Heterocyclic derivatives
 This invention relates to heterocyclic derivatives useful for treating or preventing testosteron 5.alpha.-reductase mediated diseases such as alopecia, ache, prostatism and the like, which can be represented by the following formula: ##STR1## to a process for their production, to a pharmaceutical composition containing the same and to uses thereof. 
Fujisawa Pharmaceutical Co., Ltd.
A Y A C A A
A61P Y02P A61P C07D A61P A61P
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Satoshi Akio Kozo Shinya Hirokazu
Okada Kuroda Sawada Watanabe Tanaka