Recent synthesis of morphinan and related compounds is reviewed. Synthetic methodologies are classified roughly into three categories, that is i) intramolecular arylation at the 4 a-position of 1-benzylisoquinolines, ii) formation of an ethanamine bridge between 4 b- and 9-position of phenanthrenes, iii) formation of a methylene bridge between 1 and 2'-position of 4 a-arylisoquinolines. The former two methods are rather classic, but are improved as the more practical ways to get morphinans. The last one was found after 1980 and used for a synthesis of B/C-trans-morphinans. An asymmetiric synthesis of 1-substituted isoquinolines, key precursors for morphinans, was also described.
A powerful electron acceptor 7, 7, 8, 8-tetracyano-p-quinodimethane (TCNQ) and numerous organic electron acceptors with TCNQ backbone have been of great interest, as their crystalline charge-transfer complexes could be electrically conducting. This review describes the synthesis and physico-chemical properties of TCNQ compounds synthesized until now. The extension of π-conjugation and the incorporation of heteroatoms within the molecular framework have been used for the major structural modification of TCNQ. Redox properties are recorded in appropriate tables.
Since the discovery of (2-aminoethyl) phosphonic acid (1) in ciliate protozoa various aminophosphonic acids have been found in numerous organisms. While most of the works on aminophosphonic acids, especially on 1, are concerned with their presence as phosphonolipids, peptides containing aminophosphonic acid moieties (phosphonopeptides) also have been isolated. The author describes chemical synthesis of phosphonopeptides containing natural and unnatural aminophosphonic acids together with their biological activities such as antibacterial and enzyme-inhibitory effects.
Recent studies on cleavage and formation of metal-carbon σ bonds associated with redox reactions have been reviewed. The redox states of organometallic compounds as well as the steric factors of alkyl groups are shown to play essential roles to control the stabilities of metal-carbon bonds. Irreversible electron transfer processes accompanied by cleavage and formation of metal-carbon bonds are sought to be emphasized as key reaction steps in understanding the versatile reactivities of organometallic compounds from a single, unified view.
This article describes the synthesis of novel derivatives of indigo and porphyrin, the structure and the function of which are of interest from photochemical and bioorganometallic points of view : (1) N-Substituted indigos undergo trans-cis isomerization and one- or two-electron reduction upon irradiation with visible light. The kinetic and thermodynamic profiles of these processes are greatly dependent on the nature of N-substituents. (2) Metal-carbon (or hydrogen) bond formation was demonstrated by using mono-, di-, and tri-valent rhodium porphyrins as mimics of reaction behaviors of Coenzyme B12. Novel organocobalt porphyrins such as π-complex, N, Co-bridged complex, and Cmeso, Co-bridged complex were obtained by the reactions of trivalent cobalt porphyrins with alkynes. (3) Organometallic porphyrins were converted into the N-substituted porphyrins which have recently turned out to be abnormal metabolites of cytochrome P 450, and into N (21), N (22) -bridged porphyrins which show interesting redox activities.
Synthetic studies on the macrocyclic pyrrolizidine alkaloids are described. Racemic retronecine 9 and otonecine 10 were synthesized from a common and key intermediate 15. Optically active retronecine 9 was synthesized enantioselectively from (R) - (+) -malic acid 27. An efficient enantioselective synthesis of the N- (ethoxycarbonyl) methyl Geissman-Waiss lactone 39 was achieved from (R) - (+) -malic acid 27, providing a practical synthetic route to optically active retronecine 9. Dicrotaline 6, an 11-membered pyrrolizidine alkaloid was synthesized by virtue of a newly developed method using the stannylene 64. Total synthesis of optically active integerrimine 7, a representative of the 12-membered pyrrolizidine alkaloids was achieved as follows : Optically active integerrinecic acid derivative 80 synthesized enantioselectively from (E) -2-methylhepta-2, 6-dienoic acid 74 was converted to the cyclic anhydride 82. Reaction of the cyclic anhydride 82 with the stannylene 64 gave the desired monoester 83 regioselectively. Lactonization of the monoester 83 by the Yamaguchi's method provided integerrimine MTM ether 84, which was converted to (-) -integerrimine 7.
This article deals with preparation of organocalcium compounds using calcium vapor (atoms). Calcium vapor (atoms) inserted into C-X bonds of organic halides, C-H bonds of benzene and cycloalkanes, Si-Cl and Ge-Cl bonds of chlorosilanes and chlorogermanes, and group 4 B element-group 4 B element bonds of group 4 B catenate compounds to give the corresponding organocalcium compounds, respectively. Several reactions of organocalcium compounds thus prepared with substrates were also examined.