Regioisomeric Formation of Acenaphtho[1,2-e][1,2,4]triazolo[3,4-c][1,2,4]triazines and Their Acyclic C-Nucleoside Analogues

Abstract

The oxidative cyclization of the ethylidene derivative of 3-hydrazinoacenaphtho[1,2-e][1,2,4]triazine (2) gave regioselectively the angular isomer 1-methylacenaphtho[1,2-e][1,2,4]triazolo[3,4-c][1,2,4]triazine (5). Its linear isomer 10-methylacenaphtho[1,2-e][1,2,4]triazolo[4,3-b][1,2,4]triazine (4) was synthesized by the condensation of acenaphthenequinone (6) with 3,4-diamino-5-methyl-4H-1,2,4-triazole. Condensation of 2 with a number of monosaccharides afforded the respective hydrazones 9 whose oxidative cyclization gave the corresponding 1-(polyhydroxyalkyl)acenaphtho[1,2-e][1,2,4]triazolo[3,4-c][1,2,4]triazine (10). Acetylation of 9 and 10 gave 3-[N-acetyl-N′-(polyacetoxyalkylidene)hydrazino]acenaphtho[1,2-e][1,2,4]triazine (11) and 1-(polyacetoxyalkyl)acenaphtho[1,2-e][1,2,4]triazolo[3,4-c][1,2,4]triazine (13) respectively. Periodate oxidation of 9e gave 3-(2-oxoethylidenehydrazino)acenaphtho[1,2-e][1,2,4]triazine (14).

Synthesis and Dimroth Rearrangement of 6-Cyano-l,2,4-triazolo- [4,3-a]pyrimidin-5- and 7-ones. A Novel Alkylation with Orthoesters and a New Participation of the Cyano Group in the Rearrangement

“…A suspension of 30 (0.50 g, 1.52 mmol) in acetic acid (10 ml), was treated with bromine (5 ml) in acetic acid (20 …”

Synthesis and antiviral screening of some novel pyridazine and triazolopyridazine nucleosides

“…the Experimental). The 1 H NMR and 13 C NMR spectra showed the presence of OAc groups (cf. This could be explained by acetylation of hydrazone derivatives 2a,b giving their corresponding O-acetylated sugar hydrazone derivatives 3a,b followed by oxidative cyclization [14][15][16] giving the O-acetylated cyclic C-nucleosides 4a,b (Scheme 1).…”

4′, x-Seco And 4′,x-4′,5′-Diseco C-Nucleosides From 2-Hydrazino-(3H)- Thieno [2,3-D] Pyrimidin-4-Ones

“…The mix ture was heated under reflux for 4 h. The product that separated out on cooling was filtered and recrystalized from ethanol to give colorless crys tals (0. 16 (19)(20)(21)(22) A solution of the respective sugar (10 mmol) in water (5 ml) was treated with a solution of 1 or 2 (10 mmol) in ethanol (150 ml) and a few drops of acetic acid. The mixture was boiled under reflux for 2 h. The product that separated out on cooling was filtered, washed with water followed by etha nol and dried.…”

“…The biological im portance of acyclonucleosides [1][2][3] and C-nucleosides [4][5][6][7][8][9][10][11][12][13][14] attracted our at tention towards the synthesis of acyclo C-nucleoside analogues [15][16][17][18][19][20][21][22][23][24][25] of potential chem othera peutic interest. The acyclonucleosides have been recently classified [1][2][3] according to the type of the glycon rather than the aglycon part.…”