Ethyl 2-cyano-2-propylvalerate → HCID 11218176, compound

Participants

Reaction Steps

The synthesis of this compound, which can also be called di-n-propylglycine ethyl ester, was later optimized (P. M. Hardy, l. N. Lingham, Int. J. Peptide Protein Res. 21, 392-405 (1983)). The synthesis of ethyl 2,2-di-n-propylcyanoacetate 2 gave a yield of 81%, while the subsequent reaction to give the 2,2-di-n-propylmalonic acid monoamide ethyl ester 3 gave a yield of 82%. Following further reaction with bromine and NaOH in CHCl3 at low temperature, the N-bromoamide 4 was not isolated, but, following treatment with a 4-fold excess of sodium hydroxide solution, the corresponding isocyanate 6 in a distillative yield of 81% was obtained. The latter was then refluxed with an excess of 3M HCl. Subsequent alkalinization with sodium hydroxide solution gave the amino ester 5 in a yield of 87%. The overall yield of this synthesis was about 47% starting from cyanoacetic ester 1.

Provenance & Evidence