HETEROCYCLES

■ Mathyl-lithium as a Convenient Deacylation Agent of Alkoxycarbonyl and Benzoyl Protected Secondry Hydrazides. Applicatins in the Field of Azetidinodiazepines and of Their Photoisomers

Théophile Tschamber and Jacques Streith*

*Ecole Nationale Supérieure de Chimie de Mulhouse, Université de Haute Alsace, 3, Rue Alfred Werner 68093 Mulhouse Cedez, France

Abstract

Methyl-lithium proved to be a useful deacylating reagent for alkoxycarbonyl- and benzoyl-protected secondary hydrazides, leading thereby - after protonation - to the R-CO-NR’-NH-R’’ functionality. This methodology found some application with azetidinodiazepines 1, in which the N-Y group was cleaved selectively without destruction of the β-lactam moiety.

■ Stereoselective Formal Synthesis of (±)-Monomorine I from 6-Methyl-2-piperidinone

Tatsuo Nagasaka,* Hiroki Kato, Hideki Hayashi, Masako Shioda, Hiromi Hikasa, and Fumiko Hamagichi

*School of Pharmacy, Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan

Abstract

The stereoselective formal synthesis of (±)-monomorine I from 6-methyl-2-piperidinone was achieved. A general method for the synthesis of ω-alkylated lactams is also described.

■ 1-Oxacephems with the Thienamycin-Type Side Chain(1). Synthesis and Antibacterial Activity of 7α-[(1R)-1-Hydroxyethl]1-1oxacephems Bearing Electron-Withdrawing Groups

Masayuki Murakami, Tsutomu Aoki, and Wataru Nagata*

*Shionogi Research Laboratories, Shionogi & Co. Ltd., Fukushima-ku, Osaka 553-0002, Japan

Abstract

1-Oxacephem derivatives, 2a-d, bearing the hydroxyethyl group at C_7α and some electron-withdrawing groups at C₃ were synthesized and tested for antibacterial activity. It was found that some of these compounds, in particular, 7α-hydroxyethyl-3-cyano-1-oxazephem 2d, exhibited antibacterial activity, although the potency was low. Some 7α-hydroxyethyl-2-oxo-1-oxacephems, 1a,b, were also prepared and found biologically inactive.

■ Remarkable Diastereoselectivity Exerted by Dienophile Configuration in Intramolecular Diels-Alder Reaction of Electron Deficient Heterodienes: New Chiral Entry into the Secoiridoid Monoterpenes and the Heteroyohibine Indole Alkaloids

Seiichi Takano,* Shigeki Satoh, Kunio Ogasawara, and Keiichi Aoe

*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan

Abstract

Reaction between the optically active glyceraldehyde (1Z) carrying Z-olefin and Meldrum’s acid furnished in one step the tricyclic adduct 3 with trans 5/6 ring juncture selectively under mild conditions by spontaneous condensation followed by the intramolecular Diels-Alder reaction. On the other hand, the E-olefin isomer (1E), under the same conditions, furnished the isomeric adduct 4 with cis 5/6 ring juncture selectively. The former gave a pair of the cis-fused bicyclic carbamates, (22) and (25), while the latted gave the trans-fused pair, (23) and (26), by the following transformations. Although these imply formal chiral route to the heteroyohimbine alkaloids, a new enantioselective route to a secoiridoid monoterpene, (-)-methyl elenolate (37), has also been developed.

■ Two New Fungal Azaphilones from Talaromyces luteus, with Monoamine Oxidase Inhibitory Effect

Haruhiro Fujimoto, Takanao Matsudo, Akira Yamaguchi, and Mikio Yamazaki*

*Faculty of Pharmaceutical Sciences, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan

Abstract

Two new compounds with monoamine oxidase (MAO) inhibitory effect isolated from an ascomycete, Talaromyces luteus, have been deduced to be azaphilone compounds, (8R)-7-deacetyl-O⁸,8-dihydro-7-epi-sclerotiorin and its (Z)-isomer at position 11 from their chemical and spectral data.

■ A Highly Stereoselective Synthesis of Methoxycarbonyl-Substituted Exocyclic Enol Ethers: A Synthesis of 5-Methoxycarbonylprostacyclin

Atsuo Takahashi, Chika Yamamoto, and Masakatsu Shibasaki*

*Faculty of Pharmaceutical Sciences, Hokkaido University, Kita 12 Nishi 6, Kita-ku, Sapporo, Hokkaido 060-0812, Japan

Abstract

Treatment of the diene 9 with a catalytic amount of 10% Pd-C in toluene at -50°C under H₂ (1 atm) afforded the E-methoxycarbonylsubstituted exocyclic enol ether 10E in a highly stereoselective manner (E:Z=41:1, 98%). 10E was successfully transformed into 5-methoxycarbonylprostacyclin (5).

