Mixed Iodomethanes

S. (2R,5S)-2-tert-Butyl-5-methyI-l-aza-3-oxabicyclo[3.3.0Joctan-4-one. In a 250-mL, round-bottomed flask equipped with a magnetic stirrer, 18.3 mL (0.131 mol) of diisopropylamine (Note 10) is mixed with 120 mL of dry tetrahydrofuran (THF, Note 11) under argon. At -78°C bath temperature, 88.6 mL of a 1.6 M solution of butyllithium (0.142 mol) in hexane is added and the mixture is allowed to warm to room temperature for 20 min. After the mixture is recooled to -78°C, the lithium diisopropylamide (LDA) solution is added over a period of 20 min (Note 12) to a Solution of 20.0 g (0.109 mol) of (2R,5S)-2-tert-butyl-l-aza-3-oxabicyclo[3.3.0]octan-4-one in 600 mL of dry THF in a 1-L, round-bottomed flask, precooled to -78°C. Tetrahydrofuran (20 mL) is used to rinse the 250-mL flask. After keeping the resulting solution at -78°C tor 45 min, 8.8 mL (0.142 mol) of iodomethane (Note 13) is added Over a period of 10 min. The resulting mixture is allowed to warm to 0°C over a period Of 3 hr, and 300 mL of a saturated aqueous solution of ammonium chloride is added. 

Reaction of the quaternized salts of 4-ethoxycarbonyl-3,5-dimethyl-f-phenylpyttolo(furo or thieno)[2,3-c]pyrazole 34 with the iodomethane quaternary salts of pyridine, quinoline, and isoquinoline in ethanol with catalytic piperidine gave 3-[4(f)]-monomethine cyanine dyes (e.g., 35). Additionally, 3-[2(4)]-trimethine cyanine dyes and 4-[2(4)]-di-3[2(4)]-tri-mixed methine cyanine dyes (e.g., 36 and 37, respectively) were similarly prepared from the intermediates derived by reaction of 34 with triethyl orthoformate in the presence of piperidine (Scheme 8) <2002CCS106f>. 

CH3I, form an ideal solution. The vapor pressure of bromomethane is 661 Torr and that of iodomethane is 140 Torr at 0.0°C. Calculate the vapor pressure of each of the following solutions and the mole fraction of each substance in the vapor phase above those solutions at 0.0°C (a) 0.33 mol of bromomethane mixed with 0.67 mol of iodomethane (b) 35.0 g of bromomethane mixed with 35.0 g of iodomethane. 

Methyl l-Methoxyltellurobenzoate)1 A solution of 0.171 g (1 mmol) 2-methoxybenzoyl chloride in 8 ml tetrahydrofuran is added to 0.174 g (1 mmol) of freshly prepared sodium telluride (liquid ammonia method). The mixture is stirred at 0° for 1 h and then filtered. The solvent is evaporated from the filtrate under reduced pressure. The red, oily residue is cooled to — 63° under nitrogen and mixed with 2 ml (32 mmol) iodomethane. The mixture is warmed to — 30° and stirred at this temperature for 2 h. The excess iodomethane is evaporated under reduced pressure below 0°. The residue is treated with 5 ml dichloromethane, the black mixture is filtered, and the filtrate evaporated under reduced pressure below 0° to give yellow crystals yield 84% m.p. 25°. 

A nucleophilic metal anion has been used as a reducing agent to create Zintl ion directly. [PPN]2[Fe2(CO)6(Te2)2] (169) has been synthesized by direct reaction of Na2[Fe(CO)4] with elemental tellurium.115 Although not structurally characterized by X-ray methods, the formulation of 169 is supported by several pieces of experimental evidence. It can react with itself or with the Zintl ions present to produce mixed-metal species. It reacts with iodomethane to yield [Fe2(CO)6(/z-TeMe)2] (170) (Fig. 56),... 

