10.10- dibromo-2,8-dimethyl

Other linking agents were investigated, e.g. dibromo-dimethyl-silane and dichlo-rophenylphosphine. Interesting products were obtained with diepoxides91 namely... 

The first synthesis of 4-isoxazolidinones (540) resulted from the reaction of 2,4-dibromo-2,4-dimethyl-3-pentanone with hydroxylamine (81H(16)1855>. 

Chroman-4-one, 3-bromo-2-hydroxy-synthesis, 3, 856 Chroman-4-one, 2-/-butyl- H NMR, 3, 583 Chroman-4-one, 3-/-butyl- H NMR, 3, 583 Chroman-4-one, 2,3-dibromo-dehydrobromination, 3, 828 Chroman-4-one, 3,3-dibromo-dehydrobromination, 3, 828 Chroman-4-one, 2,3-dihalogeno-synthesis, 3, 856 Chroman-4-one, 2,2-dimethyl-mass spectra, 3, 617 Chroman-4-one, 2,2-diphenyl-synthesis, 3, 852 Chroman-4-one, 3-hydroxy-synthesis, 3, 856... 

Imidazole, 4,5-dibromo-l-methyl-synthesis, S, 399 Imidazole, 4,5-di-t-butyl-synthesis, S, 483 X-ray diffraction, S, 350 Imidazole, 4,5-dichloro-chlorination, S, 398 synthesis, S, 398, 473 Imidazole, 4-(3,4-dichlorophenyl)-nitration, 5, 433 Imidazole, 4,5-dicyano-hydrolysis, S, 435-436 synthesis, S, 461, 472, 487 Imidazole, 4,5-dicyano-1-vinyl-synthesis, S, 387 Imidazole, 4,5-dihydro-mass spectra, 5, 360 Imidazole, 4-(dihydroxybutyl)-synthesis, S, 484 Imidazole, 4,5-diiodo-nitration, S, 396 synthesis, S, 400 Imidazole, 2,4-diiodo-5-methyl-iodination, S, 400 Imidazole, 1,2-dimethyl-anions... 

Pyran-2-one, 5,6-dibromo-5,6-dihydro-reactions, 3, 735 Pyran-2-one, 5,6-dihydro-allylic bromination, 3, 799 dehydrogenation, 3, 724, 799 H NMR,3, 581 synthesis, 3, 841, 843 Pyran-2-one, 4,6-dimethyl-irradiation, 3, 677 photochemistry, 3, 678 Pyran-2-one, 5,6-dimethyl-chloromethylation, 3, 680 conformation, 3, 631 Pyran-2-one, 5-f ormyl-IR Spectra, 3, 595 Pyran-2-one, 6-formyl-IR spectra, 3, 595 Pyran-2-one, 5-halo-synthesis, 3, 799 Pyran-2-one, 3-hydroxy-IR spectra, 3, 595 Pyran-2-one, 4-hydroxy-methylation, 2, 57 3, 676 pyran-4-one synthesis from, 3, 816 reactions with phosphorus oxychloride, 2, 57 synthesis, 3, 792, 794, 795, 798 tautomerism, 2, 56 3, 642 Pyran-2-one, 4-hydroxy-6-methyl-methylation, 3, 692 reactions... 

N,N-Dimethylaniline) Dimethylbenzene, see Xylene 1,3-Dimethylbutyl acetate Dimethyl carbamoyl chloride Dimethyl-1,2-dibromo-2,2-dichloroethyl phosphate, see Naled Dimethyl ether N-N-Dimethylethylamine Dimethylethoxy silane Dimethylformamide SK... 

Dimethylbenzene, see Xylene Dimethyl-1,2-dibromo-2-dichloroethyl phosphate, see Dibrom ... 

The addition proceeds most smoothly with highly functionalized (more polar) steroids as seen in examples by Bernstein and others. The polar reaction conditions pose solubility problems for lipophilic androstane, cholestane and pregnane derivatives. Improved yields can be obtained in some cases by using dimethyl sulfoxide or t-butanol " as solvents and by using sodium A-bromobenzenesulfonamide or l,3-dibromo-5,5-dimethyl hydantoin (available from Arapahoe Chemicals) as a source of positive bromine. The addition of bromo acetate and bromo formate to steroid olefins has been studied to a limited extent. ... 

Optical activity owing to restricted rotation (atropisomerism) has been demonstrated in two phenylthiophenes 2-(6-methyl-2-nitro-phenyI)-3-thiophenecarboxylic acid (41), which rapidly racemized in solution, and 2,5-dimethyl-4- (6 -methyl-2 -nitrophenyl) 3-thio-phenecarboxylic acid (42), which was optically stable (at room temperature). Recently the first bithienyl, 2,2 -dicarboxy-4,4 -dibromo-5,5 -dimethyl-3,3 -bithienyl (43), has been resolved into optical anti-podes which were optically stable. 

A comparison of ortho vs. para direct deactivation by a methoxy group has been made by Karmas and Spoerri in 2,3-dibromo-5,6-dimethyl- and 2,5-dibromo-3,6-dimethyl-pyrazine. The former gives monomethoxy-debromination with one equivalent of methanolic methoxide (65°, 6 hr) and disubstitution via 198 with excess reagent for a longer time (10 hr). In contrast, the isomeric 2,5-dibromo compound gave only monosubstitution, forming 199, under the latter conditions. 

Benzoxepin undergoes addition of bromine and chlorine to give l,2-dibromo-l,2-dihydro-3-benzoxepin (2 a) and 1,2-dichloro-l, 2-dihydro-3-benzoxepin (2b), respectively.93 The bromination reaction of dimethyl 3-benzoxepin-2,4-dicarboxylate takes the same course to give 2c.91... 

The dibromo-4,5-dihydro-3//-2-benzazepine 12 with sodium azide in dimethyl sulfoxide undergoes an interesting debromination—azidation process to yield a separable mixture of azido-3//-2-benzazepines 13 and 14.78... 

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