Letter | Published:

A New Antiviral Agent : 4-Bromo-3-methylisothiazole-5-carboxaldehyde thiosemicarbazone, M and B 7714

Nature volume 204, page 587 (07 November 1964) | Download Citation



STIMULATED by reports of the antiviral activity of some thiosemicarbazones1, and particularly of the activity against neurovaccinia of isatin β-thiosemicarbazone2,3, we sought to enhance the activity of these compounds by structural modification. Thus we synthesized N-ethylisatin β-thiosemicarbazone independently of, but somewhat later than, Bauer and Sadler4. At the same time, we had been making a systematic study of the chemistry and chemotherapeutic properties of derivatives of the new monocyclic ring system, 1,2-thiazole (isothiazole), and we observed that 3-methylisothiazole-5-carboxaldehyde thiosemicarbazone (M and B 7453) also protected mice infected intracerebrally with neurovaccinia. The relatively high toxicity of this compound (acute LD50 = 0.7 mg/g orally in mice) led us to examine related thiosemicarbazones, one of which, 4-bromo-3-methylisothiazole-5-carboxaldehyde thiosemicarbazone (M and B 7714), is considerably less toxic (acute LD50 = 4.3 mg/g orally in mice).

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  1. Research Laboratories, May and Baker, Ltd., Dagenham, Essex.

    • R. SLACK
    • , K. R. H. WOOLDRIDGE
    • , J. A. McFADZEAN
    •  & S. SQUIRES


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