Two of the key assumptions of the thin-film model (see Section 6.03.2.1.1) are that the main bodies of air and water are well mixed, i.e., that the concentration of gas at the interface between the thin film and the bulk fluid is the same as in the bulk fluid itself, and that any production or removal processes in the thin film are slow compared to transport across it. It is quite likely that there are near-surface gradients in concentrations of many photochemically active gases. Little research has been published, although the presence of near-surface gradients (10 cm to 2.5 m) in levels of CO during the summer in the Scheldt estuary has been reported (Law et al., 2002). Gradients may well exist for other compounds either produced or removed photochemically, e.g., di-iodomethane, nitric oxide, or carbonyl sulfide (COS). Hence, a key assumption made in most flux calculations that concentrations determined from a typical sampling depth of 4-8 m are the same as immediately below the microlayer may well often be incorrect. 

N-a-Amino acids (10 mg) were typically dissolved in 200 mM, pH 10 sodium metaborate buffer (1 ml), and methylated directly by the addition of a 1 1 v/v solution (20 gl) of [ C]iodomethane in acetonitrile, with rapid mixing of the sealed biphasic mixture at 37°C for 24 h. Cystine dimethyl ester, in particular, was first converted to the diamide at pH 9.5 using ammonia. Histidine amide was first acetylated prior to reaction with iodomethane. 

The temperature dependence of the C chemical shift of several haloalkanes showed that the thermal sensitivity was in the order I > Br > Cl, paralleling the heavy atom effect. As a practical thermometer, iodomethane mixed with TMS (3 1 v/v) was deemed suitable for a temperature range 208 to 303 K, and di-iodomethane mixed with cyclooctane (5 1 v/v) for the range 293 to 448 K. The linear dependences were ... 

Following a comparison of the behaviours of trialkyl phosphites, mixed alkyl phenyl phosphites and triphenyl phosphite towards iodomethane and, in the last case, the breakdown of the phosphonium salt when treated with an alcohol, Landauer and Rydon considered that all the reactions involve a stage identical with that of the normal Michaelis-Arbuzov reaction. The absence of any rearrangement during the decomposition of complexes from neopentyl phosphites, and the configurational inversion which occurs when optically active 2-halooctanes are produced from optically active phosphite triesters (themselves obtained from optically active octan-2-ol), suggest that the mode of breakdown of the intermediate complexes is of S 2 character. 

Preparation.—Conventional quaternization reactions of phosphines with alkyl halides have been used for the preparation of chiral P-hydroxyalkylphosphonium salts for use in prostaglandin synthesis and of the salts (111), (112), and (113). This approach has also been used for the preparation of polymer-bound phosphonium salts for use in subsequent Wittig reactions and of a range of co-dialkylaminoalkylphosphonium salts. The salt (114), of limited thermal stability, is formed on treatment of the parent phenylphosphaferrocenophane (67, R = Ph) with iodomethane. The oxonium salt (115) is converted into the mixed onium salt (116) on treatment with triphenylphosphine. A range of... 

The piperidine (191) was converted to the formamide (192) with acetic formic mixed anhydride or to the thioformamide (193) with N,N-dimethylthioformamide. Compound (192) was 6)-methylated with dimethyl sulphate or (193) was 5-methylated with iodomethane and either intermediate exposed to octylamine to give fenoctimine (194) Scheme 5.45.) [250, 251]. Alternatively, octylamine was converted to A, -dimethyl-octylformamidine (195) with dimethylformamide-dimethyl sulphate. Reaction of this amidine with the piperidine (191) gave fenoctimine in improved yield [252], The drug is more potent than cimetidine in suppressing gastric acid secretion in animals and clinically shows marked inhibition of food-stimulated acid secretion [250,253,254]. 

The steps of methylation are as follows. 10 mg of HP- -CD is taken into a test tube with stopper, add 3 mL dimethylsulfoxide and mix the solution. Add 50 mg sodium hydroxide dry powder and 0.5 mL iodomethane, and then fill with nitrogen. Treat with ultrasonic at room temperature for 60 min. Add 5 mL water to suspend the reaction. Extract by 3 mL chloroform. Wash the organic phase twice with 5 mL water, then distill imder reduced pressure to get faint yellow methylated product. Hydrolyze the product in 2 mol/L trifluoroacetic acid at 120 C for 1 h. 

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