Water → N-carboxymethyl-N-phosphonomethyl-2,3,4-tricarboxycyclobutanecarboxamide

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Reaction Steps

To a 28.6 grams (0.03 mole) portion of the disodium salt of N-phosphonomethylglycine, prepared as described in previous examples, there is added 4.2 grams (0.015 mole) of cyclobutane-1,2,3,4-tetracarboxylic dianhydride. A pH of about 8 is maintained with periodic additions of alkali, and further anhydride, in 4.2 grams and 1.0 gram portions, are added to complete the reaction. The reaction mixture is diluted with water and passed through a column of ion exchange resin in the acid form. The second through fourth 20 ml. cuts are collected and dried to yield N-carboxymethyl-N-phosphonomethyl-2,3,4-tricarboxycyclobutanecarboxamide (in the monohydrate form) as a cream colored brittle foam. Elemental analysis gives 33.38% carbon, 3.94% hydrogen, 3.27% nitrogen and 7.31% phosphorus as against calculated values of 32.93%, 4.02%, 3.49% and 7.72% for C11H14NO12P.H2O. ##STR21##

Provenance & Evidence