2.7- Dibromo-10-methyl

Benzene 1,4-Bis-[dibromo-methyl-telluro]- E12b, 556 (Bromierung)... 

Chlorophenyl)(2-methoxyphenyl)(4-methylphenyl)bismuthine 23 Chromium tricarbonyl 7r-complexes of triphenylbismuthine 33 Dendretic Biio-bismuthine 25 Dibromo(methyl)bismuthine 203 Dichloro(ethyl)bismuthine 204 Dichloro[2-(isopropoxycarbonyl)ethyl]bismuthine 200 Dimethylbismuth azide 74 Dimethylbismuth thiolates 73... 

Janiak et al. found that dibromo(methyl)borane MeBBr reacts with Hpzx at room temperature in the presence of NEt3 and Tl(OEt) to form [Tl(MeTpx)] in high yield.132 For the synthesis of R2B(pzx) species, sufficient pyrazolate ion is required to be present to convert [R3B(pzx)j quickly to [R2B(pzx)2], otherwise the R2B(pzx) species will dimerize to the stable pyrazabole R2B( x-pzx)2BR2. 

A rational process involving a copper catalyst in a flow tube at 360° has been worked out for the preparation of dibromo(methyl)phosphine and (bromo)dimethylphosphine and the corresponding chloro compounds ethyl halides give only poor yields by this technique, and butyl bromide does not react at all.177,178 Dichloro(trichloromethyl)phosphine has also been obtained on y-irradiation of white phosphorus in carbon tetrachloride, yields being up to 41% at 130°.179... 

It is useful to be aware that diisopropyl esters of phosphonic acids carrying additional functional groups can be dealkylated highly chemoselectively by Me3SiBr in dioxane at 60 A three-step sequence has been devised for the regioselective dealkylation of tetraalkyl esters of dichloro- and dibromo-methyl-enebis(phosphonic) acids to leave the P,P-dialkyl esters. ... 

Hunsdiecker reaction. Cinnamic acids give P-bromostyrenes or a-(dibromo-methyl)benzenemethanols on reaction with NBS (one or two equivalents, respectively) in the presence of Mn(OAc),. 

A useful one-carbon ring-expansion reaction which has been developed involves treatment of l-(dibromomethyl)-cycloalkan-l-ols with n-butyl-lithium in hexane to give the ring-expanded ketones, usually in excellent yield e.g. l-(dibromomethyl)-cyclododecan-l-ol, which was obtained by treating cyclododecanone with dibromo-methyl-lithium, gave cyclotridecanone in 89% isolated yield. ... 

The first example of alkylthiophene bromination was also demonstrated at that time. Methylthiophene which was obtained from coal tar as a mixture with toluene was reacted with bromine, and dibromo(methyl)thiophene separated from toluene. Its further bromination led to the synthesis of fully substituted tribromo(methyl) thiophene. 2-Iodo-5-methylthiophene was obtained by the same iodination procedure as iodothiophene. Deiodination with sodium allowed for the isolation of pure methylthiophene [80]. 

The cobalt-mediated reaction of diphenylmethyl(dibromo-methyl)silanes with trimethylsilylmethylmagnesium chloride yields 1,2-disilylethenes in a regio- and stereoselective fashion (eq 26). The reaction is applicable to the synthesis of... 

Preparation by demethylation of 4 -bromo-2-dibromo-methyl-4-methoxybenzophenone (SM) with boron tribromide in methylene chloride at -78° (91%). SM was obtained by bromination of 4 -bromo-4-methoxy-2-methylbenzophenone with N-bromosuccinimide in carbon tetrachloride in the presence of few dibenzoyl peroxide under irradiation at r.t. (90% MS). 

Eosin (Tetrabromofluorescein). Place 16 5 g. of powdered fluorescein and 80 ml. of rectified (or methylated) spirit in a 250 ml. flask. Support a small dropping funnel, containing 36 g. (12 ml.) of bromine, above the flask make sure that the stopcock of the funnel is well lubricated before charging the latter with bromine. Add the bromine diopwise during about 20 minutes. When half the bromine has been introduced, and the fluorescein has been converted into dibromofluor-escein, all the solid material disappears temporarily since the dibromo derivative is soluble in alcohol with further addition of bromine the tetrabromofluorescein (sparingly soluble in alcohol) separates out. Allow the reaction mixture to stand for 2 hours, filter ofiF the eosin at the pump, wash it with alcohol, and dry at 100°. The yield of eosin (orange-coloured powder) is 25 g. 

Dibromo 3 methyl 1 butene 3 4 dibromo 2 methyl 1 butene and 1 4 dibromo 2 methyl 2 butene... 

Bromination in polar solvents usually gives /n j -3,4-dibromo-2-methyl-3-buten-2-ol in nonpolar solvents, with incandescent light, the cis isomer is the principal product (194). Chlorine adds readily up to the tetrachloro stage, but yields are low because of side reactions (195). 

Bromination of isoprene using Br2 at —5 ° C in chloroform yields only /n j -l,4-dibromo-2-methyl-2-butene (59). Dry hydrogen chloride reacts with one-third excess of isoprene at —15 ° C to form the 1,2-addition product, 2-chloro-2-methyl-3-butene (60). When an equimolar amount of HCl is used, the principal product is the 1,4-addition product, l-chloro-3-methyl-2-butene (61). The mechanism of addition is essentially all 1,2 with a subsequent isomerization step which is catalyzed by HCl and is responsible for the formation of the 1,4-product (60). The 3,4-product, 3-bromo-2-methyl-1-butene, is obtained by the reaction of isoprene with 50% HBr in the presence of cuprous bromide (59). Isoprene reacts with the reactive halogen of 3-chlorocyclopentene (62). 

Bromination of 1,2-benzisoxazoles gave primarily the 5-bromo derivative, although other isomers have also been reported (67AHC(8)277). Bromination of 5-methoxy-3-methyl-l,2-benzisoxazole at room temperature gave a mixture of the 4- and 6-bromo compounds, while at elevated temperatures a 4,6-dibromo compound was produced (Scheme 27) <79IJC(B)371). 

Imidazole, 2,4(5)-dibromo-l-methyl-rate constants, 5, 400 (78JCS(P2)865, 74AJC233I) Imidazole, 4,5-dibromo-1-methyl-rate constants, 5, 400 (78JCS(P2)865, 74AJC233I) Imidazole, 4,5-dicyano-pKa, 5, 384 (B-76MI40701, 70AHC(I2)I03, 80AHC(27)24I>... 

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... 

Indole, 3-(dialkylaminomethyl-) alkylation, 4, 275 Indole, 2,3-dibromo-synthesis, 4, 215 Indole, 2,6-dibromo-3-methyl-synthesis, 4, 215 Indole, 1,3-dichloro-synthesis, 4, 214 Indole, dihydrodehydrogenation, 4, 283, 311 in non-silver photography, 1, 383 Indole, 2,3-dihydro-synthesis, 4, 327, 352 Indole, 2,3-dihydroxy-tautomerism, 4, 37, 199 Indole, 4,6-dimethoxy-... 

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... 

C5H10- 2,3-DIBROMO- -177.701 5.2964E-01 1.6349E-05 -13.35 258 C6H12 3-METHYL-1- -47.336 4.3630E-01 3.7470E-05 86.44... 

---