Triethylamine , chlorination

A mixture of 0.10 mol of the acetylenic alcohol, 0.12 mol of triethylamine and 200 ml of dichloromethane (note 1) was cooled to -50°C. Methanesulfinyl chloride (0.12 mol) (for its preparation from CH3SSCH3, (08300)30 and chlorine, see Ref. 73) was added in 10 min at -40 to -50°0. A white precipitate was formed immediately. After the addition the cooling bath was removed and the temperature was allowed to rise to -20°0, then the mixture was vigorously shaken or stirred with 100 ml of water. The lower layer was separated off and the aqueous layer was extracted twice with 10-ml portions of CH2CI2. The combined solutions were dried over magnesium sulfate and concentrated in a water-pump vacuum (note 2). The yields of the products, which are pure enough (usually 96%) for further conversions, are normally almost quantitative. 

Tetrafluoropyrimidine was converted to the antiaeoplastic 5-fluorouracil (5-FU) by a novel process based on the sequence partial exchange chlorination (61% yield), selective hydrogenolysis ia triethylamine (71% yield) and hydrolysis (85—93% yield) (464). 

However, treatment of 4-chloro-3-nitrocoumarin (81) with 2-mercaptophenol (254) provided the product of displacement of the chlorine atom 263. Treatment of compound 263 with triethylamine gave a mixture from which low yields of 266 and 267 were isolated (92ZOR1489). This fact can be explained by the formation of the o-complex 264. This complex is stabilized by carbonyl group participation and therefore an equilibrium of 263 and 265 can be expected. This is in accordance with the formed products (Scheme 41). A similar situation was described earlier for the reaction of 4,5-dichloropyridazin-6(17/)-one with the disodium salt of 2-mercaptophenol (82JHC1447). 

The sulfur analogue of the Hauser ortho-substitution rearrangement provides access to an arylacet-ic NSAID. Reaction of the aminobenzophenone 176 with ethyl methylthioacetate and tert-butyl hypochlorite gives the intermediate 178. The reaction probably proceeds by way of formation of the S-chlorinated sulfonium derivative 177 displacement on sulfur will lead to the salt 178. Treatment with triethylamine leads initially to the betaine 179. Electrocyelic rearrangement of that transient intermediate leads, after rearomatization, to the homoanthranilic acid 180. Internal ester-amine interchange leads then to indolone 181 [45]. The thiomethyl group is then removed with Raney niekel. Saponifieation of intermediate 182 affords bromfenac (183) [46J. 

A convenient modification of the Gassman oxindole synthesis was reported using ethyl (methylsulfinyl)acetate (101) activated by oxalyl chloride to generate the same chlorosulfonium salt 102 normally generated from ethyl (methylthio)acetate 100 and elemental chlorine <96TL4631>. Thus, treatment of the sulfoxide 101 with oxalyl chloride, followed by the addition of the desired aniline, triethylamine, and finally acid cyclization of 103 affords the oxindoles 104. This procedure is particularly convenient for reactions carried out on smaller scales and for anilines that ate susceptible to electrophiUc halogenation. 

The diastereomerically pure chlorides 73a and 73b afforded the corresponding P-substitution products on reaction with nucleophiles. Thus 73a and 73b could be converted readily into the corresponding alkoxy-derivatives on treatment with an alcohol in the presence of triethylamine and into aryloxy-derivatives upon treatment with the sodium salt of the appropriate phenol at room temperature. Replacement of chlorine by an alkoxy- or aryloxy-group occurred with retention of configuration, e.g., 73a gave 74a, 75a, and 76a. Similarly, 74b and 75b could be obtained from 73b (Scheme 24) [32, 38, 54],... 

Oxidation. DMSO activated by P205 (1 equiv.) and in combination with triethylamine is useful for oxidation of alcohols to ketones and aldehydes, particularly in cases where the Swern reagent results in chlorinated byproducts. Yields are typically 80-85%. 

Chlorine, Antimony trichloride, Tetramethylsilane, 4047 Chlorine, 2-Chloroalkyl aryl sulfides, Lithium perchlorate, 4047 Sulfur tetrafluoride, 2-(Hydroxymethyl)furan, Triethylamine, 4350 Titanium, Halogens, 4919... 

