1-Cyano-1,2,3-triazole-.alpha.-diazo-N-cyanoimine tautomers from cyanogen azide and acetylenes

Some reactions of 1,2-dihydropyridines with organic azides. Synthesis of diazabicylo[4.1.0]hept-4-enes, 1,2,5,6-tetrahydropyridylidene-2-cyan (sulfon, carbon) amides, and piperidylidene-2-cyan (sulfon, carbon) amides

“…Elimination of hydride would then afford the more aromatic 1,2-dihydropyridine triazole intermediate 5 which could ring open to give 6. A similar mechanism has been proposed for opening of the adducts obtained from reactions of organic azides and ethoxyacetylene (7,8).…”

“…The reaction was allowed to proceed for 1 h and then completed as described previously to afford 4g (2.1 g, 100%); ir (neat): 3210 (m, NH), 1730 (s, C=O), and 1590 (s, C=C) cm-'; 'H nmr 6: 0.9 (t, J = 7 Hz, 3H, CH2CH,CH,CH3), 1.1-1.9 (m, 6H, CH2CH2CH,CH3), 3.1 (m, 2H, H-1, H-6), 3.75 (s,3H,OCH,),4.1 (m,l H ,5.82 (m,2H, 6,6'-Di-n-brrtyl-I,2,3,6-tetrnlrycIro-2,3'-~lipyrirlyl (7) A solution of lithium hydroxide free l a (2.74 g, 20 mmol) in 67 mL dry ether was added slowly with stirring to a solution of hydrazoic acid (34.4 mL of 5.8 M, 20 mnlol) in 50 mL dry benzene under a nitrogen atmosphere at 25°C. The reaction was allowed to proceed for 24 h before warming to 25'C.…”

A Versatile Direct Approach to ortho‐Substituted Azobenzenes from Benzotriazoles

“…1‐Nitrobenzotriazole,14 was shown to react with amines; for example, piperidine gave an isolable piperidinium salt from the ring‐opened benzotriazole. There was also a report15 on the reversible thermochromic behavior of 1‐cyanobenzotriazole, which is yellow in the melt and colorless in the crystalline state. No chemical evidence was obtained to indicate that the color might arise from ring opening to give the diazo‐ N ‐cyanoimine form, and no reactions of the cyano compound were reported.…”

Denitrogenative Suzuki and carbonylative Suzuki coupling reactions of benzotriazoles with boronic acids

“… 1 One of their unique chemical properties is that they can undergo ring-chain isomerization to form the corresponding diazonium or diazo species via a Dimroth-type equilibrium ( Scheme 1A ). 2 Considerable efforts have been devoted to the development of novel transformations based on this unique reactivity. As a paradigm, recently significant advances have been made in the applications of 1-sulfonyl-1,2,3-triazoles as synthetic equivalents of diazoimines in a broad range of intriguing reactions ( Scheme 1B ).…”