■ Synthesis of 1-(Phenylsulfonyl)indol-3-yl Trifluoromethanesulfonate

Samuel C. Conway and Gordon W. Gribble*

*Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03775, U.S.A.

Abstract

The synthesis of the potentially useful intermediate 1-(phenylsulfonyl)indol-3-yl trifluoromethanesulfonate (triflate) (1), via several approaches to the corresponding indoxyl 6, is described. Of these, the direct oxidation of 1-(phenylsulfonyl)indoles (2) with magnesium monoperphthalate (MMPP) in refluxing acetic acid is the most concise route to 6.

■ Spiromines A, B, C, and D New Diterpene Alkaloids from Spiraea japonica var. acuminata Franch

Manabu Node, Xiao-jang Hao, Jun Zhou, Si-ying Chen, Tooru Taga, Yoshihisa Miwa, and Kaoru Fuji*

*Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan

Abstract

New atisine-type alkaloids, spiramines A, B, C, and D were isolated from Spiraea japonica and their structures were elucidated by chemical and spectroscopic means.

■ Convenient Synthesis of Various Terheterocyclic Compounds by Pd(0)-Catalyzed Coupling Reactions

Salo Gronowitz* and Dan Peters

*Organic Chemistry 1 Chemical Center, University of Lund, P. O. Box 124, SE-221 00, Lund, Sweden

Abstract

Various terheterocyclic compounds containing thiophene, furan, selenophene, pyridine, and thiazole rings have been obtained by the Pd(PPh₃)₄-catalyzed coupling of dihalo-substituted heterocyclic compounds with heterocyclic boronic acids, using sodium bicarbonate as base and a 1,2-dimethoxyethane - water mixture as solvent. In case when the boronic acids were not available or easily deboronated, and/or the heterocyclic halo derivatives were unstable in alkalone solution, trialkylstannylheterocyclies were used instead of boronic acids in the coupling with dihaloheterocycles, with THF as solvent and PdCl₂(PPh₃)₂ as catalyst. The naturally occuring 3’-methoxy-2,2’:5’,2"-terthiophene was prepared by a copper-promoted nucleophilic substitution of 3’-iodo-2,2’:5’,2"-terthiophene, previously prepared by Pd(0)-catalyzed coupling of 2,3,5-triiodothiophene with 2-thiophene boronic acid.

■ New Homoerythrinane Alkaloids from Phelline Species

Nicole Langlois*

*Institut des Chimie des Substances Naturelles, C.N.R.S., 1 avenue de la Terrasse, Bat. 27, 91198 Gif-sur-Yvette Cedex, France

Abstract

Four new homoerythrinane alkaloids have been isolated from the leaves of Phelline species. Robustidine 7, robustimine 8, O-methylrobustimine 9 and robusticine 11 have been characterised using spectroscpic data; the structure of the alkaloid 11 has been confirmed by chemical correlation.

■ Proton-Ionizable Crown Ethers. A Short Review

Christopher W. McDaniel, Jerald S. Bradshaw,* and Reed M. Izatt

*Department of Chemistry, Brigham Young University, Provo, UT 84602, U.S.A.

■ Heterocycles and Molecular Recognition

Julius Rebek, Jr.

*Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, U.S.A.

Abstract

The application of the heterocyclic compounds in the area of molecular recognition is explored with a number of examples. Hydrogen bonding, with its modestly directional characteristics, is shown to offer advantages in situations where recognition leads to subsequent chemical reactions.

■ Recent Advances in Synthetic Applications of Nitrile Oxide Cycliaddition (1981-1989)

Shuji Kanemasa and Otohiko Tsuge

*Instituete of Advanced Material Study, Kyushu University, 6-1, Kasuga-koen, Kasuga 816-8580, Japan

Abstract

The synthetic applications of nitrile oxide cycloadditions, developed in the 1980s, are briefly reviewed. Topics discussed in the present review are the modern developments on the generation method of nitril oxides, on the cycloadditions with multiple bonds other than carbon-carbon double and triple bonds, on reductive cleavage of the nitrogen-oxygen bonds of 2-isoxazolines, on the unmasking of functionalities, and on the asymmetric cycloadditions of nitrile oxides.