1,7-Dibromoheptane was used to alkylate both ketoesters 2 and 4 successively. Hydrolysis and decarboxylation of the resulting intermediate afforded the ethylenic diketone (6). Ozonolysis of the double bond of 6 gave the diketonic aldehyde (8). Alkaline condensation of nitroethane on the aldehydic carbonyl of the latter, followed by hydrogenation using a Pd–Pt catalyst, afforded 3-r-hydroxy-6-c-(10
                                    使用 
1,7-二溴庚烷依次将
酮酯 2 和 4 烷基化。所得中间体的
水解和脱羧得到烯属二酮(6)。6 的双键
臭氧分解得到二酮醛 (8)。
硝基乙烷在后者的醛羰基上进行碱缩合,然后使用 Pd-Pt 催化剂氢化,得到 3-r-hydroxy-6-c-(10-oxododecyl)-2-c-methylpiperidine [(±)-prosafrinine ] (1a) 和 (±)-3-epirosafrinine (1b)。1a、1b 和一些类似物的结构由 13C NMR 研究证实。