2-Benzopyran-5,8-diones, 3,4-dihydro

Similarly, reaction of 2-dimethylaminomethylene-3-oxoalkanoates or 2-di-methylaminomethylene-1,3-cyclohexanediones with 2-phenyl-5(4/7)-oxazolone 146, generated in situ from hippuric acid, affords 6-substituted 3-(benzoyl-amino)-2-oxo-2//-pyran-5-carboxylates 204 and 3-(benzoylamino)-7,8-dihydro-2//-l-benzopyran-2,5(6//)-diones 206, respectively. These compounds showed strong local anesthetic activity (Scheme 7.62). ... 

Other furocoumarins, although they have rather different structures, have very similar names, which gives rise to confusion. Thus, whereas oroselone (8) is 8-isopropenyl-2//-furo[2,3-A][l]benzopyran-2-one12 and oroselol (9) is 8-(l-hydroxy-l-methylethyl)-2 -furo[2,3- ][l]benzopy-ran-2-one, oreoselone (10) is 2-isopropyl-2,3-dihydro-7 -furo[3,2-gr][l]-benzopyran- 3,7- 2 -dione.13... 

In a TTN-mediated oxidative rearrangement route to certain linear pyranoisoflavones, the aurones (2-alkylidene-6,7-dihydro-4-methoxy-7,7-dimethyl-5//-furo[3,2- ][l]benzopyran-3(277),5-diones) (45 R1 = R2 = H, OMe) were obtained in low yields (Equation (20)) <89BCJ826,92H(34)505>. A signal at d 6.45 ppm in the H NMR spectrum due to the benzylidene proton was noted as being characteristic of the aurone system. 

Photooxygenation of natural visnagin (87) affords a variety of products including 4,9-dihydro-4,9-epidioxo-4-methoxy-7-methylidenylfuro[3,2-g]-benzopyran-5,6-dione and 9-hydroperoxy-4-methoxy-7-methyl-5H-furo[3,2-g]benzopyran-5-one. ° Similar studies have also been reported on the 4-hydroxyl derivative. 

Chlorosulfonyl isocyanate is uniquely useful for the formation of hy-dantoins from sterically hindered acid- and base-labile amino nitriles, e.g., the synthesis of optically active spirohydantoins such as the biologically active (4S)-2,3-dihydro-6-fluorospiro(4H-1 -benzopyran-4,4 -imidazolidine)-2, 5 -dione.23... 

Table 8.5. IN VITRO AND IN VIVO AR INHIBITORY ACTIVITIES OF 2,3-DIHYDRO[4tf ]- l-BENZOPYRAN-4,4 -IMIDAZOLIDINE-2, 5 -DIONES... 

Sorbinil ((4S)-2,3-dihydro-6-fluorospiro[4H-l-benzopyran-4,4 -imidazolidine7-2, S -dione)... 

Dihydro-7,8-dimethoxy-2//-1 -benzopyran-3-yl)-6-hydroxy-2,5-cyclohexadiene-l,4-dione, see A-30214... 

Dihydro- 7-hydroxy-2H-l-benzopyran-3-yl)-2,3-dimethoxy-2,5-cyclohexadiene-l,4-dione, 9CI. 7-Hydroxy-3 4 -dimethoxyisoflavanquinone [69359-09-7]... 

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