Yoshio Hayase

Anticoccidial activity of some azacyclo organoborinates

A series of new azacyclo organoborinates derivatives of piperidinyl and pyridinyl alcohols with anticoccidial activity in vivo assay system in battery trials are described. Parameters of anticoccidial efficacy that were evaluated were body weight, lesion scores and number of oocysts. Among them, di(4-chlorophenyl)(2-piperidinylmethoxy-O,N)boron,and di(3-trifluoromethylphenyl)(2-pyridinylethoxy-O,N)boron showed good anticoccidial activity against both of the important parasite, Eimeria tenella and Eimeria acervulina.

Activation of thiol esters. Partial synthesis of cytochalasins A and B

Bei Aktivierung der Thiolester (I) mit Hg(II)-Salzen in Gegenwart von tert.-Butanol (II) erfolgt S -+ O-Ester-Umwandlung zu den Produkten (III).

Fourier transform infrared and circular dichroism spectroscopic studies of hydrogen bonding in micacocidin A and micacocidin in dilute CH2Cl2 or CHCl3 solution

Abstract FTIR spectra of micacocidin A ( I ), which is a Zn complex antibiotic, the metal-free ligand micacocidin ( II ), its derivatives and their related compounds were measured in dilute CH 2 Cl 2 solution in order to elucidate the conformations of I and II in solution. Curve analysis of the spectra to separate overlapping absorption bands showed that I forms dimers due to two strong intermolecular hydrogen bonds between a hydroxy group and the phenolate anion and II exists in a folded conformation with three rings formed by intramolecular hydrogen bonds between phenolic, aliphatic and carboxylic OH groups and the N atoms of thiazoline, another thiazoline and thiazolidine, respectively. The concentration and temperature dependencies of CD spectra of I were measured in CHCl 3 and CH 3 OH solutions and CH 3 CN solution, respectively, in order to confirm the formation of the dimers of I in these solvents. The variation of the CD band by addition of ZnCl 2 to II was also measured in CH 3 OH solution. II was shown to be more easily transformed to I by Zn 2+ ion in the solution.

Activity of synthetic gibberellin A15 and (±)-gibberellin A15isolactone

The activities of (±)-gibberellin A15 ((±)-GA15) and (±)-gibberellin A15-isolactone ((±)-iso-GA15) which were obtained by stereocontrolled total synthesis and gibberellin A15 (E-GA15) synthesized by interconversion of enmein were assayed by the rice seedling test. As expected, (±)-GA15 showed half the activity of natural gibberellin A15 (GA15). E-GA15 which has a natural configuration showed the same activity as natural gibberellin A15 while (±)-iso-GA15 was almost inactive. These samples were also submitted to the cucumber hypocotyl assay. Contrary to what has already been reported, they were almost inactive.

Synthesis and Anticoccidial Activity of Some Azacyclo Organoborinates

A series of azacyclo organoborinates derivatives of piperidinyl and pyridinyl alcohols were prepared and their anticoccidial activity was tested in vitro assay system. Among them, di(4-chlorophenyl)(2-piperidinylmethoxy-O,N)-boron, di(3-trifluoromethylphenyl)( 2-piperidinylmethoxy-O,N)-boron, di(3-trifluoromethylphenyl)(2-pyridinylmethoxy-O,N)-boron, and di(3-trifluoromethylphenyl)-(2-pyridinylethoxy-O,N)boron, showed moderate anticoccidial activity against Eimeria tenella.

The significant directing effect of the cyano-group in the reduction of 5-cyano-3-oxo-steroids with complex metal hydrides

The stereochemistry of reduction of 5α- and 5β-cyano-17β-hydroxyandrostan-3-one [(la) and (Va)] and of 5α- and 5β-cyano-17β-hydroxyoestran-3-one [(lb) and (Vb)] with lithium tri-t-butoxyaluminium hydride and sodium borohydride has been investigated. Several earlier stereochemical assignments for the resulting 5-cyano-3α- and 3β-alcohols proved incorrect. In almost every case, formation of the axial alcohol is predominant, this predominance being greater with lithium tri-t-butoxyaluminium hydride in tetrahydrofuran than with sodium borohydride in ethanol. This significant directing effect of the 5-cyano-group is conspicuous and can be accounted for in terms of both steric and polar factors.

Formylolefination of carbonyl compounds

Diethyl cyclohexyliminovinylphosphonate derivatives (IX) have been synthesised. The carbanions generated from these phosphonates reacted readily with ketones and aldehydes giving the αβ-unsaturated aldimines (XI), which underwent acid hydrolysis in a two-layer system to produce the αβ-unsaturated aldehydes (XII) in good yields. This two-step conversion provides a new and potential route to αβ-unsaturated aldehydes from ketones as well as aldehydes. Several advantages of this process, including high efficiency, simplicity, and high selectivity giving trans-formylolefins, are demonstrated. An ester and a hydroxy-group react also with the reagents and therefore these groups in substrates should be preferably changed or protected in the form of an ether function such as a tetrahydropyranyl ether.