Sandmeyer Reaction Research Articles

Quinazolines and 1,4-benzodiazepines. Part XXIX. Synthesis of some 2,3-dihydro-5-pyridyl-1H-1,4-benzodiazepines

Syntheses of the three isomeric 2,3-dihydro-7-nitro-5-(2-, 3-, and 4-pyridyl)-1H-1,4-benzodiazepines from the corresponding (2-chloro-5-nitrobenzoyl)pyridines and ethylenediamine are described. The required benzoyl-pyridines were made by nitration of the appropriate (2-chlorobenzoyl)pyridines, the preparations of which are given. The 7-nitrobenzodiazepines were converted, by reduction of the nitro-group followed by the Sandmeyer reaction, into the corresponding psychopharmacologically active 7-chloro-derivatives.

An alternative to the Sandmeyer reaction

A selection of aromatic amines has been shown to react with pentyl nitrite in the presence of bromoform to give the corresponding aryl bromides in acceptable yield. Corresponding reactions with bromotrichloromethane, chloroform, and carbon tetrachloride have been proved to be synthetically less useful.

Crystal structure of the compound C6H5N2Cu2Br3, an intermediate in the Sandmeyer reaction

Crystal structure of the compound C₆H₅N₂Cu₂Br₃, an intermediate in the Sandmeyer reaction

Deuterated organic compounds XXV synthesis of 1, 4, 5, 8‐tetradeuterionaphthalene

Abstract1, 4, 5, 8‐Tetradeuterionaphthalene was synthesized from 1, 4‐dibromonaphtalene by two methods. In the first method naphthalene was repeatedly brominated in chloroform and then debrominated with zinc dust in alkaline deuterium oxide. In the second, 1, 4‐dibromonaphthalene was nitrated to produce 1, 4‐dibromo‐5‐nitronaphthalene which underwent reductive debromination with zinc in alkaline deuterium oxide to 1‐amino‐5, 8‐dideuterionaphthalene. The latter was converted into 1‐bromo‐5, 8‐dideuterionaphthalene by a modified Sandmeyer reaction which was brominated to 1, 4‐dibromo‐5, 8‐dideuterionaphthalene and then debrominated to 1, 4, 5, 8‐tetradeuterionaphthalene.

The synthesis of arylsulfonyl halides

AbstractThe synthesis of a series of arylsulfonyl chlorides by a modification of the Sandmeyer reaction as developed by Meerwein et al1 is described. This method seems applicable to the preparation of arylsulfonyl bromides, but not for arylsulfonyl fluorides. The characteristic IR vibrations of the SO2‐group are tabulated for the various arylsulfonyl halides.

1-Alkyl-2(1<i>H</i>)-pyridone誘導体の研究 (第4報)

The structure of 1-phenethyl-3-cyano-2(1H)-pyridone, reported in Part II of this series, was confirmed as (I) by the route shown in Chart 1. Further, (XII) was synthesized from (I) by the Curtius reaction and, since its diazonium salt was stable, 1-phenethyl-3-substituted-2(1H)-pyridones were prepared by its Sandmeyer reaction. Measurement of dipole moments of these compounds further confirmed the ortho effect of the dipole moment of these 3-substituted 2-pyridones, which had been assumed with small number of examples in the preceding work.

1‐chloro‐4‐nitronaphthalene from 1‐amino‐4‐nitronaphthalene

AbstractDiazotisation of 1‐amino‐4‐nitronaphthalene with hydrochloric acid and sodium nitrite, and decomposition of the diazonium salt by the Sandmeyer or Gattermann reaction, is studied in order to check the work of Franzen and Helvert and of Ferrero and Caflish 4. The compound, m.p. 61°, reported by Franzen and Helvert to be a new 1‐chloro‐4‐nitronaphthalene, creating a new type of isomerism with the known 1‐chloro‐4‐nitronaphthalene, m.p. 85°, has not been found. Improper conditions of diazotisation, e.g., high temperature, or low concentration of hydrochloric acid, as used by Ferrero and Caflish, lead to decomposition with the formation of impure 1‐nitro‐naphthalene, m.p. 58‐61°.

