Organometallic Compounds in Biological Chemistry

For this year, the last in which this Chapter will be contributed by the present author, the broad plan of previous years will be maintained. Papers have been abstracted with the interests of the organometallic chemist principally in mind. Because it is logical to review developments in, say, organo-cobaloximes, in one place, the direct biological relevance of some publications may be relatively low. 

The thermal rearrangement of cyclopropylcarbinylcobalamln to but-3-enylcob-alamin originally reported by Chemaly and Pratt, has now been studied in detail for the cobaloxime series. Careful labelling experiments support the mechanism shown in equation (1), although the authors duly point out that a bimolecular reaction initiated by a trace of cobaloxime(n) is difficult to rule out. A rearrangement of l-methylbut-3-enylcobaloxime, [equation (2)] has been studied by these workers and also by Bury et al A cyclopropylcarbinyl inter- 

A further investigation of the photolysis products of 4,5-dihydroxypentyl-(pyridine)cobaloxime and of 5,6-dihydroxyhexyl(pyridine)cobaloxime shows that the initially generated radicals rearrange by intramolecular hydrogen shifts. Furthermore, the primary radicals, which attack the vicinal diols, do so regio-selectively and show considerable primary kinetic isotope effects. In all these features the system thus mimics aspects of the diol-dehydratase enzyme system. 

The elaborate cobaloxime system (1) has been synthesized (in 7% yield) with a view to modelling the active site of the vitamin Big dependent enzyme methyl-malonyl Co-A mutase. Irradiation of (1) for short periods in methanol causes 

In a temperature-dependent n.m.r. study of alkyl cobaloximes it has been established that two differwt dynamic processes may occur, [equations (4) and (5)]. Both processes interchange the two possible r-allyl structures, (differentiated 

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Cardin, D. J., Organometallic Compounds in Biological Chemistry, Organometal. Chem. 7 [1978] 400/13. 

This Volume of the Specialist Periodical Reports Organometallic Chemistry surveys the literature for the calendar year 1980, There is no significant change in organization of the material from previous Volumes, vith the exception of organometallic compounds in biological chemistry. This topic is omitted from this Volume, but the literature of this area for both 1980 and 1981 will be reviewed in Volume 11. 

Stab, J.A., Udo, A., Brinkman, Th., Cofino, W.P. (1994). Validation of the analysis of organotin compounds in biological tissues using alkylation and gas chromatography. Applied Organometallic Chemistry, 8, 577 — 585. 

Physical organic chemistry is to be viewed as a particular approach to scientific enquiry rather than a further intellectual specialization. Thus organic compounds are taken to include organometallic compounds, and relevant aspects of physical, theoretical, inorganic and biological chemistry are incorporated in reviews where appropriate. Contributors are encouraged to provide suiRcient introductory material to permit non-specialists to appreciate fully current problems and the most recent advances. 

Santosa, S.J., Mokudai, H., Takahashi, M. and Tanaka, S. (1996) The distribution of arsenic compounds in the ocean biological activity in the surface zone and removal processes in the deep zone. Applied Organometallic Chemistry, 10(9), 697-705. 

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