Total synthesis of modified ellipticines 1c and 1f is described from 2-chloronicotinic acid and respectively 5-methoxy -indole and 5-azaindole in 11 to 13 steps with overall yields of 11% and 18%. A new route to 5-azaindole has also been developed. The synthetic strategy calls for frequent use of homo- and hetero aromatic metallation reactions necessiting resolution of problems associated with the presence of the pyridine ring. With respect to the numerous synthesis described in the litterature, the originality of this approach resides above all in the formation of ring C in basic medium.1 such conditions being dictated by the presence of the pyridine A ring in the case of 1f. Both synthesis have been extrapolated to produce several kilogrammes of final product. That first part deals with the preparation of the precursors.
Dormoy, Jean-Robert,Heymes, Alain
p. 2885 - 2914
(2007/10/02)
1H-pyrrolo [3,2-c]pyrrolidines protected in 1-position useful as intermediates
The invention relates to a process for fixing an electrophilic group in the 2-position of 1H-pyrrolo[3,2-c]pyridine N-protected in the 1-position, process which consists in protecting the 1-position in question with a labile protecting group, reacting the compound so obtained with a lithiation agent selected from a lithium amide and an alkyl lithium at a temperature between -80° C. and -20° C. and in the presence of tetramethylethylenediamine to obtain the corresponding 2-lithio derivative and then condensing the metal derivative so obtained at a temperature between -80° C. and room-temperature with a reagent capable of giving rise to an electrophilic group to form N-protected 1H-pyrrolo[3,2-c]pyridine substituted in the 2-position by an electrophilic group.
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(2008/06/13)
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