4- Bromo-2-butanone

Treating 5.5 g of 2-amino-4,5-dimethylthiazole HCl with 0.66 g of solid sodium hydroxide 15 min at 220°C yields 53% of 4.4. 5.5 -tetramethyT 2,2 -dithiazolylamine, whose structure w as proved by identification with the produa obtained from the reaction between dithiobiuret and 3-bromo-2-butanone (467). This result is comparable to the reaction between 2-aminopyridine and its hydrochloride to yield bis(pyridyl-2)amine (468). Gronowitz applied this reaction to 2-aminothiazole, refluxing it with its hydrochloride 4 hr in benzene and obtained the dimeric 2-aminothiazole (236). He proposed a mechanism (Scheme 143) that involves the addition of a proton to the 5-position of the ring to give 234. The carbocation formed then reacts on the 5-position of a second... 

Bromo-2-butanone was purchased from Fisher Scientific Company. The submitters prepared it according to J. R. Catch,... 

Direct alkylation of indoles under neutral conditions has been observed for especially reactive alkyl halides. 3-Methylbutenyl bromide gives the 3-substituted indole in acetic acid-sodium acetate at room temperature (equation 170) (69TL2485). At higher temperature in acidic solution, 1,2-dimethylindole undergoes bisallylation (equation 171) (67CJC2628). a-Halo ketones including bromoacetone, 3-bromo-2-butanone and 2-chlorocyclohexanone can alkylate 2-substituted indoles in aqueous acetic acid, but the acidic conditions used in these reactions would probably be destructive of indole itself (72JOC2010). 

Exercise 18-14 Explain why decarboxylation of 2,2-dimethyl-3-oxobutanoic acid, CH3C0C(CH3)2C02H, in the presence of bromine gives 3-methyl-3-bromo-2-butanone, CH3COC(CH3)2Br. 

Their more directed approach to hirsutic acid utilized 341 as starting material (Scheme 53).335 This diketo ester was the major product obtained from alkylation of the pyrrolidine enamine of340 with 3-bromo-2-butanone and aldolization in aqueous base. Reesterification with diazomethane and catalytic hydrogenation generated the cis-fused bicyclooctane nucleus. The subsequent Claisen alkylation of 342 proved to be stereoselective, affording 343 as the major product. Cyclization as before furnished 344 whose further transformations are currently being examined. 

The product can be prepared according to the general procedure of Theilig (1953) by reaction of 3-bromo-2-butanone with formamide. 

It can be synthesized by condensation of 3-bromo-2-butanone with isobutyramide following the procedure described by van Bergen and Kellogg (1972). 

It was prepared by Kurkjy and Brown (1952), with formamide, phosphorus pentasulfide and 3-bromo-2-butanone (see M.4), by Pittet and Hruza (1974) from ammonium dithiocarbamate and 3-bromo-2-butanone, according a previously described procedure. 

Butane-2-one, for example, thus gives a mixture containing 3-bromo-2-butanone as main product (see substitution rules on page 190) with some l-bromo-2-butanone, and the mixture can be separated by distillation at 150 mm through an efficient column with a reflux ratio of 6 l.681 Monobromoacetone can also be prepared in this way. 

To a solution of 0.5 mL CCI4 containing 0.0358 g 2-buten-2-yl tosylate (0.01585 mmol) cooled in an ice bath was added 0.025 g bromine (0.1585 mmol) the mixture was kept cold until the completion of the addition. Evaporation of solvent gave the crude product. The flask containing erythro-2,3-dibromo-2-butyl tosylate was added the 0.125 M buffer of formic acid-sodium formate, and the reaction was monitored to completion. Then the solution was neutralized with NaHCOs and extracted with CCI4. Removal of the solvent afforded 3-bromo-2-butanone. (Note No complete experimental procedure was given in the original literature.)... 

Bromoadenosine monophosphate, 99 3-Bromo-2-butanone-l,4-diol diethyl ketal, synthesis of, 393, 394 Bromocolchicine, 567-571 binding to brain extracts, 570,571 synthesis of, 569 Bromoconduritol, 369,370 inhibition of glucosidase, 381 synthesis of, 380, 381 a-Bromo-ft>-(3-cyanophenyl)alkane, 122 6-Bromo-6-deo conduritol B epoxide, active site labeling, 377-380 3-Bromo-l,4-dihydroxy-2-butanone 1,4-bisphosphate, 142, 392, 396, 397 synthesis of, 392-395... 

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