Diazomethane reaction with acid

An ethereal solution of diazomethane free from alcohol may be prepared as follows such a solution is required, for example, in the Amdt-Eistert reaction with acid chlorides (compare Section VI,17). In a 100 ml. longnecked distilling flask provided with a dropping funnel and an efficient downward condenser, place a solution of 6 g. of potassium hydroxide in... 

Johnson and co-workers also investigated the general acid-catalyzed diazomethane reaction with benzalacetone (20). When treated with 3 mole-equivalents of diazomethane, the latter is converted to the A -pyrazoline... 

Diazomethane, reaction with 2,4,6-tri-nitrobenzenesulfonic acid and dimethyl ether, 46,122 Diazonium xanthates, detonation of, 47, 107... 

Diazomethane is also useful for cyclopropanation reactions and for reaction with acid chlorides to produce diazo ketones. [See WolffRearrangement It can be used to generate methyl ethers and N-... 

Method 3. An ethereal solution of diazomethane free from ethanol may be prepared by this method such a solution is required, for example, in the Arndt-Eistert reaction with acid chlorides (compare Expt 5.130). In a 100-ml distilling flask provided with a dropping funnel and an efficient downward condenser, place a solution of 6 g of potassium hydroxide in 10 ml of water, 35 ml of carbitol (diethyleneglycol monoethyl ether) and 10 ml of water connect the condenser to two conical flasks in series containing 10 and 35 ml of ether respectively and cooled in an ice-salt bath (see Method 1). Heat the mixture on a water bath at 70-75 °C in a beaker of water placed upon a hot-plate incorporating a magnetic... 

Furan and thiophene undergo addition reactions with carbenes. Thus cyclopropane derivatives are obtained from these heterocycles on copper(I) bromide-catalyzed reaction with diazomethane and light-promoted reaction with diazoacetic acid ester (Scheme 41). The copper-catalyzed reaction of pyrrole with diazoacetic acid ester, however, gives a 2-substituted product (Scheme 42). 

Arndt-Eistert reaction is used to convert an acid compound into the next higher homologue by reaction with diazomethane... 

A valuable extension of the diazomethane reaction for the preparation of A-homosteroids was discovered by Johnson, Neeman and Birkeland " who found that a,j5-unsaturated ketones are homologated by reaction with diazomethane in the presence of either fluoroboric acid or boron trifluoride. The main product is formed by the insertion of a methylene group between the carbonyl group and the unsaturated a-carbon to give a / ,y-unsaturated ketone. 

Early investigators adduced various kinds of chemical evidence in support of a monohydroxy-dioxo structure for barbituric acid (112) (a) reaction with diazomethane afforded a mono-O-methyl deriva- iye,i59,i6o barbituric acid and its 5-alkyl derivatives are much stronger acids than the 5,5-dialkyl derivatives, and (c) the 5-bromo and 5,5-dibromo derivatives have different chemical properties. - The early physical evidence also appeared to substantiate the monoenol structure, this formulation having been suggested for barbituric acid in 1926 on the basis of its ultraviolet spectrum and again in 1934, In the 1940 s, ultraviolet spectroscopic studies led to the suggestion of other monohydroxy and dihydroxy structures for barbituric acid, whereas its monoanion was assigned structure 113 (a clear distinction between ionization and tautomerism was not made in these papers). 

Methylation of 1-hydroxyindoles can be achieved readily by the reaction with diazomethane, Mel, orMc2S04 in the presence of an appropriate base, as described in previous reviews (79MI1, 90AHC105, 91YGK205, 99H1157). Alkylation and acylation also work well with alkyl halides, acyl halides, acid anhydrides, and acids in the presence of acid activators such as DCC and so on. 

Because of the high polarity of the C=N double bonds, cyanuric chloride (120, R= Cl) is comparable with a carboxylic acid chloride. This explains its smooth reaction with diazomethane to yield dichloro-(diazomcthyl)-l,3,5-triazine (121, R = The analogous com-... 

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