Triazepines, synthesis from

Triazepine, 5-benzyl-3,7-diaryl-4,6-dihydro-imidazole synthesis from, 5, 497... 

Ring Synthesis from Acyclic Compounds 13.15.7.1 1,2,5-Triazepines... 

Synthesis of the benzothiazolo[2,3-c]-l,2,4-triazepines (96) from the corresponding benzo-thiazolylhydrazinopropionic acids (94) has been reported (Seheme 15) <93ijc(B)1I68>. It involves reduction of the initial cyclization products (95) to yield the dechlorination products, which on aerial oxidation in ethanol gave the fully unsaturated triazepines (96). 

The synthesis of diaryl-thiazolotriazepines 62 from the reaction of l,2,4-triazepine-3-thiones 63 (1.8 mmol) with 2-haloketones 64 (6.25 mmol) in ethanol under reflux for 2h was described <1999T5909> with the goal of creating new immunomodulating agents (Scheme 5). The starting triazepines were prepared by the addition of thiocyanic acid 65 to the chalcones 66 according to an already known method, followed by reaction of the intermediate 67 with hydrazine. 

In the synthesis of l,2,5-triazepine-l,5-diones, which are expected to mimic the structural features of or-peptidyl prolin-amides, the preparation of N2,N3-disubstituted derivatives 213a from the reaction of (Z)-alanine with the N2-substituted triazepines 213 resulted in lower yields. It has been reported that these fused triazepinediones could be elaborated to give constrained rir-peptidyl proline peptide mimetics of defined stereochemistry and sequence <1997J(P1)2297>. 

The solid phase parallel synthesis of tetrahydroimidazo[l,2-a][l,3,5]triazepin-2-thiones and 2-imines has been reported starting from resin-bound peptides <06JCO127>. Pyrazolo[r,5 l,6]pyrimido[4,5-rf]pyridazinones with potent and selective phosphodiesterase 5 (PDEs) inhibitory activity have been described <06JMC5363>... 

Aryl-l,2,4-triazepin-3-ones (2) were also prepared from the appropriate aryl isocyanate and 3-(methylamino)propionaldehyde diethyl acetal (Scheme 4). The yields in each reaction step were comparable to those for the synthesis of the triazin-3-ones. 

A new synthesis of 2-aryl-1,2,4-triazin-3-ones and 2-aryl-l,2,4-triazepin-3-ones from convenient starting materials has been demonstrated. Of these compounds, the triazin-3-ones were found to have herbicidal properties and with appropriate aromatic substituents, weed control can be obtained at low application rates. However, the weed control/crop tolerance ratio may limit the commercial application of the more active triazinones. 

Burger, K. Kahl, T. Seven-ring synthesis. 6. 2,2-Bis(trifluormethyl)-4,5-dihydro-l,3,5-triazepine from 4,4-his(trifluormethyl)-l,3-diazabuta-l,3-dienes. J. Fluorine Chem. 1989, 42(1), 51-58. 

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