Ethyl esters with diazoethane

Diazomethane would be a reasonable candidate for simultaneous methylator of carboxylic and phenolic functions (both acidic), were it not for its reputation for erratic behavior toward phenolic groups. However, satisfactory results were reported [226] in the conversion of acids such as homovanillic to the corresponding ethyl ether-esters with diazoethane, CH CHNj. This reagent is specific for carboxylic and... 

Ethyl-3-nitrobenzoate, monoclinic prisms, mp 47°, bp 296°. It may be prepd by saturating an ale soln of the acid with.HCl gas from the acid salt of 3 nitrobenziminoethylether from the 3-nitro acid and diazoethane and from the 3-nitro benz in boiling abs ale and HC1 gas Ref Beil 9, 378, (151), (154) [248] Ethyl-4-nitrobenzoate, pltlts (from ale), mp 57°. It may.be prepd from the acid in ale in the presence of HC1, from the methyl ester and excess ale in the presence of KOCH3 Ref Beil 9, 390 [258]... 

Reaction 33 carried out in HTO/TO is also a route for the introduction of tritium into the methylene group of esters. Diazoethane readily exchanges (lmin) its 1-H with NaOD/D20 solution at 4°C. Reaction of partially deuterated CH3CDN2 with p-02NC6H4C02D gave (l-2H)-ethyl and (l,l-2H2)-ethyl 4-nitrobenzoate. 

In the absence of acid catalysis, diazomethane reacts only with carboxylic acids (pA a 4—5) and phenols (pAa 9-10), but has no influence on aliphatic OH groups. Besides CH2N2, some more complex diazocompounds (diazoethane, diazotoluene) have been recommended for the synthesis of ethyl and benzyl esters, respectively. For the synthesis of baizyl (or substituted benzyl) esters, some special reagents have also been proposed, e.g., AA -dicyclohexyl-O-benzylurea and 1 -(4-methylphenyl)-3-benzyltriazene. 

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