Nucleophilic substitution of chlorine in 2,4-dinitrochlorobenzene by diethylamino group from triethylamine (Scheme 4.18) is a rare example when both the formed opposite-charged ion radicals exist together in the bulk solution for a long time. 

It is not surprising that chloro esters 1, 2 readily add thiols, catalyzed by sodium thiolates or triethylamine, to give the corresponding 2-(r-organylthiocy-clopropyl)-2-chloroacetates 85,86 (Scheme 22) [15 b, 22b, 27]. This reaction with thiophenol has been used to quantify the Michael reactivity of 1-Me, 2-Me, 3-X in comparison to simple acrylates (see above). With an excess of PhSH, the nucleophilic substitution of the chlorine in 85 a (but not in 85h) proceeded to give the corresponding bis(phenylthio) derivative in 63% yield [15bj. Alkali thiolates (e.g. NaSMe, NaSBn) add smoothly onto 1-Me, 2c-Me and 2p-Me at - 78 °C, because at this temperature subsequent nucleophilic substitution of the chlorine is much slower [7l, 9]. The Michael additions of sodium phenylselenide and sodium arylsulfenates onto 1-Me and their synthetic utility have been discussed above (see Table 1). 

Another methodology for the in situ preparation of nitrile oxide is the dehydro-halogenation of hydroxymoyl chlorides vrith triethylamine. Hydroxymoyl chlorides are accessible by the reaction of aldoximes vrith chlorinating agents such as NCS (N-chlorosuccinimide). Isoxazolines of C50 and C70 [293-295] with R = Ph, alkyl, 4-C5H4OCH3 4-C5H4CHO, amino acid [305], dialkoxyphosphoryl [296, 297] or ferrocene [298] have been synthesized in ca. 20 0% yields. The latter reaction is slower than the dehydration of nitroalkanes and requires one equivalent of hydroxymoyl chloride whereas excess nitroalkane is necessary for an optimum reaction [293]. 

With sulfur and triethylamine in dimethylformamide, compounds (86) give (89) (Equation (21)) <89JPR243>. With thiols or KjS, sulfides are produced (e.g., (90) and (91)), which show spasmolytic activity in vitro <86MI 404-01 >. Smooth 5N2-displacements of chlorine occur with phenol, thiophenol, SCN, and thiourea in dimethylsulfoxide. However, with K2CO3 or sodium cyanide, (86) (Ar = Ph) affords the trimers (92) or (93) (Scheme 32). With electron-deficient trans alkenes, stereoselective formation of cyclopropanes (94) was observed (Scheme 32). No reactions occur with maleates <66HCA412>. 

Acetone, Sulfuric acid. Chlorine, Calcium chloride Triethylamine, Acetonitrile, Methylenedinitramine, 4,5-Dichloro-l,3-dioxolan-2-one. Silica gel. Benzene, Ethanol Picric acid. Sulfur, Potassium nitrate. Sulfuric acid. Sodium hydroxide... 

The a-face of 104 is considerably more hindered than the (3-face, a supposition that was supported by the difficulties encountered in the reduction of 101 and 107. Increasing the steric bulk of the chlorinating agent should favor attack on the (3-face of 104, thus providing a greater relative amount of chloroindolenine 108. When 104 was treated with t-BuOCl in pyridine instead of triethylamine, the desired chloroindolenine... 

Similar oxidation of alcohols has been carried out with dimethyl sulfoxide and other reagents317 in place of DCC acetic anhydride,318 SOy-pyridine-triethylamine,319 trifluo-roacetic anhydride,320 oxalyl chloride,321 tosyl chloride,322 chlorine,323 bromine,324 AgBF4-Et3N,325 P205-Et3N,326 phenyl dichlorophosphate,327 trichloromethyl chloroformate,328 tri-... 

A significant feature in the synthesis of 2,2-disubstituted tetrahydropyrans from diethyl malonate is the selective chlorination by trifluoromethanesulfonyl chloride of carbanions which can be formed using triethylamine or DBU as the base (79TL3645). Monoalkylation of the diester with l-bromo-4-tetrahydropyranyloxybutane leads to the alcohol (237 R = H)... 

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