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RESEARCH

Ο CHERiNG CORP. has revealed its meth­ods of synthesis for prednisone (Meti-corten) and prednisolone (Meticor-telone), the new cortical hormones for rheumatoid arthritis therapy (C&EN, Feb. 14, page 598) . Schering has two methods—one chemical (start­ing with dihydrocortisone acetate or allodihydrocortisone acetate), the other biological (starting with cortisone or hydrocortisone).

Until now, Schering has had little to say of its methods. Other producers have been equally reluctant to discuss details. Merck only claims it uses a chemical and microbiological conver­sion. Upjohn says the same, but ad­mits progesterone is the starting mate­rial. Pfizer says it produces predni­solone from a naturally occurring vege­table steroid (Mexican yam) by an "unusual" combination of chemical syn­thesis and fermentation.

Here, for the first time, are the Schering chemical and biological pro­cedures:

• Chemical Synthesis. Schering uses two starting materials to prepare prednisone: dihydrocortisone acetate or allodihydrocortisone acetate. Both

are considered readily available inter­mediates of cortical hormone synthesis.

Either is brominated with bromine in acetic acid forming a mixture of di-bromides. After dehydrobromination by collidine, the mixture is separated by chromatography. Prednisone (Δ1 de-hydrocortisone acetate) is then formed by saponification, according to a report not yet published in JACS.

If desired, prednisone may be con­verted into prednisolone. In principle the procedure is similar to the conver­sion of cortisone into hydrocortisone. Prednisone is treated with semicarba-zide, then reduced with potassium borohydride. Further treatment with nitrous acid gives prednisolone in 5% yields.

• Biological Transformations. With yields so low, Schering turned to the use of microorganisms.

After introduction of cortisone, Schering developed a method for pre­paring the 11, 21-diacetate of hydro­cortisone. Neither chemical methods nor body enzymes could effect a cleav­age of the Il-acetate.

However, it was known that 21-ace-tate groups could be hydrolyzed to the

corresponding 21-carbinol groups b y action of microorganisms. Therefore?, Schering used Corynebacterium simplex to accomplish the acetate cleavage*. The expected reaction did not take place; instead, a new product was formed. After further studies of this substance, Schering tried C. simplex on cortisone. Two products were pro>-duced. One was identified as a diol, the other prednisone.

Again, as in the chemical synthesis, prednisone could be converted into prednisolone by semicarbazide treat­ment. Schering also found that predni­solone can be prepared directly from hydrocortisone by C. simplex.

In either biological transformation, an alcoholic solution of the starting product is added to C. simplex grown in a nutrient medium of 0.1 to Vfa Difco yeast extract, according to JACS, Aug. 5. After about 24 hours culture, the resulting broth is extracted witli chloroform and final products crystal­lized from acetone. Yields are about 70%.

)> Proof of Structure. Throughout the course of these cortical steroid in­vestigations it was necessary to identify

3 6 7 0 C&EN SEPT. 5, 1955

New Arthritis Drugs-Here's How Chemically

the various steroids formed. In partic­ular, those from biological transforma­tions had to be compared with those from chemical synthesis. This structure proof was usually accomplished by a series of degradation experiments.

Prednisone was proved by oxidation with sodium bismuthate in aqueous ace­tic acid. The product was identified as A^adrenosterone. Infrared spectrum showed characteristic bands for the Δ1·*-diene-3-one system, 11-carbonyl group, and 17-carbonyl group. Also, dibro-mination of etiocholane-3,ll,17-trione followed by conventional collidine de-hydrobromination gives Δ1 adreno-sterone. These reactions were con­sidered adequate proof of prednisone.

The degradation process was a little different for identification of predni­solone. Sodium bismuthate oxidation forms an intermediate, A^-androsta-diene-11 £-ol-3,17-dione. Pyridine-chromic acid oxidation of the interme­diate then forms the A^adrenosterone.

Proof of the relationship between prednisone and prednisolone was ob­tained by acetylation of prednisolone with acetic anhydride. Oxidation by chromic acid then forms prednisone.

Modernizing Leather Tanners Council embarks on two-year, $60 ,000 research program to produce better leather more cheaply

.PACED with increasing competition from plastics, the leather industry has set out on a program of self improve­ment. Acting through 25 companies of the Tanners Council of America, the industry will lay out $60,000 (over two years) to find quicker, less expensive methods of producing high quality leather.

The research will be carried out at a new center established by the Tanners Council at Lowell Technological Insti­tute. It is designed specifically to im­prove beamhouse procedure, which deals with removal of hair and prepara­tion of skins for tanning. Research will go on in three phases: • Laboratory, to develop new proce­dures. • Pilot plant, to investigate conven­tional procedures, as well as new proc­esses turned up in the laboratory phase. • Plant, in conjunction with the spon­soring companies.

Leader of the project is Thomas C. Thorstensen, a Ph.D. chemical engineer. Thorstensen was a research associate at Lehigh for five years where he worked on chromium compounds for the leather industry; for the past four years he has been a research chemist develop­ing specialty chemicals for leather with

the J. S. Young Co. of Baltimore. Thorstensen will work closely with Lowell's leather department, which offers the only undergraduate degree program in leather engineering.

The project will also activate a grad­uate study program in the leather de­partment. The first fellowship has been awarded to Henry Szczepanik.

Cutter Verdict The Cutter incident started April 26

when six cases of polio were reported among children who had received Salk vaccine made by Cutter Laboratories. The verdict came Aug. 25 from the Public Health Service. Its investiga­tion showed: • Polio resulted from presence of in­fective amounts of live virus. • Reasons for presence of the virus could not be found. Nothing pointed to contamination as a source, but data suggest combination of inadequacy of virus inactivation and failure of safety tests were responsible for live virus re­maining undetected.

Cutter now plans to resume making and distributing vaccine under the new standards.

rTwo labeled hormones are avail­able free of charge to qualified investi­gators from National Institute of Ar­thritis and Metabolic Diseases- Both labeled at position 4 with C14, they are: A14-anchosten-llj8-ol-3,17-dione and 21-desoxyhydrocortisone. Letters concisely describing the proposed re­search may be sent to Endocrinology Study Section, Division of Research Grants, National Institutes of Health, Bethesda 14, Md. t National Vitamin Foundation ap­propriated $151,000 for grants-in-aid of research in 1954; $21,000 was given for educational purposes. The founda­tion has now appropriated over $1 mil­lion in its nine years. r Applications for medical research fellowships for 1956-57 wall he ac­cepted by National Academy of Sci­ences-National Research Council until Dec. 1. Applications may be obtained from Fellowship Office, NAS-NRC, 2101 Constitution Ave., N.W., Wash­ington 25, D. C. r Grants under the FuI bright Act will be made in over 20 countries for 1956-57. The awards for lecturing or ad­vanced research will be made by the Conference Board of Associated Re­search Councils, Committee on Inter­national Exchange of Persons, 2101 Constitution Ave., Washington 25, D. C. Applications are due by Oct. 1, 1955.

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