Sapogenins 359

The biosynthesis of the Cja-bufadienolides, aglycones of the cardiac glycosides, e.g. hellibrigenin (III) is not known. 

These are C27 sterols in which the side chain has been metabolized to a spiroketal. They are formed from cholesterol by a pathway illustrated for diosgenin in Fig. 18. Sapogenins are the aglycones of the naturally occurring saponins which are 3- 7-gly-cosides. 

Following are a few examples of steroidal saponins with their respective sources  

Give a brief account of the ANDROGENS. How would you synthesize Testosterone from  

What are Follicular Hormones Classify them and describe the synthesis of one potent drug from each class. 

Name aprominent Corpus Luteum Hormone and discuss its synthesis from aglycoside obtained 

Discuss Cardiac Glycosides by giving its plant source, three important known genins, structure of the corresponding glycosides and their uses. 

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Progesterone can be manufactured from cholesterol, from certain steroid sapogenins and from stigmasierol. 

During this period of intense synthetic research, a search for inexpensive raw materials for the partial synthesis of steroids was initiated. Abundant quantities of the sapogenin diosgenin [512-04-9] were isolated from plant sources and used for the industrial preparation of steroids (9). 

Sapogenins and Saponins. Steroids isolated from a variety of plant sources that contain a spiroketal between hydroxyl moieties at C16 and C26 and a carbonyl at C22 are called sapogenins (33). 

Sapogeniiis of the dammaran type were isolated from the leaves and roots of the plant Panax no-toginseng, native to China One of these sapogeniiis has the elemental eomposition C30//52O4 and produees the set of NMR results 51. What is the strueture of the sapogenin ... 

Many functional groups are stable to alkaline hydrogen peroxide. Acetate esters are usually hydrolyzed under the reaction conditions although methods have been developed to prevent hydrolysis.For the preparation of the 4,5-oxiranes of desoxycorticosterone, hydrocortisone, and cortisone, the alkali-sensitive ketol side chains must be protected with a base-resistant group, e.g., the tetrahydropyranyl ether or the ethylene ketal derivative. Sodium carbonate has been used successfully as a base with unprotected ketol side chains, but it should be noted that some ketols are sensitive to sodium carbonate in the absence of hydrogen peroxide. The spiroketal side chain of the sapogenins is stable to the basic reaction conditions. 

With the shift of raw materials, first from cholesterol to bile acids, then to plant sapogenins such as diosgenin, 17- keto steroids were no longer directly available, and improved methods for the degradation of 20-ketopregnanes (which were the principal products from these new sources) had to be developed. 

The ready availability and low cost of A -20-keto steroids from the degradation of sapogenins has led to intensive study of methods for the preparation of androstanes via these intermediates. The simplest, most practical and most widely used method on a production scale is the Beckmann rearrangement of -20-oximinopregnenes ... 

Sandwich chamber 126,127 Sapogenins 43,195, 206, 411 -, steroid 69, 206 -, trifluoroacetates 69 Saponins 7,109, 411, 430 Sarcosine 435 Scandium cations 144 Scanners, optical trains 30, 39 S-chamber see Sandwich chamber Scintillators 12 Sebacic acid 178,233,249, 308 Selectivity... 

Saponins are a family of glycosides (sugar derivatives) widely distributed in plants. Each saponin consists of a sugar moiety bound to a sapogenin (either a steroid or a triterpene). The immunostimulatory properties of the saponin fraction isolated from the bark of Quillaja (a tree) has been long recognized. Quil A (which consists of a mixture of related saponins) is used as an adjuvant in selected veterinary vaccines. However, its haemolytic potential precludes its use in human vaccines. Research efforts continue in an attempt to identify individual saponins (or derivatives thereof) that would make safe and effective adjuvants for use in human medicine. 

Shibata, S., Tanaka, O., Ando, T., Sado, M., Tsushima, S., and Ohsawa, T. (1966). Chemical studies on oriental plant drugs. XIV. Protopanaxadiol, a genuin sapogenin of ginseng saponins. Cheni. Pharm. Bull. 14, 595-600. 

Saponins are glycosylated natural products with soap-like properties [3]. The aglycones (sapogenins) are either triterpenoid- or steroid-derived. Dicotyledonous... 

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