2.4- Dimethylpyrrole-3-carboxylate

Pyrroles and furans also undergo the Gattermann aldehyde synthesis with HC1 and HCN, furan gives furfuraldehyde and 2-methylindole gives 2-methylindole-3-carboxaldehyde. The Houben-Hoesch ketone synthesis is also applicable to the preparation of acyl derivatives of furans and pyrroles, e.g. ethyl 2,4-dimethylpyrrole-3-carboxylate with MeCN and HC1 yields (81). 

C9H13CISi 1-chloro-4-(trinnethylsilyl)benzene 10557-71-8 479.15 41.884 1.2 17329 C9H13N02 ethyl 2,4-dimethylpyrrole-3-carboxylate 2199-51-1 564.15 50.081 1,2... 

The reactions of ethyl 2,4-dimethylpyrrole-3-carboxylate with a number of primary amines and an excess of formaldehyde lead to the formation of 2,3-dihydro-l//-imidazo[l,5-a]pyrroles. The reaction of cyclohexylamine, which, as indicated in the foregoing section, would not be expected to yield a product involving two pyrrole nuclei, does result in the formation of the dihydroimidazopyrrole in 70% yield as shown in Scheme 6. ... 

The structure of batrachotoxin was confirmed by a partial synthesis from batrachotoxinin A. This proved feasible using a mixed anhydride prepared from 2,4-dimethylpyrrole-3-carboxylic acid and ethyl chlorofor-mate (Scheme I). A variety of analogs of batrachotoxin were prepared in a similar manner. These compounds are documented in Table 4. A dihydro-batrachotoxin was prepared by sodium borohydride reduction (Scheme II) and apparently is subject to allylic rearrangement to other dihydroproducts 251). 

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