7 mg 0 28 mmol of the compound 5 was dissolved in a mixture of 4 ml of pyridine with 4 ml of acetic anhydride to which 30 ml of dimethyl aminopyridine was added followed by stirring for 15 hours at room temperature the medium of the reaction solution was distilled off and the residual product was refined by a silica gel column wakogel c 300 40 g chloroform methanol 10 0 25 whereby 447 mg yield 109 of the compound 8 was obtained element analysis molecular formula c 76 h 88 o 24 n h 2 o calculated value c 64 40 h 6 40 n 0 99 measured yalue c 64 26 h 6 22 n 1 15 440 mg 0 31 mmol of the compound 8 was dissolved in 40 ml of methanol and the solution was catalytically reduced for 5 hours at room temperature by 300 mg of 10 pd c the reaction solution was then filtrated and the matrix solution was distilled off whereby 245 mg yield 91 of the compound 9 was obtained element analysis molecular formula c 34 h 52 o 24 n calculated value c 47 55 h 6 10 n 1 63 measured value c 47 03 h 5 86 n 1 88 7 ml of pyridine and 7 ml of acetic anhydride were added to 240 mg 0 28 mmol of the compound 9 so as to dissolve the latter.