Photochemical Reactivity of 2‐Azido‐1,3‐thiazole and 2‐Azido‐1,3‐benzothiazole: A Procedure for the Aziridination of Enol Ethers

Abstract

Direct irradiation of a mixture of the azido–tetrazole tautomers of 2‐azido‐1,3‐thiazole and 2‐azido‐1,3‐benzothiazole in toluene solution gives products arising from the intermediate nitrene, which in turn undergoes ring opening in the case of 2‐azido‐1,3‐thiazole to give a polymer, and dimerization in the case of 2‐azido‐1,3‐benzothiazole to give [1,3]benzothiazolo[2′,3′:3,4][1,2,4,5]tetraazino[6,1b][1,3]benzothiazolein low yields. When irradiation is performed in the presence of methyl acrylate or various enol ethers, aziridination of the double bond is observed, with good yields in the case of enol ethers. Among these, 1‐(6‐methyl‐3,4‐dihydro‐2H‐pyran‐2‐yl)ethanone undergoes aziridination with complete diastereoselectivity to give the (1RS,3RS,6SR) diastereomer.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Theoretical Study of the Substituent and Solvent Effects on Azide-Tetrazole Equilibrium of 2-Azido-1,3-benzothiazoles

“…The density-functional theory (DFT) [17], using the hybrid B3LYP functional, and the second order Møller-Plesset (MP2) perturbation theory [18] were employed to optimize the geometries of the studied species using different Pople [19] basis sets as implemented in Gaussian 09W package [20]. Transition states were determined by varying the N3-N12 distance and optimizing the remaining structural parameters for each choice of the N3-N12 distance.…”

Heterocyclic chemistry

“…6 This reaction is believed to proceed via an intermediate aminonitrene which arises from the action of the PhI(OAc) 2 in Scheme 7, the first time that such a process has been observed (previous reactions of azides with enol ethers proceed via 1,3-dipolar cycloaddition). 7 Aziridine formation via intramolecular 1,3-dipolar cycloaddition and nitrogen extrusion led to the aziridinopyrrolobenzodiazepines shown in Scheme 8, where the products are of interest as DNA-intercalating antitumour antibiotics. 8 Finally, the use of the aza-…”

Di‐ and Trifluorinated 2‐Azidobenzimidazole Derivatives: Synthesis, Photooxygenation, and 19F NMR Prediction

“…A similar observation as for 22 was made on irradiation of 2-azido-1,3-thiazole and of 2azidobenzothiazole. [9] If the 6-position was unsubstituted, regioselective 6-oxygenation took place in yields between 48 % and 91 % (Scheme 4, Scheme 2. Route to 4,7-difluoro, 5,7-difluoro, and 4,5,7-trifluoro derivatives of 2-azidobenzimidazole via N-methylnitroanilines (TBABr: tetrabutylammonium bromide, TBAT: tetrabutylammonium difluorotriphenylsilicate).…”