Acetone as reagent

Acetoacetic ester s. y -Keto-carboxylic acid esters C-Acetoacetylation with diketene 24,708 N-Acetoacetylation with diketene 24, 334, 708 Acetone as reagent (s. a. under Sensitizers) 22, 324 Acetonitrile... 

The acetone test reagent consists of a 0 1 per cent, solution of 2 4-dinitro-phenylhydrazine and is prepared as follows Dissolve 0-25 g. of 2 4-dinitrophenyl-hydrazine in 60 ml. of water and 42 ml. of concentrated hydrochloric acid by warming on a water bath cool the clear yellow solution and dilute to 250 ml. with water. The acetone test is considered negative when 5 ml. of the reagent and 4-5 drops of the distillate give no cloudiness or precipitate of acetone 2 4-dinitro-phenylhydrazone within 30 seconds. After a negative test is obtained, it is stron y recommended that the mixture in the flask be refluxed for 5-10 minutes with complete condensation and then to collect a few drops of distillate for another test. If no acetone is now detected, the reduction is complete. 

Selective oxidation of secondary alcohols to ketones is usually performed with CrOj/HjSO, I I in acetone (Jones reagent) or with CrOjPyj (Collin s reagent) in the presence of acid-sensitive groups (H.G. Bosche, 1975 C. Djerassi, 1956 W.S. Allen, 1954). As mentioned above, a,)S-unsaturated secondary alcohols are selectively oxidized by MnOj (D.G. Lee, 1969 D. Arndt, 1975) or by DDQ (D. Walker, 1967 H.H. Stechl, 1975). 

Procedure. Prepare a 0.25 per cent solution of diphenylcarbazide in 50 per cent acetone as required. The test solution may contain from 0.2 to 0.5 part per million of chromate. To about 15 mL of this solution add sufficient 3M sulphuric acid to make the concentration about 0.1M when subsequently diluted to 25 mL, add 1 mL of the diphenylcarbazide reagent and make up to 25 mL with water. Match the colour produced against standards prepared from 0.0002M potassium dichromate solution. A green filter having the transmission maximum at about 540 nm may be used. 

A simple, high-yield procedure for the conversion of ArTlXj into ArjTlX compounds has recently been described 90). This symmetrization reaction, the mechanism of which is not known, can be effected by treatment of the ArTlX2 compound either with triethyl phosphite or with hot aqueous acetone. As a wide variety of ArTlXj compounds can now be easily prepared by electrophilic thallation of aromatic substrates with thallium(III) trifluoroacetate (q. v.), symmetrization represents the method of choice for the preparation of the majority of ArjTlX compounds. Only about twenty mixed compounds, RR TIX, have been prepared so far, and the only general synthetic procedure available consists of a disproportionation reaction between an RTIX2 species and another organometallic reagent [e.g., Eqs. (5)-(7)]. 

It has been known for a long time that polynitroaromatic compounds produce colored products in contact with aUcafis [1]. These color reactions have been extensively used for the identification of nitroaromatic explosives. In the Janowski reaction [7], a solution of the polynitroaromatic compound (di- or trinitroaromatic) in acetone is treated with concentrated aqueous KOH solution. 1,3,5-Trinitrobenzene (TNB) and 2,4,6-trinitrotoluene (TNT), treated with 30% aqueous KOH, produced violet-red and red colors, respectively. Many variations of the Janowski reaction were reported, using KOH or NaOH in aqueous or ethanoHc solutions as reagents, and dissolving the explosives in acetone, ethanol or acetone-ethanol mixture [3,8]. The reaction was used both for spot tests and for spraying TLC plates [9]. 

Phenol is the major source of Bakelite and phenol resins, which are utihzed in many commodities worldwide phenol is also used as reagent for syntheses of dyes, medicines and so on. The industrial demand for phenol has increased every year and its production now exceeds 7.2 megaton year 94% of the worldwide production of phenol is processed in the cumene process. The cumene process involves the reaction of benzene with propene on acid catalysts like MCM-22, followed by auto-oxidation of the obtained cumene to form explosive cumene hydroperoxide and, finally, decomposition of the cumene hydroperoxide to phenol and acetone in sulfuric acid (Scheme 10.3) [73],... 

Irreversible Transesterification. A new preparation of chiral glycerol acetonide (2,2-dimethyl-l,3-dioxolane-4-methanol) involving an enantioselective hydrolysis of 2-0-benzylycerol diacetate to the (R)-monoacetate catalyzed by a lipoprotein lipase (47) has recently been developed. In an effort to prepare the (S)-enantiomer, we have used the aforementioned irreversible transesterification reaction using isopropenyl acetate as an acylating reagent, which upon reaction gives acetone as a... 

The compound in which the 3-keto group is reduced to a hydrocarbon interestingly still acts as an orally active progestin. The preparation of this compound starts with the hydrolysis of dihydrobenzene (13-2) to afford 19-nortestosterone (15-1). Reaction with ethane-1,2-thiol in the presence of catalytic acid leads to the cyclic thioacetal (15-2). Treatment of this intermediate with Raney nickel in the presence of alcohol leads to the reduced desulfurized derivative (15-3). The alcohol at 17 is then oxidized by any of several methods, such as chromic acid in acetone (Jones reagent), and the resulting ketone (15-4) treated with hthium acetylide. There is thus obtained the progestin lynestrol (15-5) [18]. 

Nitromethane anion gives the corresponding N-allyl-3-(2-nitro-ethyl)- 2,3-dihydro-1-H-indole in 60% yield after photostimulated reaction with the bromide analogue, and in the presence of the enolate ion and acetone as an entrainment reagent (Scheme 10.51) [67]. 

Carbon-carbon bond formation is one of the oldest and most important topics of organic chemistry, and for a long time has been dominated by Friedel-Crafts and Grignard reactions. The former are based on stabilized carbocations as reagents and are exemplified by benzene alkylation (Equation 1), while the latter involve stabilized carbanions and are exemplified by acetone alkylation (Equation 2). 

Example 12.1 Poly (methyl methacrylate) is used in the manufacture of resins and plastics. The traditional synthesis of the monomer, methyl methacrylate, uses acetone and hydrogen cyanide as reagents, followed by the acidic hydrolysis and esterification of the nitrile group, as shown below ... 

The reduction of an aldehyde or ketone by this equilibrium reaction is readily accomplished by removal of the acetone as it is formed. In are-view of the literature to 1943, experimental conditions and limitations of the reaction have been discussed. Aluminum isopropoxide is superior to other metallic alkoxides that have been used. Yields are better, and the technique for determining the completion of the reaction is simpler. Procedures for the preparation of the reagent are described. A solution made by dissolving amalgamated aluminum in isopropyl alcohol is used directly, or the aluminum isopropoxide is purified by distillation. Best results are obtained when molecular amounts of the alkoxide are used. 

The concentration of formaldehyde in the chamber air is determined spectrophotometrically after sampling in bottles. Chromotropic acid (j or acetyl-acetone (i) were used as reagents Acetylacetone reacts more specific with formaldehyde but the reaction requires a higher temperature to be quantitive. 

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