OLLIS

Fleming, I. 1979, Organic Silicon Chemistry, in Barton, D. Ollis, W. D. (eds.). Comprehensive Organic Chemistry, Vol. 3, p. 539, Pergamon Press Oxford... 

The mesoionic compounds are derived from pyrazolium salts (22) when R is replaced by a negatively charged heteroatom, like the anhydro-4-hydroxypyrazolium hydroxide (28). According to Ollis and Ramsden (76AHC(l9)l) they belong to the mesoionic class B type. 

The term mesoionic was suggested originally to describe compounds of the sydnone (129) or sydnone imine (130) type (49JCS307, 50JCS1542). Since then this term has been applied somewhat indiscriminately to a variety of heterocyclic molecules which can be represented formally as zwitterions. The original, rather restrictive definition put forward by Baker and Ollis (55CI(L)910) was later made even more so by Ollis and Ramsden (76AHC(19)1), and it is this most recent definition which now appears to be the most useful. 

Ollis and Ramsden state that A compound may be appropriately called mesoionic if it is a five-membered heterocycle which cannot be represented satisfactorily by any one covalent or polar structure and possesses a sextet of electrons in association with the five atoms comprising the ring . From the point of view of systematic nomenclature, compounds of this type are difficult to deal with, since most available nomenclature systems are designed so as to name one particular bond- and charge-localized canonical form. 

Various methods have been employed to overcome this difficulty. For example, a method used by Chemical Abstracts involves naming the dihydro derivative of the heterocyclic ketone (or imine or exocyclic alkene) form, and adding the words mesoionic didehydro derivative (example 131). A similar approach, favoured by Ollis (76AHQ19)1), involves naming the corresponding cation hydroxide, with the prefix anhydro (indicating removal of the elements of water) (example 132). 

Goldman, A., Ollis, D.L., Steitz, T.A. Crystal structure of muconate lactonizing enzyme at 3 A resolution. 

Bailey, J. E. and Ollis, D. E. Biochemical Engineering Fundamentals, 2nd ed., MeGraw-Hill Cheniieal Engineering Series, 1988. 

This chapter solely reviews tlie kinetics of enzyme reactions, modeling, and simulation of biochemical reactions and scale-up of bioreactors. More comprehensive treatments of biochemical reactions, modeling, and simulation are provided by Bailey and Ollis [2], Bungay [3], Sinclair and Kristiansen [4], Volesky and Votruba [5], and Ingham et al. [6]. 

J. E. Bailey and D. F. Ollis, Biochemical Engineering Eundamentals, McGraw-Hill, New York, 1986. 

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