Dihalogen

Die 14N-NMR-Spektren von z.B. 3,4-Dimelhyl-nin3bzw. 3,4-Diacctyl-furazan-2-oxid113 so-wie von 3,4-Diaryl-113 und 3,4-Dihalogen-furazan-2-Oxiden113 zeigen in alien Fallen nur ein breites Signal. 

Stepp, T.A., Camper, N.D., Paynter, M.J.B. (1985) Anaerobic microbial degradation of selected 3,4-dihalogenated aromatic compounds. Pest. Biochem. Physiol. 23, 256. 

Rohrbaoher A, Williams J and Janda K C 1999 Rare gas-dihalogen potential energy surfaoes PCCP 1 5263-76... 

Amino-l-naphthalenecarboxyhc acid can be converted, by dia2oti2ation and treatment with ammoniacal cuprous oxide, to l,l -binaphthalene-8,8 -dicarboxyhc acid [29878-91-9] (48). Treatment of (48) with concentrated sulfuric acid yields anthranthrone. The dihalogenated anthranthrones are valuable vat dyes. 

Although chlorine azide and bromine azide tend to give some dihalogen adducts, these reagents have been used in the presence of alcohol, ester and epoxy functions without interference.In the case of 17a-acetoxy-A -progesterone, a selective addition to the 6,7-double bond is obtained. ... 

With a,p-dihalo- or a-halo-a,p-unsaturated carbonyl derivatives A significant number of examples exist in which a,P-dihalogenated carbonyl derivatives undergo reactions with thioglycolates in the presence of base to produce thiophenes. " The reactions have been shown to occur through intermediate a-halo-a,P-unsaturated carbonyl derivatives produced by the elimination of HX. Thus the use of a-halo-a,P unsaturated carbonyl systems in place of the a,P-dihalocarbonyl compounds was found to efficiently provide thiophenes upon reaction with thioglycolates. In a modification of the work of Fiesselmann, readily accessible methyl-2-chloroacrylate 23 and 2-chloroacrylonitrile 24 have been used in this sense to provide 25 and 26, respectively. 

Prereactive dihalogen complexes with O- and S-heterocycles as Lewis bases in the gas phase 99AG(E)2686. 

A rather broadly applicable method leading to products which can be further modified starts from 3,8-diaryl-l,2-diazacycloocta-2,8-dienes 4.23,24 With /V-bromosuccinimide dihalogenation occurs which, after a double dehydrohalogenation, gives 3,8-diphenyl-1,2-di-azocine (5 Ar = Ph, X = H) in low yield. The reaction with sulfuryl chloride to give tetra-... 

Variable results have been reported for the halogenation of thieno[2,3-6]quinoline (123). Initial attack was mainly at the 3-position, but it was difficult to avoid the formation of 2,3-dihalogenated products, even when only 1 mol of halogen was used (predictions are for 2- and 3-substitution [77ZN(B)1331]). Bromine buffered in chloroform gave the 3-monobromo derivative, but analogous chlorination gave a mixture that included some... 

Bei der Hydrogenolyse aromatischcr Halogenide 2 und bei der selektiven Reduktion alicyclischer geminaler Dihalogen-Verbindungen13 wird ein Vierzentren-Mechanismus angenommen. 

Geminale Dihalogen-aziridine werden durch Tributyl-zinnhydrid selektiv zu Halo-gen-aziridinen reduziert2. 

Bei l,4-Dihalogen-butinen-(2) lauft die Reaktion in zwei verschiedenen Richtungen1,4. Aus 2,5-Dichlor-2,5-dimethyl-hexin-(3) wird der Whiting-Reaktion analog (s. S. 72) 53°/u2,5-Dimethyl-hexadien-(2,4) und nur 14%, 2,5-Dimethyl-hexadien-(2,3) erhalten1. 

Primare Phosphine werden durch Reduktion von Phosphonsaureestern (vier Hy-drid-Aquivalenten eines Organo-silans) oder aus Dihalogen-phosphinen (zwei Hy-drid-Aquivalenten) bei 150-200° erhalten, wobei das Phosphin unmittelbar aus dem An-satz herausdestilliert werden kann z.B. ... 

Vicinale Dihalogen-alkane lassen sich durch das System Titan(III)-chlorid/Lithiumala-nat bzw. Titan(IV)-chlorid/Lithiumalanat unter Eliminierung der Halogen-Atome in guten Ausbeuten zu Alkenen reduzieren (die Ausbeuten liegen hoher als bei den Reduk-tionen mit Zink und die Reaktion verlauft einfacher als mit Natrium in flussigem Ammo-niak)7 ... 

Geht man von 1,2-Dihalogen-Derivaten Oder 1,2-Halogenhydrinen aus, so werden un-ter Eliminierung Alkene erhalten. 

Dihalogen- und Trihalogen-methan-Derivate werden zu Methanen hydrodehaloge-niert. 

Dihalogen-triorgano-bismut Ag,G Triorgano-bismut Bd. XIII/8, S. 601. 

The interatomic distance values given are stated to hold for hexahalogen, rym-trihalogen and -dihalogen benzenes. We expect the distances in these different compounds to be different, however and investigation of these and other halogen compounds is under way in this Laboratory. De Laszlo has also reported values of C-Br and C-I distances in ethylenic and acetylenic compounds in a letter to Nature, 130, 474 (1936). 

Dioxygenases that are exploited at present do not provide general access to antipodal cis-diols and a combined chemoenzymatic strategy is required. While oxidation of bromobenzene (and other mono- and dihalogenated precursors) with TDO expressing cells gives the corresponding (—)-dihydrodiol in excellent... 

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