Description Hmb protection of amide bonds has been shown to inhibit aggregation of ′difficult′ peptides, thereby leading to products of increased purity [1-6]. Retention of Hmb groups on the cleaved peptide can greatly improve the solubility of protected peptide fragments [7, 8] and otherwise intractable sequences [9-11]. Furthermore, using a Hmb protected derivative for incorporation of the residue linked to the carboxyl group of Asp or Asn residues has been found to suppress formation of aspartimide and piperidide related by-products [12-14]. For a comparison of the efficiency of Hmb and pseudoprolines in preventing aggregation, see [15].The product number for this product was previously 04-12-1134..