Sandmeyer Reaction Research Articles

Sandmeyer cyanation of arenediazonium tetrafluoroborate using acetonitrile as a cyanide source

Palladium-catalyzed cyanation of aryldiazonium tetrafluoroborate using acetonitrile as a non-metallic cyanide source was achieved in the presence of Ag2O under ambient air, eliminating the involvement of highly toxic CuCN used in the traditional Sandmeyer reaction, in which the CN group comes from metallic cyanides.

ChemInform Abstract: Copper‐Mediated Cascade Synthesis of Diaryl Sulfones via the Sandmeyer Reaction.

A convenient and efficient method for the copper-mediated cascade synthesis of diaryl sulfones via the Sandmeyer reaction has been developed. The protocol uses readily available aryl amines and arylsulfinic acids as the starting materials, isoamyl nitrite as the diazotizating reagent of the aryl amines, and the method shows mild reaction conditions and high tolerance towards various functional groups in the substrates.

Total aerobic destruction of azo contaminants with nanoscale zero-valent copper at neutral pH: Promotion effect of in-situ generated carbon center radicals

In this study, nanoscale zero-valent copper (nZVC) was synthesized with a facile solvothermal method and used for the aerobic removal of azo contaminants at neutral pH for the first time. We found that both Cu(I) and OH generated during the nZVC induced molecular oxygen activation process accounted for the rapid total destruction of azo contaminants in the nZVC/Air system, where nZVC could activate molecular oxygen to produce H2O2, and also release Cu(I) to break the –NN– bond of azo contaminants via the sandmeyer reaction for the generation of carbon center radicals. The in-situ generated carbon center radicals would then react with OH produced by the Cu(I) catalyzed decomposition of H2O2, resulting in the generation of low molecular weight organic acids and their subsequent mineralization. The indispensible role of Cu(I) catalyzed sandmeyer reaction and the promotion effect of in-situ generated carbon center radicals on the rapid total destruction of azo contaminants in the nZVC/Air system were confirmed by gas chromatography–mass spectrometry analysis. This study can deepen our understanding on the degradation of organic pollutant with molecular oxygen activated by zero valent metal, and also provide a new method to remove azo contaminants at neutral pH.

Copper(I)‐Oxide‐Mediated Cyanation of Arenediazonium Tetrafluoroborates with Trimethylsilyl Cyanide: A Method for Synthesizing Aromatic Nitriles

AbstractA Cu2O‐mediated cross coupling of arenediazonium tetrafluoroborates with trimethylsilyl cyanide to form aromatic nitriles is presented. This protocol tolerates a wide range of functional groups and gives good to excellent yields under mild conditions. Cu2O provides appealing and convenient access to aromatic nitriles compared with the traditional Sandmeyer reaction with toxic CuCN via nucleophilic substitution under relatively harsh conditions.

ChemInform Abstract: The Trifluoromethylating Sandmeyer Reaction: A Method for Transforming C—N into C—CF3

AbstractReview: 23 refs.

ChemInform Abstract: A Mild and Convenient Synthesis of 1,2,3‐Triiodoarenes via Consecutive Iodination/Diazotization/Iodination Strategy.

AbstractA variety of triiodoarenes (III) and (IX) is synthesized by bis‐iodination of anilines followed by a Sandmeyer reaction.

Synthesis and Characterization of Heteroatom-Bridged Bis-spirobifluorenes for the Application of Organic Light-Emitting Diodes

Pure 2-iodo-9,9'-spirobifluorene was synthesized by an efficient method without troublesome iodination of 9,9-spirobifluorene (SP) or the Sandmeyer reaction of 2-amino-9,9'-spirobifluorene. A series of main group element-bridged bis-9,9'-spirobifluorene derivatives were synthesized via coupling reactions of 2-iodo-9,9'-spirobifluorene and main group element-containing precursors. These heteroatom-bridged bis-spirobifluorenes show large triplet state energy gaps, high glass transition temperatures, and varied charge-transporting properties advantageous to the host materials for blue phosphorescence organic light-emitting diodes.

Copper-Mediated Cascade Synthesis of Diaryl Sulfones via the Sandmeyer Reaction

A convenient and efficient method for the copper-mediated cascade synthesis of diaryl sulfones via the Sandmeyer reaction has been developed. The protocol uses readily available aryl amines and arylsulfinic acids as the starting materials, isoamyl nitrite as the diazotizating reagent of the aryl amines, and the method shows mild reaction conditions and high tolerance towards various functional groups in the substrates.

