5-Aryl-2-halogen

Nuclear halogen atoms also show many of the reactions typical of aryl halogens, (i) They can be replaced with hydrogen atoms by catalytic (Pd, Ni, etc.) or chemical reduction (HI or Zn/H2S04). For example, halogenopyrazoles with HI and red phosphorus at 150 °C... 

In these compounds the following substituents can be present alkyl,alkenyl,aryl, halogen,sulfonic acid, amino, hydroxyalkyl, acyl, and carboxyl. The cleavages of 5,5 - (109) and 3,5 -diisoxazolyl (111) proceed similarly both isoxazole rings are cleaved in the former (109—> 110). ... 

Bei der Reduktion von Chinonen mit N,N-Diathyl-hydroxylamin in Essigsaure-athylester zu Hydrochinonen werden weder Aryl-, Halogen- noeh Azo-Gruppen angegrif-fen (s.Bd. VII/3a, S. 650). 

A wide range of carbon-carbon double bonds undergo chain polymerization. Table 3-1 shows monomers with alkyl, alkenyl, aryl, halogen, alkoxy, ester, amide, nitrile, and heterocyclic substituents on the alkene double bond. 

M = metal R4 = alkyl, aryl, halogen, trialkyltin, etc. Y = acetate, sulfonate, etc. 

Allenes have the 1,2-diene structure (I), where R1, R2, R3, R4 = H, alkyl, aryl, halogen, heterocyclic, ether, etc. Since the terminal methylene groups lie... 

Nuclear halogen atoms also show many of the reactions typical of aryl halogens. 

Phosphorinanes (1), R being H, alkyl, aryl, halogen, OR, NR2 and others, are known. Like open chained P compounds of CN = 3, most of these compounds are air sensitive and non-crystalline. The six-membered ring is nearly always in a chair conformation. Both structures (la) and (lb) are possible, R being axial (a) or equatorial (e). 

Reaction XLIV. (b) Condensation of Alkyl and Aryl Halogen Compounds with the Sodio- and other Metallo-derivatives of Ethyl Aceto-acetate and its Homolognes. (A., 186, 214 201, 143 213, 143.)—Like malonic ester, acetoacetic ester contains two 1 3-carbonyl groups with a methylene group in position 2. It is only to be expected then that it yields with metallic sodium or sodium alcoholate sodio-derivatives from which mono- and di-, alkyl and aryl homologues can be obtained by treatment with a suitable halide, including halogen esters. Acetoacetic acid... 

This cyclization is a reaction developed by Mori, who carried out a series of investigations with tin reagent 33. Fluoride is a much more reactive anion for initiation than any of the other halides, although it often leads to decomposition of the starting materials. In the case of vinylic or aryl halogen compounds the iodides are easier to transform than the bromides, and chlorides are unrcactive. The carbonyl group can be derived from either an aldehyde or a ketone, and even esters are sufficiently electrophilic.22... 

Structures of compounds in entries 16-20 are all based on the type (LXXXII), in which R1 and R2 can be alkyl, aryl, halogen, a metal carbonyl group, or part of a cyclic system. 

R e = alkyl, alkoxy, thioether, ester amino, aryl, halogen etc. 

J. A. Lindley, Copper Assisted Nucleophilic Substitution of Aryl Halogen, Tetrahedron 1984, 40, 1433. 

J. A. Lindley, Copper Assisted Nucleophilic Substitution of Aryl Halogen, Tetrahedron 1984, 40, 1433. J. S. Sawyer, Recent Advances in Diaryl Ether Synthesis, Tetrahedron 2000, 56, 5045- 5065. 

D. Alkyl/Aryl Halogen Exchange with Dihalogens or Hypohalites. 551... 

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