Amine-carboxyboranes

Trimethyl amine carboxyborane can be synthesized from the cyanoborane precursor [30353-61-8] according to equations 5 and 6 (12). 

Hall, I.H., S.Y Chen, K.G. Rajendran, A. Sood, B.E. Spielvogel, and J. Shih. 1994. Hypolipidemic, antiobesity, anti-inflammatory, anti-osteoporotic, and anti-neoplastic properties of amine carboxyboranes. Environ. Health Perspec. 102(Suppl. 7) 21-30. 

Dembitsky, V. M., Srebnik, M. Synthesis and biological activity of -aminoboronic adds, amine-carboxyboranes and their derivatives. Tetrahedron 2003, 59(5), 579-593. 

K. G. Rajendran, S. Y., Chen, A. Sood, B. F. Spielvogel, I. H. Hall, The anti-osteoporotic activity of amine-carboxyboranes in rodents, Biomed. Pharmacother., 1995, 49, 131-140. 

This carboxyborane can undergo an amine exchange reaction with Hquid ammonia (eq. 7) to yield the boron analogue of glycine, the simplest alpha-amino acid (13). There has been a great deal of work on the pharmacological activity of these amino acid analogues (14). 

The unusual structure 125 displays an acylborane group the latter was formed from carboxyborane as a complex with secondary or tertiary amines, imidazole, or pyridine derivatives. The synthetic pathway (Scheme 31) consisted in an oxidation with NBS, substitution with cyanide, then treatment with 2-aminopyridine <2004JOM3567>. 

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