Study on the Sandmeyer Reaction via an Unstable Diazonium Ion in Microreactors with Reaction Rate Analyses

Study on the Sandmeyer Reaction via an Unstable Diazonium Ion in Microreactors with Reaction Rate Analyses

The Trifluoromethylating Sandmeyer Reaction: A Method for Transforming CN into CCF3

A means to trifluoromethylate: The beneficial properties imparted by the trifluoromethylation of aromatic compounds continue to drive the discovery of novel reagents and reactions for the late-stage introduction of such moieties. Highlighted here is the recently discovered Sandmeyer trifluoromethylation approach, which now permits aromatic amines to be substrates in a direct trifluoromethylation strategy.

Azides – Diazonium Ions – Triazenes: Versatile Nitrogen-rich Functional Groups

For more than 100 years, nitrogen-rich compounds such as azides, diazonium ions, and triazenes have proved to be extremely valuable. Because these functional groups can be easily introduced into various substrates, they are frequently used nowadays. More importantly, they can be converted into a great number of other functional groups. The scope of this article is thus to summarize possible synthetic routes for the formation of these functional groups as well as to highlight some of the most prominent applications of these exciting moieties in chemical biology and combinatorial chemistry. Many of the most famous name reactions such as the Staudinger reduction, Staudinger ligation, Sandmeyer reaction, Wallach reaction, Mitsunobu reaction, Huisgen reaction, Balz–Schiemann reaction, Meerwein arylation, Pschorr reaction or Gomberg–Bachmann reaction are covered.

A NEW ROUTE FOR THE SYNTHESIS OF ISOMERIC BENZO[ b ]FUROINDOLES

A new synthesis of 1H-benzo[ b ]furo[3,2- f ]- and 1H-benzo[ b ]furo[2,3- e ]indoles was described. The corresponding ring-fused isatins, synthesized by the Sandmeyer reaction, were utilized as initial compounds. The reduction of the last to the unsubstituted benzo[ b ]furoindoles depends both on the nature of the substituent, and on the reaction conditions. Authors: T. O. Dzhashi, T. E. Khoshtariya, L. N. Kurkovskaya, N. T. Mirziashvili, and M. I. Sikharulidze. English Translation in Chemistry of Heterocyclic Compounds , 1999, 35 (10), pp 1237-1241 http://link.springer.com/article/10.1007/BF02323385

Silver-Mediated Trifluoromethylation of Aryldiazonium Salts: Conversion of Amino Group into Trifluoromethyl Group

A novel strategy for aromatic trifluoromethylation by converting aromatic amino group into CF3 group is reported herein. This method, which can be considered as trifluoromethylation variation of the classic Sandmeyer reaction, uses readily available aromatic amines as starting materials and is performed under mild conditions.

Design and Biological Evaluation of 2,2′-Dinitrodiphenylmethane Derivatives

Synthesis of 4,4 �,5,5 �-tetrabromo-2,2 �-dinitrodiphenylmethane and 5,5 �-dibromo-2,2 �- dinitrodiphenylmethane from 4,4 �-diamino-5,5 �-dibromo-2,2 �-dinitrodiphenylmethane are reported. 4,4 �,5,5 �-Tetrabromo-2,2 �-dinitrodiphenylmethane (TBNDPM) have been synthesized by a simple and convenient method employing Sandmeyer's reaction of 4,4 �-diamino-5,5 �-dibromo-2,2 �- dinitrodiphenylmethane (ABNDPM) with cuprous bromide and hydrobromic acid and 5,5 �-dibromo- 2,2 �-dinitrodiphenylmethane (BNDPM) has obtained by treatment of ABNDPM with hypophosphorous acid and cuprous oxide. The structures of the synthesized compounds are assigned on the basis of elemental and spectral analysis (UV-visible, FTIR and 1 H-NMR). The synthesized compounds have

Sandmeyer reaction repurposed for the site-selective, non-oxidizing radioiodination of fully-deprotected peptides: Studies on the endogenous opioid peptide α-neoendorphin

Standard radioiodination methods lack site-selectivity and either mask charges (Bolton-Hunter) or involve oxidative reaction conditions (chloramine-T). Opioid peptides are very sensitive to certain structural modifications, making these labeling methods untenable. In our model opioid peptide, α-neoendorphin, we replaced a tyrosyl hydroxyl with an iodine, and in cell lines stably expressing mu, delta, or kappa opioid receptors, we saw no negative effects on binding. We then optimized a repurposed Sandmeyer reaction using copper(I) catalysts with non-redoxing/non-nucleophilic ligands, bringing the radiochemical yield up to around 30%, and site-selectively incorporated radioactive iodine into this position under non-oxidizing reaction conditions, which should be broadly compatible with most peptides. The 125I- and 131I-labeled versions of the compound bound with high affinity to opioid receptors in mouse brain homogenates, thus demonstrating the general utility of the labeling strategy and of the peptide for exploring opioid binding sites.

