NMR Study of the Tautomeric Behavior of N-(α-Aminoalkyl)tetrazoles

N-Morpholinomethyl-5-lithiotetrazole: A Reagent for the One-Pot Synthesis of 5-(1-Hydroxyalkyl)tetrazoles

An efficient, one-pot method for the preparation of 5-(1-hydroxyalkyl)tetrazoles is reported. N-Morpholinomethyl-5-lithiotetrazole, generated by the deprotonation of 4-(N-tetrazolylmethyl)morpholine with LiHMDS, undergoes addition to ketones and aldehydes (both aromatic and aliphatic) to form 5-(1-hydroxyalkyl)tetrazoles in a high yield, after acidic workup. The reported protocol displays a broad substrate scope and functional group tolerance, avoids the use of cyanide- or azide-based reagents, and provides access to sterically congested and unsaturated tetrazoles, which are difficult to access by other means.

A combined experimental and theoretical study of the tautomeric and conformational properties of (5-phenyl-tetrazol-2-yl)-acetic acid methyl ester

The tautomeric and conformational properties of a new tetrazole derivative are studied in a combined approach that includes the analysis of the experimental vibrational data together with theoretical calculation methods, especially in terms of natural bond orbital (NBO) population analysis. Moreover, the molecular and crystal structure was determined by single crystal X-ray diffraction. The compound crystallized as the 2-tautomeric form, monoclinic space group P21/c with Z=4, a=10.0630(14), b=8.2879(11), c=12.8375(18) Å, β=105.546(3)°, V=1031.5(2) Å(3). The tetrazole and phenyl rings are coplanar with the acetate group oriented perpendicular to the plane. The NBO analysis showed that delocalizing interactions of the lpp(N2) lone pair orbital contributes to a strong resonance interactions with both adjacent π(∗)(N3N4) and π(∗)(N1C5) antibonding orbitals of the tetrazole group.

A rapid metal free synthesis of 5-substituted-1H-tetrazoles using cuttlebone as a natural high effective and low cost heterogeneous catalyst

A convenient, rapid and metal free synthesis of 5-substituted-1H-tetrazoles by [3 + 2] cycloaddition reaction of nitriles with sodium azide. Cuttlebone as a natural low cost heterogeneous catalyst affords 5-substituted-1H-tetrazoles rapidly with high efficiency.

Cu(ii) immobilized on aminated epichlorohydrin activated silica (CAES): as a new, green and efficient nanocatalyst for preparation of 5-substituted-1H-tetrazoles

Reusable nanocatalyst was prepared and characterized an efficient and environmentally benign method of 5-substituted-1H-tetrazole synthesis was introduced.

Tandem regioselective synthesis of tetrazoles and related heterocycles using iodine

A one-pot, tandem process has been developed for the synthesis of a library of tetrazoles from aryl isothiocyanates. Condensation of aryl isothiocyanates with ammonia, and aryl amines (R-NH(2)) provided mono, 1,3-disubstituted symmetrical and unsymmetrical thioureas, which on desulfurization with molecular iodine (I(2)) led to formation of the corresponding heterocumulene (cyanamides or carbodiimides). The in situ generated heterocumulene on subsequent treatment with sodium azide at room temperature gave corresponding tetrazoles. The product regioselectivity for unsymmetrical 1,3-disubstituted thioureas was found to be correlated with the basicities (pK(a)'s) of the parent amines attached to the thiourea. Aryl-sec-alkyl unsymmetrical thioureas gave thioamido guanidino products rather than the 5-aminotetrazoles produced by HgCl(2) mediation of the reaction. Bis-thioureas derived from aryl isothiocyanates and hydrazine gave thiadiazoles exclusively.