新抗生素康乐霉素Ｃ已从Ｎｏｃａｒｄｉａｍｅｄｉｔｅｒｒａｎｅｉｖａｒ．ｋａｎｇｌｅｎｓｉｓ１７４７－６４的发酵液中分离出来。它对革兰氏阳性菌有弱抗菌活性，但具有很强的免疫抑制作用。康乐霉紊Ｃ具有苯骄［ａ］惠的碳架，本文根据光谱分析和单晶Ｘ－衍射分析来阐明康乐霉素Ｃ的结构，确定为：［４ａＲ，６ａＲ，１２ａＲ，１２ｂＳ］ｏｒ［４ａＳ，６ａＳ，１２ａＳ，１２ｂＲ］－４ａ，５，６，６ａ，１２ａ，１２ｂｈｅｘａｈｙｄｒｏ－４ａ，８－ｄｉｈｙｄｒｏｘｙ－３ｍｅｔｈｙｌｂｅｎｚ（ａ）ａｎｔｈｒａｃｅｎ－１，７，１２（４Ｈ）－ｔｒｉｏｎｅ． The new antibiotic, cancinomycin C, has been obtained from Nocardia mediterraneivar. kanglensis1747-64 fermentation broth isolated. Gram-positive bacteria it has weak antibacterial activity, but has a strong immunosuppressive effect. In the case of Campylobacter C, there is a carbon rack with benzene arginine [a]. In this paper, the structure of the quinuclidine C is elucidated by spectral analysis and single crystal X-ray diffraction analysis and confirmed as [4aR, 6aR, 12aR, 12bS] 6aS, 12aS, 12bR] -4a, 5,6,6a, 12a, 12bhexahydro-4a, 8-dihydroxy-3methylbenz (a) anthracen- 1,7,12 (4H) -trione.