Copper-Promoted Sandmeyer Trifluoromethylation Reaction

A copper-promoted trifluoromethylation reaction of aromatic amines is described. This transformation proceeds smoothly under mild conditions and exhibits good tolerance of many synthetically relevant functional groups. It provides an alternative approach for the synthesis of trifluoromethylated arenes and heteroarenes. It also constitutes a new example of the Sandmeyer reaction.

Ethyl 3-bromo-4-cyano-5-[(2-ethoxy-2-oxoethyl)sulfanyl]thiophene-2-carboxylate

The title compound, C12H12BrNO4S2, was obtained by the Sandmeyer reaction from ethyl 3-amino-4-cyano-5-[(2-eth­oxy-2-oxoeth­yl)sulfan­yl]thio­phene-2-carboxyl­ate. The dihedral angle between the thiophene ring and linked CO2 ester group is 2.0 (5)°.

Synthesis of Tetrasubstituted Pyrazoles through Different Cyclization Strategies; Isosteres of Imidazole Fungicides

Formerly unknown 3-chloro-4,5-diaryl-1-methylpyrazoles have been prepared through two different synthesis pathways, one of which starts from 2,3-diarylacrylonitriles, the second from 3,3-dichloro-1,2-diarylpropenones. Both approaches rely on the cyclocondensation of diarylated three-carbon synthons with hydrazine derivatives and possess some unique features. One route uses a cyclization reaction, during which a chlorine atom is directly installed at the pyrazole ring that normally would be introduced in subsequent halogenation steps. The second pathway applies the Sandmeyer reaction to introduce this chloro substituent; an approach that is rarely described at the pyrazole nucleus. The obtained tetrasubstituted pyrazoles are isosteres of highly active imidazole fungicides and show good control of Uncinula necator (grape powdery mildew).

ChemInform Abstract: Novel Synthesis of 5‐Amino‐3‐bromo‐1‐(tert‐butyl)‐1H‐pyrazole‐4‐carbonitrile: A Versatile Intermediate for the Preparation of 5‐Amino‐3‐aryl‐1‐(tert‐butyl)‐1H‐pyrazole‐4‐carboxamides.

A simple, novel, and efficient route for the synthesis of 5-amino-3-aryl-1-(tert-butyl)-1H-pyrazole-4-carboxamides 1 has been devised. Preparation of pyrazole bromide 3 from potassium tricyanomethanide can be accomplished in only two steps in good yield and features a selective Sandmeyer reaction on the corresponding diaminopyrazole. This allows for a more versatile synthesis of 5-amino-3-aryl-1-(tert-butyl)-1H-pyrazole-4-carboxamides 1 than was previously possible.

ChemInform Abstract: An Efficient Route to 1,3,5‐Triazido‐2,4,6‐tricyanobenzene.

Benzonitriles and organic azides are of particular importance as components of dyes, herbicides, natural products, and drugs [1 – 6]. For example, it is possible to convert the nitrile group into a variety of other functional groups. Therefore benzonitriles are important intermediates for the synthesis of biologically important structures such as benzoic acid derivatives, benzyl amines, benzyl amides, and heterocyclic compounds. Due to the diverse applications of benzonitrile numerous synthetic possibilities have been developed. In particular, the Rosenmund-von-Braun reaction [7] (reaction of aryl halides with copper(I) cyanide) and the Sandmeyer reaction [8] (reaction of arene-diazonium salts with copper(I) cyanide) are used. The problem of both methods is the formation of stoichiometric amounts of heavy metal salts. Therefore, today aryl cyanides are produced primarily by the ammoxidation of the corresponding toluenes [9, 10]. This process requires harsh reaction conditions and shows a lack of tolerance of other functional groups. Another way to generate the nitrile group is the stepwise construction of a CN moiety by application of a series of classical organic synthesis steps as shown in Scheme 1. Here we report on the stepwise synthesis and full characterization of binary 1,3,5-triazido-2,4,6tricyanobenzene. Results and Discussion