3-bromo-1,1 -dichloro-2-methyl

The oxazolo[3,4-a]azepinones 4, in which 5 7 ring fusion imparts considerable planarity and hence antiaromatic character on the ring system, undergo spontaneous dimerization.153 The mode of dimerization appears to depend on the nature and position of substituents. The unsubstituted system and the 9-chloro derivative 4 (R1 = Cl R2 = H) produce the exo.anti-dimers, e.g. 5, upon spray-vacuum pyrolysis at 300 C, whereas the 7-/ert-butyl, 7-bromo, 7-methyl, and 7,9-dichloro (4, R1 = R2 = Cl) compounds yield the exo,syn-dimcrs, e.g. 6. 

A mixture of 1- and 3-chloro, 1,3-dichloro, and 1,3,5-trichloro derivatives was obtained on chlorination of imidazo[l, 5-a]pyrazine (172). Bromination gave similar results (75JHC207,75JOC3373 84MI24). The 8-chloro compound is best made from the 8-oxy derivative of 172. When the 1-bromo-3-methyl derivative of 172 was treated in turn with aqueous bromine and excess dilute caustic soda, the pyrazine ring was destroyed to give 4-bromo-2-methylimidazole-5-aldehyde (75JOC3373). 

This method of preparation of a halobenzaldehyde is of wide application and has been used for the preparation of the following substituted benzaldehydes 2-bromo-5-methyl-,4 2,3-dichloro-and 2,4-dichloro-,5 2-chloro-4-methyl-,-iodo-, />-fluoro-, 2-iodo-4-methyl-, and 6-iodo-3-methyl-.9... 

C7H6BrN02 1 -bromo-2-methyl-3-nitrobenzene 55289-35-5 538.66 47.611 2 10269 C7H6CI20 2,6-dichloro-3-methylphenol 13481-70-4 510.15 44.860 1,2... 

C5H10CI2 1,3-dichloro-2-ethylpropane. .. 190.45 13.577 2 5608 C5H11Br 2-bromo-2-methyl butane 507-36-8 207.83 6.577 2... 

Formation of a C-H and a C-C bond at the expense of a C-Br and a C-Si bond occurs when 1 -bromo -1 -trimethylsilylcyclopropanes are treated successively with butyllithium and dichloro-methyl methyl ether at — 95°C and yield cyclopropyl trimethylsilyl ketones The 1-... 

Bis-[chloromcthyl]-2, 2 -dichloro- 646 2-Bis-[4-methoxy-phenyl]- 1699 2-Bis-[4-methyl-phenyl]- 1699 l -Bis-[trimethylsilyl]- 1691 (Bis-[triphenylphosphan]-chloro-nickelo)-2,2,2, 2 -tetramethyl- 225 3 (or 3,3 )-Bis-[trimethylsilyl]-2,2 -dichloro- 2710 Bromo- 1443 Bromo-l-methoxy- 1508 Bromo-1-methoxy- 1508 Bromo-1-methyl- 1271 Bromo-1-methyl- 1271, 2699 Chloro- 946 Chloro-l-cyano- 558 Chloro-1, 2-dimethyl- 550 Chloro-2,2(or 2,3)-dimethyl- 558, 559 Chloro-3-ethyl-2-methyl- 558 Chloro-l-methyl- 2699 Chloro-2-methyl- 551 Chloro-2,2,2 -trimethyl- 558 Chloro-2,2,3,3-tetramethyl- 558, 559 ( 1 -Cyclopentenyl)-1 -methoxy- 1889 2 -Dibromo-2,2-dichloro-l-methyl- 2194, 2 -Dibromo-l,r-dimethyl- 2700 (2,2-Dibromo-cthcnyl)-2-phcnyl- 1792, 2-Dibromo-l-methyl- 1271 (Dibromomethylen)-l-methyl- 2302, 2-Dibromo-l-methyl-3-methylen- 2302, 2 -Di-tcrt.-butyl-2,2 -dimethyl-3,3.3, 3 -tetra-bromo- 2413... 

