Formaldehyde-Sodium iodide

Mannich cyclization. Reaction of the alkynylamine 1 with formaldehyde, sodium iodide (3 equiv.), and camphorsulfonic acid (CSA, 1 equiv.) results directly in the piperidine 2 in 81-90% yield. In the absence of Nal, no cyclization is observed even after a reaction at 100° for 3 hours. The vinylic iodide group is useful for elaboration to exocyclic tetrasubstituted double bonds. 

The same workers42 obtained an optically inactive racemate, 2,4 3,5-dimethylene-D,L-xylitol, by the direct methylenation of the pentitol in the presence of concentrated hydrochloric acid. Acetolysis of the racemate and treatment of the resulting diacetyl-acetoxymethyl-methylene-xylitol (XV) with sodium methoxide afforded 2,4-methylene-xylitol which was identified by its failure to react with periodate (see page 146).42 The labile methylene group may have occupied either the 1,3(3,5)- or the 1,5-position, but the latter possibility was eliminated on the grounds that the p-toluenesulfonate of the dimethylene-xylitol could be converted, by exchange with sodium iodide, into an iodo-desoxy-dimethylene-xylitol, and thence, by reduction, into a desoxy-dimethylene-xylitol, identical with that obtained when the known l-desoxy-2,3,4,5-diisopropylidene-D,L-xylitol was treated with formaldehyde and hydrochloric acid.42... 

Treatment of the monoethylidene-D-mannitol with lead tetraacetate or periodate resulted in the consumption of two molecular equivalents of oxidant with the concomitant production of one mole of formaldehyde, one mole of formic acid and a monoethylidene-D-erythrose, the latter being identified by its conversion into the known crystalline D-erythrosazone.118 This evidence limited the choice of structure for the mannitol acetal to the 1,3- and 2,3-compound (4,6- and 4,5- are the respective identical structures). Two additional facts eliminated the latter alternative, first, the tetratosyl ester gave only one mole of sodium p-toluenesulfonate when heated with sodium iodide in acetone, and secondly, the same monoethylidene-D-mannitol was obtained from the above 1,3,4,6-diethylidene-D-mannitol by acidic hydrolysis.118 For these reasons Bourne, Bruce and Wiggins118 assigned to the mono-, di- and tri-ethylidene-D-mannitols, respectively, the 1,3-, 1,3 4,6- and 1,3 2,5 4,6- structures. 

Overman has shown that camphorsulfonic acid can also be used in nucleophile-promoted alkyne-iminium cyclizations. Alky-lamines can react with formaldehyde and sodium iodide to yield piperidines in good yield. This methodology has been applied in the total synthesis of pumiliotoxin A (eq 4). ... 

C. (E)-1-Benzyl-3-(1-iodoethyUden9)piperidine (3). A 250-mL, one-necked, round-bottomed flask containing a magnetic stirring bar and a reflux condenser topped with a rubber septum inlet is flushed with argon and charged with 4.0 g (21 mmol) of alkynylamine 2, 11 g (73 mmol) of sodium iodide (Note 9), 35 mL of 37% w/w formaldehyde solution, 5.4 g (22 mmol) of camphorsulfonic add monohydrate (Note... 

Determine for each solute whether the solubility will be greater in water, which is polar, or in benzene (CgH ), which is nonpolar (a) bromine (Br2>, (b) sodium iodide (Nal), (c) carbon tetrachloride (CCI4), and (d) formaldehyde (CH2O). 

Solution (a) Bromine is more soluble in benzene. (b) Sodium iodide is more soluble in water. (c) Carbon tetrachloride is more soluble in benzene. (d) Formaldehyde is more soluble in water. Think About It Remember that molecular formula alone is not sufficient to determine the shape or the polarity of a polyatomic molecule. It must be determined... 

In the presence of sodium bicarbonate, sodium formaldehyde sulfoxylate (Rongalite) converts perfluoroalkyl iodides and bromides to the corresponding carboxylates Less decarboxylation to the monohydroperfluoroalkanes occurs when the bromides are used [16] (equation 17)... 