?Diazoation? of p-hydroxybenzoic and 1-phenol-4-sulfonic acids

1. The Rodionov-Matveev reaction was extended to p-hydroxybenzoic acid and 1-phenol-4-sulfonic acid, and diazo compounds were obtained in yields of 75–90%. 2. When the Sandmeyer reaction was carried out on the diazo solution obtained from p-hydroxybenzoic acid, 3-chlora-4-hydroxybenzoic acid and 4-chloro-2-nitrophenol were formed. This indicates that the primary reaction products were 5-carboxy-2-hydroxybenzenediazonium and 4-hydroxy-3-nitrobenzenediazonium salts.

Dispersing Agents in Reaction Media

P -Aminobenzoic acid was dispersed in a polyethylene glycol 400 and water solution. The dispersed acid underwent a normal Sandmeyer reaction to give p -cyanobenzoic acid in good yields.

A study of the mechanism of the Sandmeyer reaction

The one-electron-transfer mechanism for the Sandmeyer reaction, proposed by W. A. Waters in 1942 has now been confirmed by diagnostic experiments. Its initial stage, Ar ·N + 2 + Cu + → Ar · + N 2 + Cu 2+ , has been shown to produce free aryl radicals capable of initiating vinyl polymerization; this observation is also true for related reactions of diazonium salts for which analogous one-electron-transfer mechanisms have been suggested. The cupric ions thus produced are oxidizers that, like ferric ions, can effect chain-ending of vinyl polymerization. They bring about the final step in the Sandmeyer reaction by a similar process that apparently involves chlorine atom transfer; Ar · + Cl—Cu—Cl → Ar —Cl + Cu—Cl. Product studies show that cupric ions are needed to enable the Sandmeyer reaction to give aryl chlorides in high yield; in their absence other reactions of aryl radicals can occur extensively. Molecular weight measurements with acrylonitrile polymers indicate that in dilute solution up to 35% of the initial aryldiazonium cations can produce free aryl radicals by interaction with cuprous ions in chloride solutions, but that in more concentrated solutions the secondary reaction with the cupric chloride generated occurs so extensively that the full cycle of the Sandmeyer reaction becomes predominantly an intramolecular process.

抗黴剤の合成化学的研究 (第4報)

1) In order to find the effect on the bridging sulfur atom in diphenyl sulfide-type compounds by the Sandmeyer reaction, experiments were carried out on 4-(4-nitrophenylthio)aniline. It was thereby found that the use of hydrobromic acid in diazotization, reacted at 0°, chiefly afforded 4-(4-nitrophenylthio)bromobenzene (IV) while the reaction temperature of 0° to 40° chiefly afforded 4-(4-nitrophenylsulfinyl)-bromobenzene (V). The use of conc. nitric acid for diazotization afforded (IV) when the reaction temperature was -20°, but (V) if carried out at 0°.2) By the electrolytic reduction of 2-methyl-6-(4-nitrophenylthio)benzothiazole (I), its 4-amino compound (II) was obtained in a good yield.3) The amino compound was submitted to the Sandmeyer reaction by diazotization with hydrobromic acid at 0° and substituted with bromine, chlorine, iodine, and hydroxyl group.4) Anti-candida tests of these new compounds showed that (II) alone was effective in inhibiting the growth of C. albicans at 10, 000 dilution.

