The preparation of 3-(5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl)propan-1-amine 2a and 3-[(7R)-7-methyl-5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl]propan-1-amine 2b, key intermediates in the synthesis of α_Vβ₃ antagonists, is described. The syntheses rely on the efficient double Sonogashira reactions of 2,5-dibromopyridine 3 with acetylenic alcohols 4a/4b and protected propargylamines 10a−e followed by Chichibabin cyclizations of 3,3‘-pyridine-2,5-diyldipropan-1-amines 9a/9b.

中文翻译：

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方法的5,6,7,8-四氢-1,8-二氮杂萘的碎片的合成为α _V β _3个整联蛋白拮抗剂

3-（5,6,7,8-四氢-1,8-萘啶-2-基）丙-1-胺2a和3-[（7 R）-7-甲基-5,6,7的制备，8-四氢-1,8-二氮杂萘-2-基]丙-1-胺2B，在α的合成关键中间体_V β ₃拮抗剂，进行说明。合成依赖于2,5-二溴吡啶3与炔属醇4a / 4b和受保护的炔丙基胺10a - e的有效双重Sonogashira反应，然后将3,3'-吡啶-2,5-二苯基二丙烷-1-胺9a的奇奇巴宾环化/ 9b。