Enzymatic hydrolysis of cellulose for sugar production offers advantages of higher conversion, minimal by-product formation, low energy requirements, and mild operating conditions over other chemical conversions. The development of a kinetic model, based on observable, macroscopic properties of the overall system, is helpful in design and economic evaluation of processes for sugar conversion and ethanol production. A kinetic model is presented, incorporating enzyme adsorption, product inhibition, and considers a multiple enzyme and substrate system. This model was capable of simulating saccharification of a lignocellulosic material, rice straw, at high substrate (up to 333 g/L) and enzyme concentrations (up to 9.2 FPU/mL) that are common to proposed process designs.
(R,R)-Formoterol (1) is a
long-acting, very potent β2-agonist,
which is used as a bronchodilator in the therapy of asthma
and
chronic bronchitis. Highly convergent synthesis of enantio-
and
diastereomerically pure (R,R)-formoterol fumarate
is achieved
by a chromatography-free process with an overall yield of
44%.
Asymmetric catalytic reduction of bromoketone 4 using
as
catalyst oxazaborolidine derived from (1R,
2S)-1-amino-2-indanol and resolution of chiral amine 3 are the origins
of
chirality in this process. Further enrichment of enantio-
and
diastereomeric purity is accomplished by crystallizations of
the
isolated intermediates throughout the process to give
(R,R)-formoterol (1) as the pure stereoisomer (ee, de
>99.5%).
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