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1.4- Dimethyl-5,6-dihydro-2,3 pyrazinedione

Again, only one example of this synthesis has been reported. Like the analogous substrate (140), isobutyl 1,1 -dimethyl-5,8-dioxo-1,5,6,7,8,8a-hexahydro-3//-thia-/oIo13,4-a pyrazine-3-carboxyIic acid (142) underwent hssion and desulfurization (on stirring with ethanolic Raney nickel at 20°C for 12 h) to afford an hydropy-razine, this time l-isobutoxycarbonylmethyl-6-isopropyl-3,6-dihydro-2,5(l//, 4H)-pyrazinedione (143) in 89% yield.1255... [Pg.69]

Benzylidene-4,7-dimethyl-2-phenyl-l-oxa-4,7-diazaspiro[2.5]octane-5,8-dione (151) gave 3-bcnzoyl-6-bcnzylidcne-l,4-dime(hyl-3,6-dihydro-2,5(177, 477)-pyrazinedione (152) (TsOH, PhMe, reflux, water removal ( ), 18 h 73%).1030... [Pg.70]

Dibenzylidene-l,4-dimethyl-3,6-dihydro-2,5(1//,4//)-pyrazinedione (285) gave 3-benzylidene-6-(a-bromobenzyl)-6-hydroxy-l,4-dimethyl-l,4-dimethyl-3,6-di-hydro-2,5(l//, 4//)-pyrazinedionc (286) [NBS/H20—dioxane (— HOBr), 20°C, 12 h erythro and threo isomer, 50 and 33%, respectively, after separation],1030 also analogous reactions.1036... [Pg.122]

R = H) gave 3-[2-(tert-butyldimethylsiloxy)ethyl]-l,4-dimethyl-3,6-dihydro-2,5(17/,47/)-pyrazinedione (156, R = SiBu Mc2) (Bii MciSiCl, trace 4-Me2N-pyridine, EtjN, CH2CI2,0 20°C, 3 days 98%). ... [Pg.215]

See other pages where 1.4- Dimethyl-5,6-dihydro-2,3 pyrazinedione is mentioned: [Pg.1043]    [Pg.34]    [Pg.83]    [Pg.140]    [Pg.162]    [Pg.215]    [Pg.225]    [Pg.337]    [Pg.29]    [Pg.34]    [Pg.68]    [Pg.82]    [Pg.83]    [Pg.140]    [Pg.202]    [Pg.215]    [Pg.225]    [Pg.337]    [Pg.289]   
See also in sourсe #XX -- [ Pg.28 ]



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3,6-Pyrazinedione, 1,2-dihydro

3,7-Dimethyl-6,7-dihydro

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