Substd. thiophenes prepn. by dehydrogenation - of dihydrothiophenes or disulphido-bis-dihydrothiophenes, using halogen (cpds.)

摘要

Prepn. of thiophenes of formula involves (i) dehydrogenation of dihydrothiophenes of formula (II) by means of phosphoric acid chloride or bromide SO2Cl2, SO2Br2, Cl2, Br2, I2, or R10 -CO-N(X)-R9 or (ii) dehydrogenation of disulphido-(3,3')-bis-(dihydrothiophenes) of formula (III): or of dihydrothiophenes of formula (IV) by means of SO2Cl, SO2Br2 or Cl2. In the formula R1 is a gap. (V):- R3-O-, R3-S-, r3-2N-, R3-SO3-, R3-CO-S- or R3-CO-O-; R2 is -CO-OR3, -CN, -CO-NR32 or -CO-R4; R3 and R4 are (cyclo)aliphatic, araliphatic or aromatic gps, and R3 may also be H; R1 and R2 may also together form a gp. R5 is H; R6 is -N-R8, -O-, or -S-; R7 is a (cyclo)aliphatic araliphatic or aromatic gp., or R5 and R7 may form, with the 2 adjacent C atoms, part of an aromatic residue; R8 is H or an aliphatic gp.; R9 is H or -CO-R10-R10 is an (ar)aliphatic or aromatic gp., or 2 R10 gps. may form together a -CO-R11 or -NX-C(R3)2-CO- gp.; R11 is an alkylene gp.; R12 has the same meaning as R1; R13 has the same meaning as R12 or when R12 is (V), R13 may be a gp.: X is Cl or Br; and n = 0 or 1.