抗黴剤の合成化学的研究 (第2報)

1) The melting point of 2-methyl-6-bromobenzothiazole had been rather irregular but was determined as melting at 86-87° by the utilization of ferricyanide oxidation-cyclization of p-bromothioacetanilide and bromine substitution of 2-methyl-6-aminobenzothiazole by the Sandmeyer reaction.2) Application of phosphorus pentasulfide and potassium sulfide to the acetanilide compound was found to be accompanied by the formation of a small amount of aniline as a by-product.3) Dozens of 2-methlybenzothiazole derivatives having ether bonding at 6-position were obtained by the Ullmann reaction of 2-methyl-6-bromobenzothiazole and potassium salt of phenols.4) Some discrepancies were found in the data of 2-methyl-6-phenoxybenzothiazole obtained in the present experiments and those appearing in past literature. In order to find correct data, the compound was submitted to synthetic examinations by the (i) Ullmann reaction of 2-methyl-6-bromobenzothiazole and phenoxides and (ii) oxidative cyclization of 4-phenoxythioacetanilide (m.p. 103-104.5°) with potassium ferricyanide. It was thereby found that the compound melting at 85-87° obtained in the present experiment was the correct one.5) Antifungal tests (chiefly test with Candida) of the intermediates and new compounds failed to reveal any marked substances.

Search for physiologically active compounds

An improved method for the preparation of 7-amino-4-methyl coumarin is described. The corresponding halo-substituted coumarins prepared from the amino compound by diazotisation and Sandmeyer reaction have been found to be more toxic to fish than the 7-methoxy-4-methyl coumarin and far less toxic than the corresponding 3-phenyl coumarins.

The synthesis of para‐aminosalicylic acid. I. The synthesis of C‐14 carboxyl‐labeled p‐aminosalicylic acid

A procedure is described for the synthesis of C‐14 carboxyl‐labeled p‐aminosalicylic (4‐amino‐2‐hydroxybenzoic) acid. The Sandmeyer reaction, using potassium radiocyanide, is employed in the synthesis of p‐nitrosalicylic acid, which is, in turn, reduced by catalytic hydrogenation at room temperature.

Synthèse de 1‐alcoyl‐2‐bromo‐3,5 dinitro‐benzènes

AbstractThe synthesis of 1‐alkyl‐2‐bromo‐3,5‐dinitro‐benzenes, where the alkyl group is represented by CH3, C2H5, (CH3)2CH and (CH3)3C— is described. The general scheme which was chosen is the following: the various o‐alkyl‐phenols were dinitrated, either after sulfonation (case of o‐cresol and o‐tert‐butyl phenol), or directly, in acetic acid. The 2‐alkyl‐4,6‐dinitro‐phenols obtained were methylated, than treated with NH3. From the resulting 2‐alkyl‐4,6‐dinitro‐anilines, the 1‐alkyl‐2‐bromo‐3,5‐dinitro‐benzenes were prepared by a Sandmeyer reaction.

2-Dimethylamino-6-hydroxybenzothiazole

Sandmeyer reaction of 2-amino-6-methoxy (or ethoxy)-benzothiazole (I) gave the 2-chloro derivative (II) which was condensed with dimethylamine to (III) and dealkylated to 2-dimethylamino-6-hydroxybenzothiazole (IV). The accompanying table shows the comparison of the melting points of the objective compound and the intermediates obtained during the course of the present syntheses with those described in existing literature.

Action of Na2SO4 and other Salts on the Sandmeyer's Reaction of Iso-nitroso Acetanilide Formation

Action of Na2SO4 and other Salts on the Sandmeyer's Reaction of Iso-nitroso Acetanilide Formation

Syntheses of <i>p</i>-Nitrophenyl-ketones. I

p-Nitro-acetophenone, an important starting material for the synthesis of chloramphenicol, was prepared from p-amino-acetophenone by the Sandmeyer's reaction in a 65% yield. This method will be recommended for its simplicity in manipulation and also from the economical view-point.

S 40. The preparation of halogeno-compounds by a new modification of the Sandmeyer reaction

S 40. The preparation of halogeno-compounds by a new modification of the Sandmeyer reaction

S 10. The kinetics and mechanism of the sandmeyer reaction

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