Various substituted phenyl isocyanates 270 [179, 180], i.e. 2,3-dichloro-, 2,5-dichloro-, 2,6-dichloro-, 2-bromo-4-methyl-, 2,4-dibromo-, 4-chloro-2-phenoxy-, 4-butyloxy-2-chloro-, 4-chloro-2-(4-chlorophenoxy)-, 4-chloro-2-(4-chlorophenylsulfanyl)-, 4-chloro-2-[2]naphthyloxy-, 2-chloro-4-(4-chlorophenoxy)-, 2-chloro-4-trifluorome-thoxy-, 2-chloro-4-phenoxy-, 2-chloro-4-decyloxy-, 2-chloro-4-(4-chlorophenylsul-fanyl)-, 2-(4-bromophenylsulfanyl)-4-chloro-, 2,4-bis(4-chlorophenylsulfanyl)-, and 2prepared with triphosgene in dioxane at 100 °C starting from the corresponding anilines 269 [180]. 

Furan-2-carbonyl chloride, 5-alkyl-3,4-dichloro-synthesis, 4, 690 Furancarboxamides rotational isomerism, 4, 543 Furan-2-carboxylic acid, 5-acetylamino-ethyl ester reactions, 4, 647 Furan-2-carboxylic acid, amino-properties, 4, 708 Furan-2-carboxylic acid, 5-bromo-nitration, 4, 603, 711 Furan-2-carboxylic acid, 3-methyl-methyl ester bromination, 4, 604 Furan-2-carboxylic acid, 5-methyl-nitration, 4, 602... 

Dichlorothiophene can also be used for the synthesis of 3-substituted thiophenes, since it can be smoothly acylated and chloro-methylated in the 3-position, and the halogens can then be readily removed at the appropriate stage. 3-Thenylsuccinic acid (28) has thus been obtained by treating 2,6-dichloro-3-thenylsuccinic acid with sodium amalgam. 2-Bromo-3-thenylbromide can be utilized in a similar way. ... 

Dichloro-2-methyl-3-phenylsulfonylquinoxaline 1,4-dioxide (55, R = S02Ph) gave 2-bromo-6,7-dichloro-3-methylquinoxaline 1,4-dioxide (55, R = Br) (48% HBr, 80°C, 30 min then 20°C, 12 h 31%) 2-methyl-3-phenylsulfonylquinoxaline 1,4-dioxide gave 2-chloro-3-methylquinoxaline 1,4-dioxide (35% HCl, 70°C, 15 min 87% several analogs likewise). ... 

Another example of a selective dehalogenation in the carbohydrate field has been reported by Hanessian and Plessas.83(b) Catalytic hydrogenation of methyl 4-0-benzoyl-3-bromo-2,6-dichloro-2,3,6- tri-deoxy-a-D-mannopyranoside over palladium-on-carbon in the presence of barium carbonate gave methyl 4-0-benzoyl-6-chloro-2,3,6-... 

Boron trifluoride and boron trifluoride-diethyl ether complex can be used as a source of fluoride ions in the presence of hypobromites and hypochlorites, e.g. methyl hypobromitc, tert-butyl hypobromite, methyl hypochlorite in carbon tetrachloride at 25 C. The addition of bromine monofluoride" and chlorine monofluoride" to various alkenes is accompanied by the formation of the corresponding alkoxybromides and alkoxychlorides which hinder the isolation of the halofluorinated products.57 jV-Bromo- and A -chloro-substiluted alkyl- and arylamines. -amides, and -imides, A -chloro-A,-methylamine, A -bromo-A -methylamine, A -chloro-A, /V-dimethylamine, A-bromo-A.A-dimethylamine, ACV-dichloro-A -methylamine, V,fV-dibromo-,V-mcthylaminc, A -bromosuccinimide, -V-chlorosuccinimide, Af-bromoacct-amide, A.A -dichlorourethane, can be used in the reaction instead of the hypohalites. The reactions with various alkenes conducted in dichloromethane at room temperature in the presence of boron trifluoride-diethyl ether complex produce bromofluoro and chlorofluoro addition products in 40-80 % yield. However, the reactions are complicated by the addition of A -halo-succinimides and Af.A-dichlorourcthane to the C = C bonds.58... 

Methyl 4,6-dichloro-4,6-dideoxy-a-D-galacto-pyranoside115 Methyl 4,6-dichloro-4,6-dideoxy-ct-D-gluco-pyranoside"6 Sedoheptulosan monohydrate 2,7-anhydro-/3-D-oitro-heptulopyrano.se monohydrate117 Methyl 6-bromo-6-deoxy-a-D-galactoside118... 

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