Naphtho triazines

Naphtho[ 1,2-h]thiophene-2-carboxylic acid synthesis, 4, 893 Naphthothiophenes synthesis, 4, 881, 907, 914 Naphthothiophenes, dihydrosynthesis, 4, 113 Naphtho[ 1,2-c]thiophenes synthesis, 4, 891 Naphtho[2, l-h]thiophenes synthesis, 4, 907 Naphtho[2,3-h]thiophenes synthesis, 4, 905, 908-909 Naphtho[ 1,8-de][l,2,3]triazine, 2-methyl-reactions... 

Naphtho[2,l-e][l,2,4]triazine-l-carboxylic acid, 3-0X0-1,4-dihydro-synthesis, 3, 453 Naphthotriazines betaines synthesis, 2, 69 N aphtho-1,2,4-triazines synthesis, 3, 445 Naphtho[ 1,2- e][ 1,2,4]triazines synthesis, 3, 433 Naphthop, 1 -e][l, 2,4]triazines synthesis, 3, 433... 

Naphtho[2,l-6]furo[2,3-c][l,2,4]triazines 198 were prepared (88JHC-1117) by the reaction of 4-5-benzocoumaran-2,3-dione with thiosemicar-bazide to give 195, whose ethylation in the presence of sodium hydroxide gave 197 via 196. Reaction of 197 with aniline gave 198 via the first displacement of the ethylthio group whose product could be isolated with a shorter reaction time. On the other hand, the similar sequence of reactions on coumaran-2,3-diones differs markedly from that of 4,5-benzocoumaran-2,3-diones, where the cyclization of 195 to 198 could not be effected. The behavior of the later dione resembles that of isatin and thianaphthenequinone (Scheme 41). 

Naphtho analogues, naphtho[2,l-e]tetrazolo[l,5-6][l,2,4]triazine, naph-tho[l,2-e]tetrazolo[l,5-b][l,2,4]triazine, and naphtho[2,3-e]tetrazolo[l,5-Zj][1, 2,4]triazine, were prepared (82JOC3168 84JOC3199) by cyclization of the respective hydrazine with sodium nitrite in acetic acid or by azide displacement of a leaving group. Elucidation of the site of annulation of the tetrazole ring was accomplished by X-ray analysis and l3C-NMR spectroscopy (Scheme 189). 

Naphtho[l, 2 4,5]thiazolo[3,2-h][l,2,4]triazines 1052 were prepared by cyclocondensation of aminoiminonaphthothiazole 1051 with an acetylenedicarboxylate. Methyl ester 1052 was tested in vitro for anti-HIV activity and was inactive (91MI6). 

In 2-Oxo-2,3-dihydro-(naphtho-[l,2-e]-l,2,4-triazin)-l-oxiden werden die N-oxid-Gruppen durch Athanol schnell und in guten Ausbeuten reduziert. Dagegen werden die... 

Naphtho[l,8-de][l,2,3]triazine 114 can be alkylated with a variety of alkyl halides and lithium diisopropylamide (LDA) to give alkylated derivatives 115. Reduction of 115 with aluminium amalgam cleaves the naphthotriazine moiety to afford substituted a-aminoacids 116 in good overall yields <00TL6665>. 

In a similar manner, starting from 2-methylchloride-naphtho[l,8-de][l,2,3]triazine and magnesium, via a novel sonication-promoted Barbier reaction, an a-aminomethyl carbanion equivalent is generated which reacts in situ with a variety of carbonyl compounds. Subsequent catalytic hydrogenolysis of the triazine moiety yields the corresponding amines <00TL4685>. Sterically controlled regiospecific cyclization of aldose-5-ethyl-l,2,4-... 

Diazotization of substituted o-aminobenzylamines of the type 28, R = alkyl, aryl, acyl, gives 3-substituted 3,4-dihydrobenzo-l,2,3-triazines (29). o-Aminobenzylamine does not react similarly, but gives a product to which structure 30 has been assigned. Treatment of 1,8-diaminonaphthalene (31, R H) with nitrous acid gives naphtho[l,8-... 

Alkylation of l/f-naphtho[l,8-de]triazine (32, R = H) was originally believ to proceed exclusively at Nj, but this is now known to be incorrect. Perkins showed in 1964 that treatment of 32, R = H, with either dimethyl or diethyl sulfate in ethanolic sodium hydroxide gives a 1 1 mixture of the N,- and Nj-derivatives 32, R = Me, Et, and 132, R = Me, Et, respectively. The structure of 132, R = Me, followed largely from... 

Straightforward synthesis of some substituted naphtho[l, 4]triazines 108 and quinolino[l,2,4]triazines 109-112, via the cyclocondenstion of nitronaphthalenes and nitroquinolines with guanidine have been reported <99JOC3361>. 

---