abstract |
The reaction of 2,2-difluorobenzo-1,3-dioxole with (a) an alkali metal or an alkali metal compound and then (b) a compound R1-Z1 in which Z1 is a leaving group, or with an aldehyde produces compounds of formula I <IMAGE> (I) wherein R1 is -OH, -SH, -CHO, -CN, -COOH, -B(OH)2, -COX, with X being Cl or Br, or is -COOR2, -SiR32 or -B(OR2)2, with R2 being a C1-C12alcohol moiety without the hydroxy group, wherein R1 is further -CnH2nCOOR2, with n being an integer from 1 to 4, or linear or branched C1-C12hydroxyalkyl which is unsubstituted or is substituted by -F, -CN, C1-C6alkoxy, phenyl, fluorophenyl, C1-C4alkoxy-phenyl, C1-C4alkylthio-phenyl, C1-C4alkyl-phenyl, C1-C4fluoroalkyl-phenyl, nitrophenyl or by cyanophenyl, or wherein R1is a benzyl alcohol which is unsubstituted or is substituted by F, C1-C4alkoxy, C1-C4alkylthio, C1-C4alkyl, C1-C4fluoroalkyl, nitro or by cyano, or is C1-C12acyl, or wherein R1 is a radical of formula II <IMAGE> (II) wherein R5 is -CN, -CF3, -COOR2, -CONH2, -CO-NHR2 or -CONR22, R3 and R4 are a direct bond or each is H, or R3 is H and R4 independently has the meanings of R5, or R3 and R4 together are -CH2-NR6-CH2-, -CH2-NR6-CO- or -CO-NR6-CO- wherein R6 is the radical of a removable protecting group, or wherein further R1 is a radical of formula III be prepared from the compounds of formula I. 3-(2,2-difluorobenzodioxol-4-yl)-4-cyanopyrrole can be prepared by reacting 4-metallo-2,2-difluorobenzodioxole (III) with an unsaturated nitrile and then with a sulfonylmethyl isocyanide in a one-pot process. The compounds III are novel intermediates. |