Synthesis of tetrazole ribonucleosides and their evaluation as antiviral agents. 2. 5-Amino-1-(beta-D-ribofuranosyl)-1H-tetrazole and 5-amino-2-(beta-D-ribofuranosyl)-2H-tetrazole.

Synthesis of 5-amino-1-(beta-D-ribofuranosyl)-1H-tetrazole and 5-amino-2-(beta-D-ribofuranosyl)-2H-tetrazole is described. X-Ray crystallography was first used to establish the stereochemical configuration of the two isomers. By conducting 13C NMR analysis on these isomers with known structures, i.e., N1beta, a correlation is developed for determining the N-ribosyl attachment site of tetrazole ribonucleosides. Results are also presented on antiviral testing of these synthetic 5-aminotetrazole ribonucleosides against influenza A2/Asian/J305 virus infection in mice.

A dopamine receptor model and its application in the design of a new class of rigid pyrrolo[2,3-g]isoquinoline antipsychotics.

A hypothetical model of the interaction of antipsychotic drugs with the dopamine receptor is described. This three-dimensional molecular model has been developed on the basis of plausible intermolecular interactions between pharmacophoric groups of diverse types of antipsychotic drugs and postulated amino acid side chain substituents of the receptor protein. Three essential binding sites (one possibly required for antagonism) and one lipophilic auxiliary binding site are identified. The geometry is defined via the three-dimensional structures of drugs exhibiting receptor activity, including (R)-apomorphine, (+)-dexclamol, and molindone (whose crystal structure has been determined). A new conformationally rigid pyrrolo[2,3-g]isoquinoline derivative has been designed to conform to the receptor model. The compound (+/-)-1 (2,6-dimethyl-3-ethyl-4,4a,5,6,7,8,8a,9-octahydro-4a,8a-trans-1H-pyrrolo[2,3-g] isoquinolin-4-one; Ro 22-1319) exhibits potent antipsychotic-like activity. The activity is stereospecific, residing in the (-) enantiomer, predicted and confirmed by X-ray crystal structure analysis of (-)-1.HCl to have the 4aR,8aR absolute configuration.

Synthesis of tetrazole ribonucleosides and their evaluation as antiviral agents.

Synthesis of 1-beta-D-ribofuranosyltetrazole and two 5-substituted derivatives, i.e., the 5-carboxamide and 5-acetamide, is described. The stereochemical structure of the parent tetrazole ribonucleoside has been established by means of nuclear Overhauser effect and x-ray crystallography. By analogy to the parent compound, the two 5-substituted tetrazole nucleosides are also assigned the beta configuration on the basis of the NMR coupling constant of the anomeric proton and the site of N-ribosylation is determined by 13C NMR studies. Results are also presented on antiviral testing of these synthetic tetrazole nucleosides against influenza A2/Asian/J-305 virus infection in mice.

Production of a novel red pigment, rubrolone, by Streptomyces echinoruber Sp. Nov. II. Chemistry and structure elucidation.

Streptomyces echinoruber sp. nov. produces several red pigments. The major component, rubrolone, has been identified as 8(R),9(R),10(S),10a(R)-tetrahydro-9,10,10a,11-tetrahydroxy-3,8-dimethyl-1-propyl-6aH(S)-pyrano[2",3":5',4]furo[2',3':5,6]azuleno[2,3-c]pyridine-5,13-dione (1) by single crystal X-ray analysis of a suitable derivative. A second pigment, B, is probably structurally closely related.

Conglobatin, a novel macrolide dilactone from Streptomyces conglobatus ATCC 31005.

Fermentation of deposited cultures of Streptomyces conglobatus, known to produce the polyether antibiotic, ionomycin has resulted in the isolation and characterization of a second metabolite, conglobatin (C28H38N2O6). X-Ray analysis revealed a dimeric macrolide dilactone structure for conglobatin, similar to the structures of the mold metabolites vermiculin and pyrenophorin, from which the absolute configuration of conglobatin has been inferred. The dimer consists of two molecules of 7-hydroxy-8-oxazoyl-2,4,6-trimethyl-2-octenoic acid joined by two ester linkages.

Isolation and characterization of three novel polyether antibiotics and three novel actinomycins as cometabolites of the same Streptomyces sp. X-14873, ATCC 31679.

Streptomyces sp. X-14873 (ATCC 31679) has been found to produce a number of secondary metabolites. Three have been identified as the novel actinomycins, X-14873B, C and D, each of which contains both proline and 3-hydroxy-5-methylproline. Potentially, the most important microbial product from this fermentation is the novel polyether antibiotic X-14873A which differs from lysocellin only in the substituents at carbons C-4 and C-5 in the tetrahydropyranyl ring. The methyl group and proton in lysocellin are replaced by an ethyl and hydroxyl group, respectively in X-14873A. In addition, two other novel polyethers, X-14873H and G, were isolated and shown to differ from 1 in lacking a carboxyl group and in the case of 3, possessing an ether bridge across the terminal tetrahydrofuranyl ring system.

Isolation and characterization of four polyether antibiotics, X-14889A, B, C, and D, closely related to lysocellin and the ferensimycins.

