Triazolate complexes synthesis

T) -CsH Pr4) with [W(CO) 5 (thf) ] leads a tetracarbonyl tungsten complex [W(CO)4P2Nl2Cp 2] which can be oxidised with MesSlOOSlHes to give the first example of a complex containing a M3-PO ligand, (Cp Ni-W(CO)4-NiCp (ps-PO)2] The synthesis and molecular structure of a 1,2,4-triazole complex [W(co)sL]... 

Fig. 10 The synthesis of heteroleptic copper amido-l,2,3-triazole complexes (54a-f) and the X-ray structure of the heteroleptic copper(I) amido-1,2,3-triazole complex, 54f [169]. Hydrogen atoms and counter ions have been omitted for clarity...

Scheme 12 Synthesis of hybrid NHC-1,2,3-triazole complexes (81) (i) propargyl bromide, MeCN, reflux, 2 d (ii) Cu(S04)-5H20, Na ascorbate, MeCN, 60°C, 2 d (Hi) [Pd(allyl)Cl]2, KOt-Bu, THF, RT, 4 h...

Another interesting scavenger is polymer-supported anthracene, developed by Porco for the scavenging of dienophiles [109]. An example of its application to the synthesis of a complex 5,8-dihydro-(l,2,4)triazolo[l,2-a]pyridazine-l,3-diones via hetero-Diels-Alder reaction followed by removal of the excess of triazole-3,5-dione under microwave irradiation is depicted in Scheme 24. For this particular example, moving from thermal heating (toluene, 100 °C) to a microwave-assisted protocol (DCE, 150 °C) reduced scavenging time from 3 h to just 15 min. 

Azidorhodium complexes are of considerable structural interest, but limited applicability can be expected from the unusual triazole synthesis illustrated in Scheme 125.190 It is also difficult to envisage synthetic utility from reactions in which organic azides are decomposed by transition metal carbonyls. Thus 2-arylbenzotriazoles are formed in such reactions on... 

Chloromethyl-l,2,4-triazoles can be valuable intermediates in the synthesis of more complex compounds containing a 1,2,4-triazole moiety, and they can be accessed using a number of established methods for the synthesis of the triazole ring system. However, these processes often give variable yields and require much work to construct the starting material. A more convenient procedure has been developed, by which a hydroxymethyl-1,2,4-triazole is converted to the chloromethyl derivative by reaction with thionyl chloride (Equation 20 and Table 6) <2006S156>. 

Due to the important pharmacological applications of this system, in particular the antidepressant trazodone, numerous articles deal with either its synthesis, or its incorporation into more complex substances, as a pharmacophore (see Section 11.13.12). Synthetic methods have been reviewed <1996CHEC-II(8)367>, and most of them are still in use or have been modified. Recent literature essentially focuses on the formation of the triazole ring. 

Aminotriazoles which are appropriately substituted at the C(5)-position are important intermediates for the synthesis of 8-azapurines. These reactions have been reviewed <86AHC(39)ll7>. The pharmaceutically useful acyclonucleosides bearing 1,2,3-triazolines and 8-azapurines have been synthesized <888879). 4,5-Diaminotriazoles react with 1,2-dicarbonyl reagents to give 1,2,3-triazolo[4,5- )]pyrazines. 4,5-Diamino-2-phenyltriazole and sulfur monochloride afford the triazolo[4,5-c][l,2,5]thiadiazole (855) <86AHC(40)129>. The synthesis of triazolopyridines from triazoles has been described in a review <83AHC(34)79>. For further applications of substituted triazoles in preparations of complex heterocycles, see Section 4.01.4. 

Ketenes rarely produce [3+ 2]-cycloaddition products with diazo compounds. The reaction possibilities are complex, and nitrogen-free products are often obtained (5). Formation of a cyclopropanone represents one possibihty. Along these lines, the synthesis of (Z)-2,3-bis(trialkylsilyl)cyclopropanones and (Z)-2-trialkylsilyl-3-(triethylgermyl)cyclopropanones from diazo(trialkylsilyl)methanes and appropriate silyl- or germylketenes has been reported (256,257). It was found that subsequent reaction of the cyclopropanone with the diazoalkane was not a problem, in contrast to the reaction of diazomethane with the same ketenes. The high cycloaddition reactivity of diazomethylenephosphoranes also extends to heterocumulenes. The compound R2P(C1)=C=N2 (R = N(/-Pr)2) reacts with CS2, PhNCO and PhNCS to give the corresponding 1,2,3-triazole derivative (60). 

Since the discovery of triazole formation from phenyl azide and dimethyl acetylenedicarboxylate in 1893, synthetic applications of azides as 1,3-dipoles for the construction of heterocychc frameworks and core structures of natural products have progressed steadily. As the 1,3-dipolar cycloaddition of azides was comprehensively reviewed in the 1984 edition of this book (2), in this chapter we recount developments of 1,3-dipolar cycloaddition reactions of azides from 1984 to 2000, with an emphasis on the synthesis of not only heterocycles but also complex natural products, intermediates, and analogues. 

Arion VB, Reisner E, Fremuth M, Jakupec MA, Keppler BK, Kukushkin VY, Pombeiro AJL (2003) Synthesis, X-ray diffraction structures, spectroscopic properties, and in vitro antitumor activity of isomeric (1H-1, 2, 4-Triazole)Ru(III) complexes. Inorg Chem 42 6024—6031... 

Figure 3.122 Synthesis of spacer-free Janus bis-carbene complexes using triazole as the...

Sutter, J.P., Kahn, M.L., Golhen, S. et al. (1998) Synthesis and magnetic behavior of rare-earth complexes with N,0-chelating nitronyl nitroxide triazole ligands example of a [Gd organic radical 2] compound with an 5=9/2 ground state. Chemistry - A European Journal, 4, 571-576. 

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