Abstract
Recently, new amino glycoside antibiotics having 1, 4-diaminocyclitol have been found successively. We reported that Streptomyces sannanensis KC-7038 produces sannamycins A, B and C which belonged to this group. Upon further investigation, we have isolated seven new components of sannamycin named sannamycins E [4], F[5], G [6], H [7], J[8], K [9]and L [10], and elucidated the structures of these components using chemical degradation and various spectrometric methods.
The 1H-NMR spectrum of [5] i ndicated the presence of a N-formylglycyl group, and the alkaline hydrolysis of the component gave sannamycin C. These results suggested that the structure of [5] is 2'-N-(N-formylglycyl)sannamycin C. The structure of [8] was decid ed to be 6'-N-demethyl compound of sannamycin C [ 3 ]by comparing the 1H-NMR spectrum of [8] with that of [3]. Tetra-N-acetyl compound of [6] was methanolyzed with 5.5 m ol [dm-3 methanolic hydrogen chloride to give methyl di-N-acetyl α- and β-purpurosaminides C 12] and [13] and a bis(acetylamino)cyclitol [14]. From the spectrometric data of [6] and [the N-deacetyl compound of [14], the structure of [ 6 ] was determined to be 6'-N-demethy1 4-epi-sannamycin B. The structure of [7]was determind to be 6'-N-demethyl-4-epi-sannamycin C in the same manner as described for [6]. The structure of 4 was determined to be 3-O-demethyl compound of [7] by O-demethylation of [7] with concentrated hydriodic acid. The MS and the 1H-NMR data of [9] indicated the presence of 4', 5'-unsaturated purpurosamine C, and the structure of [9] was decided to be 4', 5'-didehydro compound of [4] The structure of [10] was decided to be 4-N-demethyl compound of [4] by comparing the 1HNMR spectrum of [10] with that of [4].
