Thionyl bromide, reaction with

The 3 -bromo-2 ,3 -dideoxydidehydrouridine derivative (70) has been prepared as indicated briefly in Scheme 10. The thionyl bromide reaction also gave some of the 2 -bromo-2. 3 -dideoxy-3 -phenylselenyl product with D-xy/o-configuration, which on elimination gave the 2 -bromoalkene. 0... 

Both reactants m the Williamson ether synthesis usually originate m alcohol pre cursors Sodium and potassium alkoxides are prepared by reaction of an alcohol with the appropriate metal and alkyl halides are most commonly made from alcohols by reaction with a hydrogen halide (Section 4 7) thionyl chloride (Section 4 13) or phosphorus tri bromide (Section 4 13) Alternatively alkyl p toluenesulfonates may be used m place of alkyl halides alkyl p toluenesulfonates are also prepared from alcohols as their imme diate precursors (Section 8 14)... 

Chemical Properties. Thionyl chloride chemistry has been reviewed (169—173). Significant inorganic reactions of thionyl chloride include its reactions with sulfur trioxide to form pyrosulfuryl chloride and with hydrogen bromide to form thionyl bromide [507-16-4]. With many metal oxides it forms the corresponding metal chloride plus sulfur dioxide and therefore affords a convenient means for preparing anhydrous metal chlorides. 

Acid chlorides are prepared from carboxylic acids by reaction with thionyl chloride (SOCl2), as we saw in the previous section. Similar reaction of a carboxylic acid with phosphorus tribromide (PB ) yields the acid bromide. 

Thiocarbonyl tetrachloride, 46, 21 m Thiocresol (Warning), 47, 107 Thionyl chloride, 46, 16 98 Thiophosgene 46, 21 Thiophosphoryl chloride, reaction with methylmagnesium bromide to i lelci tetramethylbiphosphine disulhdc 46,102... 

Radical phthalocyanine species, e.g. 6, can be prepared by the reaction of thionyl chloride or thionyl bromide with metal phthalocyanines. In these cases, the phthalocyanine ligand only carries the charge — l.349... 

In contrast to uridine,389 cytidine does not yield a 5 -chloro-5 -deoxy derivative on reaction with N,N-dimethyl(chlorometh-animinium) chloride instead 2,2 -anhydrocytidine is formed.395 However, thionyl chloride or bromide in hexamethylphosphor-amide at room temperature achieves this selective replacement of the primary hydroxyl group of halogen in cytidine, and also in adenosine, in respective yields of 80 and 75% for the chloro compounds, and 55 and 30% for the bromo analogs.396... 

In 1963, an asymmetric synthesis of chloroallenes was reported by the SNi reaction of propargyl alcohols with thionyl chloride [34]. Since then, rearrangement of pro-pargylic precursors has been one of the most useful methodologies for the synthesis of allenes [35]. Treatment of 84, obtained by asymmetric reduction with LiAlH4-Dar-von alcohol complex, with thionyl bromide gave 86 as the major product via 85 (Scheme 4.21) [36],... 

Thiocarbonyl tetrachloride, i6, 21 Thionyl chloride, 45, 16, 98 Thiophosgene, 45, 21 Thiophosphoryl chloride, reaction with methylmagnesium bromide to yield tetramethylbiphosphine disulfide, 45,102 Toluenesulfonybromide, 46, 88 Trichloroacetyl fluoride, 46, 6 1,1,3-Trichloiio- -nonane, 46,104 Tricyclo[2.2.1.0 ]heptan-3-ol, 45,... 

Butoconazole Bntoconazole, l-[4-(4-chlorophenyl)-2-[(2,6-dichlorophenyl)thio]butyl]-IH-imidazole (35.2.12), is synthesized from 4-chlorobenzylmagnesium bromide, which is reacted with epichloridrine to make 4-(4 -chlorophenyl)-l-chlorobutan-2-ol (35.2.10), which is reacted with imidazole in the presence of sodium to make 4-(4 -chlorophenyl)-l-(lH-imidazolyl)butanol-2 (35.2.11). The hydroxyl group in the last is replaced with a chlorine atom npon reaction with thionyl chloride, which is then by the reaction with 2,6-dichlorothiophenol bntoconazole [27,28], is obtained. 

Selective chlorination or bromination of the 5 -hydroxyl group in unprotected D-ribonucleosides has been achieved75 by treatment with thionyl chloride or thionyl bromide, respectively, in hexamethyl-phosphoric triamide at room temperature for 10-15 hours the 5 -deoxy-5 -halogeno derivatives of cytidine and adenosine have been prepared in this way. The reactions presumably occur by way of alkoxyphosphonium salts as intermediates.78... 

The addition of hydrogen bromide and sulfur dioxide to phenylpropiolic acid (210) in diethyl ether at -50 °C is reported to give 3-bromobenzo[6]thiophene-2-carboxylic acid (211) (75ZOR1776). If hydrogen bromide and sulfur dioxide can react under these conditions to give thionyl bromide, the reaction is similar to the reaction of thionyl chloride with unsaturated acids, reported in the previous section. 

IV-Sulfinylbenzamide, produced by the reaction of benzamide and thionyl chloride, reacts with styrene oxide in the presence of tetraethylammonium bromide to give the 1,4,3,5-oxathiadiazepine (616) as the major product (71BCJ2836). 

Alcohols can be converted to alkyl halides by reaction with thionyl chloride, SOCI phosphorous trichloride, PCI phosphorous pen-tachloride, PCI or phosphorous tribromide, PBr3. For example, ethyl chloride or ethyl bromide can be prepared from ethyl alcohol via reactions with sulfur and phosphorous halides. 

Cyanogen bromide reacts with threo- 2-piperidyl carbinol (278) to form the trans imine (279). The latter is also formed from the erythro 1-carbamate (280) using thionyl chloride for the cyclodehydration reaction. The latter reaction therefore proceeds by inversion of the configuration at the carbinol carbon atom (73AP284). 

Thionyl bromide can be prepared by the reaction of SOCl2 with HBr at low temperatures. 

II, 2.4]-triazin-3(2/y)-one (151, R = Me, R = H) (70JHCI23I). Similarly, 150 (R = Me) reacts with a-cyanobenzyl p-toluene sulfonate lPhCH(CN)OTS] or a-cyanobenzyl bromide PhCH(CN)Br] to afford 151 (R = Me, R = Ph) (7IJHC62I). Structure 151 was proved by its reduction with diborane to 152, which was also obtained by an independent synthesis involving the reaction of 153 with thionyl chloride followed by base-catalyzed cyclization (70JHCI231 71JHC621). To ascertain whether the methyl group at the I-position in 150 (R = Me) influences the direction of cyclization, the thione 150 (R = H) was allowed to condense with a-cyanobenzyl-p-toluene sulfonate and ethyl a-bromophenylacetate. In both cases 151 (R = H, R = Ph) was obtained. Compound 150, however, on reaction with 1,2-dibromoethane, furnished another bicyclic system (154). The difference in the behavior of 150 toward dibromoethane and other reagents such as ethyl bromoacetate and a-cyanobenzyl p-toluene... 

Halogenated ribomdeosides Ribonucleosides can be converted convetiieatly into 5 -chlorinated and 5 -brominated ribonucleosides by reaction with either tiionyl chloride or thionyl bromide in combination with HMPT, For example,, 5 -chl(>ro-5 -desoxycytidine (1) and 5 -bromo-5 -desoxyadcno,sine (2) have been prepared ir. satisfactory yields in this way. 

Reactions with thionyl chloride and acetyl chloride have been described (838). f This reaction with phosphoryl bromide. 

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