PROOF OF FERMAT'S LAST THEOREM FOR ALL PRIME EXPONENTS LESS THAN 4002

Novel 4-hydroxy-2-benzimidazoline-thione compound of the formula: wherein R is lower alkyl; R1 and R2, which can be the same or different, are hydrogen or lower straight-chained or branched alkyl or R1 and R2 together represent alkylene; and R3 is a hydrogen atom or an acyl radical; and the pharmacologically acceptable salts thereof; have marked beta -receptor blocking action and are outstandingly useful in the treatment or prophylaxis of cardiac and circulatory diseases.