Compounds of the formula
wherein:
R₁ is cyano or nitro;
R₂ and R₃ are independently hydrogen or lower alkyl; and
R₄ is alkyl; alkenyl; optionally substituted phenyl or phenyl lower alkyl; -(CH₂)mOR₂ or -(CH₂)mN(R₂)₂; wherein m is an integer of 1-5 and R₂ is as defined above;
or a pharmaceutically acceptable ester or acid addition salt thereof;
are smooth muscle relaxants, particularly useful in the treatment of hypertension.
immunomodulating properties of this family of compounds we initiated a medicinal chemistry program aimed at finding novel prodigiosin derivatives with improved immunosuppressive activity and lower toxicity. Utilizing an unprecedented and flexible way of assembling the prodigiosin frame, a number of new derivatives have been prepared and tested leading to the choice of 4-benzyloxy-5-[(5-undecyl-2H-p