Streptomyces sp. X-14889 (NRRL 15517) has been found to produce a number of novel polyether antibiotics and an orange pigment. One of the antibiotics, X-14889B (3) was identified as ferensimycin A, which in turn is an isomer of the well-studied polyether antibiotic, lysocellin (1). Of the three other antibiotics, X-14889C (4) is a lower homolog of ferensimycin A and antibiotics X-14889A (2) and D (5) which are respectively the descarboxy and anhydro-descarboxy forms of this same molecule. The latter compound, X-14889D is of interest as it contains an ether bridge across the terminal tetrahydrofuranyl ring in an analogous relationship to that reported earlier for antibiotics X-14873A (6) and G.

Ro 22-5417, a new clavam antibiotic from Streptomyces clavuligerus. III. Absolute stereochemistry.

The complete stereostructure of the new antibiotic Ro 22-5417 has been established as 3-[(3S,5S)-7-oxo-1-aza-4-oxabicyclo[3.2.O]hept-3-yl]-L-alanine. This result together with the synthesis of an (3R,5R)-L-analog allowed us to postulate that clavams require the R-configuration at the ring juncture for beta-lactamase inhibitory activity, while the opposite S-stereochemistry is essential for antifungal activity.

Isolation and characterization of a novel polyether antibiotic of the pyrrolether class, antibiotic X-14885A.

Antibiotic X-14885A is a polyether antibiotic belonging to the class of these natural acid ionophores known as pyrrolethers. The structure of the antibiotic was elucidated by X-ray crystallographic analysis of the hydrated sodium salt, which crystallized as a tetramer containing four antibiotic and water molecules and four atoms of sodium. Antibiotic X-14885A differs from the most well-known member of the class, A-23187, in two respects: the aromatic N-methylamino group present in the latter is replaced by a phenolic hydroxyl, and one of the four aliphatic methyls is replaced by a proton. Antibiotic X-14885A is active against Gram-positive bacteria and the spirochete, Treponema hyodysenteriae.

Isolation and characterization of antibiotic X-14547A, a novel monocarboxylic acid ionophore produced by Streptomyces antibioticus NRRL 8167.

A novel carboxylic acid ionophore, antibiotic X-14547A, closely related to the polyether antibiotics has been isolated along with four other metabolites from fermented cultures of a new strain of Streptomyces antibioticus. The structure, determined by X-ray analysis of the R(+)-1-amino-1-(4-bromophenyl)-ethane salt contained pyrrole carbonyl and trans-butadienyl chromophores in addition to the unusual tetrahydroindane bicyclic ring system. A second novel metabolite was identified as 3-ethyl-1,3-dihydro-3-methoxy-2H-indol-2-one.

Microbial products. VI Five novel metabolites related to benz[a]anthracene from an unidentified actinomycete designated X-14881.

Five metabolites of actinomycete X-14881 were isolated from the fermentation broth and characterized. The major component was identified as [3R-(3 alpha,6a beta,7 beta,12 alpha,12a alpha)] or [3S-(3 beta,6a alpha, 7 alpha,12 beta,12a beta)]-6a, 7,12-trihydroxy-3,4,6a, 7,12, 12a-hexahydro-8-methoxy-3-methylbenz[a]-anthracen-1(2H)-one; the other four are closely related derivatives thereof.

Microbial products. VIII. Azinothricin, a novel hexadepsipeptide antibiotic.

Azinothricin was isolated from the culture filtrate of Streptomyces sp. X-14950 in crystalline form. It represents a new type of hexadepsipeptide antibiotic as it contains a 19-membered cyclodepsipeptide ring composed of six unusual amino acids and bearing a novel C21 side chain. Azinothricin was identified as [(3S,4S,7R(S*),10S,17R,20S,23R)[2S(2'R*,5'S*, 6'S*)3S*]]-alpha-ethyl-6-(3-ethyl-1, 5-dimethyl-4-oxo-1,5-heptadienyl)- N-(1,8, 14,15,18,21,27-heptaaza-21-hydroxy-7-(1-hydroxyethyl)-2,6,9,16,19, 22-hexaoxo-4-isopropyl-20-(methoxy-methyl)-17,18-dimethyl-5-oxa tricyclo [21.4.0.0(10,15)]heptacosan-3-yl)tetrahydro-alpha, 2-dihydroxy-5-methyl-2H-pyran-2-acetamide and is primarily active against Gram-positive microorganisms.

Antimetabolites produced by microorganisms. XII (S)-alanyl-3-[alpha-(S)-chloro-3-(S)-hydroxy 2-oxo-3-azetidinylmethyl]-(S)-alanine, a new beta-lactam containing natural product.

(S)-Alanyl-3-[alpha-(S)-chloro-3-(S)-hydroxy-2-oxo-3-azetidinylmethyl]-(S)-alanine was isolated from a fermentation broth of an unidentified Streptomyces species 372 A. The structure was determined by single crystal X-ray diffraction analysis. The substance inhibits the growth of several strains of gram-positive and gram-negative bacteria in a chemically defined medium but growth inhibition is relieved by addition of L-glutamine to the medium.

A new semisynthetic macrolide antibiotic 3-O-oleandrosyl-5-O-desosaminylerythronolide A oxime.

A new antibiotic, 3-O-oleandrosyl-5-O-desosaminylerythronolide A oxime (3) was produced from erythronolide A oxime (1) by the oleandomycin-producing culture, Streptomyces antibioticus ATCC 11891. The structure of 3 was determined by degradative studies and confirmed by X-ray analysis. Compound 3 was found to be less active, but more stable to acid, then erythromycin A oxime.