Michael-type addition of azoles of broad-scale acidity to methyl acrylate

• Sławomir Boncel,
• Kinga Saletra,
• Barbara Hefczyc and
• Krzysztof Z. Walczak

Beilstein J. Org. Chem. 2011, 7, 173–178, doi:10.3762/bjoc.7.24

• 4-nitropyrazole, 3,5-dimethyl-4-nitropyrazole, 4(5)-nitroimidazole, 4,5-diphenylimidazole, 4,5-dicyanoimidazole, 2-methyl-4(5)-nitroimidazole, 5(4)-bromo-2-methyl-4(5)-nitroimidazole and 3-nitro-1,2,4-triazole to methyl acrylate as an acceptor was carried out. The optimisation process involved the

• use of an appropriate basic catalyst (DBU, DIPEA, NaOH, NaH, TEDA), a donor/base/acceptor ratio and the reaction temperature. The reactions were performed in DMF as solvent. Target Michael adducts were obtained in medium to excellent yields. Importantly, for imidazole and 1,2,4-triazole derivatives

• , no corresponding regioisomers were obtained. Keywords: imidazole derivatives; methyl acrylate; Michael-type addition; pyrazole derivatives; 1,2,4-triazole derivatives; Introduction Derivatives of azoles are important biologically active compounds. Many, especially those containing imidazole

Synthesis of 3-(phenylazo)-1,2,4-triazoles by a nucleophilic reaction of primary amines with 5-chloro- 2,3-diphenyltetrazolium salt via mesoionic 2,3-diphenyltetrazolium- 5-aminides

• Shuki Araki,
• Satoshi Hirose,
• Yoshikazu Konishi,
• Masatoshi Nogura and
• Tsunehisa Hirashita

Beilstein J. Org. Chem. 2009, 5, No. 8, doi:10.3762/bjoc.5.8

• mechanism is proposed for the formation of the triazoles via Type B mesoionic tetrazolium-5-aminides. Keywords: formazan; mesoionic compounds; nucleophilic substitution; tetrazolium; 1,2,4-triazole; Introduction Mesoionic compounds can be classified into two families, type A and type B mesoions, according

• preparation of this chlorotetrazolium salt 2 and its reactions with amines, which involve the unexpected formation of 3-(phenylazo)-1,2,4-triazole derivatives. Results and Discussion The 5-chloro-2,3-diphenyltetrazolium salt 2 was prepared in an analogous manner to the corresponding 1,3-diphenyl isomer 1 [6

• presence of triethylamine, 1,5-diphenyl-3-(phenylazo)-1H-1,2,4-triazole (3a) was formed in 50% yield. The expected substitution product, 2,3-diphenyl-5-(benzylamino)tetrazolium salt 4a, was not found in the reaction mixture. Interestingly, when the base was changed to solid sodium carbonate or sodium

A practical synthesis of the ¹³C/¹⁵N- labelled tripeptide N-formyl- Met-Leu-Phe, useful as a reference in solid- state NMR spectroscopy

• Sven T. Breitung,
• Jakob J. Lopez,
• Gerd Dürner,
• Clemens Glaubitz,
• Michael W. Göbel and
• Marcel Suhartono

Beilstein J. Org. Chem. 2008, 4, No. 35, doi:10.3762/bjoc.4.35

• h; 3. piperidine, 30 min. d) HCOOEt, over night. e) TFA, EDT, H2O, TIS (94 : 2.5 : 2.5 : 1), 4.5 h. All reactions were carried out at room temperature. Abbreviations: MSNT = 1-(mesitylene-2-sulphonyl)-3-nitro-1,2,4-triazole, MeIm = N-methylimidazole, DIC = diisopropylcarbodiimide, HOBt = 1

Development of potential manufacturing routes for substituted thiophenes – Preparation of halogenated 2-thiophenecarboxylic acid derivatives as building blocks for a new family of 2,6-dihaloaryl 1,2,4-triazole insecticides

• John W. Hull Jr.,
• Duane R. Romer,
• David E. Podhorez,
• Mezzie L. Ash and
• Christine H. Brady

Beilstein J. Org. Chem. 2007, 3, No. 23, doi:10.1186/1860-5397-3-23

• , USA The Dow Chemical Company, Process Analytical Sciences, 1897 Building, Midland, MI 48674, USA 10.1186/1860-5397-3-23 Abstract Background Dow AgroSciences has been investigating a new family of functionalized 2,6-dihaloaryl 1,2,4-triazole insecticides featuring specifically targeted insecticidal

• -thiophenecarbonitrile 3 paved the way for the development of viable commercial processes for XR-693 and XR-906, members of a new class of 2,6-dihaloaryl 1,2,4-triazole insecticides that exhibit selective activity against aphids, mites, and whiteflies coupled with low mammalian toxicity. The process development work for

• lost to insects. [2] Dow AgroSciences has been investigating a new family of functionalized 2,6-dihaloaryl 1,2,4-triazole insecticides featuring specifically targeted insecticidal activity coupled with low mammalian toxicity. [3][4][5][6] With broad spectrum control of both chewing and sap-feeding

2-Arylhydrazononitriles as building blocks in heterocyclic synthesis: A novel route to 2-substituted- 1,2,3-triazoles and 1,2,3-triazolo[4,5-b]pyridines

• Saleh M. Al-Mousawi and
• Moustafa Sh. Moustafa

Beilstein J. Org. Chem. 2007, 3, No. 12, doi:10.1186/1860-5397-3-12

• refluxing 2a with hydroxylamine hydrochloride in DMF/piperidine afforded 1,2,3-triazoles whose structure was established by X-ray crystal structure. [11] On the other hand reacting 2b with hydroxylamine hydrochloride in DMF/piperidine afforded 5-amino-1,2,4-triazole via a rare Tiemann-like rearrangement. In

• al, [14] and the possibility that the really formed product is the 5-amino-1,2,4-triazole 7. We decided to investigate further the chemical reactivity pattern of the cyclized product (Scheme 1) to support our conclusion. Compound 5 was reacted with malononitrile in refluxing DMF to yield the

Microwave assisted synthesis of triazoloquinazolinones and benzimidazoquinazolinones

• Aboul-Fetouh E. Mourad,
• Ashraf A. Aly,
• Hassan H. Farag and
• Eman A. Beshr

Beilstein J. Org. Chem. 2007, 3, No. 11, doi:10.1186/1860-5397-3-11

• nearly quantitative yields within few minutes during the reaction of aromatic aldehydes with 5-amino-1(H)-1,2,4-triazole (or 2-aminobenzimidazole) and dimedone in DMF. Conclusion Microwave irradiation can be used as a facile and general method for the construction of a wide variety of

• benzimidazoquinazolinones using microwave irradiation. Results and Discussion The synthesis of 9-aryl-dimethyl-5,6,7,9-tetrahydro-1,2,4-triazolo-[5,1-b]quinazolin-8(4H)-ones by refluxing equimolar amounts of aromatic aldehydes (1, C6H5-, 4-OCH3-C6H4-, 4-NMe2-C6H4-, 4-Cl-C6H4- and 4-NO2C6H4-), 5-amino-1(H)-1,2,4-triazole (2