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Sir: A new antibiotic, leucinostatin, was isolated from the culture filtrate of Paecilomyces lilacinus A-267. The peptide antibiotic has antitumor activity on Ehrlich solid carcinoma, antimicrobial activity against Gram-positive bacteria and a wide range of fungi.1) Leucinostatin was found to be a mixture of several components which were separated by alumina column chromatography to give mainly leucinostatins A and B. In this communication we describe the properties of leucinostatin A and the structure elucidation of one of its components, a novel amino acid. Leucinostatin A (1), mp 98-101°C; [a]D -11 .0° (c 0.1, MeOH); max (EtOH) 202 and 220 (sh) nm; vmas (CHCI,) 3280, 1705, and 1645 cm-1, has the molecular formula C62H111N11O13 confirmed by field desorption mass spectrometry [m/z 1218 (MH+)]. The 1H and 13C NMR spectra of 1 exhibited the presence of an N,Ndimethylamino moiety (oH 2.37, s), a 2•-monosubstituted a,9-unsaturated amide (oH 6.19, d, J=16 Hz, and 5, 120.9, d; ox 6.86, dd, J=16 and 8 Hz, and o, 150.6, d), a ketone (oc 211.0, s), and amides (5c 160 ~ 180, about 8 Xs). Leucinostatin A gives no reaction with ninhydrin, but a positive Dragendorff reaction. These data indicated that 1 is a basic peptide antibiotic. Acid hydrolysis of leucinostatin A with 6 N HCI (110°C, 20 hours) followed by chromatography on a cellulose column (BuOH AcOH H,O, 4: 1: 2) afforded an unidentified amino acid (2) as well as other amino acids; L-leucine, Lthreo(3 -hydroxyleucine,2) cis4 -methylL -proline,8) a-aminoisobutyric acid, (3-alanine, and (S)N 1, N 1-d imethylpropane-1, 2-d iamine. The amino acid (2) gave a faint-yellow color with ninhydrin. Recrystallization from CHCl3 acetone gave the pure amino acid (2), colorless prisms, mp 197~199°C (decomp.); [a]D +8.9° (c 0.09, MeOH); FDMS m/z 214 (MH+). The IR spectrum shows absorptions at 3300-2400, 1718 (ketone), and 1630 cm-1 (carboxylate). The 400 MHz 1H NMR spectrum (Fig. 1) consists of a series of well resolved peaks, which allow the assignment of all the hydrogens. Their coupling partners were assigned by proton spindecoupling experiments and the results are summarized in the Table 1. The unusually low chemical shift for C-6-H is probably due, in part, to the protonated nitrogen atom next to C-6. The equatorial protons at C-3 and C-5 were confirmed by the observation of Wletter long range coupling. Thus, irradiation of the signal at 0 1.72 leads the signal at o 2.20 to a clean splitting (ddd, J=14.4, 3.7, and 3.4 Hz). On the basis of these results, the structure of the unidentified amino acid is that of 4-methyl-6(2 oxobutyl) 2 piperidinecarboxylic acid (2). The substituents at C-2 and C-4 could be assigned to be as equatorial and that at C-6 as axial.

journal of antibiotics

Isolation of leucinostatin A and one of its constituents, the new amino acid, 4-methyl-6-(2-oxobutyl)-2-piperidinecarboxylic acid, from Paecilomyces lilacinus A-267.