Glossary of Terms Used in Combinatorial
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Macroporous Resin: Polymer which
contains a permanent network of pores independent of the state of swelling
of the resin. This class of resin thus displays much better solvent
tolerance than gel-type resins 18.
Magic Angle Spinning: NMR strategy
in which the tube is rotated at very high speed and at a specific angle
which cancels out the line broadening effects of inhomogeneities in
the sample. This yields high resolution and high sensitivity which are
very useful in trace analysis or in looking at solid phase synthesis
Markush Structure: Similar to
a generic structure,
but more flexible in that the substituents on the core structure need
not be precisely enumerated, e.g. 'alkyl' rather than 'CH3-,
MAS: see Magic Angle
Mask: Device which acts as a barrier to the
passage of a reagent (often light see photolithography).
A pattern of holes in the mask allows selective passage of reagent and
results in a corresponding pattern of reagent deposition or photodeprotection
on a surface placed behind the mask. This allows the generation of spatially
addressable libraries 61,62.
MPS: multiple parallel synthesis (see parallel
Member: a) specific compound which is
included in a library; b) the uncharacterized physical product of a
library synthesis 14.
Merrifield Resin: p-(chloromethyl)
Mesh Size: The density of wires in
a sieve. Often used as a measure of particle size, for example, of solid
supports. A resin whose particle size is quoted as 100-200-mesh
will pass through a 100-mesh filter but is trapped by a 200-mesh filter,
and consists of particles whose diameter is between 75 and 150 mm.
There are, unfortunately, several standard scales for this measurement
but which differ only very slightly from one another.
Monomer: Member of a building
block set which can be repeatedly incorporated into a library
to give a set of compounds of repeating structure; e.g. amino
acids in a peptide library.
MPS: Multiple parallel synthesis:
see Parallel Synthesis
Multiple Simultaneous Synthesis: see Parallel
Neural Network: Technique for optimizing
a desired property given a set of items which have been previously characterized
with respect to that property (the 'training set'). Features of members
of the training set which correlate with the desired property are 'remembered
and used to generate a model for selecting new items with the desired
property or to predict the fit of an unknown member 64,65.
Null Reagent: Concept whereby one
of a set of pools is subjected to
no reaction at a particular stage of a combinatorial synthesis. It is
often necessary to record this as a null event to maintain congruence
in computational records of the library.