10 °C, after which he added potassium iodide and water and titrated the iodine set free with thiosulphate. Dickenson78 oxidized dimethyl sulphoxide in malt, wort or beer with Na2S2Os. In... 

Halogenation of 106 with triphenylphosphine, iodine, and imidazole provided the iodo derivative 109. On treatment with lithium aluminum hydride, 109 was converted into two endocyclic alkenes, 110 and di-O-isopro-pylidenecyclohexanetetrol, in the ratio of 2 1. Oxidation of 110 with dimethyl sulfoxide - oxalyl chloride afforded the enone 111.1,4-Addition of ethyl 2-lithio-l,3-dithiane-2-carboxylate provided compound 112. Reduction of 112 with lithium aluminum hydride, and shortening of the side-chain, gave compound 113, which was converted into 114 by deprotection. ... 

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