ORGANOPHOSPHORUS COMPOUNDS AS POTENTIAL FUNGICIDES. PART II. AMINOALKANE-, GUANIDINOALKANE-, AND THIOUREIDOALKANE-PHOSPHONIC ACIDS: PREPARATION, SPECTROSCOPY, AND FUNGICIDAL ACTIVITY

Abstract

A range of α-amino-, ω-amino-, α-guanidino-, and ω-guanidinoalkanephosphonic acids has been prepared for the purpose of studying their spectroscopic features and fungicidal activity. In addition, α-thioureido-octanephosphonic acid and thioureylene-1,1-bis(1-octanephosphonic acid) were isolated during the preparation of α-guanidino-octanephosphonic acid. ³¹P, ¹H, and ¹³C nmr spectral data which were obtained for solutions of the amino-and guanidino-compounds in D₂O or D₂O/D₂SO₄, and for the thioureido compounds in DMSO-d ₆, are discussed together with previously reported data for the aminophosphonic types. FAB mass spectrometry generally gives strong pseudomolecular ions [MH]⁺ for the zwitterionic amino-and guanidino-compounds with relatively simple fragmentations. Fungicidal activity of the α-aminophosphonic acids was found to be greater than for the ω-amino compounds, with maximum activity at a chain length of three carbon atoms when used as a seed dressing for the control of Drechslera spp. Moderately good activity was shown by the thioureido compounds against a number of fungal organisms in vitro but the guanidino-compounds exhibited low activity.

Key Words:

• Organophosphorus
• fungicides
• aminophosphonic acids
• guanidinophosphonic acids
• NMR spectroscopy
• FAB mass spectrometry.