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Abstract
Substituted aminomethylene-bis(phosphinates) are obtained in good yield by the interaction of substituted aminomethylenedichlorides with phosphonites or from the three component reaction consisting of a primary amine, orthoformates and the half-esters of phosphonous acids. 3-Methylpyridyl-2-amino-methylene-bis(O-ethyl-methylphosphinate) hydrolizes easily in water to give the corresponding acid in which neither of the nitrogen atoms is protonated
Amino- and alkylamino-methylene-bis(phosphonates) are obtained, in high yield, by the hydrogenolytic debenzylation of the corresponding benzyl-derivatives, using Pd/C as a catalyst. Aminomethylene-bis(phosphonate), H2NCH[P(O)(OC2H5)2]2 (7) is a water-clear liquid which can be molecularly distilled, b.p. 125–127°/0.1 Torr., 31P + 20.28 ppm, JPCH 20.5 Hz. On prolonged standing at 20°C it forms slowly a half-ester. 7 gives the typical reactions of a primary amine. Thus on treatment with dimethylformamid-dimethylacetal it yields a formamidine 10, with isocyanates it forms urea derivatives e.g. 11 and 12, and with aldehydes Schiff's bases are produced e.g. 13 to 18. The latter can be hydrogenated using Pt/C as catalyst to give monosubstituted aminomethylenediphosphonates e.g. 23 and 24. However on hydrogenation of 18 over Pt/C 7 was obtained. Thus 2-pyrrylmethyl represents a new, with H2/Pt/C, cleavageable group when bound to nitrogen.
Acylation of 7 yields the corresponding acyl-derivatives, e.g. 19 and 20, and interaction with cyanamide produces guanidinomethylene-diphosphonate 21.
