Propanone reaction with

Electrochemical reduction of a,a -dibromoketones affords the unstable cyclo-propanone, which is in equlibrium with the dipolar intermediate 22. The cyclopro-panone hemiacetal is isolated in yields of 40 - 85 % from reaction in acetonitrile and methanol at -20 °C [99], The dipolar form can be trapped in a cycloaddition process with furan [100], Reaction with acetic acid leads to the a-acetoxy-ketone.[101]. Unstable three membered heterocyclic rings are intermediate in the reduction of sulphur and phosphorus linked dibromo compounds 23. In these reactions, the heteroatom is extruded leaving ci - and trans-stilbenes as the isolated products [102,103],... 

Bupropion The synthesis of bupropion, I-3(-chlorophenyl)-2-[(I,I-dimethyIethyl)amino]-I-propanone (7.3.5), begins with the reaction of 3-chlorobenzonitriIe, with ethylmagnesium bromide to give 3-chloropropiophenone (7.3.3). Brominating this with bromine gives 3-chloro-a-bromopropiophenone (7.3.4), which on reaction with tert-butylamine gives bupropion (7.3.5) [54-58]. 

The second example was the pyruvate decarboxylase catalyzed formation of (ll )-l-hydroxy-l-phenyl-2-propanone (PAC) with benzaldehyde as substrate (Fig. 5 a) [64]. This second reaction shows one potential limitation of this method. Some compounds are too volatile for direct measurement by MALDl mass spectrometry or they do not ionize directly due to their nonpolar character. In this case, these compounds have to be derivatized prior to their measurement in order to reduce their volatihty and to introduce ionizable functions. This is, however, often very easy using well estabhshed quantitative reactions, e.g., formation of oximes from aldehydes and sugars (Fig. 5b). 

Some interesting synthetic applications have been found by Strauss for the interactions of 3,5-dinitropyridine with carbanions, as generated in situ by base-promoted CH ionization, to yield bicyclic systems by meta bridging,12 under conditions favoring a similar reaction with 1,3,5-trinitrobenzene.9 3,5-Dinitropyridine reacts with 1,3-diphenyl-2-propanone and triethylamine to give the bridged ion 76, according to Scheme 5. The reaction consists... 

Although the hydroxy group is a relatively poor leaving group, its base-catalyzed nucleophilic substitution by the mechanism shown in Scheme 69 accounts not only for the hydrogenolysis of the 3-hydroxymethylindoles, but also for their SN reactions with ethoxide ions, cyanide ions and with piperidine. Nucleophilic substitution on 2-hydroxymethyl-pyrroles is generally precluded by the faster formation of the bis(2-pyrrolyl)methanes, but the synthesis of 2-cyano-2-(2,5-dimethyl-3-pyrroIyl) propanes from 2,5-dimethylpyrrole, propanone and potassium cyanide probably results from an SN reaction of the cyanide ion upon the initially formed 3-pyrrolylcarbinol (81USP4248784). The formation of (294)... 

Propanone reacts with trichloromethane in the presence of potassium hydroxide to give 1,1,1-trichloro-2-methyl-2-propanol. What is likely to be the mechanism of this reaction What further evidence could be gained to establish the mechanism (If you do not see a possible answer, refer to Section 14-7B for helpful information.)... 

The important difference between 2-propanone and ethanol as acids is that the rate of establishment of equilibrium with 2-propanone or similar compounds where ionization involves breaking a C-H bond is very much slower than the corresponding reaction with O-H bonds. 

Propanone (acetone) vapor undergoes a photodissociation reaction with 313-nm light with somewhat less than unity. Absorption of light by 2-propanone results in the formation of an excited state that has sufficient energy to undergo cleavage of a C-C bond (the weakest bond in the molecule) and form a methyl radical and an ethanoyl radical. This is a primary photochemical reaction ... 

Production of two molecules of excited 2-propanone per molecule of 8 is not possible under the same conditions because this would correspond to a reaction with AH0 of at least 156 kcal above formation of two moles of ground-state ketone. 

This synthetic procedure, using the hydrochloride salt of the amine and sodium cyanoborohydride in methanol, seems to be quite general for ketone compounds related to 3,4-methylenedioxyphenylacetone. Not only were most of the MD-group of compounds discussed here made in this manner, but the use of phenylacetone (phenyl-2-propanone, P-2-P) itself appears to be equally effective. The reaction of butylamine hydrochloride in methanol, with phenyl-2-propanone and sodium cyanoborohydride at pH of 6, after distillation at 70-75 °C at 0.3 mm/ Hg, producedN-butylamphetamine hydrochloride (23.4 g from 16.3 g P-2-P). And, in the same manner with ethylamine hydrochloride there was produced N-ethyl-amphetamine (22.4 g from 22.1 g P-2-P) and with methy lamine hydrochloride there was produced N-methylamphetamine hydrochloride (24.6 g from 26.8 g P-2-P). The reaction with simple ammonia (as ammonium acetate) gives consistently poor yields in these reactions. 

The pyrolysis of propanone is a chain reaction with possible mechanism... 

There are several ways to accomplish this synthesis. One approach would follow the example described in eq. 11.13. Reaction of 1-phenyl-2-propanone with methylamine would give an imine. Reduction of the imine would afford methamphetamine, which would give methamphetamine hydrochloride upon reaction with HCI. 

The regioselectivity of the Paterno-Biichi reaction with acyclic enol ethers is substantially higher than with the corresponding unsymmetrically alkyl-substituted olefins. This effect was used for the synthesis of a variety of 3-alkoxyoxetanes and a series of derivatives [55]. The diastereoisomeric cis-and tnms-l-methoxy-l-butenes were used as substrates for the investigation of the spin state influence on reactivity, regio- and stereoselectivity [56]. The use of trimethylsilyloxyethene 62 as electron rich alkene is advantageous and several 1,3-anhydroapiitol derivatives such as 63 could be synthesized via photocycloaddition with l,3-diacetoxy-2-propanone 61 (Sch. 17) [57]. 

More recently, Bravo et al. [158] described the synthesis of optically pure fluoro-substituted isoxazolidines by 1,3-dipolar cycloaddition of acyclic nitrones to chiral methyl enol ethers of 3-fluoro-l-sulfinyl-2-propanones. Reaction of 191b with 200 (room temperature, 10 days) afforded only one adduct, exo(t)-... 

This compound has been obtained by oxidation of 1,1, l-trifluoro-2-propanone (Aldrich) with potassium oxomonosulfate. It is about as stable as dimethyldioxi-rane, but is markedly more reactive in oxygen transfer reactions. Thus it converts... 

Garcia eta/, studied the reaction of the homochiral (iJ)-3- -tolylsulfinyl propanone 75 with Pd(OAc)2 in acetic acid at 70 °C under nitrogen for 48 h which yielded the enantiomerically pure trimer on. o-palladated compound 76 containing a stereogenic carbon directly joined to the Pd atom (Equation 11) <1996TA139>. 

When certain jS-keto-dithioesters (87) are treated with Grignard reagents, thiophilic addition occurs and 2-hydroxycyclopropanone dithioketals (88) are produced (Scheme 35) Only one isomer is obtained and a concerted cis-homo-l,4-addition has been proposed to account for the stereospecificity observed. Along somewhat similar lines, Giusti and coworkers have synthesized several cyclopropanone ketals by treating l,3-dibromo-2-propanone ketals with active metals (Table 20). Allenes are a byproduct in this reaction. Dihaloketals may also be cyclized electrolytically (Table 21). ... 

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