Benzofurans 5-amino

Intramolecular C-C bond formation in the furan precursor is the main synthetic method for furobenzazepines. 2-Hydroxybenzonitrile 35c produces the corresponding benzofuran benzazepine dione 36c when reacted with o-carboxymethyl bromoacetophenone in refluxing DMF (Scheme 6, Section 2.1.1.2 (1991JHC379)). Alternatively, benzofurobenzazepinone 91 can be synthesized starting from benzofuran amino ester 90 by intramolecular acylation... 

The base-promoted ring contraction of 3-bromo-2-pyrones to 2-furoic acids cf. Scheme llOd) is a well exemplified reaction 01CB1992,69JCS(C)1950,73JCS(P1)1130> which has also been applied to the obtention of benzofuran-2-carboxylic acids frorn 3-bromocoumarins 08CB830,70KGS(S2)166), Similar base treatment of 3-amino-2-pyrones provides pyrrole-2-carboxylic acids (Scheme IlOe) 75JHC129). 

Chromanone, 3-acetamido-2-methyl-reduction, 3, 729 Chromanone, 3-amino-synthesis, 3, 734 Chromanone, 3-arylidene-thermoisomerization, 3, 722 Chromanone, 3-benzylidene-thermolysis, 3, 728 Chromanone, 3-bromo-2-hydroxy-benzofuran from, 3, 729 Chromanone, 6,8-dimethyl-hydroxymethylation, 3, 731 Chromanone, 2,3-epoxy-as synthon, 3, 735... 

The effect of other substituents on the products of alkaline hydrolysis is well illustrated in the conversion of 4-chloromethylcoumarin (293) to the benzofuran-3-acetic acid (294) in high yield (79CHE815), of 4-hydroxy-6-phenacylpyran-2-one (259) into the benzophenone (295) (70T5255) and of 5-amino-3-methylisocoumarin (297) (formed from the nitro compound 296) into the indole (298) <76JCS(P1)1073, 81CPB249). 

Bcnzofuran-4,7-dioncs have been synthesized regioselectively by [3 + 2] photoaddition of 2-hydroxy-1,4-benzoquinones with a range of alkenes (equation 185)664. The reaction occurs in 30-60% yield and is a useful method for the synthesis of the benzofuran ring system, which is important in natural products like acamelin665. Substituted naphthoquinones may also be used in this reaction666,667 and this has lead to a very simple two-step synthesis of maturinone. In a similar reaction, a [3 + 2] photoaddition reaction of 2-amino-1,4-naphthoquinones with electron-rich alkenes gave 13-82% yields of 2,3-dihydro-177-bcn/ /]indole-4,9-diones in a single-step process which involved photolysis followed by oxidation (equation 186)668,669. 

Benzofuran 3-(Amino-methoxy-carbonyl-methyliden)-4-nitro-l -... 

Benzimidazol-3-oxid 2-Ethoxycarbo-nyl-5-methoxy- E8c, 227 [(4-OCH3 - 2-N02 - Ar) - NH -CH2-COOR + Na-OR] 2-Benzofuran 5-Amino-l-(l-nitro-propyl)-3-oxo-l, 3-dihydro-iV/lc, 513... 

Azetidin 2-Oxo-l-(2,4,6-trimethoxy-benzyl)- El6b, 550 (aus Azetidin) 1-Benzofuran 3-Amino-2,3-dime-thyl-2-ethoxycarbonyl-5-hydro-xy-2,3-dihydro- E6b/1, 109 [HjC—C(NH2) = C(CH3) -COOR 1,4-Chinon] Bernsteinsaure -(benzyloxyamid)-ethylester E5, 1151 (R —CO — CHN2 + Ar —O—NH2) Carbamidsaure N-(4-Methyl-... 

SYNS BENZOFURAN, 3-(p-(2-(DIETHYLAMINO)-ETHOXY)BENZOYL)-2-ETHYL- p-(2-(DIETHYL-AMINO)ETHOXY)PHENYL 2-ETHYL-3-BENZOFURAN-YL KETONE KETONE, p-(2-(DIETHYLAMINO)ETHO-XY)PHENYL 2-ETHYL-3-BENZOFURANYL L 2642-LABAZ METHANONE, (4-(2-(DIETHYLAMINO)ETHO-XY)PHENYL)(2-ETHYL-3-BENZOFURANYL)-(9CI)... 

SYNS ETHANONE, l-(2-ETHYL-7-(2-HYDROXY-3-((l-METHYLETHYL)AMINO)PROPOXY)-4-BENZO-FURANYL)- 2-ETHYL-4-ACETYL-7-(2-HYDROXY-3-ISOPROPYLAMINOPROPOXY)BENZOFURAN KETONE, 2-ETHYL-7-(2-HYDROXY-3-(ISOPROPYL-AMINO)PROPOXY)-4-BENZOFURANYL METHYL... 

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