Woodward s strychnine synthesis commences with a Fischer indole synthesis using phenylhydrazine (24) and acetoveratrone (25) as starting materials (see Scheme 2). In the presence of polyphosphor-ic acid, intermediates 24 and 25 combine to afford 2-veratrylindole (23) through the reaction processes illustrated in Scheme 2. With its a position suitably masked, 2-veratrylindole (23) reacts smoothly at the ft position with the Schiff base derived from the action of dimethylamine on formaldehyde to give intermediate 22 in 92% yield. TV-Methylation of the dimethylamino substituent in 22 with methyl iodide, followed by exposure of the resultant quaternary ammonium iodide to sodium cyanide in DMF, provides nitrile 26 in an overall yield of 97%. Condensation of 2-veratryl-tryptamine (20), the product of a lithium aluminum hydride reduction of nitrile 26, with ethyl glyoxylate (21) furnishes Schiff base 19 in a yield of 92%. 

Tetramethyl-/ -phenylenediamine has been obtained in low yield by the reaction of />-phenylenediamine with various alkylating agents such as methyl iodide, methanol in the presence of hydrochloric acid at 170-200°, or formaldehyde and formic acid. In addition it has been prepared by methylating / -dimethyl-aminoaniline using methanol in the presence of hydrochloric acid at 170 -200°, followed by treatment of the resulting salts with aqueous ammonia at 180 190°. In the most recent >ro-cedure, / -phenyIenediamine was alkylated with sodium chloro-... 

Methyl ferf-butvl ether. Thiram Carbon monoxide, see Acetaldehyde. Atrazine. Bromacil. Dalapon-sodium. Dieldrin, 1.4-Dioxane, Diuron, Formaldehyde, Formic acid, Malathion, Maleic anhydride. Methanol, Methyl chloride. Methylene chloride. Methyl iodide, 2-Methylpropene, fV-Nitrosodimethylamine, Oxalic acid, Phorate, Picloram, 2,4,5-T, TCDD, Tolnene, Triflnralin... 

Tolmetin Tohnetin, l-methyl-5-n-tolylpyrrol-2-acetic acid (3.2.61) is synthesized from 1-methylindole, which is aminomethylated using formaldehyde and dimethylamine, forming 2-dimethylaminomethyl-l-methylindol (3.2.57). The product is methylated by methyl iodide, giving the corresponding quaternary salt (3.2.58). Reaction of the product with sodium cyanide gives l-methylpyrrole-2-acetonitrile (3.2.59), which is acylated at the free... 

Mercapto-l,2,4-thiadiazoles are distinctly acidic. The pK of 5-thio-3-methyl-l,2,4-thiadiazole at 25°C is 5.18 <65AHC(5)119>. The position of equilibrium in the tautomers of 5-thio-l,2,4-thiadiazoles (10) (R = H) appears to be on the thione side (11) or (12). The solid state IR spectrum of (10) (R = Ph) shows no sign of SH absorption <92PS(66)32i>. However, treatment of (10) (R = Ph, / -Tol) with diazomethane does not produce any A-methylated products, but only the 5-methyl derivatives (137) (R = Ph, /)-Tol). Methylation of (10) (R = Ph) with methyl sulfate and with methyl iodide in sodium hydroxide gives only the S-methyl derivatives (137) (Scheme 31) <92PS(66)321>. In 1989 Yousef et al. reported that (10) (R = Ph) reacted with aromatic sulfenyl chlorides and with formaldehyde to give the A-substituted products (26) and (27) (Scheme 31). At the same time, alkylation... 

Another total synthesis of sufentanil has been described the cyclization of 2-(2-thienyl)ethylamine with allyl-trimethylsilane and formaldehyde gives 4-hydroxy-1-[2-(2-thienyl)ethyl]piperidine, which is oxidized with oxalyl chloride in DMSO/dichloromethane to 1-[2-(2-thienyl) ethyl]piperidin-4-one. The epoxidation of this compound by means of trimethylsulfonium iodide and the sodium salt of DMSO yields the spiro-epoxide, which is opened with... 

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