3-formyl-2-thiophenecarboxylic acid

    Parameter     ppm  Hz

      D(A)         7.81
      D(B)         7.57
      D(C)        10.61
       J(A,B)          5.20
       J(A,C)          0.70
       J(B,C)          0.30
     
      D(D)         9.71
     
     GRONOWITZ,S. ET AL. ARK.KEMI. 21, 265 (1963)