Steroids

Steroids

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  STEROIDS PREAPRED BY :AZMIN MOGAL (M PHARM; SEM -1) GUIDED BY : Mr. STEPHENAVVARU(Ph.d SCHOLER) DEPARTMENT: PHARMACEUTICALCHEMISTRY
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  INTRODUCTION  A steroidis an organic compound with four rings arranged in a specific molecular configuration.  The steroid core structure is composed of seventeen carbon atoms(17), bonded in four "fused" rings.  Three six-member cyclohexane rings (rings A , B and C in the first illustration) and one five-member cyclopentane ring (the D ring). Steroids vary by the functional groups attached to this four- ring core and by the oxidation state of the rings. Cyclopentanoperhydrophenanthrene ring
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  NOMANCLATURE Almost all steroidsare named as derivatives of any one of the following basic steroidal ring. 1. 5 (α or β) gonane (C =17) 2. 5 (α or β) estrane (C=18)
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  3. 5 (αor β) andrastane (C=19) 4. 5 (α or β) pregnane (C=21)
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  5. 5 (αor β) cholestane (C=27)  Solid line indicate groups above the plane of the nucleus (β-configuration) and dotted line denote groups below the plane (α- configuration).  The configuration of the hydrogen (-H) at C-5 position is always indicate in the name.  Compounds with 5-α cholestrane belongs to the ‘allo series’ while compounds derived from the 5-β-cholestane belongs to the ‘normal series’.  If the double bond is not between sequencely numbered carbon, in that case both carbons are indicated in the name.
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   The symbolΔ(delta) is used to indicate C=C bond in steroids.  When a methyl group is missing from the side chain , these is indicated by the prefix ‘nor’ with the number of the carbon atom which are disappear. Δ - Androstane 5
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  STEREOCHEMISTRY OF STEROIDS ■There are six asymmetric carbon atoms 5,8,9,10,13,14 in the nucleus, therefore 64 optically active forms are possible. ■ Cholestane , enfrostane and pregnane exist in two conformations: 1. chair form 2. boat form 5-α-cholestane
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  ■ Chair formis more stable then boat form due to less angle strength , therefore all cyclohexane ring in steroid nucleus exist in the chair form. ■ The absolute stereochemistry of the molecule and any substituents is shown with solid bond (β-configuration) and dotted bond (α-configuration). ■ The aliphatic side chain at C-17 position is always assumed to be β- configuration. ■ The term cis and trans are sometimes used to indicate the backbone stereochemistry between the rings . example; 5-α- steroid are A/BTRANS. 5-β- steroids are A/B CIS. 5-α-Steroid A/B trans 5-β-Steroid A/B cis
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  ■ If A/Bfusion cis and trans both position possible or position is unknown ,it is indicated by waving lines/bonds. trans/cis
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  R
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  CLASSIFICATION OF STEROIDS 1.Sterols:- where R is an aliphatic side chain.They contain usually one or more hydroxyl groups(-OH) attached in alicyclic linkage 2. Sex Hormones:- where R bears a ketonic (C=O) or hydroxyl group(-OH) and mostly possess a two carbon side chain 3.Cardiac Glycoside :where R is a lactone ring.The gylcosides also contains sugars linlked through oxygen in other parts of the molecule. Normally on hydrolysis it yields this sugar together with cardiac aglycon. 4. Bile Acids :- where R is essentially a five-carbon side chain ending with a carboxylic acid moiety 5.Sapogenins :- where R contains an oxacyclic (etheral) ring system.
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  cholesterol sterol Sex hormone Cardiacglycoside Bile acids Sapogenin
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  STEROL & ITSCHEMISTRY ■ Sterols is also known as steroid alcohols, are a subgroup of the steroids and an important class of organic molecules. ■ They occur naturally in plants, animals, and fungi, with the most familiar type of animal sterol being cholesterol. Cholesterol is vital to animal cell membrane structure and function and a precursor to fat-soluble vitamins and steroid hormones. Sterol chemical structure
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  ■ Sterol isdivided into three classes : 1. Zoosterol : sterol which is obtained from animal origin. Example; Cholesterol 2. Phytosterol: derived from the plant source. Example; Sitosterol 3. Mycosterol : obtained from fungi such as yeast. Example; Ergosterol - Sitosterol Cholesterol β