Regioselective nitration of 3-acetylindole and its N-acyl and N-sulfonyl derivatives

Cytochrome P450–catalyzed L-tryptophan nitration in thaxtomin phytotoxin biosynthesis

“…The resulting ferrous-O 2 /ferric-superoxide complex undergoes further reduction and dehydration to form a ferryl complex (Fe(IV)=O porphyrin cation radical; often referred to as “compound I”) that oxidizes the substrate 10 . To examine the involvement of O 2 in the TxtE-catalyzed nitration reaction, we incubated the enzyme with L-tryptophan, NADPH, DEANO and spinach Fd/Fr under an 18 O 2 atmosphere. High resolution MS analysis of the resulting L-4-nitrotryptophan showed that it was >90% labeled with a single 18 O atom (Fig.…”

Spiro[pyrrolidine-3,3′-oxindoles] and Their Indoline Analogues as New 5-HT6 Receptor Chemotypes

“…N -chlorosuccinimide [ 37 ] was used in the first experiments as halogenating reagent, providing the Cbz-protected spiro[pyrrolidine-3,3′-oxindole]. The phenylsulfonylation was performed either by using lithium-hexamethyl disilazane [ 38 ] and sodium hydride [ 39 ] as deprotonating agents and acid scavengers. Finally, the deprotection of the Cbz-group by hydrogenation [ 40 ] resulted in the desired 1-(phenylsulfonyl)spiro[indoline-3,3′-pyrrolidin]-2-one ( 17 ) compound.…”

Nitro and related compounds

“…At Ϫ15 to Ϫ10 ЊC only 3-acetyl-5-nitroindole is formed (85% yield), while at 60 ЊC only 3-acetyl-6-nitroindole is formed. 20 A procedure for the nitration of fullerenes has been developed using a mixture of nitric acid and copper powder in benzene (nitrogen dioxide is created in situ). The degree of nitration is dependent on the concentration of nitrogen dioxide, temperature and the reaction time.…”