Polycyclic triazoles

Additional examples of syntheses of polycyclic triazoles continue to be reported. 2-(2 -Hydroxyphenyl)benzotriazole (84) is prepared in >90% yield from azointermediate (83) by reaction with Raney nickel and DMSO, DMS or thiophene [95JAP07228577]. 2-Methylbenzo-triazole (85) is cyclized under acidic conditions and subsequently converted into the chloro analog (86) by treatment with POCl3 [95FES47],... 

There are several cases of polycyclic triazolines, obtained by azide addition to the strained olefinic bond in bi- and tricyclic systems, that are susceptible to retro Diels-Alder reaction to yield 1-substituted triazoles. A well-established example is the monoadduct from norbornadiene and phenyl azide, which decomposes at 90-100°C to give 1-phenyltriazole and a cyclopentadiene (Scheme 138).2s 97—" 1 47 430 Similarly, the cycloadduct from the reaction of 7-oxabenzonorbornadiene and 1-azidoadamantane, when heated at 110°C, affords good yields of l-(l-adamantyl)-l,2,3-triazole in a retro Diels-Alder reaction.155... 

Oxidation of certain iV-methoxyphenylazetidinones gave tetracyclic products. The action of CAN on triazole 498 gave 499 and lead tetraacetate reacted with tetrazole 500 to yield 501 C1999T8457, 2003JCM759>. Other routes to polycyclic /3-lactams are listed in Table 5. 

The cycloadducts of cyclooctatetraene and its substituted derivatives with 4-phenyl- and 4-methyl-37/-triazole-3,5(4//)-dione and diethyl diazenedicarboxylate are intermediates in the synthesis of polycyclic structures5 10 l2 23. Furthermore, pyrolysis of the diethyl diazenedicarboxylate cycloadduct 12 affords diethyl 1.2.4a,8a-tetrahydro-l,2-cinnolinedicarboxylate with undetermined stereochemistry of the ring fusion23. 

Phenyl- and 4-methyl-4H-l,2,4-triazole-3,5-dione are often used as reactive dienophiles with subtituted norbornadienes and other polycyclic 1,4-dienes. 2-Trimethylsilyl-, 2-chloro-, 2-cyano- and 2-methoxycarbonylnorbornadiene react with 4-phenyl-4i/-l,2,4-triazole-3,5-dione in dichloromethane at room temperature to give the corresponding homo-Diels-Alder adducts 18, accompanied by [2 + 2] cycloaddition, rearrangement, insertion and polymerization products. 

Table 6. Cyclopropyl Derivatives by the Dipolar Addition of 4-Methyl- or 4-Phenyl-l,2,4-triazole-3,5-dione to Strained Polycyclic Alkenes ...

The reactions between 4-amino-1,2,4-triazoles and 2-polyfluoroacylcycloalkanone lithium salt form polycyclic nitrogen-containing heterocycles with polyfluoroalkyl substituents (99IZV562) (Scheme 111). 

In the present review, preparation of 1,2,3-triazoles with substituents at positions 1, 4, and 5 has been divided into three parts condensation reactions and rearrangements, selective preparation of trisubstimted triazoles from disubstituted precursors, and formal [3+2] cycloaddition reactions involving alkynes (Fig. 2). Fused polycyclic 1,2,3-triazoles are out of the scope of this review. For simplicity, all the triazoles described in this review will be 1,2,3-triazoles and will be called triazoles. ... 

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