360ChemInform Abstract The structure of the title compound, the major component of the calichemicin complex (isolated from Micromonospora echinospora ssp. calichensis and known as LL-E33288 antibiotics) is investigated in part by chemical (derivatization, degradations etc.) and physical methods. It can be shown that the title compound consists of four glycosidic units, a hexasubstituted benzene moiety and an undefined C18H16NO4S3 unit. The exact configuration of the ethylamino sugar is unknown. In the following paper the structure of the undefined aglycone is reported.

361ChemInform Abstract Further chemical and physical investigations on the structure of the title compound, in addition to the results of the preceding paper, establish its complete structure as (I).

No abstract

Culture LL-F42248, preliminarily identified as an unusual Streptomyces species, was found to produce the novel antibiotic 1, designated LL-F42248a. This compound, which is related to the coproduced pyrrolomycin C (2)i:) is the first tricyclic member of this family and is the only chiral pyrrolomycin reported to date.2) The culture was grown in a 30-liter tank fer

The nitro group of dioxapyrrolomycin (1) was shown to be introduced via direct biochemical nitration in cultures of the producing organism Streptomyces fumanus containing K'5N'803 as the sole source of nitrogen; the nitro group of dioxapyrrolomycin produced under these conditions contained the same ratio of 1 8 0 to 15N as was present in the labelled nitrate precursor, the extent of 1 8 0 enrichment of the nitro group being determined by negative electron impact mass spectrometry and 15N n.m.r. spectroscopy. 353

271ChemInform Abstract The reactions of the new (malonato)-Pt(II) complexes (III) with various amines (trans-1,2-cyclohexanediamine, 2,2-dimethyl-1,3-propanediamine, tetrahydro-4H-pyran-4,4-dimethanamine, cyclohexylamine, propylamine, benzylamine) lead to a new general synthesis of antitumor sym. and dissym. (malonato)-Pt(II) complexes of the type (V) and (X). Reaction of (IIIa) with trans-(-)-1,2-cyclohexanediamine (IV) is studied in detail. Structures of the intermediate (VI)•13 H2O (space group P1, Z=1), formed at 40 rc C and isolated with 90% yield, and of the end product (Va)•H2O (C2, Z=4), obtained from (VI) in 80% yield (H2O, 100 rc C), are determined.

The proton NMR spectra of a series of tetraaryl‐3,7‐diazabicyclo[3.3.1]nonanes, 5–12, have been assigned with the aid of nuclear Overhauser difference spectroscopy. The NOE's together with spin lattice relaxation times have been used to show that these molecules adopt the chair‐boat conformation with all aryl groups being equatorial. This conformation and the torsional angles of the aryl groups are similar to those found in the solid state. Analogous studies have been carried out with tetra‐ and pentaaryl‐1,3‐diazaadamantanes, 3, 4, 13, and 14. A surprisingly low barrier of rotation (4b: δG 298≠ = 42 kJ. mol−1) has been found for the two 1,3‐diaxially oriented aryl groups in these systems. Carbon‐13 chemical shift data are reported for the above compounds. Those of the 3,7‐diazabicyclononanes 5–12 are found to be consistent with the proposed chair‐boat conformation. Nitrogen‐15 chemical shift data and 13C‐15N coupling constants are also in accord with this conformation. A stereoselective reduction of 4,8,9,10‐tetrakis(3,5‐dimethylphenyl)‐1,3‐diaza‐6‐adamantanone (4b) to the corresponding alcohol 15 and the ready acidcatalyzed rearrangement of this alcohol to 16, the first example of the 9‐oxa‐1,5‐diazatricyclo‐[5.3.1.03,8]undecane ring system, is described.

The synthesis, stability, and antitumor activity of a series of water-soluble third generation platinum(II) complexes have been described. Among these complexes, [2,2-bis(aminomethyl)-1,3- propanediol-N,N'] [1,1-cyclobutanedicarboxylato(2-)-O,O']platinum(II) and [1,1-cyclobutanedicarboxylate(2-)-O,O'](tetrahydro-4H-pyran-4,4- dimethanamine-N,N'-)platinum(II) have shown the greatest promise for further investigation and are currently under clinical evaluation.