Review of US patents in the field of organic process development published during May and June 2004

摘要

This review of patents contains 20 from a selection of 255, and they cover a variety of topics that, it is hoped, will be of interest. The heart and obesity problems that are common in western society means there are a great many drugs already available or under development to treat these conditions. Hence, the statins continue to stimulate great interest in the treatment of obesity and heart problems. An improved drying process for one type of crystalline atorvastatin is disclosed. Other patents on statins describe two new polymorphs of orlistat and a new synthesis of fluvastatin. Another drug used to treat heart diseases is plavix, and a method of racemising the unwanted enantiomer has been described. The synthesis of a range of novel diazo compounds is described that can be used in the preservation of old manuscripts by deacidification. Atropisomers exhibit chirality due to hindered rotation, and a range of such pyridine derivatives is described that are used as chiral catalysts in asymmetric acylation reactions. A new route to the piperidine intermediates that are useful in preparing the antihistamine drug fexofenadine is disclosed. The importance of mixing raises its head again in a process for oxidation of alcohols using TEMPO. The procedure is a continuous process in which the reagents are fed separately to a tube where they are mixed with a static mixer. This is said to require short residence times and gives improved selectivity and productivity. The use of drugs in areas far removed from the original use brings an unusual finding. The drug eflornithine was developed to treat African sleeping sickness and has been found to be useful in the treatment of unwanted facial hair. Two patents cover a novel method of producing meso-zeaxanthin which is used to treat age-related macular degeneration. The chemistry covered in these patents is extensive and not clearly explained. Hence, the review here has merely scratched the surface; anyone who has a particular interest in this subject is strongly advised to consult the patents. Factor Xa is involved in the coagulation of blood, and two patents from different companies disclose details of compounds that can inhibit this. As is often the case, experimental details in patents may be lacking in detail. In this collection there are two patents that claim improved methods for preparing compounds and yet provide no experimental details to back up the claim. On the other hand two other patents give details of making substantial quantities of chemicals and provide an indication that the processes are capable of being used commercially. As usual, the advantages are those claimed in the patent unless this reviewer has personal knowledge, and there is no legal or commercial significance in the choice of patents for review.