N-Protected L-phenylalanines 1a,b were transformed, via the corresponding Weinreb amides 2 and ethynyl ketones 3, into chiral enamino ketones 4 (Scheme 1). Similarly, L-threonine 6 was transformed in four steps into the enamino ketone 10. Cyclocondensations of 4 and 10 with pyrazolamines 11, benzenecarboximidamide (12), and hydrazine derivatives 18 afforded N-protected 1-heteroaryl-2-phenylethanamines
通过相应的Weinreb
酰胺2和
乙炔基
酮3,将N-保护的
L-苯丙氨酸1a,b转化为手性
烯氨基
酮4(方案1)。同样,
L-苏氨酸6分四个步骤转化为
烯氨基
酮10。的Cyclocondensations 4和10与pyrazolamines 11,
苯甲(12),和
肼衍
生物18得到ñ -保护的1 -杂芳基-2- phenylethanamines 15A -e,16、17和21a – k和1-杂芳基-1-
氨基
丙烷-2-醇23a,b具有良好的收率(方案2和3)。最后,通过催化
氢化
脱保护得到游离胺22a - g和24a,b(方案3)。