Benzopyrazoles

Extensive reviews have been pubUshed, covering the Hterature to about 1967 (1 3). Pyrazoles and the benzopyrazoles have been well reviewed in References 4 and 5. More up-to-date reviews, though much narrower in scope, have been pubUshed on pyrazole oxides (6), dihydropyrazoles as insecticides (7), the anticancer dmgs anthrapyrazoles (8,9), and pyrazole sulfonylureas as herbicides (10). 

Pyrrolo[2,1 -c][l, 4]benzodiazepines synthesis, 7, 614 Pyrrolo[l, 6]benzodiazocines synthesis, 7, 515 Pyrrolo[3,4-c]benzopyrazoles reactions, 6, 1034 Pyrrolobenzothiazoles synthesis, 4, 785 Pyrrolo[l, 2-c]benzotriazines synthesis, 4, 240 Pyrrolo[3,4-c]cinnolines synthesis, 4, 240... 

Benzopyrazoles, see Indazoles Benzo-l-thia-2,3-diazole 136 f., 192, 225 Benzo-l,2,3-triazene 225 Benzotriazinones 133 f. 

ESTER, 43, 100 BenzOpyrazole, 43, 69 3-Benzoylpropionic acid, condensation with benzaldehyde to give a-benzylidene-y-phenyl-A t-bu-tenolide, 43, 3... 

Benzophenone, conversion to ethyl /S-hydroxy-0,0-diphenylpro-pionate, 44, 57 Benzophenone oxime, 44, 52 Benzopyrazole, 42, 69 3-Benzoylpropionic add, condensation with benzaldehyde to give a-benzylidene-y-phenyl-A y -bu-tenolide, 43, 3 N-Benzylacetamide, 42,18 n-Benzyiacrylamide, 42,16 Benzyl alcohol, reaction with acrylonitrile, 42,16... 

Carbenes insert into the N=N bond of azo compounds and the unstable adducts rearrange spontaneously to produce benzopyrazoles (e.g. Scheme 7.31) [37,38], The reactions of azo compounds with dichlorocarbene is also catalysed by tertiary amines [36] and, under such conditions, azoxyarenes produce the benzimidazoles, presum-... 

Pyrazole was hydrogenated over palladium on barium sulfate in acetic acid to 4,5-dihydropyrazole (A -pyrazoline), and 1-phenylpyrazole at 70-80° to 1-phenylpyrazolidine [478]. In benzopyrazole (indazole) and its homologs and derivatives the six-membered ring is hydrogenated preferentially to give... 

Benzophenone, 2-amino, 32, 8 THIO-, 35, 97 Benzopyrazole, 39, 27 -Benzoquinone, 35, 26 Benzoylacetanilide, 37, 2 Benzoylacetic acid, ethyl ester,... 

Most solid-phase syntheses of pyrazoles are based on the cyclocondensation of hydrazines with suitable 1,3-dielectrophiles. The reported examples include the reaction of hydrazines with support-bound a,(3-unsaturated ketones, 1,3-diketones, 3-keto esters, a-(cyano)carbonyl compounds, and a, 3-unsaturated nitriles (Table 15.19). Pyrazoles have also been prepared from polystyrene-bound 3-(hydrazino)esters, which are generated by the addition of ester enolates to hydrazones (Entry 7, Table 15.19 see also Section 10.3). Benzopyrazoles can be prepared from support-bound hydra-zones using the reaction sequence outlined in Figure 15.11. Oxidation of a polystyrene-bound benzophenone hydrazone yields an a-(acyloxy)azo compound. Upon treatment with a Lewis acid, this intermediate is converted into a 1,2-diazaallyl cation,... 

Figure 15.11. Synthesis of benzopyrazoles by intramolecular electrophilic amination [242].

Intramolecular replacement of fluorine by nitrogen has been used for the formation of fused heterocycles, i.e. derivatives of indole,187 - 189 2,3-dihydroindole.190 benzopyrazole.191 benzo-pyridazine,192 benzoxazine,193194 bcnzothiadiazole,193 quinoline,196-198 and benzothiazinc (e.g., 9).194 1"-200... 

Delete Benzodiazole or Benzopyrazoles from the title Make [59] instead of 59 and [308] instead of 308 Indazolonimides instead of Indazolonimide Name should read I -Amino-mesitylene 1 -Amino-1,3,5 -trimethyl-benzene 3,5- Dimethyl benzyl amine or Mesitylamine,... 

Under similar conditions (NaOH, 20°C, 13h), l-phenyl-5-methanesulfonyltetrazole 286 reacts with 1-imidazole, 1-benzimidazole, or 1-benzopyrazole to give the corresponding l-phenyl-5-azolyl derivatives in 68-78% yield <1996CHE1300>. 

Arylamines are commonplace, as components of molecules with medicinally or electronically important, catalytic active, or structurally interesting properties. An aryl-nitrogen linkage is included in nitrogen heterocycles such as indoles [4,5] and benzopyrazoles, conjugated polymers such as polyanilines [6-12], and readily oxidized triarylamines used in electronic applications such as 4,4 -bis(3-methylphe-... 

The aluminum chloride-catalyzed rearrangement of the multiring bisphenylhydrazone (147) gave two [l,2-c 4,5-c ]benzopyrazoles <82TL4493>. Functionalized benzenes of the type (148), available by reduction of many heterocycles, react with carbonyl compounds to construct a variety of benzodiheterocycles of the general type (149). 

The pyrrolo[3,4-c]benzopyrazole (51 R1 =Ph, R2 = Me, R3 = C02Et) reacts with DMAD giving the cycloadduct (52 R1 = Ph, Rz = Me, R3 = C02Et). Reaction with N-phenyl-maleimide in boiling xylene slowly gives compound (53), presumably formed by elimination of methylamine from the primary adduct (79JOC622). 

Die systematische Bezcichnung Benzo[c]pyrazoI entsprechend der IUPAC-Nomenklatur wird zumindest ffir Benzopyrazol und seine Benzohomologen weder im Ring index noch von Chemical Abstracts verwendet, sondern der Trivialname Indazol (/. B als IH-lndazol, CA.Reg. Nr. 271-44-3) in Analogic zu Tndol. Auch die entsprechenden benzokondensierten Derivate werden z. B. als Benzo[c]indazol, nicht aber als die entsprechenden Naphthopyrazole benannt, d.h. Indazol wird als bicyclische Stammkomponente ffir Ringkondensationen verwendet. 

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